Low soil temperature and drought stress conditions at flowering stage affect physiology and pollen traits of rice
RAO Gang-shun1*, Umair Ashraf1, 2*, KONG Lei-lei1, MO Zhao-wen1, XIAO Li-zhong1, ZHONG Ke-you1, Fahd Rasul2, TANG Xiang-ru1?
1 Department of Crop Science and Technology, College of Agriculture, South China Agricultural University/Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture and Rural Affairs, Guangzhou 510642, P.R.China 2 Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan
Low temperature and drought stress are the major constraints in rice productivity worldwide.? This study investigated the influence of low soil temperature and/or drought stress on physiology and pollen traits of two rice genotypes viz., Guinongzhan and Yueza 763 at flowering stage.? The experiment included four treatments, i.e., under the greenhouse natural growth conditions (UC) taken as control, drought stress (DS), the soil water potential was kept at ?0.035 to ?0.045 MPa (DS), low soil temperature (LT) maintained at 19 to 21°C, combined LT and DS (LT+DS, LD).? Results showed that LT, DS, and LD substantially reduced net photosynthetic rate (Pn) and the maximal photochemical efficiency of PSII (Fv/Fm), whilst transpiration rate (Tr) was markedly enhanced by under LT in both rice genotypes.? The malondialdehyde (MDA) contents were enhanced under LT, DS, and LD in Guinongzhan, whilst the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were regulated by LT, DS, and LD in both rice genotypes.? Furthermore, anther dehiscence rate, pollen numbers on stigma, pollen viability and pollen germination rate, and anther starch contents were obviously reduced under LT and DS of both rice genotypes.? Stress conditions substantially reduced the yield and yield components, i.e., effective panicles, seed set percentage, grain/panicles, 1 000-grain weight, and grain yield of both genotypes and the effects were more apparent in Guinongzhan than those in Yueza 763 whilst combined LT and DS proved more damaging than individual stress.
Fund: This study was supported by the National Natural Science Foundation of China (31271646), the Natural Science Foundation of Guangdong Province, China (8151064201000017), the Agricultural Research Projects of Guangdong Province, China (2011AO20202001), and the Agricultural Standardization Project of Guangdong Province, China (4100 F10003).
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