春小麦光合生理和产量对干旱-复水的响应

Response of Photosynthetic Physiology and Yield of Spring Wheat to Drought-Rewatering

为探究不同生育时期土壤干旱对不同抗旱性小麦品种光合生理特性和产量的影响,以抗旱性弱品种“新春22号(XC22)”和抗旱性强品种“新春6号(XC6)”为试验材料,在土柱栽培和大田条件下,分别设置常规灌溉(CK)、分蘖期轻度干旱(W1)、分蘖期中度干旱(W2)、拔节期轻度干旱(M1)和拔节期中度干旱(M2)5种处理,研究小麦叶片叶面积指数(LAI)、叶绿素含量、气体交换参数和叶绿素荧光参数及地上部干物质积累、穗重与产量的变化。结果表明:抗旱性弱品种“XC22”受水分胁迫影响更大,复水后恢复能力较弱,仅W1处理能恢复到与CK相等水平。同“XC22”相比,抗旱性强品种“XC6”在M1处理后,“补偿效应”表现更加明显,RuBPC酶活性、气体交换参数与叶绿素荧光参数均能在复水后快速恢复至CK水平,较其他处理恢复能力更强,乳熟期其净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)与叶绿素荧光参数的暗适应下最大荧光产量(Fm)、光适应下最大荧光产量(Fm′)、PSⅡ实际光合量子产量(ΦPSⅡ)、光化学淬灭系数(qp)较CK分别显著提高11.39%,7.50%,7.38%和7.86%,6.78%,17.24%,2.48%。轻度干旱处理并未减少小麦干物质积累和产量,反而有助于穗重的增加,且“XC6”在M1处理下,干物质积累、穗重与产量均显著高于CK。光合参数与产量的相关与通径分析表明,产量与Pn、Gs、Fm、Fm′、qp呈极显著正相关,且Pn在产量形成中的促进作用更大。春小麦花后光合生理特性的恢复与保持受拔节期水分胁迫影响更显著。在新疆滴灌模式下,生育前期轻度干旱胁迫,有利于抗旱性强品种小麦复水后光合性能改善,增加地上部干物质积累,促进光合产物向生殖器官的转运,有利于产量形成。

In order to explore the effects of soil drought at different growth stages on photosynthetic physiological characteristics and yield of different drought resistant wheat varieties.Taking"Xinchun 22(XC22)"with weak drought resistance variety and"Xinchun 6'(XC6)"with strong drought resistance variety as the materials,under soil column cultivation and field conditions,five treatments were set up:conventional irrigation(CK),mild drought at tillering stage(W1),moderate drought at tillering stage(W2),mild drought at jointing stage(M1)and moderate drought at jointing stage(M2),respectively.The changes of leaf chlorophyll content,leaf area index(LAI),gas exchange parameters,chlorophyll fluorescence parameters,above-ground dry matter accumulation,panicle weight and yield of wheat were studied.The results showed that the drought-resistant variety"XC22"was more affected by water stress and its recovery ability was weaker after rewatering.Only W1 treatment could recover to the level of stalemate with CK.Compared with"XC22",the"compensation effect"of strong drought resistant variety"XC6"was more obvious after M1 treatment.The RuBPC enzyme activity,gas exchange parameters and chlorophyll fluorescence parameters could quickly recover to CK level after rehydration,which was stronger than other treatments.At milk stage,the net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr)and maximum fluorescence yield under dark adaptation(Fm),maximum fluorescence yield under light adaptation(Fm'),actual photosynthetic quantum yield(ΦPSⅡ)and photochemical quenching coefficient(qp)of PSⅡwere significantly increased by 11.39%,7.50%,7.38%and 7.86%,6.78%,17.24%,2.48%,respectively,compared with CK.Mild drought treatment did not reduce dry matter accumulation and yield of wheat,but contributed to the increase of ear weight,and the dry matter accumulation,ear weight and yield of"XC6"under M1 treatment were significantly higher than CK.The correlation and path analysis between photosynthetic parameters and yield showed that yield was significantly positively correlated with Pn,Gs,Fm,Fm'and qp,Pn was the most important promoting factor in yield formation.The recovery and maintenance of photosynthetic physiological characteristics of spring wheat after anthesis were more strongly affected by water stress at jointing stage.Under the drip irrigation model in Xinjiang,mild drought stress at the early growth stage was beneficial to improve the photosynthetic performance of drought-resistant wheat varieties after rewatering,increase the accumulation of aboveground dry matter,promote the transport of photosynthate to reproductive organs,and facilitate the formation of yield.