不同滴灌定额对玉米花后叶片光合性状及籽粒生长发育的影响

Effects of Different Drip Irrigation Quotas on Photosynthetic Characteristics of Leaves and Grain Growth and Development of Maize after Anthesis

为探讨玉米应对不同滴灌定额的生理响应机制,在控制条件下开展2 a池栽试验,以2个具有耐旱性差异的玉米品种为材料,设置CK1(耐旱型品种、500 mm)、T1(耐旱型品种、350 mm)、T2(耐旱型品种、200 mm)、CK2(干旱敏感型品种、500 mm)、T3(干旱敏感型品种、350 mm)和T4(干旱敏感型品种、200 mm)6个处理,分析玉米叶片光合、叶绿素荧光、光合响应特性及籽粒灌浆特性、籽粒中激素含量、淀粉合成酶活性、产量的变化。结果显示,随滴灌定额减少玉米R3期叶片净光合速率(Pn)等4项光合参数、光系统Ⅱ最大光化学量子产量(Fv/Fm)等4项叶绿素荧光参数均呈下降趋势,气孔限制百分率(Ls)和非光化学猝灭系数(NPQ)呈增加趋势。玉米叶片表观量子效率(AQE)等10项光合响应相关参数均随滴灌定额减少而下降,CK1、T1与CK2处理光补偿点(LCP)与光饱和点(LSP)、CO_(2)补偿点(CCP)与CO_(2)饱和点(CSP)间差值范围较其他处理大。籽粒灌浆速率在开花后25 d达到峰值,T2和T4处理较CK1和CK2处理显著下降。随滴灌定额减少籽粒中细胞分裂素(CTK)、生长素(IAA)含量下降,脱落酸(ABA)含量增加。T2和T4处理籽粒中酸性蔗糖转化酶、蔗糖合酶、淀粉合成酶与腺苷二磷酸葡萄糖焦磷酸化酶活性均较CK1和CK2处理显著下降。玉米产量随滴灌定额减少而显著下降,T1处理较CK1处理仅下降3.45%~4.51%。T1处理与CK1和CK2处理在上述指标间均无显著差异。采用T1处理的玉米叶片仍能维持光合性能和光系统Ⅱ结构,增强叶片对光与CO_(2)适应能力,玉米籽粒相关激素含量和淀粉合成相关酶活性增加,有效调控了籽粒生长发育及灌浆进程,玉米产量及其构成因素均表现较佳。

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 maximum photochemical quantum yield of photosystemⅡ(Fv/Fm),decreased with the decrease of drip irrigation quota,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 decreased with the decrease of drip irrigation quota.The range of differences between light compensation point(LCP)and light saturation point(LSP),CO_(2)compensation point(CCP)and CO_(2)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 anthesis,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 adenosine 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 difference 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 photosystemⅡstructure,enhanced the adaptability of leaves to light and CO_(2),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.