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1
Seeley, Schuyler D., Hossein Damavandy, J. LaMar Anderson, Richard Renquist, and Nancy W. Callan. "Autumn-applied Growth Regulators Influence Leaf Retention, Bud Hardiness, Bud and Flower Size, and Endodormancy in Peach and Cherry." Journal of the American Society for Horticultural Science 117, no. 2 (1992): 203–8. http://dx.doi.org/10.21273/jashs.117.2.203.
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Foliar applications of growth regulators (GR) in early autumn induced leaf retention (LR) on peach [Prunu,s persica (L.) Batsch.] and `Montmorency' tart cherry (Prunus cerasus L.) trees. In `Johnson Elberta' peach, the relative effectiveness of GRs on LR was NAA = Promalin (BA + GA4+7) > GA4+7 > GA3 > BA > control, and on leaf detachment pull force (PF) NAA > BA + GA4+7 > GA4+7 = GA3 > BA3 > BA > control. Relative GR-induced chlorophyll (CL) content in retained leaves was BA + GA4+7 > GA4+7 > GA3 > BA > control > NAA. Relative xanthophyll (XN) content of retained leaves was NAA > control > BA > GA3 = GA4+7 = BA + GA4+7. Treating only half of a peach tree with NAA did not affect LR on the untreated side. NAA decreased subsequent bud and flower size in peach. Bud hardiness was enhanced by NAA in `Johnson Elberta' peach but not in `Redhaven' peach or in `Montmorency' tart cherry. NAA increased hardening on both the leafy treated (foliated) and untreated (defoliated) sides of half-treated `Johnson Elberta' trees. Increased endodormancy duration, as measured by GA3 forcing of terminal leaf buds, was proportional to LR. Chemical names used: N-(phenylmethyl)- 1H-purin-6-amine (BA); (1a,2ß,4bß,10ß)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-l,lO-dicarboxylic acid,l,4a-lactone (GA3, GA4+7); l-naphthaleneacetic acid (NAA).
2
Greene, Duane W. "GA4 AND GA7 INFLUENCE FLOWER BUD FORMATION AND RUSSET DEVELOPMENT ON APPLE." HortScience 27, no. 11 (1992): 1163c—1163. http://dx.doi.org/10.21273/hortsci.27.11.1163c.
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GA4+7 and GA4 substantially reduced russeting of `Golden Delicious' in four different years. There were indications that GA4 was more effective than GA4+7 at reducing russeting. The influence of gibberellins on flowering was variable and not always related to crop load. GA4 increased flowering in one experiment, had no influence in two experiments, and inhibited flowering in two experiments. GA7 either inhibited flowering or had no effect. There were indications that GA4 may partially reverse the inhibitory effect of GA7 on flowering in some instances.
3
Bell, Michelle L., Roy A. Larson, and Douglas A. Bailey. "THE EFFECTS OF BA + GA4+7 AND DIKEGULAC-SODIUM GA4+7 ON INITIATION AND DEVELOPMENT OF VEGETATIVE SHOOTS OF AZALEA." HortScience 25, no. 9 (1990): 1092G—1093. http://dx.doi.org/10.21273/hortsci.25.9.1092.
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Experiments were designed to determine if the combination of 6-benzyl adenine + gibberellic acid 4+7 can promote increased lateral shoots of desirable number and length on azaleas (Rhododendron simsii Planch.). The use of dikegulac-sodium with the addition of GA4+7 was also investigated to determine if GA4+7 could overcome decreased plant height and diameter caused by dikegulac application. Treatments were applied by spraying 204 ml·m-2 to pinched plants of mean diameter and mean height of 16 and 13 cm, respectively, potted in 1.3 liter plastic containers. Shoot number, plant height and plant diameter were measured 9 weeks after application for the commercially prominent cvs. `Gloria' and `Prize'. Preliminary results indicate that 2100 mg·l-1 ai BA + 2100 mg·l-1 ai GA4+7 increases number of lateral shoots. Initial results suggest the addition of 2100 mg·l-1 ai GA4+7 to 3900 mg·l-1 ai dikegulac overcomes inhibition of internodal elongation induced by dikegulac alone. Further studies will determine the effectiveness of Promalin (N-(phenylmethyl)-1H-purine-6-amine + GA4+7, 1:1) as a pinching agent on azaleas.
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Bell, Michelle L., Roy A. Larson, and Douglas A. Bailey. "THE EFFECTS OF BA + GA4+7 AND DIKEGULAC-SODIUM GA4+7 ON INITIATION AND DEVELOPMENT OF VEGETATIVE SHOOTS OF AZALEA." HortScience 25, no. 9 (1990): 1092g—1093. http://dx.doi.org/10.21273/hortsci.25.9.1092g.
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Experiments were designed to determine if the combination of 6-benzyl adenine + gibberellic acid 4+7 can promote increased lateral shoots of desirable number and length on azaleas (Rhododendron simsii Planch.). The use of dikegulac-sodium with the addition of GA4+7 was also investigated to determine if GA4+7 could overcome decreased plant height and diameter caused by dikegulac application. Treatments were applied by spraying 204 ml·m-2 to pinched plants of mean diameter and mean height of 16 and 13 cm, respectively, potted in 1.3 liter plastic containers. Shoot number, plant height and plant diameter were measured 9 weeks after application for the commercially prominent cvs. `Gloria' and `Prize'. Preliminary results indicate that 2100 mg·l-1 ai BA + 2100 mg·l-1 ai GA4+7 increases number of lateral shoots. Initial results suggest the addition of 2100 mg·l-1 ai GA4+7 to 3900 mg·l-1 ai dikegulac overcomes inhibition of internodal elongation induced by dikegulac alone. Further studies will determine the effectiveness of Promalin (N-(phenylmethyl)-1H-purine-6-amine + GA4+7, 1:1) as a pinching agent on azaleas.
5
Reaney, Martin J. T., Lawrence V. Gusta, Suzanne R. Abrams, and Albert J. Robertson. "The effects of abscisic acid, kinetin, and gibberellin on freezing tolerance in smooth bromegrass (Bromus inermis) cell suspensions." Canadian Journal of Botany 67, no. 12 (1989): 3640–46. http://dx.doi.org/10.1139/b89-445.
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The effects of kinetin and gibberellic acids (GA3, GA4, GA7, GA9, and a mixture of GA4,7,9) on cold hardening, dehardening, and growth of smooth bromegrass (Bromus inermis Leyss. cv. Manchar) suspension cultures treated with abscisic acid (ABA) were determined. Bromegrass cells treated with 75 μM racemic ABA for 7 days at 25 °C tolerated −37 °C, whereas cells treated with both racemic ABA (75 μM) and a mixture of GA4, GA7, and GA9 (total gibberellic acid concentration 100 μM) were similar in hardiness to the controls (LT50, −10 °C). GA4,7,9 at concentrations greater than 10 μM inhibited the growth of cells. Although 400 μM GA4,7,9 was lethal to cells, 75 μM ABA overcame the lethal effect but did not overcome growth inhibition. The twofold reduction in cell water content due to 75 μM ABA treatment for 7 days was partially overcome by GA4,7,9 at concentrations greater than 400 μM. GA4, GA7, and GA9 were equally effective at limiting growth and inhibiting freezing tolerance induced by ABA, whereas GA3 had little effect on cold hardiness, growth, and water content. During the first 4 days, kinetin at concentrations greater than 100 μM inhibited growth of both control cells and cells treated with ABA. Kinetin (> 100 μM) also inhibited freezing tolerance induced by abscisic acid after 4 days, but had no effect after 8 days. Bromegrass cells treated with 75 μM ABA for 7 days were hardened to −37 °C but dehardened to −12 °C after transfer to fresh medium minus ABA after 12 days at 10 °C. GA4,7,9 (40 μM) had no effect on the rate of dehardening, whereas kinetin increased the rate of dehardening.
6
McArtney, Steven J., and Li Shao Hua. "GA3, GA4+7, and GA7 Inhibit Flower Bud Formation and Reduce Alternate Bearing in Apple (Malus domestic Borkh.)." HortScience 30, no. 4 (1995): 787F—788. http://dx.doi.org/10.21273/hortsci.30.4.787f.
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A single spray of either GA3 or GA4+7 at full bloom reduced the severity of the alternate bearing cycle of `Braeburn' apples, measured as the proportion of flowering spurs over the 2 years following treatment. Increasing the concentration of GA3 applied in the light-flowering year linearly reduced the proportion of flowering spurs in the following year and linearly increased the proportion of flowering spurs 2 years after treatment. Application of GA3 or GA4+7 at full bloom inhibited flower bud formation on spurs only, whereas, in a separate experiment, GA3 or GA7 applied later than 8 weeks after bloom inhibited flower bud formation on 1-year wood only. Thus, delayed GA treatments may provide suitable technology for the selective removal of fruit from 1-year wood in apple.
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Talaie, A., and J. Mojtahed. "522 Study on the Effect of GA4+7, GA3, and Dimethoate on Russeting of `Golden Delicious' Apple." HortScience 34, no. 3 (1999): 535E—535. http://dx.doi.org/10.21273/hortsci.34.3.535e.
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Skin russet in apple fruit, which causes a considerable decrease in marketing and exporting potentials, is one of the major problems in the word fruit markets. In this project, the effect of GA4+7, GA3, and dimethoate on russeting of `Golden Delicious' apple was examined. A complete randomized-block design with 13 treatments and four replications was used. In all treatments, the trees had the same size and medium growth and were homogeneous. The distances between trees were 6 x 6 m and the age was 18 years. The total number of trees, including controls, was 52. The 12 treatments were GA4+7 and GA3 with 10 ppm and 20 ppm concentrations in one and two times of spray in petal fall (PF) and PF + 10 days. Dimethoate at a concentration of 0.03% and 0.05% in one and two times of spray in PF and PF + 10 days. Fruit russeting was reduced in all treatments except with GA3. The largest decrease of russeting was caused by GA4+7, especially with 20 ppm and also dimethoate with a significant decrease in russeting. Seed number also decreased significantly with GA4+7 and GA3, but dimethoate had no significant effect on TSS, while ACD ratio was decreased significantly by GA4+7 and dimethoate, but GA3 had no significant effect. Compared with the control, the treatment did not show differences with the other characteristics.
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Ahmad, Iftikhar, John M. Dole, and Bruno T. Favero. "Pulsing With Low Concentration Gibberellin Plus Benzyladenine or Commercial Floral Preservatives Affect Postharvest Longevity, Quality, and Leaf Chlorosis of Cut Lilies and Gladioli." HortTechnology 24, no. 5 (2014): 560–64. http://dx.doi.org/10.21273/horttech.24.5.560.
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Effects of pulsing with different concentrations of gibberellin plus benzyladenine (GA4+7 + BA), a proprietary mixture of GA4+7 plus BA in a commercial floral preservative (GA4+7 + BA + preservative), or a propriety mixture of sugar plus acidifier developed for bulbous flowers (floral bulb preservative) were studied on postharvest performance and quality of cut lily (Lilium hybrids) and gladiolus (Gladiolus hybrids) flowers. Pulsing of cut stems of lily with GA4+7 + BA at 5 or 2 mL·L−1 GA4+7 + BA + preservative for 20 hours at 3 ± 1 °C extended the vase life and controlled leaf chlorosis of ‘Cobra’ oriental lily and ‘Cappuccino’ and ‘Dot Com’ asiatic lily. Cut ‘Orange Art’ asiatic lily performed best when pulsed with GA4+7 + BA at 10 mg·L−1. For cut gladiolus, pulsing with GA4+7 + BA at 10 mg·L−1 extended the vase life of ‘Alice’, ‘Mammoth’, and ‘Passion’, while ‘Scarlet’ had the longest vase life when pulsed with 5 mg·L−1 GA4+7 + BA. GA4+7 + BA + preservative also extended the vase life and controlled leaf chlorosis, but the floral bulb preservative had no effect on vase life extension or preventing leaf chlorosis of lilies. Gladiolus cultivars had no or minor leaf chlorosis during vase period. Overall, overnight pulsing with GA4+7 + BA or GA4+7 + BA + preservative extended the vase life and prevented leaf chlorosis and can be used by growers and wholesalers for maintaining quality of cut stems.
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Johnson, Clarence. "218 Effect of Promalin and GA4/7 on Marketable Asparagus Shoots Harvested." HortScience 34, no. 3 (1999): 479E—479. http://dx.doi.org/10.21273/hortsci.34.3.479e.
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Spraying 9-month-old UC157F1 asparagus plants (Asparagus officinalis L.) with aqueous solutions of GA4/7, BA, and promalin ranging from 0 to 200 ppm in 200-ppm increments and using the mother-stalk method showed that BA continued to produce the most marketable shoots and obtained a higher level of effectveness. GA4/7 showed significance on several days during the harvest period. On the final day, there was no significant difference found for either GA4/7 or promalin. BA produced marketable shoots earlier than promalin, but in the end, both these chemicals were equally effective. Early interaction with GA4/7 × BA resulted in delayed shoot emergence. Promalin is a mixture of GA4/7 and BA.
10
Ranwala, N. K. Damayanthi, and Dennis R. Decoteau. "Involvement of Gibberellins in Phytochrome-regulated Stem and Petiole Elongation in Watermelon Plants." HortScience 33, no. 3 (1998): 493f—494. http://dx.doi.org/10.21273/hortsci.33.3.493f.
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Phytochrome-regulated stem and petiole elongation is of great horticultural importance due to their effects on height and compactness of plants. Although it is believed that phytochrome action during cell elongation is controlled via gibberellin (GA) biosynthesis, conclusive evidence has not been presented. In this study, watermelon plants pre-treated with GAs or GA biosynthesis inhibitors were briefly exposed to red (R) or far-red (FR) at the end of photoperiod to investigate the involvement of GAs in phytochrome-regulated stem and petiole elongation. Two-week-old watermelon plants were applied with either GAs, GA3 (25 ppm) or GA4+7 (25 ppm), or GA biosynthesis inhibitors, paclobutrazol (early stage inhibitor, 2 ppm) or prohexadione-Ca (late stage inhibitor, 200 ppm). Following chemical application, plants were treated with low-intensity R or FR light for 15 min at the end of photoperiod for 8 days. The increased petiole length and increased dry mass partitioned to petioles caused by FR were further increased when plants were pre-treated with GA3 and GA4+7, but reduced when plants were pre-treated with paclobutrazol or prohexadione-Ca. Pre-treatment with paclobutrazol or prohexadione-Ca further reduced the petiole length and dry mass partitioned to petioles caused by R alone, but effects of R were reversed when plants were pre-treated with GA3 and GA4+7. Petiole growth changes were significant after 2 to 3 days of treatments and there was no light or growth regulator effects on stem growth. Low leaf chlorophyll content and higher photosynthesis resulted in FR-treated plants were not observed when plants were pre-treated with paclobutrazol or prohexadione-Ca. Prohexadione-Ca was more effective in reversing FR induced petiole elongation than paclobutrazol, while GA4+7 was more effective than GA3 in promoting the effects of FR and reversing the effects of R. These results provide further evidence that phytochrome regulated growth changes in watermelon are due to the changes in GA biosynthesis. It is also suggestive that phytochrome has differential regulation of GA biosynthesis.
11
Philipson, J. J. "The promotion of flowering in large field-grown Sitka spruce by girdling and stem injections of gibberellin A4/7." Canadian Journal of Forest Research 15, no. 1 (1985): 166–70. http://dx.doi.org/10.1139/x85-027.
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Mature 14-year-old grafted Piceasitchensis (Bong.) Carr. which were field grown and 6 m tall were given stem injections of gibberellin A4/7 (GA4/7) alone and in combination with girdling. The GA4/7 was applied twice, at 100 or 250 mg per application. GA4/7 alone produced a large and significant stimulation of the numbers of both pollen and seed cones, with means of about 200 pollen and 90 seed cones per tree, and 90% of the clones flowering; both levels of GA4/7 application stimulated flowering to approximately the same extent. The girdling treatment enhanced flowering when environmental conditions facilitated light flowering of the controls, and also increased the response to 100 mg GA4/7. The stimulation of flowering was carried over into the 2nd year after treatment, but only when both girdling and GA4/7 had been applied together.
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Pharis, Richard P., Debra Tomchuk, Frederick D. Beall, R. Marie Rauter, and Gyula Kiss. "Promotion of flowering in white spruce (Piceaglauca) by gibberellin A4/7, auxin (naphthaleneacetic acid), and the adjunct cultural treatments of girdling and Ca(NO3)2 fertilization." Canadian Journal of Forest Research 16, no. 2 (1986): 340–45. http://dx.doi.org/10.1139/x86-058.
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Flowering (production of seed cone buds) of white spruce (Piceaglauca (Moench) Voss) grafts and of 55-year-old trees was significantly promoted by the application of gibberellin A4/7 (GA4/7). Use of GA4/7 accompanied by the adjunct cultural treatment of nondestructive girdling was especially effective. When GA4/7 was injected into a branch, the flowering stimulus was translocated upwards, thereby yielding up to a fivefold increase (72 female cone buds per propagule) in flowering. Clonal propagules sprayed to drip off with GA4/7 + auxin (naphtaleneacetic acid) averaged 116 female cone buds per propagule (a 12-fold increase over controls) with a 100% frequency of flowering. Pollen cone bud production and number of male flowering plants also tended to increase with the most successful flowering treatments. When GA4/7 was applied to 55-year-old trees with nondestructive, overlapping stem girdles and auxin, treatments were significantly effective (6- to 27-fold increases, respectively). When GA4/7 + Ca(NO3)2 was applied to 55-year-old trees, there was a tendency (nonsignificant) to increase (4- to 16-fold) flowering, relative to GA4/7 alone. White spruce, because of its very sporadic flowering and usually nominal response to GA4/7 alone, should be classed as a "recalcitrant conifer species." Use of the GA4/7 plus appropriate adjunct cultural treatments (high temperature, water stress, girdling) and (or) auxin is, thus, recommended if significant flowering and seed cone production is desired.
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Bell, Michelle L., Roy A. Larson, and Douglas A. Bailey. "Vegetative Growth Responses of Florist Azaleas to Dikegulac, GA4+7, and 6-Benzylamino Purine." HortScience 32, no. 4 (1997): 690–93. http://dx.doi.org/10.21273/hortsci.32.4.690.
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Dikegulac, dikegulac + GA4+7, BA, and Promalin (GA4+7 + BA) were evaluated as lateral shoot-inducing agents on greenhouse forcing azalea, Rhododendron cultivars Gloria and Prize. The addition of GA4+7 (1000 or 2000 mg.L-1) to a commercial rate of dikegulac (3900 mg.L-1) did not effectively increase plant diameter or leaf width compared to plants sprayed with dikegulac alone. The combination of dikegulac and GA4+7 (3900 + 2000 mg.L-1, respectively) was more phytotoxic than dikegulac alone. Foliar sprays of BA and Promalin at 1000 and 2000 mg.L-1 and 1000 and 1816 mg.L-1, respectively, did not increase lateral shoot count. Neither the addition of GA4+7 to dikegulac nor the use of Promalin is a viable alternative to dikegulac application for inducing lateral branch development of dikegulac-sensitive cultivars. Chemical names used: Na 2,3:4,6-Bis-0-(l-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid (dikegulac), (lα,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-l,10-dicarboxylic acid l,4a-lactone (GA4+7),N-(phenylmethyl)-lH-purin-6-amine (BA), and Promalin [1:1 (wt/wt) GA4+7 and BA].
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McArtney, Steven, Dave Ferree, John Schmid, J. D. Obermiller, and A. Green. "Effects of Prohexadione-Ca and GA4+7 on Scarf Skin and Fruit Maturity in Apple." HortScience 41, no. 7 (2006): 1602–5. http://dx.doi.org/10.21273/hortsci.41.7.1602.
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A series of experiments were undertaken to compare the effects of individual and combined applications of GA4+7 and prohexadione-Ca (P-Ca) on scarf skin and fruit quality parameters on red strains of `Rome Beauty' and `Gala' apples. Three applications of GA4+7 at 10-day intervals beginning at petal fall (PF) significantly reduced scarf skin severity in all experiments. A single application of P-Ca at PF had no effect on scarf skin in one experiment but reduced scarf skin severity in two further experiments. Combining P-Ca with the first of three GA4+7 sprays as a tank mix reduced the severity of scarf skin more effectively than either material alone in two of three experiments at P < 0.05 and in all three experiments at P < 0.10. Combining P-Ca with the first application of GA4+7 as a tank mix generally reduced scarf skin as effectively as applying P-Ca and the first GA4+7 spray two days apart, although in one experiment, greater scarf skin control was achieved when P-Ca was applied 2 days after the first GA4+7 spray. A single application of P-Ca at PF consistently reduced, and three applications of GA4+7 consistently increased, mean fruit weight at harvest compared with the control. The economic benefits as a result of reducing scarf skin severity with P-Ca and GA4+7 sprays will need to be balanced against the negative effect of P-Ca on mean fruit weight. There is no antagonism between early season P-Ca and GA4+7 sprays for scarf skin control, and P-Ca may increase the efficacy of GA4+7 sprays for scarf skin control in apple.
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Hall, Melvin R. "Early Sweetpotato Plant Production Increased by GA3 and BA Plus GA4+7." HortScience 29, no. 2 (1994): 126. http://dx.doi.org/10.21273/hortsci.29.2.126.
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Ranwala, Anil P., Garry Legnani, and William B. Miller. "Minimizing Stem Elongation During Spray Applications of Gibberellin4+7 and Benzyladenine to Prevent Leaf Chlorosis in Easter Lilies." HortScience 38, no. 6 (2003): 1210–13. http://dx.doi.org/10.21273/hortsci.38.6.1210.
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Several experiments were conducted to find effective ways of utilizing gibberellin4+7 (GA4+7) and benzyladenine (BA) to prevent leaf chlorosis during greenhouse production of Easter lilies (Lilium longiflorum Thunb.) while minimizing the undesirable side effects on stem elongation. On an absolute concentration basis, GA4+7 was much more effective than BA in preventing leaf chlorosis. Excessive levels of GA4+7, however, tended to cause stem elongation. When applied at around the visible bud stage, if the foliage was well covered with the spray solution, 25 mg·L-1 of GA4+7 was adequate for maximum protection against leaf chlorosis. Increasing the GA4+7 concentration above 25 mg·L-1 gave no additional benefit on leaf chlorosis. Two possible modes of GA4+7 uptake during a foliar spray application (absorption through leaves and stems, and root uptake of the extra run-off) were studied in terms of their relative contribution to leaf chlorosis and stem elongation. Although both modes of uptake prevented leaf chlorosis, foliar uptake was much more effective than root uptake. However, GA4+7 taken up by the roots contributed mainly to stem elongation. When sprayed to leaves on only the lower half of the plant, a 10-mL spray of either 25 or 50 mg·L-1 of each GA4+7 and BA was enough for complete protection against leaf chlorosis. Increasing volumes had no additional benefit on leaf chlorosis, but increased the chances of unwanted stem elongation.
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Khan, Muhammad Aaqil, Muhammad Hamayun, Amjad Iqbal, et al. "Gibberellin application ameliorates the adverse impact of short-term flooding on Glycine max L." Biochemical Journal 475, no. 18 (2018): 2893–905. http://dx.doi.org/10.1042/bcj20180534.
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Flooding is an abiotic stress that creates hypoxic conditions triggered by redox potential leading to restricted growth and grain yield in plants. In the current study, we have investigated the effect of exogenous gibberellins (GA4+7) on soybean under flooding stress. A regulatory role of GAs on biochemical changes in soybean plants [including chlorophyll contents, endogenous bioactive GA1 and GA4, endogenous jasmonic acid (JA) and abscisic acid (ABA)] has been elucidated after 3 and 6 h of flooding stress. The modulation of stress-related bio-chemicals and their genetic determinants [for instance, ABA (Timing of CAB expression1—TOC1, ABA-receptor—ABAR) and NO (S-nitrosoglutathione reductase—GSNOR1, NO overproducer1—NOX, and nitrite reductase—NR)] in response to short-term flooding stress were also explored. The current study showed that exogenous GAs rescued chlorophyll contents, enhanced endogenous bioactive GA1 and GA4 levels, endogenous jasmonic acid (JA) and checked the rate of ABA biosynthesis under short-term flooding. The exo-GAs induced the glutathione activity and reduced the resulting superoxide anion contents during short-term flooding in Pungsannamul soybean. Exo-GAs also triggered the endogenous S-nitrosothiols (precursor for increased NO production) that have been decreased over the time. Moreover, the exo-GAs could impinge a variety of biochemical and transcriptional programs that are ameliorative to plant growth during short-term flooding stress. The presence of GA1 and GA4 also confirms the presence of both C13-hydroxylation pathway and non-C13-hydroxylation pathway in soybean, respectively.
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Knoche, Moritz, Bishnu P. Khanal, and Matej Stopar. "Russeting and Microcracking of ‘Golden Delicious’ Apple Fruit Concomitantly Decline Due to Gibberellin A4+7 Application." Journal of the American Society for Horticultural Science 136, no. 3 (2011): 159–64. http://dx.doi.org/10.21273/jashs.136.3.159.
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The effect of four applications of gibberellin A4+7 [GA4+7 (10 mg·L−1 at 10-day intervals beginning with petal fall)] on water-induced russeting, formation of microcracks. and on fruit growth and deposition of the cuticular membrane (CM) was studied in developing ‘Golden Delicious’ fruit (Malus ×domestica Borkh.). Submerging developing apple fruit in deionized water for 48 h induced russeting in untreated control but not in GA4+7-treated fruit. Immersing in water during early fruit development, 19 days after full bloom (19 DAFB), resulted in more russeting than immersions occurring later (139 DAFB). Water on the outer surface of epidermal segments increased the frequency of microscopic cracks in untreated controls but to a lesser degree in GA4+7-treated fruit. The effect of GA4+7 on water-induced russeting and formation of microcracks was larger during early as compared with later stages of fruit development. Fruit treated with GA4+7 consistently had fewer microcracks as compared with non-treated control fruit. GA4+7 had no effect on amounts or rates of cutin or wax deposition, strain, or mechanical properties of the CM as compared with the non-treated control. Thus, the decrease in russeting and formation of microcracks in the cuticle of GA4+7-treated fruit must be accounted for effects on underlying epi- and hypodermal tissues.
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McArtney, Steven, J. D. Obermiller, and A. Green. "Prohexadione-Ca Reduces Russet and Does Not Negate the Efficacy of GA4+7 Sprays for Russet Control on ‘Golden Delicious’ Apples." HortScience 42, no. 3 (2007): 550–54. http://dx.doi.org/10.21273/hortsci.42.3.550.
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A series of four experiments were undertaken to evaluate the effects of individual and combined applications of prohexadione-Ca (P-Ca) and GA4+7 primarily on fruit russet, but also on fruit set, fruit weight, early season shoot growth, and fruit maturity of ‘Golden Delicious’ apples (Malus × domestica Borkh.). A single application of P-Ca (138 to 167 mg·L−1) at petal fall (PF) reduced the severity of russet in three of the four experiments; however, multiple applications of 20 ppm GA4+7 at 10-day intervals beginning at PF generally reduced russet more effectively than P-Ca. P-Ca did not reduce the efficacy of GA4+7 sprays for russet reduction. However, GA4+7 sprays reduced the inhibitory effects of P-Ca on shoot growth measured 30 days after PF. A single application of P-Ca at PF had no effect on mean fruit weight at harvest. Fruit size was lowest for the combined P-Ca and GA4+7 treatment in every experiment, although there was a significant interaction between P-Ca and GA4+7 sprays on mean fruit weight in only one experiment. There were no consistent effects of P-Ca and GA4+7 sprays, alone or in combination, on fruit maturity parameters at harvest. These data show that a single application of P-Ca at PF reduced russet severity, and the effects of P-Ca and GA4+7 sprays on russet can be additive. The economic benefits resulting from a reduction in russet severity after combined P-Ca and GA4+7 sprays will need to be balanced against their occasional negative effect on fruit size. Chemical names used: prohexadione-calcium [3-oxido-4-propionyl-5-oxo-3 cyclohexenecarboxylate formulated as Apogee (27.5% a.i.)].
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Andreoli, Claudinei, and Anwar A. Khan. "Improving Papaya Seedling Emergence by Matriconditioning and Gibberellin Treatment." HortScience 28, no. 7 (1993): 708–9. http://dx.doi.org/10.21273/hortsci.28.7.708.
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Papaya (Carica papaya L.) seeds germinated poorly at 25C in the presence of gibberellin (GA4+7) or following matriconditioning at 25C for 4 days. However, a combined treatment of matriconditioning and GA4+7 for 4 days synergistically promoted germination and seedling emergence. Drying the seeds after conditioning reduced the percentage of seedling emergence in the combined treatment involving 400 μm GA4+7 only. Combining matriconditioning with 100 or 200 μm GA4+7could effectively reduce germination time and improve seedling emergence and is recommended as a standard procedure for testing papaya seed germination.
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Harkess, Richard L., and Robert E. Lyons. "Gibberellin- and Cytokinin-induced Growth and Flowering Responses in Rudbeckia hirta L." HortScience 29, no. 3 (1994): 141–42. http://dx.doi.org/10.21273/hortsci.29.3.141.
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BA and GA4+7, were applied to vegetative, mature Rudbeckia hirta plants at the beginning of long days (LD). There were no synergistic effects, but BA inconsistently affected branching and had no effect on flowering. Floral initiation of the terminal inflorescence was promoted by GA4+7, although axillary inflorescences were not. Increasing GA4+7 levels decreased the time to terminal inflorescence anthesis. However, the interval between the terminal and second axillary inflorescence anthesis was increased. The net result was no significant effect on the time to second axillary inflorescence anthesis. Gibberellins may enhance the LD effect on the apical meristem of Rudbeckia, but axillary meristems, which initiate later, remained unaffected. Chemical names used: benzyladenine (BA), gibberellin4+7, (GA4+7).
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Fogal, W. H., G. Jobin, H. O. Schooley, S. J. Coleman, and M. S. Wolynetz. "Stem incorporation of gibberellins to promote sexual development of white spruce, Norway spruce, and jack pine." Canadian Journal of Forest Research 26, no. 2 (1996): 186–95. http://dx.doi.org/10.1139/x26-022.
Full textAbstract:
Stem incorporation of gibberellins (GA4/7 60:40) by injecting a liquid formulation or implanting a solid formulation was evaluated for promoting sexual reproductive development and for effects on vegetative development and foliage chlorosis in seedling and grafted white spruce, Piceaglauca (Moench) Voss; seedling Norway spruce, Piceaabies (L.) Karst.; and jack pine, Pinusbanksiana Lamb., seed trees. Spruces were treated with a single application of 0.76 or 1.53 mg GA4/7 per square centimetre of stem cross-sectional area at breast height during the late stage of shoot elongation (June 9 for white spruce and June 19 and 20 for Norway spruce). Jack pine was treated with a single early (July 5) or late (August 15) application of 1.53 mg GA4/7/cm2 or a split early–late application of 0.76 mg GA4/7/cm2. Results were evaluated in the subsequent season (i) by counting seed and pollen strobili, developing vegetative shoots, latent vegetative buds, and dead buds and (ii) by assessing foliage chlorosis and mortality. The numbers of seed strobili were increased by injections of GA4/7 at low and high application rates on seedling white spruce and Norway spruce and by the high application rate on grafted white spruce; implants were effective on seedling white and Norway spruce at the high application rate. In jack pine, the number of seed strobili was not increased by GA4/7. The numbers of pollen strobili were not significantly increased by GA4/7 treatments to white spruce or Norway spruce but were increased on jack pine by a single early injection at the high rate and split injections at the low rate. The number of developing vegetative shoots was reduced by GA4/7 injections at both rates on white spruce grafted trees and Norway spruce; the implants reduced them only on the grafted white spruce given the low rate. For the spruces, treatments with GA4/7 did not influence bud mortality. Foliage chlorosis and mortality, evident on jack pine but not on white or Norway spruce trees, was more severe with injections than with implants.
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Lenahan, Olivia M., Matthew D. Whiting, and Donald C. Elfving. "Gibberellic Acid Inhibits Floral Bud Induction and Improves `Bing' Sweet Cherry Fruit Quality." HortScience 41, no. 3 (2006): 654–59. http://dx.doi.org/10.21273/hortsci.41.3.654.
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This paper reports on the potential of gibberellic acid (GA3 and GA4+7) to reduce sweet cherry (Prunus avium L.) floral bud induction and balance fruit number and improve fruit quality in the season following application. In 2003, GA3 was applied to `Bing'/`Gisela 1' trees at 50 and 100 mg·L-1 at the end of stage I of fruit development, end of stage II, and on both dates. These treatments were compared to the industry standard application of 30 mg·L–1 applied at the end of stage II and an untreated control. Fruit quality was evaluated in the year of application (i.e., nontarget crop) and return bloom, fruit yield and quality were assessed in the subsequent season (2004). In 2003, GA3 delayed fruit maturity proportional to rate. In 2004, bloom density and fruit yield were related negatively and linearly to GA3 concentration. GA3 reduced the number of reproductive buds per spur and did not affect the number of flowers per reproductive bud. Nonspur flowering at the base of 1-year-old shoots was more inhibited by GA3 than flowering on spurs. Double applications significantly reduced bloom density and yield versus single applications. Trees treated with two applications of 50 and 100 mg·L–1 yielded fruit with 7% and 12% higher soluble solids, 15% and 20% higher firmness, and 7% and 14% greater weight, respectively. However, no treatment improved crop value per tree. In a separate isomer trial, GA3 and GA4+7 were applied to `Bing'/`Gisela 1' trees at 100 and 200 mg·L–1 at both the end of stage I and II in 2004. GA3 and GA4+7 applied at 100 mg·L–1 reduced bloom density similarly by 65%. GA3was more inhibiting than GA4+7at 200 mg·L–1, reducing bloom density by 92% versus 68%. We observed a 4- to 5-day delay in flowering from both GA formulations at 200 mg·L–1. At both concentrations, GA3 reduced yield by 71% and 95% versus 34% and 37% reduction by GA4+7. Fruit weight and soluble solids were unaffected but fruit firmness was increased by all treatments (6% to 17%). However, crop value per tree was highest from untreated control because improvements in fruit quality were insufficient to offset reductions in yield. GA3 shows potential as a novel crop load management tool in productive `Bing' sweet cherry orchard systems.
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Webber, J. E., S. D. Ross, R. P. Pharis, and J. N. Owens. "Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative process in Douglas-fir. II. Effects on shoot elongation and its relationship to flowering." Canadian Journal of Forest Research 15, no. 2 (1985): 348–53. http://dx.doi.org/10.1139/x85-056.
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Shoot elongation and female flowering response were assessed for gibberellin A4/7 (GA4/7) and root-pruning (RP) treatments in 9- and 10-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings of families with good- and poor-flowering histories. In families with a poor-flowering history, stem injections of GA4/7 significantly enhanced elongation of third-whorl terminal shoots but produced no flowering response. In families with a good-flowering history, GA4/7 treatment had no effect on shoot elongation but did result in a significant increase in seed-cone buds. In contrast, root-pruning significantly retarded shoot growth in families with both good- and poor-flowering histories and was also the single most effective treatment for enhancing flowering. Combined, GA4/7 plus RP had a synergistic effect on flowering and GA4/7 partially overcame the inhibition of shoot growth caused by RP alone. These results are consistent with a hypothesis that exogenous and endogenous gibberellins are used preferentially for vegetative growth processes, with increased flowering occurring only after a threshold concentration of effector gibberellins is reached.
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Gianfagna, T. J., R. H. Merritt, and J. D. Willmott. "632 GA4/7 and Light Level Affect Flowering and Plant Height of New Cultivars and Genetic Lines of Aquilegia ×hybrida Sims." HortScience 35, no. 3 (2000): 506D—506. http://dx.doi.org/10.21273/hortsci.35.3.506d.
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Aquilegia cultivars `Songbird Bluebird', `Songbird Robin', `Dove Improved', `Colorado Violet/White' and five cultivars from new experimental genetic lines (`Red and White', `Rose and White #1', `Rose and White #2', `Scarlet and Yellow' and `White') will flower without vernalization, but little is known of their response to light or plant growth regulators. Plants were started from seed on 5 Jan. 1999 and grown in either natural light or 33% shade, and treated with gibberellins (GA4/7) at the seven-leaf stage. Flowering time, number of flowers/plant, and plant height were evaluated through 31 May 1999. All five cultivars from the new genetic lines bloomed during the study. `White', grown in shade and treated with GA4/7, bloomed 2 weeks earlier (115 days) than untreated plants grown in natural light (130 days). `Songbird Robin', treated with GA4/7, bloomed in 146 days, and was the only other cultivar to bloom. Flower numbers were greater in natural light than in 33% shade. GA4/7 increased flowering for four of five cultivars, in the new genetic lines, grown in natural light. In shade, GA4/7 increased flowering for three of five cultivars. Height response to GA4/7 was significant in both natural light and 33% shade. Four of the five cultivars in the new genetic lines were taller when treated. All five of these cultivars were taller when grown in natural light verses 33% shade. `White' and both `Rose and White' cultivars were consistently taller, bloomed earlier and were more floriferous when treated with GA4/7.
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McArtney, Steven, Duane Greene, Terence Robinson, and James Wargo. "Evaluation of GA4+7 plus 6-Benzyladenine as a Frost-rescue Treatment for Apple." HortTechnology 24, no. 2 (2014): 171–76. http://dx.doi.org/10.21273/horttech.24.2.171.
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Freeze events during bloom can be a relatively frequent occurrence in many apple (Malus ×domestica) production areas in the United States that significantly reduce orchard productivity and profitability. This study investigated the potential for a proprietary mixture of gibberellin A4 + A7 and 6-benzyladenine (GA4+7 plus 6-BA) to increase fruit set and cropping of apple following freeze events at three locations across the United States during bloom in 2012. GA4+7 plus 6-BA increased fruit set in two of five experiments, and increased fruit number and yield per tree in three of five experiments. GA4+7 plus 6-BA increased fruit set and yield of ‘Taylor Spur Rome’ following freezes on two consecutive days during bloom when the minimum temperature reached 23.9 and 28.4 °F. Fruit set was increased due to a stimulation of parthenocarpic fruit growth. Using locally obtained market prices, GA4+7 plus 6-BA treatments increased the crop value of ‘Taylor Spur Rome’, ‘Ginger Gold’, and ‘Jonagold’ by $3842, $977, and $6218 per acre, respectively. Although GA4+7 plus 6-BA application(s) after a freeze increased fruit set and cropping in some instances, tree yields were well below the average yields previously obtained in the test orchards.
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Kim, Hye-Ji, and William B. Miller. "EFFECTS OF GA4+7 AND BA APPLICATION ON POSTPRODUCTION QUALITY IN `SEADOV' POT TULIP FLOWERS." HortScience 41, no. 3 (2006): 491D—491. http://dx.doi.org/10.21273/hortsci.41.3.491d.
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The effect of GA4+7 plus benzyladenine (BA) on postproduction quality was investigated in `Seadov' tulips (Tulipa gesneriana). Potted tulips at half-colored bud stage or full-bloom stage were sprayed with a range of GA4+7 plus BA, and placed in a simulated consumer environment (SCE) in order to determine effectiveness of the compound at each stage. Regardless of plant stage, treatment with GA4+7 plus BA effectively improved individual flower longevity and whole plant longevity in the range of concentrations tested. GA4+7 plus BA had a strong effect on enhancing flower longevity when sprayed to mature (fully colored) buds, and a lesser effect on immature (green) buds, and whole plant longevity increased with higher doses of GA4+7 plus BA. When applied to open flowers, however, concentrations over 50 mg·L–1 reduced individual flower and whole plant longevities relative to lower concentrations resulting from unwanted full-opening of older flowers and exaggerated gynoecium growth. Concentrations as low as 10 mg·L–1 significantly increased longevity of tulip flowers of all age classes. The effects of enhancing postproduction quality of `Seadov' pot tulips were primarily derived from the BA component of the compound.
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Marquard, Robert D., and James W. Hanover. "Floral response of Piceaglauca to gibberellin A4/7, napthaleneacetic acid, root-pruning, and biennial treatment." Canadian Journal of Forest Research 15, no. 4 (1985): 743–46. http://dx.doi.org/10.1139/x85-124.
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The floral response of 6-year-old seedling white spruce (Piceaglauca (Moench) Voss.) was evaluated after treatment in 1981 with the gibberellin mixture of A4 and A7 (GA4/7), napthaleneacetic acid (NAA), and root-pruning. To evaluate the effectiveness of biennial treatment, trees treated in 1981 were again treated in 1983 and compared with a second group of trees treated only in 1983. Trees treated in 1981 with 500 mg•L−1 GA4/7 plus 25 mg•L−1 NAA and root-pruning averaged 42 female strobili per tree and control trees remained vegetative. Root-pruning significantly reduced terminal shoot growth and shoot water potential. No male strobili were produced on study trees. Trees treated in 1981 and again in 1983 were as productive (based on female counts) as trees treated only in 1983. Two treatments in 1983 significantly enhanced female strobilus production over the control: (i) 500 mg•L−1 GA4/7 alone and (ii) 250 mg•L−1 GA4/7 plus root-pruning. These treatments averaged 150 and 192 female strobili per tree, respectively; control trees averaged 30. Biennial treatment with GA4/7 and root-pruning can effectively continue to increase female cone production of white spruce.
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Smith, Ronald F. "Effects of stem injections of gibberellin A4/7 and paclobutrazol on sex expression and the within-crown distribution of seed and pollen cones in black spruce (Picea mariana)." Canadian Journal of Forest Research 28, no. 5 (1998): 641–51. http://dx.doi.org/10.1139/x98-034.
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Two experiments in black spruce (Picea mariana (Mill.) BSP) seedling seed orchards were established to determine if a stem injection of paclobutrazol (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl) could be used as an adjunct treatment to increase the efficacy of stem injections of gibberellins A4 and A7 (GA4/7). Trees received a single injection of GA4/7 and (or) paclobutrazol shortly after vegetative bud burst. There was a dose-dependent but nonlinear increase in the production of cones of both sexes in response to stem injections of either GA4/7 or paclobutrazol. The optimum rate of GA4/7 for stimulating pollen-cone production was 3.3 mg, whereas the most seed cones were induced on trees receiving 11 mg. The sex ratio (number of seed cones/number of pollen cones) increased with the rate of GA4/7 applied. Injecting paclobutrazol also promoted cones of both sexes equally, resulting in sex ratios comparable with that of the control trees. Treatments did not affect the total numbers of buds (vegetative, latent, and cone) produced. Seed- and pollen-cone buds occurred in positions that would have otherwise developed vegetatively and become latent, respectively. The mechanisms whereby paclobutrazol could affect flowering in black spruce are discussed. The use of paclobutrazol as an adjunct to GA4/7 treatments in black spruce seedling seed orchards appears effective, practical, and safe.
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Greenwood, Michael S., Gregory W. Adams, and Michele Gillespie. "Stimulation of flowering by grafted black spruce and white spruce: a comparative study of the effects of gibberellin A4/7, cultural treatments, and environment." Canadian Journal of Forest Research 21, no. 3 (1991): 395–400. http://dx.doi.org/10.1139/x91-049.
Full textAbstract:
Flower stimulation treatments, including gibberellin A4/7 (GA4/7) application, root-pruning, and greenhouse environment during the latter part of shoot elongation, were applied to grafted, clonal black spruce (Piceamariana (Mill.) B.S.P.) and white spruce (Piceaglauca (Moench) Voss) of roughly the same size and age. In addition, the size of pot-grown ramets of both species was increased by inducing additional growth cycles by several applications of a chilling treatment followed by an 18-h photoperiod in a heated greenhouse. This treatment doubled the height growth of both species over a 2-year period, and female cone bud production was promoted by GA4/7. GA4/7 also promoted female flowering on field-grown material, but root-pruning had little effect; black spruce was more responsive to GA4/7 (10× increase) than white spruce (3× increase). Male flowering in black spruce was consistently, and sometimes significantly, inhibited by GA4/7, but was promoted in white spruce. In the latter case the response was not statistically significant. In contrast, male flowering was increased in potted trees of both species by allowing shoots to elongate 50–75% outdoors, after which the trees were moved into a greenhouse.
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Owings, Allen D., and Steven E. Newman. "BRANCHING AND VEGETATIVE GROWTH MODIFICATION OF PHOTINIA X FRASERI WITH EXOGENOUS PLANT GROWTH REGULATORS." HortScience 25, no. 8 (1990): 850b—850. http://dx.doi.org/10.21273/hortsci.25.8.850b.
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Four rates of seven plant growth regulators were foliar-applied to 11.4 liter containers of Photinia × fraseri after initial root establishment. Growth regulators studied were uniconazole, paclobutrazol, dikegulac-sodium, ancymidol, 6-BA, GA4+7 and, 6-BA + GA4+7. Six months after application, plant height, plant width, growth index, and number of lateral and terminal branches were recorded. Applications of uniconazole (30 mg a.i./liter), 6-BA alone or in combination with GA4+7, and dikegulacsodium stimulated lateral branching. The number of lateral branches increased linearly as paclobutrazol rates increased from 60 to 180 mg a.i./liter. Growth index decreased with increasing application rates of uniconazole and paclobutrazol, while the growth index of photinia treated with other growth regulators wasn't affected by application rate. Plant height was increased in GA4+7 treated plants.
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Currey, Christopher J., Roberto G. Lopez, Vijay K. Rapaka, James E. Faust, and Erik S. Runkle. "Exogenous Applications of Benzyladenine and Gibberellic Acid Inhibit Lower-leaf Senescence of Geraniums during Propagation." HortScience 48, no. 11 (2013): 1352–57. http://dx.doi.org/10.21273/hortsci.48.11.1352.
Full textAbstract:
After postharvest shipping, the lower leaves of zonal geranium (Pelargonium ×hortorum) cuttings often turn chlorotic and necrotic during rooting in a propagation environment. Our objective was to quantify the efficacy of spray applications of the plant growth regulators (PGRs) benzyladenine (BA) and/or gibberellic acid (GA) at various stages in propagation to reduce lower-leaf senescence and evaluate effects on subsequent rooting. In Expt. 1, cuttings of ‘Patriot White’ geraniums were harvested and treated with BA (2.5 or 5.0 mg·L−1), BA + GA4+7 (2.5 or 5.0 mg·L−1 each), or GA3 (0.5 or 2.0 mg·L−1) either before or after a 2-day storage period simulating commercial shipping. Post-shipment application of all PGRs eliminated leaf yellowing compared with cuttings treated pre-shipment, but rooting was inhibited. In Expt. 2, the promotion of rooting from a rooting hormone preceding treatment with BA (1.25 to 5.0 mg·L−1), BA+GA4+7 (1.25 to 5.0 mg·L−1 each), or GA3 (0.25 to 2.0 mg·L−1) was evaluated on ‘Patriot White’ geranium cuttings after a 2-day simulated shipping. Applying rooting hormones increased the percentage of fully rooted cuttings treated with BA and/or GA from 16.4% to 51.8%. In Expt. 3, cuttings of different geranium cultivars from a commercial producer varied in susceptibility and suppression of leaf yellowing after BA + GA4+7 applications. We conclude that foliar applications of BA + GA4+7 can suppress lower-leaf senescence and rooting during propagation of some geranium cultivars, and the inhibition of rooting can be at least partially overcome with an application of rooting hormone.
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Marler, Thomas E., and Michael V. Mickelbart. "Application of GA4+7 to Stem Enhances Carambola Seedling Growth." HortScience 27, no. 2 (1992): 122–23. http://dx.doi.org/10.21273/hortsci.27.2.122.
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Growth response of containerized carambola (Averrhoa carambola L.) seedlings to GA applied to trunks in lanolin paste were studied under glasshouse conditions. Gibberellic acid at 0, 250, 500, or 750 mg·liter and an untreated control (no lanolin) were used. Internode length and increases in plant height and trunk cross-sectional area (TCA) did not differ for control and 0 mg·liter plants, but mostly increased with concentration of GA. Increase in TCA was determined in a second study with control and treated plants, using 500 mg GA/liter. Mean recommended graftable size (7 mm) was reached in 47 days in plants that were GA treated, and 93 days in control plants, suggesting that GA may be used to shorten nursery time for producing graftable carambola seedlings. Chemical name used: gibberellic acid (GA.,+,).
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Kim, Hye-Ji, and William B. Miller. "GA4+7 plus BA enhances postproduction quality in pot tulips." Postharvest Biology and Technology 51, no. 2 (2009): 272–77. http://dx.doi.org/10.1016/j.postharvbio.2008.07.002.
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Whitman, Catherine M., Royal D. Heins, Roar Moe, and Keith A. Funnell. "GA4+7 plus benzyladenine reduce foliar chlorosis of Lilium longiflorum." Scientia Horticulturae 89, no. 2 (2001): 143–54. http://dx.doi.org/10.1016/s0304-4238(00)00238-7.
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Black, Brent L., and Mark K. Ehlenfeldt. "Foliar Applications of GA4+7 Reduce Flowering in Highbush Blueberry." HortScience 42, no. 3 (2007): 555–58. http://dx.doi.org/10.21273/hortsci.42.3.555.
Full textAbstract:
Precocious varieties of highbush blueberry (Vaccinium corymbosum L.) may overcrop during the first few seasons in the fruiting field, adversely affecting plant establishment. Reducing or preventing bloom in the nursery and during establishment would be beneficial in preventing early cropping and reducing the risk of infection by pollenborne viruses. We investigated the efficacy of foliar applications of GA4+7 for suppressing flower bud initiation in blueberry. One-year-old rooted cuttings of ‘Bluecrop’ were obtained from a commercial nursery and established in 11-L pots at the Philip E. Marucci Blueberry and Cranberry Research Center, Chatsworth, N.J. Three separate experiments were conducted over three seasons with ‘Bluecrop’ (and ‘Duke’ in 2005) highbush blueberry where foliar applications of GA4+7 were made at concentrations ranging from 50 to 400 mg·L−1 a.i., with timing treatments ranging from 7 July to 15 Sept., with 10 replicate plants per treatment. Floral and vegetative buds were counted the following spring. In the first study, the greatest degree of flower bud suppression resulted from applications at 400 mg·L−1 repeated weekly from 7 July to 1 Sept. However, these treatments also reduced total vegetative bud number and plant height. In the two subsequent studies, the largest treatment effect resulted from three weekly applications in late August and early September, where flower bud numbers were suppressed by 70% to 85% for ‘Bluecrop’ and 95% for ‘Duke’ while total vegetative growth was unaffected.
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Preece, John E. "Growth stimulation ofEuphorbia lathyris L. by GA4+7 and BA." Journal of Plant Growth Regulation 9, no. 1-4 (1990): 85–88. http://dx.doi.org/10.1007/bf02041946.
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Ryan, George F. "Effect of Growth Regulator and Nitrogen on Height and Branching of Skimmia reevesiana." Journal of Environmental Horticulture 3, no. 2 (1985): 71–74. http://dx.doi.org/10.24266/0738-2898-3.2.71.
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Application of gibberellins A4 + 7 (GA4 + 7) or 6-benzylamino purine (BA) stimulated a second growth flush on plants of Skimmia reevesiana Fort. that had completed normal spring growth. Plants treated with GA4 + 7 were up to 130% taller than untreated plants at the end of the first season, and up to 50% taller after a growth flush the following spring without re-treatment. The number of shoots was increased more than 100% by BA at 4000 ppm, without affecting height. Promalin (BA + GA4 + 7) at 2000 ppm of each active ingredient increased height 50% the year of treatment, and the number of shoots more than 160%. There was not a significant difference in height after the next spring flush. Increasing the amount of nitrogen (N) supplied to the plants increased the number of shoots the second season and decreased plant height. Application of GA4 + 7 tended to counteract these effects of N.
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Vargas-Hernandez, J.-Jesus, and Jeniffer-Ivette Vargas-Abonce. "Effect of giberellic acid (GA4/7) and girdling on induction of reproductive structures in Pinus patula." Forest Systems 25, no. 2 (2016): e063. http://dx.doi.org/10.5424/fs/2016252-09254.
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Aim of study: Seed production in forest tree species commonly takes a long time due to the length of the juvenile stage. Even though several treatments have been used to induce early flowering in conifer species, experience on their use in subtropical Pinus species is limited. This study aimed to evaluate the effect of GA4/7 dose (0, 1.27 and 2.54 mg cm-2) and application time (July-October), alone or in combination with partial stem girdling, on male and female strobili production in young Pinus patula Schiede ex Schltdl. et Cham. clones. Area of study: Nine clones with different flowering background of high-elevation Pinus patula growing in a six-year old seed orchard established in Central México (Aquixtla, Puebla) at 2,800 m elevation.Material and methods: Two independent flowering trials (FT1 and FT2) were carried out in the seed orchard during the 2009 and 2010 flowering cycles; similar factors were evaluated at both trials but time of application, clones tested, and experimental design used varied for each of them. Partial stem girdling was done at the base of the trunk and the GA4/7 solution was injected into the xylem above the point of girdling. The following spring, the percentage of trees with strobili and the number of strobili per tree were determined for both male and female structures.Main results: Significant differences (p ≤ 0.05) among clones in flowering capacity were found at both trials. None of the treatments applied in FT1 resulted in an increase of strobili formation, most probably because they were applied too late in the growing season. In FT2, however, application of GA4/7 combined with partial stem girdling increased the percentage of trees with strobili and the number of strobili of both sexes, particularly when applied in early July. Partial stem girdling was more effective on promoting male strobili than female ones in gibberellin-treated grafts.Research highlights: Timing of GA4/7 application and stem girdling was important, with a significant interaction with clones tested in FT2 on production of male strobili but not on female strobili. Application of 1.27 mg cm-2 GA4/7 and stem girdling in July promoted the highest percentage of trees with strobili, and increased 25-fold the number of female strobili and 5-fold the number of male strobili per tree as compared to the control treatment. Thus, operational use of this induction treatment would be valuable to increase and accelerate seed production in Pinus patula seed orchards in the region.Keywords: early flowering; gibberellins; juvenile stage; seed orchard; seed production.Abbreviations: GA: Gibberellic acid; GA4: Gibberellic acid 4; GA7: Gibberellic acid 7; GA4/7: Mix of gibberellic acids 4 and 7; FT1: Flowering trial carried out in the 2009 season; FT2: Flowering trial carried out in the 2010 season.
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Sanabria, L. G., and S. E. Newman. "PLANT GROWTH MODIFICATION AND WATER USE OF HIBISCUS ROSA-SINENSIS `BRILLIANT' PLANTS BY UNICONAZOLE WITH VARIOUS COMBINATIONS OF PLANT GROWTH REGULATORS." HortScience 25, no. 9 (1990): 1125e—1125. http://dx.doi.org/10.21273/hortsci.25.9.1125e.
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Various uniconazole (Sumagic™) rates were either sprayed or drenched alone or in combination with 6-BA and GA4+7 (Promalin™) or dikegulac-sodium (Atrinal™) on Hibiscus rosa-sinensis `Brilliant'. The rates of uniconazole were 0, 5, 10, and 15 mg a.i./L; 6-BA and GA4+7, 25 mg a.i./L each; and dikegulac-sodium 1000 mg a.i./L.Plant height was reduced by uniconazole when drenched at rates as low as 5 mg/L and 15 mg/L when sprayed. Dikegulac-sodium slightly counteracted the effects of uniconazole. Uniconazole activity was increased when either sprayed or drenched with application of 6-BA and GA4+7 resulting in greater height reduction.Transpiration and stomatal diffusive resistance of plants drenched with uniconazole alone was erratic; however, when uniconazole was sprayed or drenched and mixed with 6–BA and GA4+7 or dikegulac-sodium transpiration increased.
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Elsysy, Mokhles A., and Peter M. Hirst. "Molecular Basis of Flower Formation in Apple Caused by Defoliation and Gibberellins." Journal of the American Society for Horticultural Science 144, no. 6 (2019): 414–19. http://dx.doi.org/10.21273/jashs04760-19.
Full textAbstract:
Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major challenge for apple industries around the world. ‘Honeycrisp’ is a high value apple cultivar, but consistent flowering is difficult to achieve. Apple flower formation is affected by factors including defoliation, girdling, and gibberellin (GA4+7) and 1-naphthaleneacetic acid (NAA) applications. However, the molecular mechanisms that regulate the effects of these factors are not well understood. We studied the effect of local spur defoliation, GA4+7 and NAA applications on ‘Honeycrisp’ flower formation. Furthermore, we investigated the effect of local defoliation and local GA4+7 application on the transcript levels of two major flower formation genes in the meristems of apple spurs. The floral inhibition gene terminal flower1-1 (MdTFL1-1) and floral promoting genes flowering locus T (MdFT1 and MdFT 2) of apple. Local application of GA4+7 and defoliation treatments inhibited flower formation, but NAA applications were without effect. Defoliation treatments were accompanied by a significant reduction in MdFT1, 2 transcript levels compared with controls early in the growing season. Conversely, GA4+7 application was accompanied by a significant increase in MdTFL1-1 transcripts compared with controls throughout the growing season. These results indicate that GA4+7 inhibits flower formation by upregulating the inhibitory MdTFL1-1, and defoliation acts by downregulating transcript levels of MdFT1, 2 early in the growing season. We also provide evidence that defoliated bourse buds may receive flowering promotion signals from other parts of the tree in the absence of their local leaves.
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Eysteinsson, Throstur, and Michael S. Greenwood. "Effects of maturation and gibberellin A4/7 on flowering and branching characteristics of Larixlaricina." Canadian Journal of Forest Research 23, no. 1 (1993): 14–20. http://dx.doi.org/10.1139/x93-003.
Full textAbstract:
Flowering and the flowering response to the plant growth regulator gibberellin (GA4/7) were assessed on potted, greenhouse-grown tamarack (Larixlaricina (Du Roi) K. Koch) grafts made from ortets aged 1 to 74 years. Female flowering decreased with ortet age, whereas male flowering remained similar, resulting in an increased proportion of pollen cones with age. The decrease in total flowering with age was not adequately explained by smaller size or lower vigor of the older scions. Scions from the youngest ortets produced more, but shorter, second-order branches than scions from older ortets. GA4/7, applied in foliar sprays beginning at the start of long-shoot extension, resulted in increased flowering of both sexes, with a proportionately greater increase in female flowering by scions from younger ortets but a roughly equal increase in flowering of both sexes by scions from the oldest ortets. Furthermore, the overall flowering response to GA4/7 (proportionate to control) increased with ortet age. GA4/7 did not affect branch terminal increment, but did increase overall second-order lateral increment slightly.
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Ross, S. D., J. E. Webber, R. P. Pharis, and J. N. Owens. "Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative process in Douglas-fir. I. Effects on flowering." Canadian Journal of Forest Research 15, no. 2 (1985): 341–47. http://dx.doi.org/10.1139/x85-055.
Full textAbstract:
In two seed orchard trials, profuse female flowering was induced in young, but ontogenetieally mature grafts of inherently poor-flowering clones (1979) and in 9-year-old seedling-origin trees of both good- and poor-flowering families (1981) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) by the cultural treatment of root-pruning in conjunction with stem injections of the gibberellin A4 and A7 (GA4/7) mixture. Promotion of male flowering, however, was confined to the more sexually mature grafts. As an individual treatment in the 1981 study, root-pruning was more effective than GA4/7, particularly for the poor-flowering families which did not respond well to GA4/7 alone. The two treatments combined had a highly synergistic effect on both male and female flowering, the synergism being relatively greater for the poor-flowering than for the good-flowering families. Although GA4/7 was not tested alone on grafted propagules, its use with root-pruning enhanced an already significant increase in seed- and pollen-cone buds from root-pruning alone by 540 and 92%, respectively. These and subsequent trials have shown root-pruning +GA4/7 to be a most effective cone-bud enhancement treatment for use in young Douglas-fir breeding and seed production orchards.
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Owings, Allen D., and Steven E. Newman. "GROWTH ENHANCEMENT OF PHOTINIA × FRASERI WITH FOLIAR APPLICATIONS OF GROWTH REGULATORS." HortScience 25, no. 9 (1990): 1125b—1125. http://dx.doi.org/10.21273/hortsci.25.9.1125b.
Full textAbstract:
The action of foliar-applied uniconazole, paclobutrazol, dikegulac-sodium, ancymidol, 6-BA, GA4+7, and 6-BA + GA4+7 On container–grown Photinia × fraseri was studied over a one year period. Vegetative growth habit was evaluated at three month intervals. Shoot dry weight and histological examination of stern anatomy in the apical meristematic region was conducted at experiment termination.Several plant growth regulators, primarily uniconazole, 6-BA, 6-BA + GA4+7, and dikegulac-sodium, stimulated lateral branching. Linear increases in lateral branching occurred as application rates increased. High application rates of uniconazole and paclobutrazol created an asymmetrical growth habit and decreased dry weight accumulation.
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Eriksson, Urban, Gunnar Jansson, and Curt Almqvist. "Seed and pollen production after stem injections of gibberellin A4/7 in field-grown seed orchards of Pinus sylvestris." Canadian Journal of Forest Research 28, no. 3 (1998): 340–46. http://dx.doi.org/10.1139/x97-219.
Full textAbstract:
The effects of stem injections of gibberellin A4/7 (GA4/7) were studied in two experiments conducted in two different field-grown seed orchards of Pinus sylvestris L. Both experiments were carried out during years with favourable conditions for floral induction, i.e., higher temperatures and less precipitation than average years. In experiment 1, cone production and the number of filled seeds per graft increased significantly, the latter by about 60% compared with the control. Filled seeds per graft increased in experiment 2 as well, although the increase was not statistically significant. In both experiments, GA4/7 treatment significantly reduced the 1000-seed weight but did not significantly affect the number of filled and empty seeds per cone. In both experiments, grafts stimulated to increase seed production tended to produce smaller cones. In experiment 2, pollen production was significantly increased after stem injections of GA4/7. The increase above the control was about 90%. There was a tendency for stem injections of GA4/7, which were intended to increase seed production, to reduce pollen production. Clonal effects were significant for all variables tested in the study. No damage to the treated grafts were observed that could be attributed to the treatment. The use of stem injections of GA4/7 as an operational means in seed orchards of P. sylvestris is therefore recommended.
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Ranwala, Anil P., and William B. Miller. "Hormone Sprays and Supplemental Light Prevent Cold-storage-induced Postharvest Leaf Chlorosis and Abscission in `Stargazer' Hybrid Lilies." HortScience 33, no. 3 (1998): 536c—536. http://dx.doi.org/10.21273/hortsci.33.3.536c.
Full textAbstract:
Rapid leaf chlorosis and abscission limits the use of cold storage for post-production short-term holding of potted lilies. We investigated the effects of storage temperature, storage irradiance and pre-storage foliar sprays of gibberellin and/or cytokinin on postharvest leaf and flower quality of Lilium sp. `Stargazer' hybrid lilies. Storage of “puffy bud” stage plants at 4, 7, or 10 °C in dark for 2 weeks induced leaf chlorosis within 4 days in a simulated consumer environment, and resulted in 60% leaf chlorosis and 40% leaf abscission by 20 days. Cold-storage also reduced the duration of flower bud opening, inflorescence and flower longevity, and increased flower bud abortion. Providing light up to 40 μmol·m–2·s–1 during cold-storage at 4 °C significantly delayed leaf chlorosis and abscission and increased the duration of flower bud opening, inflorescence and flower longevity. Foliar sprays of ProVide (100 mg·L–1 GA4+7) and Promalin [100 mg·L–1 GA4+7 and 100 mg·L–1 benzyladenine (BA)] effectively prevented leaf chlorosis and abscission at 4 °C, while ProGibb (100 mg·L–1 GA3) and ABG-3062 (100 mg·L–1BA) were not effective. Accel (10 mg·L–1 GA4+7 and 100 mg·L–1 BA) showed intermediate effects on leaf chlorosis. Flower longevity was increased and bud abortion was prevented by all hormone formulations except ProGibb. The combination of light (40 μmol·m–2·s–1) and Promalin (100 mg·L–1 GA4+7 and 100 mg·L–1 BA) completely prevented cold-storage induced leaf chlorosis and abscission and significantly improved flower opening and overall plant quality.
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Han, Susan S. "Growth Regulators Reduce Leaf Yellowing in Easter Lily Caused by Close Spacing and Root Rot." HortScience 35, no. 4 (2000): 657–60. http://dx.doi.org/10.21273/hortsci.35.4.657.
Full textAbstract:
The development of greenhouse leaf yellowing in Easter lilies (Lilium longiflorum Thunb.) was significantly reduced by the application of growth regulator solutions containing gibberellins 4 and 7 (GA4+7) or benzyladenine (BA). Solutions containing BA alone significantly reduced leaf yellowing on plants caused by close spacing but were less effective than GA4+7. Application of BA alone, however, was not effective against root rot-induced leaf yellowing. When plants were treated with GA4+7 or BA + GA4+7 around the visible bud stage, nearly all of the leaves remained green until the end of the growing season. These growth regulators, however, increased the final height of the plants by 8–10 cm. The developmental rate and size of the flower buds, as well as the length of the pedicels were not affected by the growth regulator treatments. Thus application of these growth regulators greatly improved the quality of the leaves without compromising the quality and timing of the flowers. Chemical name used: N-(phenylmethyl)-1H-purine-6-amine (benzyladenine, BA).
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Ranwala, Anil P., and William B. Miller. "Gibberellin4+7, Benzyladenine, and Supplemental Light Improve Postharvest Leaf and Flower Quality of Cold-stored `Stargazer' Hybrid Lilies." Journal of the American Society for Horticultural Science 123, no. 4 (1998): 563–68. http://dx.doi.org/10.21273/jashs.123.4.563.
Full textAbstract:
Experiments were conducted to evaluate storage temperature, storage irradiance and prestorage foliar sprays of gibberellin, cytokinin or both on postharvest quality of Oriental hybrid lilies (Lilium sp. `Stargazer'). Cold storage of puffy bud stage plants at 4, 7, or 10 °C in dark for 2 weeks induced leaf chlorosis within 4 days in a simulated consumer environment, and resulted in 60% leaf chlorosis and 40% leaf abscission by 20 days. Cold storage also reduced the duration to flower bud opening (days from the end of cold storage till the last flower bud opened), inflorescence and flower longevity, and increased flower bud abortion. Storage at 1 °C resulted in severe leaf injury and 100% bud abortion. Providing light up to 40 μmol·m-2·s-1 during cold storage at 4 °C significantly delayed leaf chlorosis and abscission and increased the duration of flower bud opening, inflorescence and flower longevity, and reduced bud abortion. Application of hormone sprays before cold storage affected leaf and flower quality. ProVide (100 mg·L-1 GA4+7) and Promalin (100 mg·L-1 each GA4+7 and benzyladenine (BA)) effectively prevented leaf chlorosis and abscission at 4 °C while ProGibb (100 mg·L-1 GA3) and ABG-3062 (100 mg·L-1 BA) did not. Accel (10 mg·L-1 GA4+7 and 100 mg·L-1 BA) showed intermediate effects on leaf chlorosis. Flower longevity was increased and bud abortion was prevented by all hormone formulations except ProGibb. The combination of light (40 μmol·m-2·s-1) and Promalin (100 mg·L-1 each GA4+7 and BA) completely prevented cold storage induced leaf chlorosis and abscission.
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Al-Juboory, Karim H., and David J. Williams. "USE OF GROWTH REGULATORS TO ENHANCE LATERAL BRANCHING OF ALGERIAN IVY (HEDERA CANARIENSIS L.)." HortScience 25, no. 9 (1990): 1085d—1085. http://dx.doi.org/10.21273/hortsci.25.9.1085d.
Full textAbstract:
Three node stem cuttings of Algerian Ivy Hedera canariensis were sprayed with growth regulators to incipient runoff under greenhouse conditions. The results demonstrated that the combination of BA + GA4+7, (Promalin) promoted branching of Algerian Ivy better than applications of BA or GA4+7 alone. Plants treated with Atrinal developed more shoots per node than those treated with GA4+7, BA, or Promalin. Increasing concentration of Atrinal from 0 to 3000 ppm, also reduced branch length and leaf number for both pinched and unpinched plants. 2,3,5—triodobenzoic acid (TIBA) significantly increased the branching of Algerian Ivy, although plant shape was not commercially acceptable due to epinasity of the foliage.
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Cui, Wenwen, Quanhao Song, Bingyun Zuo, Qingfang Han, and Zhikuan Jia. "Effects of Gibberellin (GA4+7) in Grain Filling, Hormonal Behavior, and Antioxidants in High-Density Maize (Zea mays L.)." Plants 9, no. 8 (2020): 978. http://dx.doi.org/10.3390/plants9080978.
Full textAbstract:
Dense plant cultivation is an efficient approach to improve maize production by maximizing the utilization of energy and nutrients. However, dense plant populations may aggravate the abortion rate of young grains, resulting in fewer kernels per ear. The rate and duration of grain-filling play decisive roles in maize grain yield. Therefore, to increase plant density, enhancing the grain-filling rate, extending the growth period of individual maize plants and regulating crop senescence would be the first priority. In this study, we examined the regulatory effects of GA4+7 under two application methods: shanks and silks were moistened by cotton full with GA4+7 solution at concentrations of 0, 10, 60, and 120 mg L−1. The results showed that GA4+7 improved the grain-filling rate by increasing the content of auxin, gibberellin, zeatin, and abscisic acid in grains compared to control plants. In addition, the auxin, gibberellin, and zeatin contents in the grains were positively and significantly correlated with the maximum grain weight and the maximum and mean grain-filling rates. Moreover, GA4+7 increased the activities of superoxide dismutases, catalases, and peroxidases and reduced the malondialdehyde content in leaves compared with untreated plants. At the concentration of 60 mg L−1, GA4+7 showed the greatest effect on shank and silk applications (Sh-60 and Si-60) followed by 10 mg L−1 (Sh-10) for shank treatment and 120 mg L−1 (Si-120) for silk treatment. Our results suggest that a concentration of 60 mg L−1 GA4+7 for shank and silk application may be efficiently used for changing the level of hormones in grains and antioxidant enzymes in ear leaves, which may be useful for enhancing grain-filling rate and delaying leaf senescence, resulting in an increase in maize grain yield.