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草业学报 ›› 2012, Vol. 21 ›› Issue (3): 308-313.

• 研究简报 • 上一篇    下一篇

不同放牧强度下羊草的光合特性日动态变化   ——以呼伦贝尔草甸草原为例

邓钰1,2,柳小妮1,辛晓平2*,闫瑞瑞2,王旭2,杨桂霞2,任正超1   

  1. 1.甘肃农业大学草业学院 草业生态系统教育部重点实验室,甘肃 兰州 730070;
    2.中国农业科学院农业资源与农业区划研究所 呼伦贝尔草原生态系统国家野外科学观测研究站,北京100081
  • 出版日期:2012-06-20 发布日期:2012-06-20
  • 通讯作者: E-mail:xinxp@sina.com
  • 作者简介:邓钰(1986-),女,云南昭通人,在读硕士。
  • 基金资助:
    国家973项目(2010CB833502),公益性行业(农业)科研专项(201003019,201003061,200903060),现代农业产业技术体系建设专项,国家自然科学基金(30960264)和中央级公益性科研院所基本科研业务费专项资金(202-21)资助。

Diurnal dynamics of photosynthetic characteristics of Leymus chinensis under different
grazing intensities taking the Hulunber meadow steppe as an example

YANG Gui-Xia2, REN Zheng-Chao1   

  1. 1.College of Pratacultural Science, Gansu Agricultural University, Key Laboratory of Grassland Ecology System, Gansu Agricultural University, Ministry of Education, Lanzhou 730070, China;
    2.Hulunber Grassland Ecosystem Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China)
  • Online:2012-06-20 Published:2012-06-20

摘要: 在连续放牧方式下,探索羊草的光合特性对不同放牧强度的响应,利用Li-6400便携式光合测定仪对呼伦贝尔羊草草原1个封育对照试验区和5个不同放牧强度试验区内羊草叶片的光合特性进行日变化测定,并与放牧强度(R)进行相关性分析。研究结果表明,8月16日和9月2日,6个试验区内羊草叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)的日变化既有单峰曲线也有双峰曲线变化,而胞间CO2浓度(Ci)日变化呈U字型。围封内羊草的Pn、Tr、Gs均高于放牧区;且羊草的Pn、Tr、Gs均随着放牧强度的增大而下降,Ci则升高;放牧强度越大,其降幅和增幅也越大。Pn、Tr、Gs与R之间均呈显著的负相关关系(P<0.05),Ci与R呈显著的正相关关系(P<0.05);而且6个放牧强度梯度下的Pn、Tr、Gs和Ci在2 d之间有极显著差异(P<0.01)。因此,放牧胁迫和水热条件对羊草的光合作用有抑制作用。

Abstract: To explore the response of photosynthetic characteristics of Leymus chinensis to different grazing intensities under continuous grazing, the diurnal dynamics of photosynthetic characteristics in five grazing plots and one enclosing plot were measured using Li-6400 Portable Photosynthesis System. The correlations between the traits of parameters and grazing intensities (R) were analyzed. Daily variation of net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) appeared as a single peak curve and a double-peak curve in all plots on 16th August and 2nd September respectively, but intercellular CO2 concentration (Ci) showed a U shape trend. In the enclosed plot, Pn, Tr, and Gs were higher than those in the grazed plots. In addition, Pn, Tr, and Gs decreased with an increase in grazing intensity, but Ci increased. It is suggested that the variation range is greater under higher grazing intensities. There were significant negative correlations between Pn, Tr, Gs and R but Ci was significantly positively correlated with R. There were significant differences in Pn, Tr, Gs and Ci among 6 grazing intensities on the two dates. Hence, herding intensity and hydrothermal conditions can inhibit photosynthesis by L. chinensis.

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