جستجوی مقالات مرتبط با کلیدواژه "electron transfer" در نشریات گروه "زیست شناسی"

Cold is one of the most important abiotic stresses that limits crop growth and yield worldwide. In order to investigate how 20-day-old barley seedlings adapt to short-term cold stress, the present study was carried out in a factorial experiment with four replications in the seed laboratory of Karaj Seedling and Seed Breeding Research Institute. The experimental factors included barley cultivars (cold-sensitive Karon, semi-cold-tolerant Fasih, and cold-tolerant Makoi) and cold stress with three levels of 4, 8, and 22 oC (control). Temperature treatments were applied to barley seedlings for 48 hours. The results of analysis of variance showed that the interaction of cold and cultivar was significant on most of the measured traits in this study. The mean comparison also showed that the highest value of F0 was observed in Karun and Fasih cultivars at 8 oC and in Makoi cultivar at 4 oC, while in all three cultivars, Fv value and chlorophyll a content decreased with decreasing temperature. The ratio of Fm/Fv in Makoui and Fasih cultivars decreased with decreasing temperature, however no significant change was observed in Karon cultivar. In addition, with decreasing temperature, malondialdehyd (MDA) and H2O2 concentration and peroxidase (POX) activity increased in all three cultivars, especially Karon cultivar, but catalase (CAT) and super oxid dismutase (SOD) activity were not affected by the cultivar, and the highest CAT and SOD activity were obtained at 8 and 4 oC, respectively. The obtained results showed that the cultivars more tolerant than the sensitive cultivar (Karon) at low temperatures by limiting the production of compounds such as H2O2 and MDA, had higher chlorophyll content and photosynthetic efficiency, which probably reflects greater adaptation to cold.

Salinity stress can affect the growth and composition of secondary metabolites in medicinal plants. Salvia is an important medicinal and economic plant in the world. Different species of Salvia are grown in Iran. In the present study, a factorial experiment was conducted in a completely randomized design with ten replications. The effects of different salinity concentrations including 0, 50, 100 and 150 mM sodium chloride on the performance of the photosynthetic electron transport chain in two sensitive and resistant species of salvia were investigated by JIP-test method. The results of this study showed that with increasing salinity concentration, the activity of oxygen evolving complex (Fv / Fo) decreased in both species, but this decrease was more in susceptible species (Salvia officinallis) than resistant species. Salinity also reduced electron transfer to electron acceptors (φPo, ψo and φEo), electron transfer to photosystem I (φRo), active reaction centers (RC/CS), and performance index for transfer of electrons from photosystem II to I (PI total) decreased with increasing salinity concentration. The results of this study also showed that the negative effects of salinity stress on these parameters in the susceptible species (Salvia officinalis) were more than the resistant species (Salvia verticillata).