Glechoma longituba (Nakai) Kupr. is a perennial shade plant with pharmaceutical importance. The aim of this study was to investigate the effects of light intensity on the growth, photosynthesis, and accumulation of secondary metabolites in G. longituba grown under six different light environments. The high light intensity decreased the leaf size, specific leaf area, and aboveground dry mass, the number of grana per chloroplast, the number of lamella per granum, the thickness of the grana, the apparent quantum efficiency, the chlorophyll (Chl) content, the concentrations of ursolic and oleanolic acid. The high light increased the stomatal density, the stoma size, the number of chloroplast per a cell, the chloroplast size, the dark respiration rate, the light saturation point, the light compensation point, and the Chl a/b ratio. With the reduction in the light intensity, the light-saturated net photosynthetic rate, the aerial dry mass per plant, and the yields of ursolic and oleanolic acid decreased after an initial increase, peaking at 16 and 33% of sunlight levels. Overall, the 16 and 33% irradiance levels were the most efficient in improving the yields and qualities of the medicinal plant. The lower light demand and growth characteristics suggest that G. longituba is an extremely
shade-tolerant plant and that appropriate light intensity management might be feasible to obtain higher yields of secondary metabolites in agricultural management., L. X. Zhang, Q. S. Guo, Q. S. Chang, Z. B. Zhu, L. Liu, Y. H. Chen., and Obsahuje bibliografii
Leaf stomatal density (SD), net photosynthetic rates (PN), and stomatal conductance (gs) of Hordeum vulgare and Pisum sativum cultivars in Himalaya increased with altitude. Higher PN and leaf temperature under low CO2 partial pressure at high altitudes could evoke a higher gs and SD to allow sufficient influx of CO2 as well as more efficient leaf cooling through transpiration. and S. K. Vats, N. Kumar, S. Kumar.
Growth characteristics such as leaf area, fresh and dry mass, and shoot length, and physiological parameters such as photosynthetic and transpiration rates, stomatal conductance, and water use efficiency were reduced by blister blight significantly more in a susceptible tea clone TES-34 than in a tolerant clone SA-6. Also the contents of total sugars, nitrogen, amino acids, proteins, polyphenols, and catechin were reduced more in diseased plant leaves. However, the reduction was more prominent in susceptible than in tolerant clone. Among the different hybrids of tea, Assam hybrid UPASI-3 was highly susceptible to blister blight followed by Cambod UPASI-27 and China UPASI-9. Similarly, tea seedling cv. Caline was highly susceptible to blister blight when compared to tea clone UPASI-3. Susceptibility of tea cultivars to blister blight infection is connected with many physical barriers including leaf area, shoot length, moisture contents, and other physiological and biochemical parameters. and R. Premkumar, P. Ponmurugan, S. Manian.
Seedlings of green gram (Vigna radiata cv. ADT-1 and CO-5) were exposed to daily showers of simulated acidic rain (H2SO4 : HNO3 : HCl, 4 : 2 : 1, v/v) for 10 d. The effects were analysed after 5 and 10 showers, respectively. Rain of pH 2.5 inhibited seedling growth and biomass accumulation, though in other acidic levels the effects were mostly inconsistent. Both cultivars had high degree of surface wettability indicated by high leaf surface contact angles and water-holding capacity. Treated leaves were thinner with smaller mesophyll cells. Stomatal index and trichome density were lower in contrast to epidermal cell density and stomatal frequency which increased with increasing acidity. Decreases in chlorophyll (Chl), carotenoid (Car), and starch contents in cv. ADT-1 at pH 2.5 were observed after 5 showers, while in cv. CO-5 decreases were noted only after 10 showers. In contrast to total sugar levels, the protein content of cv. CO-5 was augmented significantly after simulated acidic rain (SAR) treatment. and G. Kumaravelu, M. P. Ramanujam.