秸秆和紫云英覆盖还田对玉米光合生理特性的影响

Effects of straw and milk vetch mulching and returning to the field on maize photosynthetic physiological characteristics

为探究秸秆和紫云英覆盖还田对玉米光合生理特性的影响,设置半量秸秆覆盖(HS)、全量秸秆覆盖(WS)、紫云英覆盖(M)、半量秸秆加紫云英覆盖(HS+M)、全量秸秆加紫云英覆盖(WS+M)、无覆盖(CK)6个处理,于玉米乳熟期测定光合气体交换参数的日变化、光响应曲线以及叶片生理指标和干物质量等。结果表明,净光合速率和气孔导度都呈“双峰”曲线变化,胞间二氧化碳浓度(C_(i))和蒸腾速率(T_(r))整体呈“单峰”曲线变化;HS+M处理的日平均净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))最高且较CK处理分别显著增加了33.44%、60.81%、33.36%,而各处理间的日平均胞间Ci差异不大;光响应曲线中,WS+M处理的Pnmax和LSP的实测值在各处理中最高,分别为23.46、1900 mol·m^(-2)·s^(-1),且各处理的光响应曲线拟合决定系数均高于0.99;Rubisco和PEPC的活性在各处理间均表现为:WS+M>HS+M>M>WS>HS>CK,各处理中,以WS+M处理的Rubisco和PEPC活性最高分别为12.92 U·L^(-1)、6.59 U·L^(-1),且较CK处理高出1.12和1.59倍;玉米穗位叶叶面积和地上部分单株干物质量都以WS+M处理最高,分别较CK处理显著增加了16.40%、46.32%;气体交换参数与玉米叶片生理指标间均呈正相关关系。本研究结果表明,将秸秆、绿肥覆盖还田可提高玉米的光合作用能力,促进玉米地上部分干物质积累,为玉米最终增产提供物质基础。

To explore the effects of corn straw and milk vetch mulching and returning to the field on photosynthetic physiological characteristics of maize,six treatments were set through field experiments,including half straw mulch(HS),full straw mulch(WS),milk vetch mulch(M),half straw with milk vetch mulch(HS+M),whole straw with milk vetch mulch(WS+M),and no mulch(CK).Diurnal variation of photosynthetic gas exchange parameters,light response curve,leaf physiological indexes and dry matter weight were measured at milking stage of maize.The results showed that P_(n) and G_(s) show a“bimodal”curve variation,while C_(i) and T_(r) showed a“unimodal”curve variation.The average daily P_(n),G_(s) and Tr of HS+M were the highest and significantly increased by 33.44%,60.81%and 33.36%when compared with CK,respectively.The average daily C_(i) among different treatments was not significantly different.For the light response curves,the measured values of Pnmax and LSP of WS+M were the highest among all treatments,which were 23.46、1900 mol·m^(-2)·s^(-1),respectively.The fitting determination coefficients of light response curves were all higher than 0.99.The activities of Rubisco and PEPC in all treatments were as follows:WS+M>HS+M>M>WS>HS>CK.Among all the treatments,the highest activity of Rubisco and PEPC in WS+M treatment were 12.92 U·L^(-1) and 6.59 U·L^(-1),respectively,which were 1.12 and 1.59 times higher than that of CK.WS+M had the highest ear leaf area and dry matter of per plant,which were significantly increased by 16.40%and 46.32%respectively when compared with CK.There was a positive correlation between gas exchange parameters and physiological indexes of maize leaf.In summary,the straw and milk vetch mulching improved the photosynthetic capacity and promote the dry matter accumulation of aboveground part of maize,and thus increasedthe maize yield.