Tesi sul tema "Mycorrhizas Physiology"

Thesis (MSc)--Stellenbosch University, 2000.<br>ENGLISH ABSTRACT: This investigation was undertaken to determine whether elevated concentrations of dissolved inorganic carbon (DIC) supplied to plant roots could improve plant growth and alleviate the effects of salinity stress on tomato plants infected with arbuscular mycorrhizae. Lycopersicon esculentum cv. FI44 seedlings were grown in hydroponic culture (pH 5.8) with 0 and 75 mM NaCI and with or without infection with the fungus Glomus mosseae. The root solution was aerated with ambient CO2 (360 ppm) or elevated CO2 ( 5 000 ppm) concentrations. The arbuscular and hypha I components of mycorrhizal infection as well as the percentages total infection were decreased or increased according to the variation in seasons. The plant dry weight of mycorrhizal plants was increased by 30% compared to non-mycorrhizal plants at elevated concentrations of CO2, while the dry weight was decreased by 68% at ambient CO2 concentrations. Elevated CO2 also stimulated the growth of the mycorrhizal fungus. Elevated CO2 increased the plant dry weight and stimulated fungal growth of mycorrhizal plants possibly by the provision of carbon due to the incorporation of HCO)- by PEPc. Plant roots supplied with elevated concentrations of CO2 had a decreased CO2 release rate compared to roots at ambient CO2. This decrease in CO2 release rate at elevated CO2 was due to the increased incorporation of HC03- by PEPc activity. Under conditions of salinity stress plants had a higher ratio of N03-: reduced N in the xylem sap compared to plants supplied with 0 mM NaCI. Under salinity stress conditions, more N03- was transported in the xylem stream possibly because of the production of more organic acids instead of amino acids due to low P conditions under which the plants were grown. The N03· uptake rate of plants increased at elevated concentrations of CO2 in the absence of salinity because the HCO)- could be used for the production of amino acids. In the presence of salinity, carbon was possibly used for the production of organic acids that diverted carbon away from the synthesis of amino acids. It was concluded that mycorrhizas were beneficial for plant growth under conditions of salinity stress provided that there was an additional source of carbon. Arbuscular mycorrhizal infection did not improve the nutrient uptake of hydroponically grown plants.<br>AFRIKAANSE OPSOMMING: In hierdie studie was die effek van verhoogde konsentrasies opgeloste anorganiese koolstof wat aan plant wortels verskaf is, getoets om te bepaal of dit die groei van plante kan verbeter asook of sout stres verlig kon word in tamatie plante wat met arbuskulêre mikorrhizas geïnfekteer was. Lycorpersicon esculentum cv. FJ44 saailinge was in water kultuur gegroei (pH 5.8) met 0 en 75 mM NaCI asook met of sonder infeksie met die fungus Glomus mosseae. Die plant wortels was bespuit met normale CO2 (360 dele per miljoen (dpm)) sowel as verhoogde CO2 (5 000 dpm) konsentrasies. Die arbuskulere en hife komponente, sowel as die persentasie infeksie was vermeerder of verminder na gelang van die verandering in seisoen. Die plant droë massa van mikorrhiza geïnfekteerde plante by verhoogde CO2 konsentrasies was verhoog met 30% in vergelyking met plante wat nie geïnfekteer was nie, terwyl die droë massa met 68% afgeneem het by gewone CO2 konsentrasies. Verhoogde CO2 konsentrasies het moontlik die plant droë massa en die groei van die fungus verbeter deur koolstof te verskaf as gevolg van die vaslegging van HCO)- deur die werking van PEP karboksilase. Plant wortels wat met verhoogde CO2 konsentrasies bespuit was, het 'n verlaagde CO2 vrystelling getoon in vergelyking met die wortels by normale CO2 vlakke. Die vermindering in CO2 vrystelling van wortels by verhoogde CO2 was die gevolg van die vaslegging van HC03- deur PEPk aktiwiteit. Onder toestande van sout stres, het plante 'n groter hoeveelheid N03- gereduseerde N in die xileemsap bevat in vergelyking met plante wat onder geen sout stres was nie, asook meer NO)- was in die xileemsap vervoer moontlik omdat meer organiese sure geproduseer was ten koste van amino sure. Dit was die moontlike gevolg omdat die plante onder lae P toestande gegroei het. Die tempo van NO.; opname was verhoog onder verhoogde CO2 konsentrasies en in die afwesigheid van sout stres omdat die HCO)- vir die produksie van amino sure gebruik was. In die teenwoordigheid van sout was koolstof moontlik gebruik om organiese sure te vervaardig wat koolstof weggeneem het van die vervaardiging van amino sure. Daar is tot die slotsom gekom dat mikorrhizas voordelig is vir die groei van plante onder toestande van sout stres mits daar 'n addisionele bron van koolstof teenwoordig is. Arbuskulere mikorrhiza infeksie het 'n geringe invloed gehad op die opname van voedingstowwe van plante wat in waterkultuur gegroei was.

Copies of author's previously published works inserted.<br>Bibliography: leaves 189-212.<br>xxii, 212 leaves : ill. (some col.) ; 30cm.<br>Title page, contents and abstract only. The complete thesis in print form is available from the University Library.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2001

Copies of author's previously published works inserted.<br>Bibliography: leaves 189-212.<br>xxii, 212 leaves : ill. (some col.) ; 30cm.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2001

The overall objective of this thesis was to investigate how the arbuscular mycorrhizal (AM) symbiosis can affect the production of phytochemicals (antioxidants; rosmarinic and caffeic acid, RA & CA) in the shoots of basil (Ocimum basilicum L.). As a result of an increasing interest in natural/herbal medicines, more effort is now needed to produce herbal products of better quality, i.e. higher and standardised phytochemical concentrations. Thus, it was hypothesised that the naturally occurring AM fungi (AMF) could play an important role in improving the growth and phytochemical concentrations in medicinal herbs such as basil, as organic methods of cultivation are increasingly sought after to grow such plants. Despite a reasonable amount of information available in the literature on the changes of phytochemical concentrations in the roots of host plants following AM colonisation, very little is known about such processes in the aerial part of such plants. Furthermore, basil has hardly been studied as a host plant in AM research, and very little is known of its responsiveness to AM colonisation. As AMF are well known to improve phosphorus (P) uptake in their host plant, the first objective of this work was to obtain AM and non-mycorrhizal (NM) plants matched for tissue P concentrations and growth rates. Only under such conditions would it then be possible to separate benefits derived from improved plant P uptake from non-nutritional benefits. It was found that basil is highly responsive to P, and that under low or little P supply it is quite dependent on the AM symbiosis in order to grow. However, growth depressions were observed when growing basil in winter with Glomus intraradices, suggesting that the fungal symbiont can act as a strong sink of carbon (C) under such conditions. Thus, in order to obtain AM and NM plants with matched growth rates and tissue P concentrations, it was found that basil needed to be cultivated in summer in a soil/sand mixture with a ratio of 1:3 (w/w), along with 0.2 g/kg CaHPO4 and 25% of AM inoculum (AM plants). Under these conditions, AM plants grew as well as NM plants and G. caledonium and G. mosseae were shown to increase the concentrations of RA and CA in the shoots of basil, but not in roots. Such results were not an indirect effect of improved P uptake. In order to understand the mechanisms by which AMF increased RA and CA concentrations in basil, further experiments were set up to investigate the effect of 1) AM developmental stages, 2) nitrogen (N) supply and 3) phytohormone changes on the production of RA and CA in the shoots. None of these factors was found to contribute to increases in antioxidants in basil under AM symbiosis. Therefore, the mechanisms by which AMF affect RA and CA concentrations in basil still remain unknown. A final experiment was carried out to investigate the potential of an AM fungus to improve the growth of basil when challenged with a specific pathogen Fusarium oxysporum f.sp. basilici (Fob), which causes significant production losses. The results showed that inoculation of basil with G. mosseae not only improved plant growth compared to NM plants, but also conferred a protective effect against Fob. However, shoot antioxidant concentrations (RA, CA, total phenolics and essential oils) were not increased in AM plants compared to NM plants, and the mechanism of protection against Fob could not be elucidated. Due to the high variability of RA and CA concentrations obtained in AM plants in different experiments, it cannot be concluded that AMF confer an absolute advantage over uninoculated plants if the main concern is to obtain standardised concentrations of phytochemical in basil. On the other hand, the key results presented in this thesis do indicate that inoculating basil with AMF can be beneficial to improve its growth as well as antioxidant concentrations, compared to NM plants grown under similar conditions. Such results could be of potential interest to basil growers who wish to cultivate this medicinal herb organically (i.e. low P supply and no chemical fertilisers added).<br>http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330324<br>Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

碩士<br>國立臺灣大學<br>園藝學研究所<br>89<br>Abstract Anoectochilus formosanus Hayata is a valuable herb in Taiwan using as a multi-purposes of medicine. But they suffered from severe infection of root-rot, stem-rot and mites. Also, slow growth of A. formosanus hindered the production of this plant. Thus, this thesis aimed as follows： 1.To search for the effective inoculum ; 2.To improved the production method and speed of orchid mycorrhiza fungi (OMF) inoculum ; 3.To produce the effective OMF inoculum in large scale ; 4.To enhance the growth rate of A. formosanus. In spring, the growth of A. formosanus could be enhanced by the single inoculum inoculation of R09 or by the mixed inocula of R01+R07+R08+R09 ( R01.7.8.9 ) . While A. formosanus plants were cultivated by plastic bag cultivation method ( PBCM ), R07 or R02+R07+R08+R09 ( R02.7.8.9 ) could stimulate their growth. The effect of the temperature and the competition among OMF inocula should be considered. So, it was suggested that right timing for inoculation with proper OMF was primary important. The result of mixed inocula was not as good as expected. It was postulated that low temperature and growth medium might had some effects. Twice replication with the inoculation of effective inoculum such as R01、R02 and R04, then analyzed by SSR ( simple sequence repeat ) technique, the results showed that only R01 could be isolated. Therefore, it was recommended to use R01 isolate alone or to mix with other inoculum as mixed inoculum. Isolate of Rhizoctonia spp. encoded as R02 was an effective OMF for orchidaceae , and could highly improve the growth of A. formosanus、Hamaria discolor (Ker.) Lindl.、Phalaenopsis spp. and Paphiopedilum spp., using GY medium ( glucose 2% + yeast extract 1% ) to grow R02 isolate, and the result showed that this isolate grew better in darkness、25~30℃ temperature、growth medium pH 5.5~6.5 in glucose 2~4%, and yeast extract 1~2% medium for 10 days, then high-viability mycelia in large scale could be produced. Adding defatted ‘ Anchor ’ and full-cream ‘ Klim ’ milk powder to peat ( contaning 20% of V8 juice ) resulted in non-significant growth of OMF mycelial linear growth rate, but significantly increased the thickness of mycelia. It was found that by adding 25 g/l defatted ‘ Anchor ‘ dry milk to peat showed the best result. Sphagnum OMF inoculum was newly produced in an orchid flask (450ml in vol.). Three hundred mL in volume of wet sphagnum pre-soaked with 2.5% defatted ‘ Anchor ‘ milk powder solution ( MPS ), and adjusted the water content properly. After sterilization, then 3 pieces of OMF inoculum ( 5×5 mm2 ) were put into each orchid flask under laminard flow , then 20~70 times of viabile hyphae could be produced by incubation for 6 days. If the mycelia were grown in MPS+1/5 CM ( glucose, yeast extract and malt extract were 1 g/1, separately) , in only 4 days, high germinability and viability of mycelia could be produced.

碩士<br>國立中興大學<br>森林學系所<br>96<br>The purposes of this study were to evaluate the arbuscular mycorrhiza inoculation on the physiology of plants under salt stress. Three littoral plants, Bidens pilosa L. var. radiate, Ipomoea pes-caprae and Vitex rotundifolia, were inoculated with Scutellospoa sp. collected from sandlot in Tai-Chung Harbor (M1), and with Acaulospora sp. collected from Chu-Yun-Shan Nursery (M2), and were non-inoculated. The seedlings were irrigated with 0%, 1%, 2% and 3% sea water which is make up of sea salt, after 50 days grown in greenhouse, total biomass, nutrient concentration, proline, total soluble carbohydrate, chlorophyll and chlorophyll fluorescence of plant were then determined. The results obtained showed that among all treatment, seedlings which irrigated with 0% sea water and inoculated with M1 had the highest biomass. Nutrient N, P and K concentration of plant tissue were decreased with salt increased, but the Na and Mg concentration increased when concentration of salt increased. Those non-inoculated seedlings showed more Na and Mg accumulated in plant tissue, but less absorption of N, P and K. The concentration of proline in the plants were slightly increased when concentration of salt increased, the concentration of total soluble carbohydrate decreased when concentration of salt increased, but there were no different of starch concentration among all treatments. Plant inoculated with M1 could accumulated more organic compounds to modulate osmosis and prevent physiological drought in high salt. When salt concentration increased, seedlings chlorophyll concentration were decreased, and the chlorophyll fluorescence, Fv/Fm, ΦPSII and qP were decreased too, only qN were increased. In conclusion, inoculated arbuscular mycorrhizal fungi could increase the plant tolerance in salt. In this study, seedlings inoculated with M1 collected from sandlot in Tai-Chung Harbor had the best performance than those inoculated with M2 collected from Chu-Yun-Shan Nursery, and those non-inoculated seedlings got the worst growth.

Many mycorrhizosphere microorganisms can produce plant growth regulating compounds in vitro. Plant growth regulating compounds are known to mediate root growth and development. In reforestation practices, conifer tree seedling growth and survival are linked to rapid root growth and development after outplanting. Multifactorial experiments were conducted to document variations in conifer seedling growth, survival and endogenous root indole acetic acid (IAA) content as influenced by exogenously applied plant growth regulators and inoculation with ectomycorrhizal fungi capable of differential in vitro IAA and ethylene production. Capacity for in vitro IAA and ethylene production by mycorrhizal fungal isolates was partially correlated to levels of endogenous root IAA and root growth in inoculated seedlings as well as field transplanted nursery-grown seedlings. Although degree of correlation usually varied with fungal isolate as well as conifer species, IAA-mediated changes in root growth and seedling survival could indirectly be attributed to in vitro fungal plant growth regulator production capability. Exogenous application of plant growth regulating substances at different times during seedling growth and development resulted in significant changes in growth, survival and endogenous root IAA content of both experimental seedlings and field transplanted nursery-grown seedlings. Although effects varied with conifer species and stock types, IAA mediated increases in root growth and survival are projected to be cost beneficial. These results are not only indicative of the complexity of interactions which can occur between symbionts in the mycorrhizosphere but also suggest potential methods for manipulating plant growth regulator mediation of conifer root growth for practical purposes in reforestation.<br>Graduation date: 1994

博士<br>國立臺灣大學<br>園藝學研究所<br>92<br>Abstract The isolated orchid mycorrhizal fungi (OMF) were cultured and purified. The OMF used for inoculation belonged to Rhizoctonia spp. Binucleate OMF R02 belongs to AG-Bb, while multinucleate R04 belongs to AG-6. Using 2% of MP solution could produce the highest dry weight of OMF,s ( R02 ) hypha. Those heat-resistant lines of Anoectochilus formosanus Hayata previously collected from various parts of Taiwan by our laboratory were cultivated in the phytoton at NTU for further study. However, survival rate of the five lines （C, P, L1, L3 and T）of A. formosanus at 30/25℃ reached 70%. Heat tolerance of A. formosanus was evaluated with injury values of cell membrance thermostability at 50℃ and this could be used as importment heat tolerance index. Five lines of A. formosanus grew in Puli had higher fresh weight than those at NTU. Seeds inoculated with R02 OMF exhibited 80-86% of germination percentage 60 days in vitro on oat meal agar medium (OMA). Put filter paper on agar medium and the inoculation of OMF could promote seed germination and growth for this medical use of orchid. Effects of OMF in vitro or in vivo on the growth of A. formosanus were conducted. Results showed that A. formosanus inoculated with fungi could enhance growth and increase chorophyll contents. Plant cultured in plastic bag showed enhanced plant growth. Thus less pesticide or insecticide was needed. The fungal hypha penetrated cortex cells and formed pelotons was observed by microscopy, and results showed that was tolypophagy type of infection. Enzymatic histochchemistry test on roots of non-mycorrhizal control and inoculated with OMF were compared. The mycorrhizal root had both activities of acid and alkaline phosphatases, and non-mycorrhizal root had only acid phosphatase activity in A. formosanus. Enzyme activity and content anaysis of peroxidase, acid phosphatase, CuZnSOD and MnSOD activities were compared among root, stem and leaf and results showed that they were present in both non-mycorrhizal and OMF. SOD activity was higher in mycorrhizal than non-mycorrhizal control. Contents of polyphenol, polysaccharides, ascorbic acid and phoshate of A. formosanus were significantly higher in mycorrhizal plants. In vitro germination percentage of Haemaria discolor var. dawsoniana was the highest（65.6%）for those seeds inoculated with R02 on OMA that exhibited germination percentage for 60 days. The developmental processes of germinating seeds were observed by microscopies. Seed germination occurred after water uptake, and seed coat was ruptured by embryo. Then papilla, protocorm, apical meristem appeared. Symbiotic germination showed that OMF hypha infected root cortex cells to form pelotons intracellularly. Enzymatic histochchemistry test showed that mycorrhizal protocorms contained mass lipid, protein and polysaccharide products, but non-mycorrhizal control only contained much less lipid and polysaccharide. The inoculation of OMF both in vitro or in vivo could enhance seedling development and growth of H. discolor. R01 was better than R02 for enhancing the growth of H. discolor. Before flower development, if plants were put in 30/25℃ day/night temperature in the phytoron, flower stalk length couble be increased. Microscopies were used to observe processes of flower and seed development. Cross section of capsule development 35 days after hand pollination seeds changed from white to brown color. It was suggested that hand pollination for 40-45 days, capsules of Haemaria discolor var. dawsoniana was the best harvest period. Inoculate Rhizoctonia spp. (R01, R02 and R04 isolates) of orchid mycorrhizal fungi (OMF) could enhance seed germination, seedling and plantlet growth of Haemaria discolor var. dawsoniana×Anoectochilus formosanus Hayata, but resulted in no seed germination for F1 hybrid seeds. Plant at 30/25℃ showed that better growth than 25/20℃ and 20/15℃. Under the three studied temperature, the inoculation of OMF resulted in better growth than non-mycorrhizal control. Chorophyll content of Haemaria discolor var. dawsoniana × Anoectochilus formosanus Hayata increased as inoculated with OMF. Morphology of hybrid plant changed. The Haemaria discolor var. dawsoniana × Anoectochilus formosanus Hayata plant showed no disease and insects resistance.

碩士<br>國立中興大學<br>森林學系所<br>99<br>In this study, Scaevola sericea and Messerschmidia argentea were inoculated with two kinds ofendomycorrhizal fungi isolated from nursery (man-made cultural environment; M1), or from native coastal habitat (natural distribution; M2). Seedlings were grown in greenhouse, for 10 months, then treated with different salt concentrations (0%, 1%, 2% and 3%) and different time (1, 5, 10, 15, 30, 60 days). Finally, the biomass, plant nutrient, proline, total soluble carbohydrates, chlorophyll and chlorophyll fluorescence parameters were determined to evaluate the different treatments on plant growth and physiologic effects. With the increased salt concentration, the seedlings biomass, chlorophyll, Fv / Fm, ΦPS II and qP were decreased, but the proline, soluble carbohydrates and qN were increased. When the days of salt treatment were increased, the Na+, proline of leaves and qN were increased, but chlorophyll, Fv / Fm, ΦPS II and qP were decreased. Proline and soluble carbohydrates could be used as osmotic adjustment in leaves of S. sericea, but the increased K+ accumulation in root could increase osmotic potential. Increased proline concentration both in leaves and roots of M. argentea could resist osmotic stress. Mycorrhizal inoculation could increase the tolerance of S. sericea and M. argentea to salt stress, but buth with slight difference. The proline and soluble carbohydrates of S. sericea treated with M1 were significantly lower than those treated with M2. It showed that M1 could be more adapted to salt stress than M2. The root dry weight and phosphorus concentrations of M. argentea inoculated with M2 were higher than those inoculated with M1, but Na+, proline and soluble carbohydrates were significantly lower than those inoculated with M1. It showed that M2 could be more adapted to salt stress than M1. In conclusion, different time and salt concentrations were used to test the influences of salt stress on S. sericea and M. argentea. It showed that mycorrhizal inoculation played an important role in the growth and resistance to salt stress for seedlings growth.