A total of 159 wheat samples imported from the International Center for Agricultural Research in the Arid Areas(ICARDA)were used as the research subjects.To simulate drought conditions during the seedling stage,20％PEG-6000 was applied,while a normal nutrient solution served as the control.The effects of drought on seven physiological traits related to the seedling stage(malondialdehyde content,superoxide dismutase activity,relative conductivity,peroxidase activity,soluble sugar content,proline content,and chlorophyll content)were analyzed.Correlation analysis of drought resistance-related physiological traits in the 159 wheat samples was conducted using a 55K SNP chip.The results indicated that,following drought treatment,the levels of proline and soluble sugars increased,whereas other traits did not show consistent trends.Under normal conditions,malondialdehyde content was significantly positively correlated with peroxidase activity and highly significantly negatively cor-related with proline content;peroxidase activity was highly significantly negatively correlated with soluble sugar content.Under drought stress,soluble sugar content was significantly positively correlated with malondialdehyde content and relative conducti-vity,while chlorophyll content was highly significantly positively correlated with soluble sugar content and significantly nega-tively correlated with proline content.Association analysis identified 311 drought resistance-related markers(P＜0.001)across 24,151 SNP loci,distributed on all 21 wheat chromosomes,with contribution rates of 7.13％-21.11％.Eight stable loci were de-tected under both treatments,located on chromosomes 1B,2B,and 6A,with contribution rates of 7.85％-14.58％.Additionally,a multiple effector locus associated with both superoxide dismutase activity and soluble sugar content was found on chromosome 3D,with a contribution rate of 7.95％-8.69％.Four significant loci associated with the drought resistance coefficient of relative conductivity,peroxidase activity,chlorophyll content,and traits such as relative conductivity,peroxidase activity,proline content,and superoxide dismutase activity under drought treatment were detected on chromosomes 2D,3A,and 4A,with a contribution rate of 7.61％-14.74％.
利用优异基因资源改良小麦抗旱性是应对干旱和保障粮食安全的重要途径.结合国内外小麦抗旱性研究的最新进展和本研究组的研究实践,概述了现行主要抗旱性鉴定方法的适用对象和评价指标,以及小麦抗旱种质创新、抗旱基因资源发掘与利用等方面的研究成果,同时提出未来小麦抗旱性研究的重点任务和发展方向,即建立基于高通量表型鉴定的抗旱性综合评价技术体系,建立基于高通量基因型鉴定的抗旱基因资源发掘平台,创建基于综合运用多学科技能的智慧育种策略,以期为加快小麦抗旱性遗传改良提供信息资源和理论参考.
地表-地下接力滴灌是集膜下滴灌和地下滴灌优点于一体的新型节水控盐技术,但目前针对该技术应用效果的研究尚少.针对如何对地表-地下接力式滴灌中的地表滴灌和地下滴灌进行水量分配效果最优这一问题,设置 100%地表滴灌(W1)、75%地表滴灌+25%地下滴灌(W2)、50%地表滴灌+50%地下滴灌(W3)、25%地表滴灌+75%地下滴灌(W4)、100%地下滴灌(W5)共计 5 个处理,比较了不同水量分配下的地表-地下接力式滴灌与单一地表滴灌、单一地下滴灌对盐碱棉田土壤水盐分布和棉花产量的影响.结果表明:(1)W3 处理根区土壤含水量分布最均匀,干燥区域面积最小.(2)W4 处理窄行区域淋洗范围最大,脱盐效果最显著.(3)W3 处理棉花吐絮期总干物质量和籽棉产量最大,分别为 112.66 g和 9147 kg·hm-2;吐絮期总干物质量比W1 和W5 处理分别提高 11.3%和19.1%,籽棉产量比W1 和W5 处理分别提高 14.1%和 11.9%.地表-地下接力式滴灌处理下土壤含水量得以显著改善,在对土壤盐分进行淋洗的过程中表现出接力效应,淋洗面积和淋洗效果均有所增大.相比于单一地表滴灌和单一地下滴灌,地表-地下接力式滴灌下棉花干物质量显著增加,产量明显提高.研究表明,地表滴灌和地下滴灌之间存在良好的协同作用,采用 50%地表滴灌+50%地下滴灌模式有助于调控盐碱棉田水盐分布,提高棉花产量和水分利用效率,可为发展盐碱地新型节水灌溉技术提供理论支撑.
研究合理的秸秆覆盖耕种模式是实现半干旱区秸秆覆盖条件下玉米绿色高效生产的重要途径.开展2a大田试验,设置传统耕作模式(CK)、秸秆覆盖模式(T1)、秸秆覆盖+深松模式(T2)、秸秆覆盖+碎混模式(T3)4 个处理,研究不同秸秆覆盖耕种模式对玉米根系伤流特性、光合特性、碳氮代谢相关酶活性、生长发育、产量及其构成因素和水分利用特性的影响.结果表明:不同处理玉米根系伤流强度、伤流液中细胞分裂素(CTK)和生长素(IAA)含量均表现为T3>T2>CK>T1,脱落酸(ABA)含量表现为T1>CK>T2>T3;与CK和T1 处理相比,T2 与T3 处理的CTK和IAA含量显著增加、ABA含量显著下降.玉米叶片净光合速率(Pn)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)、蒸腾速率(Tr)、表观叶肉导度(AMC)和叶片水分利用效率(WUEL)均表现为T3>T2>CK>T1,气孔限制百分率(Ls)表现为T3
再生水灌溉是缓解水资源矛盾的有效途径,为表征再生水灌溉后土壤粒度分布(Soil particle size distri-bution,PSD)特性,通过室内土柱模拟试验,设置生活污水(W1)、再生水 1(W2)和再生水 2(W3)共计 3 种灌溉水质,并以自来水(W4)作为对照,采用马尔文激光粒度仪测定灌溉 1a后各处理土壤颗粒百分比,运用分形理论分析了 4种水质处理下土壤PSD的分形特征.结果表明:(1)4 种水质处理下土壤PSD呈单峰分布;与W4 处理相比,W1、W2、W3 处理下土壤黏粒含量增加 0.40%～6.38%,砂粒含量降低 1.58%～13.80%,土壤非均匀性增强,但各处理间差异不显著.(2)再生水灌溉下土壤颗粒呈细粒化趋势,土壤PSD多重分形参数增大,土壤PSD趋于不均匀.在 0～10 cm土层,W3 处理下土壤PSD多重分形参数容量维数D(0)、信息维数D(1)、相关维数D(2)和多重分形奇异谱宽Δα(q)最大,分别为 0.943、0.837、0.823 和 1.035;在 10～20 cm土层,W2 处理下D(0)、D(1)、D(2)和Δα(q)最大,分别为0.943、0.851、0.852 和1.009.(3)土壤PSD的多重分形参数D(0)、D(1)、D(2)、Δα(q)和α(0)与土壤黏粒含量呈显著正相关,与砂粒含量呈显著负相关,土壤分形特征由土壤中黏粒与砂粒的相对含量控制.研究表明,在试验期内,再生水灌溉下土壤PSD的空间异质性与非均匀性增大,可以通过多重分形参数进行定量表征.
