Despite the optimism of some molecular biologists, natural selection among the wild ancestors of crops is unlikely to have missed simple genetic improvements that would consistently have enhanced individual fitness. Tradeoff-free opportunities for further improvement of crop traits like photosynthetic efficiency or drought tolerance may therefore be elusive. Opportunities linked to acceptable t...

Exposure of ferredoxin-dependent glutamate synthase (EC 1.4.7.1) mutants of Arabidopsis thaliana to photorespiratory conditions resulted in the accumulation of NH(4) (+) and the inhibition of photosynthesis. However, upon transfer from 2% O(2), 350 microliters per liter CO(2), to 21% O(2), 350 microliters per liter CO(2), net photosynthesis declined at a slower rate in methionine sulfoximine tr...

Past increases in yield potential of wheat have largely resulted from improvements in harvest index rather than increased biomass. Further large increases in harvest index are unlikely, but an opportunity exists for increasing productive biomass and harvestable grain. Photosynthetic capacity and efficiency are bottlenecks to raising productivity and there is strong evidence that increasing phot...

The main objectives of this study were to elucidate the roles of silicon (Si) in alleviating the effects of 2 mM zinc (high Zn) stress on photosynthesis and its related gene expression levels in leaves of rice (Oryza sativa L.) grown hydroponically with high-Zn stress. The results showed that photosynthetic parameters, including net photosynthetic rate, transpiration rate, stomatal conductance,...

tobacco is a salt-sensitive glycophyte crop species. in this work effect of silicone (si) supplementation (1 mm as na2sio3) was studied in nicotiana rustica l. cv. basmas grown hydroponically in growth chamber under control, low (25 mm) and high (75 mm) nacl concentration for two weeks. dry matter production of leaves was depressed by salinity level as low as 25 mm and higher salt concentration...

temperature of 4-year-old Eucalyptus globulus Labill. and E. nitens (Deane and Maiden) Maiden trees were measured between 10 and 35 °C at approximately monthly intervals from early spring to midwinter. The photosynthetic temperature optimum of recently expanded leaves in the sun canopy was linearly related to the average temperature of the preceding week during the 9-month measurement period. T...

Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the gr...

The effect of different wavebands of artificial UV (UVB and UVA) and photosynthetically active radiation (PAR) was assessed in two species of the genus Ulva, U. olivascens and U. rotundata, from southern Spain in order to test for possible differences in acclimation of photosynthesis. Both species share similar morphology but are subject to different light environments: U. rotundata is an estua...

Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information fo...

in order to study of the effect of priming and salinity on physiological and chemical characteristics of wheat(triticum aestivum l.), an experiment was carried out at the experimental farm of shiraz university. results showedthat primed plants significantly reduced its gas exchanges by accelerating senescence under a series of salt stress,which became more serious along with the increasing of s...