caa a22 4500 605481113 CHVBK 20210128100419.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s11099-015-0106-5 doi (NATIONALLICENCE)springer-10.1007/s11099-015-0106-5 Effects of brassinosteroid and brassinosteroid mimic on photosynthetic efficiency and rice yield under heat stress [Elektronische Daten] [J. Thussagunpanit, K. Jutamanee, W. Sonjaroon, L. Kaveeta, W. Chai-Arree, P. Pankean, A. Suksamrarn] Brassinosteroids (BRs) have been reported to counteract various stresses. We investigated effects of exogenously applied brassinosteroid, 24-epibrassinolide (EBR), and brassinosteroid-mimic compound, 7,8-dihydro-8α-20-hydroxyecdysone (DHECD), on the photosynthetic efficiency and yield of rice (Oryza sativa L. cv. Pathum Thani 1) under heat stress. Solutions (1 nM) of EBR and DHECD were separately sprayed onto foliage of individual rice plants during their reproductive stage. Five days after the application, the plants were transferred to the day/night temperature regime of 40/30°C for 7 days and then allowed to recover at normal temperature for 7 days. We demonstrated that both DHECD and EBR helped maintain the net photosynthetic rate. The DHECD and EBR application enhanced stomatal conductance, stomatal limitation, and water-use efficiency under the high-temperature regime. DHECD- and EBR-treated plants showed an increase in the nonphotochemical quenching that was lower than that in the control plants. Moreover, DHECD and EBR treatments maintained the maximal quantum efficiency of PSII photochemistry and the efficiency of excitation capture of the open PSII center. Furthermore, the treatments with DHECD or EBR resulted in higher chlorophyll content during the heat treatment compared with the control plants. The paddy field application of 1 nM EBR and/or 1 nM DHECD at the reproductive stage during the hot season could increase the rice yield, especially, the number of filled seeds. DHECD and EBR enhanced total soluble sugar and reducing sugar in straw and more starch was accumulated in rice seeds. Consequently, our results confirmed that DHECD showed biological activities mimicking EBR in the improvement of photosynthetic efficiency and in rising the rice yield under heat stress. The Institute of Experimental Botany, 2015 7,8-dihydro-8α-20-hydroxyecdysone nationallicence 24-epibrassinolide nationallicence chlorophyll fluorescence nationallicence gas exchange nationallicence high temperature nationallicence BR(s) : brassinosteroid(s) nationallicence C i : intercellular CO2 concentration nationallicence C i/ C a : concentration ratio of intercellular CO2 and ambient CO2 nationallicence DHECD : 7,8-dihydro-8α-20-hydroxyecdysone nationallicence DHT : days after heat stress nationallicence DM : dry mass nationallicence E : transpiration rate nationallicence EBR : 24-epibrassinolide nationallicence ETR : electron transport rate nationallicence F0 : minimal fluorescence yield of the dark-adapted state nationallicence F0′ : minimal fluorescence yield of the light-adapted state nationallicence Fm : maximal fluorescence yield of the dark-adapted state nationallicence Fm′ : maximal fluorescence yield of the light-adapted state nationallicence Fs : steady-state fluorescence yield nationallicence Fv/Fm : maximal quantum yield of PSII photochemistry nationallicence Fv′/Fm′ : the efficiency of excitation capture of open PSII center nationallicence FM : fresh mass nationallicence g s : stomatal conductance nationallicence Ls : stomatal limitation nationallicence NPQ : nonphotochemical quenching nationallicence P N : net photosynthetic rate nationallicence qP : photochemical quenching coefficient nationallicence RE7 : 7 days of recovery nationallicence WUE : water-use efficiency nationallicence ΦPSII : effective quantum yield of PSII photochemistry nationallicence Thussagunpanit J. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut Jutamanee K. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut Sonjaroon W. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut Kaveeta L. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut Chai-Arree W. Department of Agronomy, Faculty of Agriculture at Kamphaengsaen, Kasetsart University, Kamphaengsaen Campus, 73140, Nakhonpathom, Thailand aut Pankean P. Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, 10240, Bangkok, Thailand aut Suksamrarn A. Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, 10240, Bangkok, Thailand aut Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/2(2015-06-01), 312-320 0300-3604 53:2<312 2015 53 11099 https://doi.org/10.1007/s11099-015-0106-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11099-015-0106-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Thussagunpanit J. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut NATIONALLICENCE 700 1- Jutamanee K. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut NATIONALLICENCE 700 1- Sonjaroon W. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut NATIONALLICENCE 700 1- Kaveeta L. Department of Botany, Faculty of Science, Kasetsart University, 10900, Bangkok, Thailand aut NATIONALLICENCE 700 1- Chai-Arree W. Department of Agronomy, Faculty of Agriculture at Kamphaengsaen, Kasetsart University, Kamphaengsaen Campus, 73140, Nakhonpathom, Thailand aut NATIONALLICENCE 700 1- Pankean P. Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, 10240, Bangkok, Thailand aut NATIONALLICENCE 700 1- Suksamrarn A. Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, 10240, Bangkok, Thailand aut NATIONALLICENCE 773 0- Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/2(2015-06-01), 312-320 0300-3604 53:2<312 2015 53 11099