外源海藻糖对灌浆期高温胁迫下小麦旗叶生理特性和产量的影响

Effects of exogenous trehalose on physiological characteristics and yield of wheat flag leaves under high temperature stress at grain filling stage

为探究外源海藻糖(TRE)对高温胁迫下灌浆期不同耐性小麦品种旗叶生理特性和产量的影响作用,于2020—2022年在安徽农业大学高新技术农业园进行试验,选用前期筛选得的耐热性差异显著的敏感型小麦品种泛麦5号(Fanmai 5,FM5)和耐热型小麦品种淮麦33(Huaimai 33,HM33)作为试验材料,设置叶面喷施清水+不高温(CK1)、清水+灌浆期高温胁迫(CK2)、10 mmol L^(–1)海藻糖+灌浆期高温胁迫(T_(10)H)、15 mmol L^(–1)海藻糖+灌浆期高温胁迫(T15H)和20 mmol L^(–1)海藻糖+灌浆期高温胁迫(T20H)共5个处理。结果表明,在高温胁迫条件下,绿叶面积、叶绿素相对含量(SPAD)和干物质积累量均显著下降,与非高温逆境相比,高温胁迫下小麦产量显著下降,穗数和穗粒数无显著变化,千粒重是减产的主导因素。与喷清水相比,喷施海藻糖后产量较高温胁迫处理有所提升,各器官干物质积累量提高,丙二醛(MDA)含量降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性提高,变化幅度在品种间存在差异,耐热品种的SPAD值降幅与丙二醛的增幅较小,但CAT活性的增幅较大,因而减产幅度较小。进一步的分析表明,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、SPAD、SOD及POD和千粒重呈极显著正相关关系,MDA和产量呈极显著负相关关系。这些结果表明高温胁迫通过降低Pn、Gs和Tr抑制小麦的光合作用,减少光合产物的生成,造成最终的减产。喷施TRE,Pn、Gs、Tr、SPAD和CAT是降低高温胁迫伤害的主要指标,敏感品种缓解效果明显。此外,开花期喷施浓度15 mmol L^(–1)海藻糖效果最好。该研究结果可为海藻糖对灌浆期高温胁迫下小麦光合响应差异机制和小麦抗氧化代谢提供理论依据。

In order to investigate the effect of exogenous trehalose(TRE)on the physiological characteristics and yield of flag leaves of wheat varieties with different tolerance under high temperature stress during grain filling period,the experiments were conducted in the high-tech agricultural park of Anhui Agricultural University from 2020 to 2022.The sensitive wheat varieties Fanmai 5(FM5)and heat-resistant wheat varieties Huaimai 33(HM33)with significant difference in heat resistance were selected as the experimental materials,there were five treatments of spraying water+non high temperature(CK1),water+high temperature stress(CK2),10 mmol L^(–1)trehalose+high temperature stress(T10H),15 mmol L^(–1)trehalose+high temperature stress(T15H),and 20 mmol L^(–1)trehalose+high temperature stress(T20H)on the leaf surface.The results showed that under high temperature stress conditions,compared to non-high temperature adversity,the green leaf area,chlorophyll relative content(SPAD),and dry matter accumulation were significantly decreased,wheat yield was significantly reduced,spike number,and spike grain number did not change significantly,and 1000-grain weight was the dominant factor in yield reduction.Compared to water spraying,the yield after spraying trehalose was higher than that under high temperature stress,the accumulation of dry matter in various organs was increased,the content of malondialdehyde(MDA)was decreased,the activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)were increased,and the range of change was different among varieties.The decrease of SPAD value of heat-resistant varieties was smaller than that of malondialdehyde,but the increase of CAT activity was larger,indicating the production reduction was small.Further analysis showed that the net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),SPAD,SOD,and POD had an extremely significant positive correlation with 1000-grain weight,while MDA had an extremely significant negative correlation with yield.These results suggested that high temperature stress inhibited photosynthesis in wheat by reducing Pn,Gs,and Tr,decreasing photosynthetic product production and causing eventual yield reduction.Spraying TRE,Pn,Gs,Tr,SPAD,and CAT were the main indicators to reduce the injury caused by high temperature stress,and the mitigation effect of sensitive varieties was obvious.In addition,the effect of spraying 15 mmol L^(–1)trehalose at flowering stage was the best.The results could provide a theoretical basis for the mechanism of wheat photosynthetic response difference and wheat antioxidant metabolism under high temperature stress during trehalose filling stage.