Academic literature on the topic 'Penn-A4'

Limited information is available on the performance under temperate conditions in the United States of recently released cultivars of creeping bentgrass (Agrostis stolonifera L.) with high shoot density for use on golf course putting greens. Fifteen cultivars were established in Aug. 1996 on a greens mix with high sand content to compare their seasonal weights and total nonstructural carbohydrate (TNC) contents. The cultivars were maintained at 3.1 mm height of cut. Shoot density counts were taken during Apr., July, and Oct. 1998. Root weights and nonstructural carbohydrate levels were assessed monthly from June 1997 through Nov. 1998. A cultivar group contrast between the high shoot density cultivars (`Penn A1', `Penn A2', `Penn A4', `Penn G1', `Penn G2', and `Penn G6') and the standard cultivars (`Penncross', `Crenshaw', `Southshore', `DF-1', `Procup', `Lopez', `SR1020', and `Providence') revealed that the former averaged 342.9 and 216.1 more shoots/dm2 on two of the three sampling dates. Root dry weights did not vary significantly (P ≤ 0.05) among the cultivars. Performing a contrast between new high shoot density cultivars and standard cultivars revealed greater root dry weight in the former during Mar. and May 1998. Differences (P ≤ 0.05) in TNC were observed on two of the 18 sampling dates, but no trends were evident.

We previously reported that the deletion of the pH sensor GPR4 causes a non-gap metabolic acidosis and defective net acid excretion (NAE) in the GPR4 knockout mouse (GPR4−/−) (Sun X, Yang LV, Tiegs BC, Arend LJ, McGraw DW, Penn RB, and Petrovic S. J Am Soc Nephrol 21: 1745–1755, 2010). Since the major regulatory site of NAE in the kidney is the collecting duct (CD), we examined acid-base transport proteins in intercalated cells (ICs) of the CD and found comparable mRNA expression of kidney anion exchanger 1 (kAE1), pendrin, and the a4 subunit of H+-ATPase in GPR4−/− vs. +/+. However, NH4Cl loading elicited adaptive doubling of AE1 mRNA in GPR4+/+, but a 50% less pronounced response in GPR4−/−. In GPR4+/+, NH4Cl loading evoked a cellular response characterized by an increase in AE1-labeled and a decrease in pendrin-labeled ICs similar to what was reported in rabbits and rats. This response did not occur in GPR4−/−. Microperfusion experiments demonstrated that the activity of the basolateral Cl−/HCO3− exchanger, kAE1, in CDs isolated from GPR4−/− failed to increase with NH4Cl loading, in contrast to the increase observed in GPR4+/+. Therefore, the deficiency of GPR4 blunted, but did not eliminate the adaptive response to an acid load, suggesting a compensatory response from other pH/CO2/bicarbonate sensors. Indeed, the expression of the calcium-sensing receptor (CaSR) was nearly doubled in GPR4−/− kidneys, in the absence of apparent disturbances of Ca2+ homeostasis. In summary, the expression and activity of the key transport proteins in GPR4−/− mice are consistent with spontaneous metabolic acidosis, but the adaptive response to a superimposed exogenous acid load is blunted and might be partially compensated for by CaSR.

Mestrado em Engenharia Agronómica / Instituto Superior de Agronomia. Universidade de Lisboa
Peat is a very important growing media in the agricultural and ornamental sectors, on golf courses, among others, but its extraction has a high environmental impact. For this reason, it is necessary to find more economical, locally produced and more sustainable alternative materials.The objectives of this work were to study three organic amendments alternatives to peat; to evaluate the effect of their residual nitrogen in the plant growth and to identify possible existing weeds. The organic amendments tested were peat (PT, control), sewage sludge compost with pine bark (NA), organic green compost (NV) and cork “earth” (CE). The grasses studied were Lolium perenne L. and Agrostis stolonifera L.. To obtain the aerial biomass production, shoot harvesting was made weekly and the dry matter was weighted. Posterior macro- and micronutrient present in the biomass was evaluated. Regarding the rootzone mixtures, the organic matter content, pH, electrical conductivity and the exchangeable acidity were analyzed as well as the extractable macro and micronutrients, and the exchangeable bases. The results showed that the grasses that grew in the rootzone mixtures with NA had the higher aerial biomass production, comparing with peat, followed by the rootzone mixture with NV. These two organic amendments were those who had higher amounts of nitrogen (N) available in the absence of N fertilization. Possible effects of antagonism between elements, namely calcium and magnesium, were due to the excess of nutrients in the rootzone mixtures, such as potassium. The weeds observed were eudicotyledonous and emerged from the organic amendment CE. Its cut would be effective, in order to control them, with the exception of the genus Sonchus spp.. The rootzone mixture where the plants had lower development and tillering was the CE and the rootzone mixtures NA and NV induced good development, as well as the rootzone mixture PT
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