2018 March Ph.D. Admissions (Final)

Friday Seminar | Nov 20 | Ritesh Kumar

AG-LAB | Friday November 20, 2015 | High Temperature Stress and Reproductive Biology
Category: Research
Posted by: ricemads33

Analysis of Effects of High Temperature Stress on Reproductive Biology of Rice

Earth surface temperature is gradually increasing. Global surface temperature in 2014 was +0.68 warmer than 1951-1980 base period in GISTEMP analysis and year 2014 is the warmest year. Rice is affected variably at its different stages of development by heat stress. But the most vulnerable stage of rice towards heat stress is reproductive stage. The process of anthesis which includes anther dehiscence, pollination, pollen germination and pollen tube growth was found to be more sensitive to heat stress. Pollen development at Meiosis I is characterized with accumulation of starch as it is an important source of energy in pollen germination. Heat stress causes decline  in pollen volume and accumulated starch in pollen grain found in poorly dehiscent anthers in the florets. Transverse section of anther of three different cultivars (tolerant and susceptible) shows presence of different number of layers separating the locule from lacuna between the septum and stomium and this difference was related to the thermotolerance and thermosuseptibility of a cultivar at reproductive stage. Heat stress affects transcriptional regulation of different developmental and heat responsive genes in floral organs. Heat stress changes antioxidant enzyme activities and lipid peroxidation (MDA) of flag leaves and spikelets. Also it was found that its effects are stronger on spikelets than on flag leaves in rice due to differences in dissipation capacity.