苜蓿叶片光合生理参数及抗氧化能力对施氮的响应  

Photosynthetic Physiological Parameters and Antioxidant Capacity of Alfalfa Leaves in Response to Nitrogen Application

作　　者：赵建涛 杨开鑫 马春晖[1] 张前兵[1] ZHAO Jiantao;YANG Kaixin;MA Chunhui;ZHANG Qianbing(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：《中国草地学报》2023年第2期46-55,共10页Chinese Journal of Grassland

基　　金：国家自然科学基金项目(32260347,32001400);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：以紫花苜蓿为研究对象,设置4个施氮量,分别为0(CK)、60(N1)、120(N2)和180(N3)kg/hm^(2),于苜蓿初花期测定叶片氮和磷含量、光合色素含量、气孔开度、抗氧化酶活性、氧化物质含量和干草产量等指标。结果表明,除第2茬氮含量外,苜蓿叶片氮和磷含量在N2处理最高,其中第3茬N2处理的氮含量最高,第1茬N2处理的磷含量最高,分别为53.85 g/kg和3.06 g/kg。与CK处理相比,叶绿素a、叶绿素b及类胡萝卜素含量均在N1或N2处理最高,且N2处理下不同茬次的最大增加量分别为11.4%、23.8%和47.1%。与CK处理相比,施氮可以提高苜蓿叶片的气孔个数和气孔开度。除第4茬超氧化物歧化酶(SOD)外,苜蓿叶片的SOD、过氧化物酶(POD)以及过氧化氢酶(CAT)活性均在N1或N2处理最高。苜蓿叶片丙二醛(MDA)、过氧化氢(H2O2)及脯氨酸(Pro)含量随施氮量增加均呈现先下降后上升的趋势,其中MDA和Pro含量在第3茬N2处理下最低,H2O2含量在第1茬N2处理下最低,分别为2.51μmol/g、1.10μmol/g和56.41μg/g。相关性分析表明,苜蓿叶片氮含量与叶绿素含量和气孔开度之间存在显著正相关关系(P<0.05),与H2O2含量呈显著负相关(P<0.05),叶片磷含量与生理参数的相关性不显著。合理的施氮量(120 kg/hm^(2))通过增加叶片氮和磷含量来提高苜蓿对外界环境变化的适应能力,进而增加苜蓿的干草产量。The nitrogen,phosphorus and photosynthetic pigment contents,stomatal aperture,antioxidant enzyme activity of alfalfa leaves,as well as alfalfa hay yield were measured at the first flowering stage under four nitrogen application rates:0(CK),60(N1),120(N2),and 180(N3)kg/hm^(2).The results showed that except for the nitrogen content of the second cut,alfalfa leaf nitrogen and phosphorus contents were the highest in the N2 treatment,with the highest nitrogen content of the third cut(53.85 g/kg)and the highest phosphorus content of the first cut(3.06 g/kg).Compared with the CK group,chlorophyll a,chlorophyll b and carotenoid contents were the highest in the N1 or N2 treatment,and the maximum increases between different cuts in the N2 treatment were 11.4%,23.8%,and 47.1%,respectively.Nitrogen application increased the number of stomatal number and stomatal aperture of alfalfa leaves compared to the CK.Superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)activities of alfalfa leaves were the highest in the N1 or N2 treatment,except for SOD activity in the fourth cut.The alfalfa leaves exhibited a decrease followed by an increase in malondialdehyde(MDA),hydrogen peroxide(H2O2)and proline(Pro)contents as nitrogen application was increased,with the lowest MDA and Pro contents recorded under the N2 treatment of the third cut and the lowest H2O2level found under the N2 treatment of the first cut,at 2.51μmol/g,1.10μmol/g and 56.41μg/g.Correlation analysis revealed a significantly positive correlation between alfalfa leaf nitrogen content and chlorophyll content as well as stomatal aperture(P<0.05).Additionally,a significant negative correlation was observed between alfalfa leaf nitrogen content and H2O2content(P<0.05).However,there was no significant correlation between alfalfa leaf phosphorus content and physiological parameters.An appropriate application of nitrogen(120 kg/hm^(2))can increase the leaf nitrogen and phosphorus contents to improve the adaptability of alfalfa to external environmental changes and thus i

关 键 词：施氮量 紫花苜蓿 生理参数 抗氧化能力 干草产量 

分 类 号：S541.9[农业科学—作物学]