Chinese Bulletin of Botany ›› 2017, Vol. 52 ›› Issue (3): 307-321.DOI: 10.11983/CBB16109

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Effect of Seasonal Grazing on Trade-off Among Plant Functional Traits in Root, Stem and Leaf of Leymus chinensis in the Temperate Grassland of Inner Mongolia, China

Yan Pan1, Jirui Gong1*, Taogetao Baoyin2, Qinpu Luo1, Zhanwei Zhai1, Sha Xu1, Yihui Wang1, Min Liu1, Lili Yang1   

  1. 1State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Resources Science & Technology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
    2College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
  • Received:2016-05-12 Accepted:2016-10-16 Online:2017-05-01 Published:2017-05-27
  • Contact: Gong Jirui
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Abstract:

Grazing represents the main way for utilization of grassland, and different seasonal grazing affects compensatory growth and regrowth by affecting the trade-off among plant functional traits. To understand the trade-off and variation among the ‘soft’ and ‘hard’ traits under different seasonal grazing, we measured soft traits such as plant height, internode length, and tillers and hard traits such as photosynthetic capacity, antioxidant system and substance contents of osmotic adjustment in root, stem and leaf of Leymus chinensis. Compared with spring grazing, under continuous grazing, L. chinensis adopts stronger avoidance and tolerance strategies. The soft traits and some hard traits, such as photosynthetic capacity, chlorophyII fluorescence characteristics and energy partition show the same trend: net photosynthetic rate decreasing in June and increasing in August. However, the plants have higher photosynthetic product in leaf under spring grazing, which is harmful for regrowth, with vast organic matter contents eaten after grazing. However, under continuous grazing, L. chinensis allocates more to stem and root, which is conducive to uptake water from soil and regrow by using the remaining organic matter. Thus, under three-year grazing, continuous grazing is better for regrowth of L. chinensis and sustainable for grassland.