春小麦光合生理和产量对干旱-复水的响应OACSCDCSTPCD

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 PSⅡ were 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.