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Rehmannia glutinosa seedlings were pretreated with choline chloride (CC) in concentrations of 0, 0.7, 2.1 and 3.5 mM, and then subjected to drought
and rewatering treatment to study the effects of CC on the generation of reactive oxygen species (O2−, H2O2), lipid peroxidation, proline accumulation, water status and photosynthesis. The results showed that pretreatment with CC
alleviated the inhibition of SOD and APX activity caused by drought stress, and therefore, the rate of O2− production and H2O2 concentration were reduced and lipid peroxidation decreased in pretreated plants. CC pretreatment also accelerated accumulation
of proline, maintained higher Ψw and RWC, deferred leaf water loss during drought stress and retarded the drop in proline
concentration after rewatering. Consequently, drought-induced decreases in Fm/F0, Fv/Fm, ΦPS2, qP, and A and increase in qNP were inhibited and the recovery of photosynthesis after rewatering was quicker in pretreated plants. Although differences
in Fv/Fm, ΦPS2 and qP between treatments were not significant, there was a general trend that the effects of CC increased with the rise of its
concentrations. The data suggested that 2.1 mM of CC be suitable for alleviating lipid peroxidation, promoting proline accumulation,
retarding leaf water loss and improving photosynthesis of R. glutinosa seedlings under drought stress. 相似文献
998.
About 20-year-old desert plants of C4 species, Haloxylon ammodendron, growing at the southern edge of the Badain Jaran Desert in China, were selected to study the photosynthetic characteristics
and changes in chlorophyll fluorescence when plants were subject to a normal arid environment (AE), moist atmospheric conditions
during post-rain (PR), and the artificial supplement of soil water (SW). Results showed that under high radiation, in the
AE, the species down-regulated its net assimilation rate (A) and maximum photochemical efficiency of PS II (Fv/Fm), indicating photoinhibition. However, under the PR and SW environments,
A was up-regulated, with a unimodal diurnal course of A and a small diurnal change in Fv/Fm, suggesting no photoinhibition. When the air humidity or SW content was increased, the
light compensation points were reduced; light saturation points were enhanced; while light saturated rate of CO2 assimilation (A
max) and apparent quantum yield of CO2 assimilation (ΦC) increased. ΦC was higher while the A
max was reduced under PR relative to the SW treatment. It was concluded that under high-radiation conditions drought stress causes
photoinhibition of H. ammodendron. Increasing air humidity or soil moisture content can reduce photoinhibition and increase the efficiency of solar energy
use. 相似文献
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L. R. Fayura D. V. Fedorovych T. M. Prokopiv Yu. R. Boretsky A. A. Sibirny 《Microbiology》2007,76(1):55-59
The yeast Pichia guilliermondii is capable of riboflavin overproduction under iron deficiency. The rib80, hit1, and red6 mutants of this species, which exhibit impaired riboflavin regulation, are also distinguished by increased iron concentrations in the cells and mitochondria, morphological changes in the mitochondria, as well as decreased growth rates (except for red6) and respiratory activity. With sufficient iron supply, the rib80 and red6 mutations cause a 1.5–1.8-fold decrease in the activity of such Fe-S cluster proteins as aconitase and flavocytochrome b 2, whereas the hit1 mutation causes a six-fold decrease. Under iron deficiency, the activity of these enzymes was equally low in all of the studied strains. 相似文献