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作 者 ：赵雪艳,汪诗平*

期 刊 ：生态学报 2009年 29卷 6期 页码：2906~2918

关键词：放牧率；叶片解剖结构；化学成分；内蒙古典型草原；

Keywords:stocking rate, plant leaf anatomical characteristics, chemical component, Inner Mongolia steppe,

摘 要 ：以内蒙古草原生态系统定位研究站15a长期放牧样地的7种主要植物（扁蓿豆、冰草、糙隐子草、冷蒿、小叶锦鸡儿、星毛委陵菜、羊草）为材料，通过对不同放牧率（无牧、轻牧、中牧、重牧）下植物叶片解剖结构（角质层厚度、表皮细胞面积、叶肉细胞面积、栅栏/海绵组织厚度、叶片厚度、中脉厚度）特征以及化学成分变化的研究，探讨不同植物对长期放牧的适应策略，从而为典型草原放牧演替规律提供理论依据。结果表明：总体上，植物角质层厚度随放牧率的增加而增加；而表皮细胞面积、叶肉细胞面积、叶片厚度等指标不同植物的反应不同。植物叶片化学成分（全N、全C、纤维素含量、叶绿素a+b及a/b）随放牧率的变化较小。放牧率对冰草、冷蒿、羊草的全C、全N、叶绿素和纤维素含量均没有显著影响（P＞0.05），但却显著降低了糙隐子草的比叶面积及星毛委陵菜和小叶锦鸡儿的叶绿素含量，提高了糙隐子草的纤维素含量及扁蓿豆叶片的全N含量（P<0.05）。因此，不同植物对放牧的反应存在着明显的种间差异，其中植物角质层厚度、表皮细胞面积、叶片厚度和中脉厚度是植物对放牧响应最为敏感的指标。

Abstract:To determine the adaptive strategies of different plant species to stocking rates, the leaf anatomical characteristics (total leaf thickness、upper and lower epidermis cells area、mesophyll thickness or area、upper and lower cuticle thickness) and their chemical components (total C、total N、fiber and chlorophyll content) of seven species (Melissitus rutenica, Agropyron cristatum, Cleistogenes squarrosa, Artemisia frigida,Caragana microphylla, Potentilla acaulis, Leymus chinensis) were studied under 15-year different stocking rates at the Inner Mongolia Grassland Ecosystem Research Station in summer 2006. The results showed that the cuticle thickness of these seven species increased with stocking rate increase, while other leaf anatomical features had inconsistent response to stocking rates. Higher stocking rate did not affect leaf total C, total N, fiber and chlorophyll contents for A. cristatum，A. frigida and L. chinensis, whereas it decreased significantly SLA (specific leaf area) of C. squarrosa and chlorophyll content of C. microphylla and P. acaulis. It increased total N of M. rutenica, fiber content of C. squarrosa compared with no-grazing. Therefore, the effects of different stocking rates on plants are species-specific. Some indicators, such as cuticle thickness, area of epidermis cells, leaf thickness and mid rib thickness, are most sensitive to grazing.

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