施氮水平和干旱锻炼后复水程度对小麦水分利用效率的影响  

Effects of nitrogen level and rewatering degree after drought priming on water use efficiency of wheat

作　　者：邢佳伊 李丽[1] 王超 郝卫平[1] 王耀生 XING Jiayi;LI Li;WANG Chao;HAO Weiping;WANG Yaosheng(Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,State Engineering Laboratory of Efficient Water Use of Crops and Disaster Loss Mitigation,Key Laboratory of Dryland Agriculture,Ministry of Agriculture and Rural Affairs,Beijing 100081,China)

机构地区：[1]中国农业科学院农业环境与可持续发展研究所/作物高效用水与抗灾减损国家工程实验室/农业农村部旱作节水农业重点实验室,北京100081

出　　处：《干旱地区农业研究》2022年第5期52-61,共10页Agricultural Research in the Arid Areas

基　　金：国家重点研发计划政府间国际科技创新合作重点专项(2018YFE0107000)。

摘　　要：以‘XR4347’冬小麦品种为供试作物,在温室内开展盆栽试验。设置低氮(N0.5,74 mg·kg^(-1)),中氮(N1.5,223 mg·kg^(-1))和高氮(N3,446 mg·kg^(-1))3个氮素水平,各氮素水平下设置3种水分处理,分别为W85:干旱锻炼(40%土壤持水量(SWHC))后复水至85%SWHC;W60:干旱锻炼后复水至60%SWHC;W40:干旱锻炼后复旱至40%SWHC,研究氮素水平及干旱锻炼后复水程度对小麦生理特性及水分利用效率的影响。结果表明:干旱锻炼后复水能够改善植株水分状况,但中氮和低氮处理时,复水程度过高降低小麦根水势(RWP)。叶片气孔导度(g)受水力信号和脱落酸(ABA)信号的调控,叶片内在水分利用效率(WUE)与g呈显著负相关关系,因此降低复水程度或增施氮肥通过调控g提高WUE。干旱锻炼后复水程度高增加小麦叶面积(LA)、地上部干物质量(SDB)和植株耗水量(PWU),促进氮素吸收,但降低根系生长。与复水程度相比,氮素水平对植株水分利用效率(WUE)的影响更显著,高氮处理在保证SDB积累的同时使PWU降低9.1%,WUE提高10.1%。植株叶片的碳同位素组成(δC)随着氮素水平的提高而增加,WUE与叶片δC呈显著正相关关系,表明叶片δC可以用来表征干旱锻炼条件下WUE的高低,增施氮肥通过增强叶片的光合能力或优化调控叶片的气孔开度提高WUE。在所有处理中,N3W85和N3W60处理在保证SDB积累的同时提高WUE,但N3W60处理的PWU显著降低10.4%且根冠比较高,相比之下更有利于小麦植株的生长且节约灌溉用水,为本试验的最优处理。因此,在干旱缺水地区,增加施氮量或干旱锻炼后适当复水,不仅可以显著降低PWU、节约灌溉用水、维持作物生长和养分吸收,还可以提高叶片和植株的WUE。A pot experiment in the greenhouse was conducted with the variety‘XR4347’of winter wheat to investigate the effects of nitrogen application and rewatering level after drought priming on physiological characteristics and water use efficiency of wheat.Three nitrogen levels consisted of low nitrogen(N0.5,74 mg·kg^(-1)),medium nitrogen(N1.5,223 mg·kg^(-1))and high nitrogen(N3,446 mg·kg^(-1)),and three water treatments under each nitrogen level comprised rewatering to 85%of soil water holding capacity(SWHC)after drought priming(40%of SWHC)(W85),rewatering to 60%of SWHC after drought priming(W60)and re-drought stress to 40%of SWHC after drought priming(W40).The results showed that rewatering after drought priming improved the water status of plants.However,the high degree of rewatering reduced the root water potential(RWP)of wheat under medium and low nitrogen treatments.Stomatal conductance(g)of leaves was regulated by both hydraulic and abscisic acid(ABA)signals.There was a significant negative correlation between intrinsic water use efficiency(WUE)and g,therefore,reducing the degree of rewatering or increasing nitrogen fertilization improved WUEby regulating g.A high degree of rewatering after drought priming increased plant leaf area(LA),shoot dry biomass(SDB)and plant water use(PWU),and promoted nitrogen uptake,but reduced root growth.Compared with the degree of rewatering,nitrogen level more pronouncedly affected plant water use efficiency(WUE).High nitrogen treatment reduced PWU by 9%and increased WUEby 10%while ensuring SDB accumulation.Besides,leaf carbon isotope composition(δC)increased with the increase in nitrogen level,and there was a significant positive correlation between WUEand leafδC,indicating that leafδC could be used to surrogate the WUEunder drought priming,and the increase of nitrogen application reduced PWU by long-term regulating the stomatal opening of leaves,thereby improved WUE.In all the treatments,N3 W85 and N3 W60 treatments improved WUEwhile ensured the accumulation of SDB.More

关 键 词：小麦 施氮量 干旱-复水 水分利用效率 δ13C 

分 类 号：S512.1[农业科学—作物学] Q945.17[生物学—植物学] S365