小麦不同绿色器官对灌浆中期高温胁迫的响应

Response of Different Green Organs to High Temperature Stress during Grain-Filling Stages in Wheat

为阐明小麦不同绿色器官对高温胁迫的响应差异及其生理机制,于2017—2019年连续两个生长季在山东省农业科学院济南试验田,以济麦22(JM22)和新麦26(XM26)为材料,采取田间搭建塑料大棚增温方式于花后12~14天(共3天)进行处理,研究小麦旗叶、穗、穗下节间和旗叶鞘等不同绿色器官的抗氧化酶活性、非光化学耗散以及叶黄素循环组分变化等生理特性。结果表明,灌浆期高温胁迫后,小麦穗、旗叶、穗下节间和旗叶鞘等器官的叶绿素含量均较对照降低,MDA含量增加,电导率增大。高温胁迫使JM22和XM26旗叶SOD活性分别较对照升高15.55%和22.60%,穗部则分别降低12.67%和23.00%,穗下节间和旗叶鞘比对照降低较少。高温胁迫加重了不同绿色器官POD活性的下降趋势,胁迫结束0天JM22和XM26旗叶、穗、穗下节间和旗叶鞘的POD活性分别较对照降低21.41%和28.73%、34.97%和47.04%、36.17%和46.89%、40.29%和50.25%。JM22和XM26旗叶CAT活性分别比对照增加13.00%和34.40%,而穗、穗下节间和旗叶鞘分别较对照降低30.09%和58.96%、1.75%和37.76%、16.20%和40.06%。高温胁迫使两品种各绿色器官的NPQ值升高,其中JM22旗叶、穗、穗下节间和旗叶鞘分别比对照增加2.94%、34.38%、34.38%和11.76%,XM26分别增加10.34%、20.00%、16.67%和14.29%。两品种不同绿色器官的过剩光能显著降低,与对照相比过剩光能降幅由大到小依次为穗>旗叶>穗下节间>旗叶鞘。各绿色器官的(A+Z)/(A+Z+V)都显著增加,其中穗下节间变化最大,其次是旗叶鞘,再次是穗,旗叶变化最小。综之,灌浆中期高温胁迫使旗叶中清除活性氧的保护性酶活性显著升高,而穗、穗下节间和旗叶鞘的保护性酶活性则降低;非叶器官通过非光化学耗散和依赖叶黄素循环的热耗散能力要优于旗叶。JM22较XM26能够更加有效地启动保护酶系统来应对高温造成的活性氧积累和膜脂过氧化,且其通过叶黄素循环和非光化学耗散过剩光能的能力也优于XM26。

Physiological characteristics including antioxidase activities,non-phtochemical dissipation and changes in lutein cycle components in wheat flag leaves,ears,peduncles and flag leaf sheaths were studied to clarify the response differences of different green organs of wheat to high temperature stress and its physiological mechanism by erecting artificial green house to increase temperature.In this study,Jimai 22(JM22)and Xinmai 26(XM26)were used as materials in Jinan experimental field of Shandong Academy of Agricultural Sciences in two consecutive growing seasons from 2017 to 2019.The results showed that chlorophyll content in flag leaves,ears,peduncles and flag leaf sheaths decreased after high temperature stress at grain filling stage,MDA content and electrical conductivity increased.Under high temperature stress,SOD activity in flag leaves of JM22 and XM26 were raised by 15.55%and 22.60%,respectively,while those in ears were dropped by12.67%and 23.00%,those in peduncle and flag leaf sheaths decreased less than the control.High temperature stress aggravated the downtrend of POD activity in different green organs.POD activity in flag leaves,ears,peduncles and flag leaf sheaths of JM22 and XM26 were reduced by 21.41%and 28.73%,34.97%and 47.04%,36.17%and 46.89%,40.29%and 50.25%,respectively,compared with the control.CAT activity in flag leaves of JM22 and XM26 increased by 13.00%and 34.40%while that in ears,peduncles and flag leaf sheaths decreased by 30.09%and 58.96%,1.75%and 37.76%,16.20%and 40.06%,respectively.High temperature stress increased the NPQ value of each green organs in the two varieties.The NPQ value in flag leaves,ears,peduncles and flag leaf sheaths of JM22 increased by 2.94%,34.38%,34.38%and 11.76%,respectively,while that of XM26 increased by 10.34%,20.00%,16.67%and14.29%.The excessive light energy in different green organs of the two varieties decreased significantly with sequence of ears>flag leaves>peduncles>flag leaf sheaths.The(A+Z)/(A+Z+V)value in each green organ increased significantly,and the change in peduncles was the largest,followed by that in flag leaf sheaths and ears,while that in flag leaves was the least.In summary,the activities of protective enzymes which remove reactive oxygen in flag leaves enhanced significantly due to high temperature stress at grain filling stage,while those in ears,peduncles and flag leaf sheaths dropped.Non-foliar green organs showed better capacities in non-photochemical dissipation and heat dissipation by xanthophyll cycle than flag leaves.JM22 started up with more efficiency protective enzymes against the accumulation of reactive oxgen and membrane lipid peroxidation that caused by high temperature than XM26,and performed better abilities in heat dissipation by xanthophyll cycle and non-photochemical dissipation.