施氮对苜蓿初花期光合日变化、叶片形态及干物质产量的影响  

Effect of nitrogen application on photosynthetic daily variation,leaf morphology and dry matter yield of alfalfa at the early flowering growth stage

作　　者：孙延亮 赵俊威 刘选帅 李生仪 马春晖[1] 王旭哲[1] 张前兵[1] SUN Yan-liang;ZHAO Jun-wei;LIU Xuan-shuai;LI Sheng-yi;MA Chun-hui;WANG Xu-zhe;ZHANG Qian-bing(College of Animal Science and Technology,Shihezi University,Shihezi 832003,China)

机构地区：[1]石河子大学动物科技学院,新疆石河子832003

出　　处：《草业学报》2022年第9期63-75,共13页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(32001400);霍英东青年教师基金(171099);兵团科技创新骨干人才计划项目(2021CB034);国家现代农业产业技术体系资助。

摘　　要：通过研究不同氮素水平下滴灌苜蓿叶片形态特征、光合日变化规律,分析不同施氮水平下滴灌苜蓿光合日变化、叶片形态与干物质产量的关系,以期进一步揭示施氮对紫花苜蓿干物质及产量形成的影响机制,进而为优化实际生产中紫花苜蓿的氮管理策略提供理论依据。采用单因素随机区组设计,设置0(CK)、60(N_(1))、120(N_(2))和180 kg·hm^(-2)(N_(3))共4个施氮水平,在紫花苜蓿初花期对光合日变化、叶片形态、叶片氮含量和苜蓿产量构成进行测定。结果表明,施氮处理下苜蓿的叶片净光合速率、蒸腾速率和水分利用效率均高于不施氮处理,施氮处理的苜蓿叶片胞间CO_(2)浓度低于不施氮处理。对净光合速率和蒸腾速率综合影响最大的环境因子是光合有效辐射。随着施氮量的增加,紫花苜蓿的叶长、叶宽、叶面积、比叶重,以及叶片干重、茎秆干重、干物质产量、叶片氮含量、淀粉和可溶性糖含量均呈先增加后降低的趋势。不同施氮水平下,对叶片形态结构影响最大的为叶面积,其次分别为比叶重、叶长和叶宽,对苜蓿干物质产量影响从大到小依次为叶片氮含量>净光合速率>叶面积>蒸腾速率>比叶重。不施氮和高氮处理下光合速率下降主要是因为光合活性受到抑制,属于非气孔因素。基于主成分分析,干物质产量、叶片形态以及光合作用综合得分最高的为N_(2)处理,其次分别为N_(3)、N_(1)和CK处理。因此,施氮肥有助于紫花苜蓿光合面积和光合速率的协同改进,有利于光合产物的生成,从而促进苜蓿干物质产量的增加,在施氮量为120 kg·hm^(-2)时提升效果最为明显。In this research,studies on leaf morphological characteristics and the diurnal changes of photosynthesis in a drip-irrigated alfalfa(Medicago sativa)crop were monitored under different nitrogen levels and the relationships between the daily changes of photosynthesis,leaf morphology,and dry matter yield were analyzed in order to better understand the mechanism of the impact of nitrogen on alfalfa dry matter yield development.The study thus provides a theoretical framework for optimizing the nitrogen management strategy of alfalfa in commercial production.The study used a single factor randomized complete block design with four nitrogen application levels of 0(CK),60(N_(1)),120(N_(2)),and 180 kg N·ha^(-1)(N_(3)).At the early flowering growth stage,daily photosynthetic variation,leaf morphology,leaf nitrogen content,and yield components were of the alfalfa were measured.It was found that the net photosynthetic rate,transpiration rate,and water use efficiency of alfalfa leaves under the nitrogen application treatments were higher than those under the non-nitrogen application treatment,and the intercellular CO_(2) concentration of alfalfa leaves under the nitrogen application treatments was lower than that under the non-nitrogen application treatment.The environmental factor that had the greatest combined effect on net photosynthetic rate and transpiration rate was photosynthetic effective radiation.The leaf length,leaf width,leaf area,and specific leaf weight of alfalfa,as well as leaf dry weight,stem dry weight,dry matter yield,leaf nitrogen content,starch,and soluble sugar content all showed a pattern of initial increase and then decrease with successive increments of N application.For different nitrogen concentrations,leaf area was the most significant factor affecting leaf morphological structure,followed by leaf specific weight,leaf length,and leaf width.The effects on dry matter yield of alfalfa were,in descending order,leaf nitrogen content>net photosynthetic rate>leaf area>transpiration rate>specific leaf we

关 键 词：紫花苜蓿 氮 叶片形态 光合日变化 干物质产量 

分 类 号：S541.9[农业科学—作物学]