Ginger (Zingiber officinale Rosc.) plantlets were propagated in vitro and acclimated under different photosynthetic photon flux densities (60 and 250 µmol m-2 s-1 = LI and HI, respectively). Increases in chlorophyll (Chl) content and Chl a/b ratio were found under both irradiances. In vitro plantlets (day 0) exhibited a low photosynthesis, but chloroplasts from in vitro leaves contained well developed grana and osmiophillic globules. Photoinhibition in leaves formed in vitro was characterized by decrease of photochemical efficiency and quantum efficiency of photosystem 2 photochemistry in HI treatment during acclimation. The new leaves formed during acclimation in both treatments showed a higher photosynthetic capacity than the leaves formed in vitro. Also activities of antioxidant enzymes of micropropagated ginger plantlets changed during acclimation. and Q. Z. Guan ... [et al.].
As a stress factor, salt induces the phosphorylation of light-harvesting chlorophyll (Chl) a/b proteins (LHCII) in Dunaliella salina. In this study, we found that the salt-induced phosphorylation of LHCII was not affected by phosphatase, and that salt simultaneously regulated both the phosphorylation of LHCII and the expression of genes encoding light-harvesting Chl a/b proteins of photosystem II (lhcb) and the gene encoding Chl a oxygenase (cao) in dark-adapted D. salina. The mRNA accumulation patterns of lhcb and cao were similar, which further affected the size of LHCII and the ratio of Chl a to Chl b. Therefore, we inferred this simultaneous regulation is one of the mechanisms of D. salina to adapt to the high-salinity environment. and W. M. Chen ... [et al.].
The global epidemic of diabetes is of significant concern. Diabetes associated vascular disease signifies the principal cause of morbidity and mortality in diabetic patients. It is also the most rapidly increasing risk factor for cognitive impairment, a silent disease that causes loss of creativity, productivity, and quality of life. Small vessel disease in the cerebral vasculature plays a major role in the pathogenesis of cognitive impairment in diabetes. Endothelin system, including endothelin-1 (ET-1) and the receptors (ETA and ETB), is a likely candidate that may be involved in many aspects of the diabetes cerebrovascular disease. In this review, we took a brain-centric approach and discussed the role of the ET system in cerebrovascular and cognitive dysfunction in diabetes., W. Li, Y. Abdul, R. Ward, A. Ergul., and Seznam literatury
The effects of soil flooding on gas exchange and photosystem 2 (PS2) activity were analyzed in leaves of Phragmites australis, Carex cinerascens, and Hemarthria altissima. Pronounced decrease in net photosynthetic rate and stomatal conductance with flooding was found only in C. cinerascens. No significant changes in PS2 activity were observed in all three species which suggests that the photosynthetic apparatus was not damaged. Among the three species, H. altissima is better adapted to flooding than P. australis and C. cinerascens. and M. Li, D. Yang, W. Li.
Gas exchange of Carex cinerascens was carried out in Swan Islet Wetland Reserve (29°48' N, 112°33' E). The diurnal photosynthetic course of C. cinerascens in the flooded and the nonflooded conditions were analyzed through the radial basis function (RBF) neural network approach to evaluate the influences of environmental variables on the photosynthetic activity. The inhibition of photosynthesis induced by soil flooding can be attributed to the reduced stomatal conductance (gs), the deficiency of Rubisco regeneration and decreased chlorophyll (Chl) content. As revealed by analysis of artificial neural network (ANN) models, gs was the dominant factor in determining the photosynthesis response. Weighting analysis showed that the effect of water pressure deficit (VPD) > air temperature (T) > CO2 concentration (Ca) > air humidity (RH) > photosynthetical photon flux density (PPFD) for the nonflooded model, whereas for the flooded model, the factors were ranked in the order VPD > C a > RH > PPFD > T. The different photosynthetic response of C. cinerascens found between the nonflooded and flooded conditions would be useful to evaluate the flood tolerance at plant species level. and M. Li ... [et al,.].
a1_We investigated the light reactions, CO2 assimilation, but also the chloroplast ultrastructure in the upper three functional leaves (flag, 2nd, and 3rd leaves) of the Chinese super-high-yield hybrid rice (Oryza sativa L.) Liangyoupeijiu (LYPJ) with ultraviolet-B (UV-B) treatment during reproductive development. Photosynthetic parameters showed that the upper 3 functional leaves of LYPJ entered into senescence approximately 15 days after flag leaf emergence (DAE). Leaves in UV-B treatment exhibited greater efficiency in absorbing and utilizing light energy of photosystem II (PSII), characterized by higher chlorophyll (Chl) content and the whole chain electron transport rate (ETR). However, UV-B radiation reduced activities of Ca2+-ATPase and photophosphorylation. The significantly decreased activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) was greatly associated with the decline in photosynthetic efficiency. The net photosynthetic rate (PN) and stomatal conductance (gs) suffered strong reductions before 25 DAE, and afterwards showed no significant difference between control and treatment. UV-B treatment delayed chloroplasts development of flag leaves. Chloroplast membranes later swelled and disintegrated, and more stromal thylakoids were parallel to each other and were arranged in neat rows, which might be responsible for better performance of the primary light reaction. It is likely that accumulation of starch and an increase in the number of lipid droplet and translucent plastoglobuli were results of an inhibition of carbohydrate transport. Our results suggest that long-term exposure to enhanced UV-B radiation was unlikely to have detrimental effects on the absorption flux of photons and the transport of electrons, but it resulted in the decrease of photophosphorylation and Rubisco activation of LYPJ., a2_The extent of the damage to the chloroplast ultrastructure was consistent with the degree of the inhibition of photosynthesis., G. H. Yu ... [et al.]., and Obsahuje bibliografii