In order to evaluate effect of weedy rice on the photosynthesis and grain filling of cultivated rice, cultivated rice ‘Nanjing 44‘ was planted in the field under different densities of weedy rice ‘JS-Y1‘ for two years. The results showed that net photosynthetic rate (PN), net assimilation rate, grain filling rate, and the grain yield of cultivated rice all decreased with increasing weedy rice density. Furthermore, yield component analysis revealed that increasing weedy rice density had the most significant effect on the percentage of filled grains and the number of rice panicles. The correlation analyses indicated that the yield of cultivated rice was highly correlated with the net photosynthetic rate and the net assimilation rate. Our results illustrated that high density of weedy rice might cause yield losses in cultivated rice by inhibition of photosynthesis and grain filling., X. M. Xu, G. Li, Y. Su, X. L. Wang., and Obsahuje bibliografii
It is known that excessive sympathetic activity and oxidative stress are enhanced in obesity. This study aimed to clarify whether exercise training (ET) attenuates sympathetic activation and oxidative stress in obesity. The obesity was induced by highfat diet (HFD) for 12 weeks. Male Sprague-Dawley rats were assigned to four groups: regular diet (RD) plus sedentary (RD-S), RD plus ET (RD-ET), HFD plus sedentary (HFD-S), and HFD plus ET (HFD-ET). The rats in RD-ET and HFD-ET groups were trained on a motorized treadmill for 60 min/day, five days/week for 8 weeks. The sympathetic activity was evaluated by the plasma norepinephrine (NE) level. The superoxide anion, malondialdehyde and F2-isoprostanes levels in serum and muscles were measured to evaluate oxidative stress. The ET prevented the increases in the body weight, arterial pressure and white adipose tissue mass in HFD rats. The NE level in plasma and oxidative stress related parameters got lower in HFD-ET group compared with HFD-S group. We have found decreased mRNA and protein levels of toll-like receptor (TLR)-2 and TLR-4 by ET in HFD rats. These findings suggest that ET may be effective for attenuating sympathetic activation and oxidative stress in diet-induced obesity., G. Li, J.-Y. Liu, H.-X. Zhang, Q. Li, S.-W. Zhang., and Obsahuje bibliografii
Two light treatments [ambient sunlight (L1) during the entire growth period and 40% shade (L2) from 40 d after sowing until 24 d after flowering] and two phosphate fertilizer treatments [no phosphate fertilizer application (P0) and a conventional phosphate fertilizer application (P1)] were used to determine how phosphate fertilizer regulates soybean [Glycine max (L.) Merr.] photosynthesis under shading. We showed that phosphorus significantly increased chlorophyll content and grain yield under shading. The light-saturated net photosynthetic rate, apparent quantum yield, maximum electron transport rate, and maximum Rubisco carboxylation rate in P1 under L2 significantly increased. Moreover, phosphate fertilizer significantly improved the electron transfer and PSII reaction center performance under shading. Therefore, phosphate fertilizer increases low light-utilization efficiency by improving PSII performance, promoting ribulose-1,5-bisphosphate regeneration, ensuring a source of carboxylate substrates, and coordinating the balance between photochemical reaction and Calvin cycle under shading.
Clonal growth is of great importance for survival, growth, expansion, and resource utilization of some species. Knowing how clonal plants respond morphologically and physiologically to different light environments can be useful to explain their occurrence and abundance patterns under specific environmental conditions. Responses of clonal growth, leaf gas exchange, fluorescence emission, and photosynthetic pigment concentrations to different light environments (100, 60, 30, and 15%) were studied in Amomum villosum, grown in the traditional way for economic purpose in Xishuangbanna, southwest China. The results showed that A. villosum attained vigorous clonal growth under 30% and 60% light, with a higher plant height, number of ramets, stolon length, thicker stems and stolons. Shade-grown A. villosum possessed a larger leaf area than that of the sun-grown plants in order to capture more light. For A. villosum, the higher
light-saturated net photosynthetic rate, light-saturation point, larger fresh and dry biomass can explained the better clonal growth for A. villosum under 30% and 60% light. Amomum villosum attained the highest values of minimal chlorophyll fluorescence under 100% light and the lowest values of maximum photochemical efficiency of PSII under 15% light. Our findings indicated that the full irradiance was too strong and 15% light was too weak for A. villosum plants. It was also verified by higher concentrations of photosynthetic pigments in the shaded plants compared to those grown under full sun light. Our results suggested that A. villosum seemed to be adapted to moderate light environment (60-30%) which was indicated by vigorous clonal growth and higher photosynthesis. This information is very useful to select clonal species for rainforest or understory projects. The cultivation of A. villosum in rainforest should not be done under too strong (100%) or too weak light environment (less than 15%)., Y. H. Guo, C. Yuan, L. Tang, J. M. Peng, K. L. Zhang, G. Li, X. J. Ma., and Seznam literatury