caa a22 4500 60548046X CHVBK 20210128100415.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s11099-015-0087-4 doi (NATIONALLICENCE)springer-10.1007/s11099-015-0087-4 Response of wheat ear photosynthesis and photosynthate carbon distribution to water deficit [Elektronische Daten] [S. Jia, J. Lv, S. Jiang, T. Liang, C. Liu, Z. Jing] Understanding distribution and transport of carbon assimilates and photosynthesis contribution to grain yield in wheat spike is important in assessing the photosynthetic process under stress conditions. In this study, photosynthetic characteristics were evaluated in a pot experiment. Transport of spike photosynthates to grain was demonstrated using 14C isotope tracer technique. Yield and key enzyme activities of C3 and C4 pathways were examined after anthesis in wheat cultivars of different drought resistance. The ear net photosynthetic rate, chlorophyll content of the spike bracts (glume, lemma, and palea), and relative water content slightly decreased under water deficit in drought resistant variety Pubing 143 (Pub) during the grain filling stage, whereas all parameters decreased significantly in drought sensitive variety Zhengyin 1 (Zhe). Grain 14C-photosynthate distribution rate fell by 3.8% in Pub and increased by 3.9% in Zhe. After harvest, the water-use efficiency of Zhe dropped by 18.7% under water deficit. Rubisco activity in ear organs declined significantly under water deficit, whereas activity of C4 pathway enzymes was significantly enhanced, especially that of phosphoenolpyruvate carboxylase and NADP-malate dehydrogenase. Water deficit exerted lesser influence on spike photosynthesis in Pub. Ear organs exhibited delayed senescence. Accumulation of photosynthetic carbon assimilates in ear bracts occurred mainly during the early grain filling and photosynthates were transported in the middle of grain filling. C4 pathway enzymes seem to play an important function in ear photosynthesis. We speculate that the high enzyme activity of the C4 pathway and the increased capacity of photosynthetic carbon assimilate transport were the reasons for the drought tolerance characteristics of ears. The Institute of Experimental Botany, 2015 14C-labelling nationallicence harvest index nationallicence malic enzyme nationallicence spike assimilate transport nationallicence Triticum aestivum L nationallicence CA : carbonic anhydrase nationallicence CAM : crassulacean acid metabolism nationallicence Chl : chlorophyll nationallicence DM : dry mass nationallicence E : transpiration rate nationallicence FM : fresh mass nationallicence MDH : malate dehydrogenase nationallicence NAD-ME : NAD-malic enzyme nationallicence NADP-MDH : NADP-malate dehydrogenase nationallicence NADP-ME : NADP-malic enzyme nationallicence OD : optical density nationallicence PEPC : phosphoenolpyruvate carboxylase nationallicence P N : net photosynthetic rate nationallicence PPDK : pyruvate orthophosphate dikinase nationallicence RWC : relative water content nationallicence TM : turgid mass nationallicence WUE : water-use efficiency nationallicence Jia S. College of Science, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Lv J. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Jiang S. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Liang T. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Liu C. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Jing Z. College of Science, Northwest A&F University, 712100, Yangling, Shaanxi, China aut Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/1(2015-03-01), 95-109 0300-3604 53:1<95 2015 53 11099 https://doi.org/10.1007/s11099-015-0087-4 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/s11099-015-0087-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jia S. College of Science, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 700 1- Lv J. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 700 1- Jiang S. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 700 1- Liang T. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 700 1- Liu C. College of Life Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 700 1- Jing Z. College of Science, Northwest A&F University, 712100, Yangling, Shaanxi, China aut NATIONALLICENCE 773 0- Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/1(2015-03-01), 95-109 0300-3604 53:1<95 2015 53 11099