Effects of Different Drip Irrigation Quotas on Photosynthetic Characteristics of Leaves and Grain Growth and Development of Maize after Anthesis
To explore the physiological response mechanism of maize to different drip irrigation quotas,a 2-year pond planting experiment was conducted under controlled conditions.Using two maize varieties with differences in drought resistance as materials,six treatments were set up:CK1(Drought resistant variety,500 mm),T1(Drought resistant variety,350 mm),T2(Drought resistant variety,200 mm),CK2(Drought sensitive variety,500 mm),T3(Drought sensitive variety,350 mm),and T4(Drought sensitive variety,200 mm)to analyse the photosynthetic,chlorophyll fluorescence,photosynthetic response characteristics,and grain filling characteristics of maize leaves changed in hormone content,starch synthase activity,and yield in grains.The results showed that four photosynthetic parameters,including net photosynthetic rate(Pn),and four chlorophyll fluorescence parameters,including maxi-mum photochemical quantum yield of photosystem Ⅱ(Fv/Fm),decreased with the decrease of drip irrigation quo-ta,while stomatal limitation percentage(Ls)and non-photochemical quenching coefficient(NPQ)increased.The apparent quantum efficiency(AQE)and other 10 photosynthetic response related parameters of maize leaves all de-creased with the decrease of drip irrigation quota.The range of differences between light compensation point(LCP)and light saturation point(LSP),CO2 compensation point(CCP)and CO2 saturation point(CSP)in CK1,T1,and CK2 treatments was larger than that in other treatments.The grain filling rate reached its peak at 25 d after anthe-sis,and the T2,and T4 treatments significantly decreased compared to the CK1 and CK2 treatments.The content of cytokinin(CTK)and auxin(IAA)in grains decreased with the decrease of drip irrigation quota,and the content of abscisic acid(ABA)increased.The activities of acid sucrose invertase,sucrose synthase,starch synthase and aden-osine diphosphate glucose pyrophosphorylase in grains of T2 and T4 treatments were significantly lower than those of CK1 and CK2 treatments.The maize yield significantly decreased with the decrease of drip irrigation quota,and the T1 treatment only decreased by 3.45％to 4.51％compared to the CK1 treatment.There was no significant differ-ence between T1 treatment and CK1 and CK2 treatment in the above indicators.The leaves of maize treated with T1 treatment still maintained the photosynthetic performance and photosystem Ⅱ structure,enhanced the adaptability of leaves to light and CO2,increased the content of hormones related to maize grains and the activity of enzymes related to starch synthesis,effectively regulated the growth and development of maize grains and the filling process,and maize yield and its components performed better.
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维普
