施氮对紫花苜蓿干旱复水后生长恢复能力的影响  

Effect of the level of nitrogen supply on the growth resilience of Medicago sativa after rewatering

作　　者：臧军蕊 张钰婷 张英豪 刘洋铭 邓文慧 刘世鹏[2] 孙娈姿[1] ZANG Junrui;ZHANG Yuting;ZHANG Yinghao;LIU Yangming;DENG Wenhui;LIU Shipeng;SUN Luanzi(College of Grassland Agriculture,Northwest A&F University,Yangling 712100,Shaanxi,China;School of Life Science,Yan’an University,Yan’an 716000,Shaanxi,China)

机构地区：[1]西北农林科技大学草业与草原学院,陕西杨凌712100 [2]延安大学生命科学学院,陕西延安716000

出　　处：《草业科学》2024年第3期620-627,共8页Pratacultural Science

基　　金：国家自然科学基金项目(32160761)。

摘　　要：植物复水后的生长恢复能力是体现植物干旱适应性的重要方面。施氮是常见的栽培措施,但施氮对紫花苜蓿(Medicago sativa)复水后生长恢复能力的影响尚不明晰。本研究在低氮(3 mmol·L^(−1))和高氮(7 mmol·L^(−1))处理下对紫花苜蓿进行水培,在培养液中添加聚乙二醇-6000模拟干旱-复水情况,在干旱结束当天、复水7 d以及24 d,测定紫花苜蓿地上和地下部的生物量、含氮量、非结构性碳水化合物以及相关酶活性。结果显示,复水24 d时,高氮处理的总生物量高于对照组(未受干旱处理)11.0%,发生了“补偿生长”,而低氮处理的生长尚未恢复,生物量低于对照组19.6%。由于“干旱记忆”,复水7 d以及24 d时,高氮处理的根冠比、根系中淀粉和可溶性糖含量显著增加(P<0.05),而低氮处理则无显著变化(P>0.05)。复水7 d,高氮下紫花苜蓿叶片蔗糖磷酸合成酶(SPS)活性下降,而蔗糖合成酶(SS)和根中酸性转化酶(AI)活性显著提高(P<0.05)。复水24 d时,与低氮处理相比,高氮处理更明显地提高了SS活性(P<0.05)。结果表明,施氮通过增强植物叶片SS酶活性,提高根系干物质、淀粉和可溶性糖的积累,从而增强紫花苜蓿复水后的生长恢复能力。Growth resilience is an important aspect of plant adaptability to drought.Nitrogen(N)application is a common cultivation measure,but its impact on growth resilience after rewatering of alfalfa(Medicago sativa)is still unclear.In this study,alfalfa grown under different N supplies(3 mmol·L^(−1) and 7 mmol·L^(−1))was rewatered after drought,which was simulated by adding polyethylene glycol-6000 in the nutrient solution.The growth,nitrogen content,content of non�structural carbohydrates,and activity of enzymes for sucrose conversion were monitored at the end of drought,and on days 7 and 24 after rewatering.On day 24 after rewatering,the dry matter of plants grown under high N condition increased by 11.0%,showing“compensatory growth”,whereas the plants grown under low N condition did not recover and their dry biomass was 19.6%lower than that of the control group(without drought treatment).Because of the“drought memory”,the plants grown under high N conditions significantly increased root-to-shoot ratio,root starch,root soluble sugar,and nitrogen content,whereas the root-to-shoot ratio,root sugar,and nitrogen content in roots did not change in plants grown under low N condition at days 7 and 24 after rewatering.On day 7 after rewatering,the activity of sucrose phosphate synthase(SPS)in leaves significantly decreased(P<0.05)in plants,whereas the activity of sucrose synthase(SS)and acid convertase(AI)significantly increased(P<0.05).On day 24 after rewatering,plants grown under high N conditions consistently maintained higher SS activity(P<0.05).The results indicate that nitrogen application increased the SS activity of plants;increased the accumulation of dry matter,starch,and soluble sugar in the root;and facilitated the growth resilience of alfalfa after rewatering.

关 键 词：抗旱性 恢复力 供氮量 根冠比 可溶性糖 淀粉 蔗糖代谢相关酶 

分 类 号：S541.9[农业科学—作物学]