Effects of water deficit on gas-exchange parameters and ribulose 1,5-bisphosphate carboxylase activation in wheat

摘要: Abstract Two spring wheat (Triticum aestivum L.) genotypes, Anza, drought resistant, and Chenab 70, susceptible, were used to study the effects of a slowly developing water stress on gas-exchange parameters ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCase; EC 4.1.1.39) activities. By day 7 experiment, two genotypes exhibited similar declines in stomatal conductance (g) (by 77%) photosynthetic CO2 assimilation rate (A) 33%). However, their leaf relative content (RWC) was still 90% total (CO2/Mg2+ activated) RuBPCase activities had declined only by 12%. 12, RWC decreased 67% for 70 58% Anza plants, while g reduced more than 95%, A 71% both genotypes. Thus, plants maintained same as even though less. Total soluble protein 30% 43% 12% average reduction chlorophyll occurred. Over 12-day an 31% activity occurred proportion activated state did not change (for Anza) or 9% 70) over course experiment. These data suggest that changes vivo are major consequence moderate severe deficits wheat.