浅埋滴灌下不同滴灌量对玉米花后碳代谢和光合氮素利用效率的影响

Effects of different amount of drip irrigation on carbon metabolism and photosynthetic nitrogen utilization efficiency of maize after anthesis under shallow buried drip irrigation

为探明浅埋滴灌下不同滴灌量对玉米花后碳代谢和光合氮利用效率的影响,以传统畦灌常规灌量(4000 m^(3)hm^(-2))为对照,设置浅埋滴灌传统畦灌常规灌量40%(W1:1600 m^(3)hm^(-2))、50%(W2:2000 m^(3)hm^(-2))和60%(W3:2400 m^(3)hm^(-2))3个处理,研究浅埋滴灌下不同滴灌量玉米产量和花后叶源特性、光合特性、光合碳代谢关键酶活性、光合氮素利用效率、非结构性碳水化合物含量的变化特征。结果表明,2018—2020年玉米籽粒产量W3与CK差异不显著,W2和W1均显著低于CK,3年产量平均降低3.91%和11.18%;滴灌下W3产量与W2差异均不显著,但显著高于W1,3年平均产量分别较W1增加17.56%、9.06%和9.56%。开花期W3和CK瞬时光合利用率、瞬时水分利用效率和瞬时羧化速率均较高且二者差异均不显著,W1均最低,气孔限制值的表现则相反。叶源特性和光合碳代谢相关酶活性花后30 d至成熟期W1和W2均低于W3,W3优于CK,其中,单株叶面积、比叶重、穗位叶叶绿素含量和光合势W3较CK平均提高了20.29%、3.03%、14.80%和21.37%,1,5-二磷酸核酮糖羧化酶、丙酮酸磷酸双激酶、苹果酸酶、苹果酸脱氢酶和磷酸烯醇式丙酮酸羧化酶活性W3分别较CK提高19.66%、12.53%、10.67%、21.17%和11.72%。花后至花后50 d,CK和W3光合氮素利用效率均较高且二者差异不显著,其中花后20 d至50 d CK和W3均显著高于W1,花后50 d至成熟期W3分别较CK、W2和W1提高3.24%、3.29%和7.40%。花后50 d至成熟期W3蔗糖最高且与CK、W1的差异显著,W3分别较W2、CK和W1提高11.31%、14.02%和43.48%;花后30 d至成熟期W3可溶性糖含量均最高,W3分别较W2、CK和W1提高14.06%、17.78%和34.20%;花后50 d至成熟期CK淀粉含量最高且与W3的差异不显著,CK分别较W3、W2和W1提高8.01%、14.52%和26.69%。由此可见,浅埋滴灌下灌量达传统畦灌常规灌量60%时,玉米花后叶源特性较好,光合碳代谢酶活性较强,光合氮素利用效率、非结构性碳水化合物含量和产量均较高,可为玉米合理灌溉和节水稳产提供理论指导。

The objective of this study is to explore the effects of different amount of drip irrigation on carbon metabolism and photosynthetic nitrogen use efficiency of maize after anthesis under shallow buried drip irrigation.Three treatments of irrigation amount 40%(W1:1600 m^(3)hm^(-2)),50%(W2:2000 m^(3)hm^(-2)),and 60%(W3:2400 m^(3)hm^(-2))of traditional border irrigation(4000 m^(3)hm^(-2)) were set to study dynamic characteristics of leaf source,photosynthesis,activities of photosynthetic carbon metabolism enzyme,photosynthetic nitrogen use efficiency,content of non-structural carbohydrate after anthesis,and yield of different amount drip irrigation under shallow buried drip irrigation.The results showed that there was no significant difference on mean yield between CK and W3,while W2 and W1 were both significantly lower than CK and the annual average yield of W2 and W1 respectively decreased by 3.91%and 11.18%compared with that of CK from 2018 to 2020.There was also no significant difference on yield W3 and W2,while W3 was significantly higher than W1.Compared with W1,the annual yield of W3 increased by 17.56%,9.06%,and 9.56%,respectively.The instantaneous photosynthetic efficiency,instantaneous water use efficiency,and instantaneous carboxylation rate of W3 and CK were both higher at flowering stage and was the lowest in W1,while the performance of stomatal limit was the opposite.The leaf source characteristics and activities of photosynthetic carbon metabolism enzyme of W2 and W1 were both lower than W3 from 30 days after anthesis to maturity,in which the leaf area,specific leaf quality,content of chlorophyll,and LAD of W3 increased by 20.29%,3.03%,14.80%,and 21.37%,respectively.Compared with CK,the activities of 1,5-diphosphate ribulose carboxylase,pyruvate phosphate double kinase,malase,malate dehydrogenase,and phosphoenolpyruvate carboxylase of W3 increased by 19.66%,12.53%,10.67%,21.17%,and 11.72%,respectively.There was no significant difference between the photosynthetic nitrogen use efficiency of CK and W3,which were both higher than W1 from 20 to 50 days after anthesis.Compared with W2,W1,and CK from 50th day after anthesis to maturity,the photosynthetic nitrogen use efficiency of W3 increased by 3.24%,3.29%,and 7.40%,respectively.Compared with W2,CK,and W1,the sucrose content of W3 were the highest from the 50th day after anthesis to maturity of which increased by 11.31%,14.02%,and 43.48%respectively.Compared with W2,CK and W1 from the 30th day after anthesis to maturity,the soluble sugar content of W3 was the highest from the 30th day after anthesis to maturity and W3 increased by 14.06%,17.78%,and 34.20%,respectively.Compared with CK,W2,and W1,the starch content of CK had no significant difference with W3,which was the highest from the 50th day after anthesis to maturity,increased by 3.35%,7.58%,and 24.93%,respectively.Consequently,when irrigation amount reached to 60%of normal irrigation amount of traditional border irrigation,maize under the shallow buried drip irrigation had better leaf source characteristics,strong activities of photosynthetic carbon metabolism enzyme,photosynthetic nitrogen use efficiency,non-structural carbohydrate content and yield,which could provide theoretical guide for rational irrigation,water saving and yield stability of maize.