| With the continues warming of the global climate and the increasing global temperature environment,the soil moisture content and precipitation patterns in different regions will have dramatic changes.Ningxia is located in the northwestern region of China,Air temperature has increased year by year,resulting in more and more serious soil drought.6-year-old fresh jujube cartivar ’Lingwuchangzao’ in Ningxia were used.The self-made open-top-chamber were used to simulate the atmospheric elevated temperature,and the wisteria precision irrigation controller(ZGH-MI-C)system were used to control the soil moisture content.Two levels of air temperature were set(natural air temperature T1,elevated atmospheric temperature T2=(T1+(2.0t0.5℃)),three levels of soil moisture were set(D1,soil moisture was 70%-75%of the maximum field water capacity;D2,the soil moisture was 50%-55%of the maximum field water capacity;D3,the soil moisture was 30%-35%of the maximum field water capacity).The ABA、ETH and GA3 content of endogenous hormones,activities of key enzymesand related gene expressions,cell wall components,sugar components,pigment content in the fruit of ’Lingwuchangzao’ were measured.The effect of elevataed temperature and drought interaction on endogenous hormones of fruits and their regulating effects on fruit qulity were analyzed for providing theoretical and practical guidance for’Lingwuchangzao’ responding to climate change.The main results are as follows:1.The interaction of elevated temperature and drought significantly affected the content of endogenous hormone in the fruit of ’Lingwuchangzao’.When the air temperature increased about 2.0℃,The content of ABA increased at different stages of fruit development.The content of ABA ETH and GA3 increased in the fruit swelling stage and white maturity period,and the content of endogenous hormones increased significantly in the fruit white maturity period,When the air temperature increased about 2.0℃,ABA,ETH and GA3 contents increased by 5.43%,16.70%and 1.36%under normal water supply,8.92%,10.79%and 10.52%under moderate drought,and 8.77%,3.91%and 12.35%under severe drought,respectively.The effects of different soil moisture content on the ETH content of fruits varied with different stages of fruit development.ETH content of fruits at swelling stage and white ripening stage under moderate and severe drought conditions were decreased by 18.20%and 22.21%,5.98%and 8.93%,respectively,compared with normal soil water supply conditions.ETH content increased by 13.15%and 25.96%,respectively,in the late stage of fruit turning color,and drought conditions promoted the accumulation of GA3 content in fruits.The effects of moderate drought on the accumulation of ABA,ETH and GA3 in fruits were intensified,while the effects of severe drought on the accumulation of GA3 in fruits were slowed down.2.The effects of elevated temperature has different on the activities of ACS,CPS and KS in the fruit of ’Lingwuchangzao’ were different in different development stages.When the air temperature increased by 2.0℃,NCED activity of fruits at the young fruit stage,white maturity stage and mid-color transformation period were increased,while ACS,CPS,and KS activities of fruits at the young fruit stage and late color transformation stage will decreased.ACS,CPS and KS activities of fruit in the swelling stage were increased by 18.55%,9.64%,25.93%under normal water supply conditions,Under moderate drought conditions,the increase was 14.24%,4.66%,13.97%,respectively,and under severe drought conditions,the increase was 18.88%,16.03%,26.92%,respectively;Different soil moisture content levels had different effects on the activities of CPS and KS in different fruit development stages.Drought promoted the activities of NCED,ACS and KS in the late fruit development stage;Elevated temperature intensified the effect of drought on the activities of NCED,ACS and KS in fruits.3.When elevated temperature was interacted with drought,the expression of ZjNCED and ZjACS genes were up-regulated in fruit at different stages of fruit development.At fruit ripening stage,ZjNCED and ZjACS genes were up-regulated by 21.70 and 13.66 times under severe drought conditions,ZjKS and ZjCPS genes are mainly up-regulated at the middle stage of fruit development.Both ZjNCED and ZjACS had highest up-regulatedunder the conditions of elevated temperature was interacted with drought.Elevated temperature intensifies the up-regulation of ZjKS and ZjCPS genes by drought in the middle stage of fruit development,and slows down the up-regulation of ZjKS and ZjCPS genes by drought in the late stage of color turning and ripening.4.Air temperature regulated fruit quality by affecting the content of endogenous hormones in fruits.The content of ABA ETH and GA3 significantly increased under elevated temperature.which positively regulates the activities of cell wall components,sugar accumulation,peel pigment and anthocyanin synthesis related enzymes.Soil moisture level has a direct effect on fruit quality.ABA,ETH and GA3 had positive regulation effects on the formation of fruit quality.The elevated temwasperature will alleviate the inhibition of soil quality formation.In conclusion,the activity of NECD,ACS,CPS,KS and the expression levels of ZjNECD,ZjACS,ZjCPS and ZjKS can be promoted by elevated temperature of about 2.0℃ to promote the synthesis of ABA,ETH and GA3 in fruits,and then to promote the formation of fruit quality of’Lingwuchangzao’.Drought had a direct effect on the formation of fruit quality. |
