紫花苜蓿叶输导组织解剖结构和光合特性对外源氮的响应  

Response of Leaf Conducting Tissue Anatomy and Photosynthetic Characteristics of Alfalfa to Exogenous Nitrogen

作　　者：张晓玲[1,2] 刘晓静[1,2] 郝凤[1,2] 

机构地区：[1]甘肃农业大学草业学院,兰州730070 [2]草业生态系统教育部重点实验室/中美草地畜牧业可持续发展研究中心,兰州730070

出　　处：《西北植物学报》2015年第8期1597-1603,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金(31460622);公益性行业(农业)科研专项(201403048-8)

摘　　要：以紫花苜蓿品种‘甘农3号’和‘陇东苜蓿’为研究材料,采用室外(防雨网室)盆栽营养液砂培法,研究了2种氮素形态(NO3--N,NH4+-N)的5个氮素水平(0、105、210、315、420mg·L-1)处理对叶片输导组织解剖结构及光合特性的影响。结果显示:(1)与无氮处理相比,供氮处理下‘甘农3号’和‘陇东苜蓿’输导组织的解剖结构和光合特性发生明显变化,叶片输导组织维管束、木质部和韧皮部面积显著增大,导管数显著增多,净光合速率、气孔导度、叶面积和叶绿素含量均显著增加,且在210mg·L-1供氮水平下达到最大值。(2)2种氮素形态相比,‘甘农3号’和‘陇东苜蓿’叶片输导组织维管束面积、木质部面积、韧皮部面积、导管数、净光合速率、气孔导度、叶面积、叶绿素含量均表现为NH4+-N处理好于NO3--N处理。(3)2品种相比,叶片输导组织维管束面积、木质部面积、韧皮部面积、导管数、净光合速率、气孔导度、叶面积、叶绿素含量表现为‘甘农3号’大于‘陇东苜蓿’。研究表明,氮素能通过改善紫花苜蓿叶片输导组织的解剖结构和光合特性,促进紫花苜蓿光合作用;各处理中以NH4+-N、210mg·L-1表现最佳,维管束面积最大,木质部、韧皮部面积大且发育好,导管数最多,而且‘甘农3号’表现更优。The anatomical structure of leaf conducting tissue and photosynthetic characteristics of alfalfa（Medicago sativa L.）were studied based on two nitrogen forms（nitrate nitrogen and ammonium nitrogen）and five nitrogen levels（0,105,210,315,420mg·L-1）.Two cultivars,‘Gannong No.3＇and‘Longdong＇,were selected as materials,and the experiment was conducted outdoors（in flashing net room）using sand culture method.The results showed that：（1）Compared with non-nitrogen treatment,the anatomical structure of leaf conducting tissue of both alfalfa cultivars changed significantly under both nitrogen treatments.The vascular bundle area,xylem area,phloem area and vessel numbers of leaf conducting tissue increased significantly.The photosynthetic rate,stomatal conductance,leaf area and chlorophyll content also increased significantly（P〈0.05）,and the maximum number occurred at nitrogen level 210mg·L-1.（2）Compared with NO3--N treatment,the vascular bundle area,xylem area,phloem area,vessel number,photosynthetic rate,stomatal conductance,leaf area and chlorophyll content increased more under NH4＋-N treatment.（3）Compared with cultivar‘Longdong＇,the vascular bundle area,xylem area,phloem area,ves-sel number,photosynthetic rate,stomatal conductance,leaf area and chlorophyll content performed better in cultivar‘Gannong No.3＇.The data showed that nitrogen can improve the anatomical structure of leaf conducting tissue and photosynthetic characteristics of alfalfa by increasing photosynthesis.The combination of NH4＋-N and 210mg·L-1 performed best in all treatments.The anatomical structure of leaf conducting tissue was improved,the vascular bundle was the biggest,both phloem and xylem showed largest area and developed well,and the number of vessel was also the largest;and‘Gannong No.3＇performed better than‘Longdong＇.

关 键 词：紫花苜蓿 外源氮素 输导能力 光合特性 

分 类 号：Q945.79[生物学—植物学]