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草业学报 ›› 2016, Vol. 25 ›› Issue (7): 52-61.DOI: 10.11686/cyxb2015323

• 研究论文 • 上一篇    下一篇

千里香杜鹃根系生物量时空动态特征及其生态适应

曹文侠, 李文   

  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, 中-美草地畜牧业可持续发展研究中心, 甘肃 兰州 730070
  • 收稿日期:2015-06-29 修回日期:2015-09-30 出版日期:2016-07-20 发布日期:2016-07-20
  • 作者简介:曹文侠(1970-),男,甘肃会宁人,副教授,博士。E-mail: caowx@gsau.edu.cn

Spatio-temporal trends for fine root biomass of alpine Rhododendron thymifolium and their significance for ecological adaptation in Qilian Mountain

CAO Wen-Xia, LI Wen   

  1. Grassland Science College of Gansu Agricultural University, Grassland Ecosystem Key Laboratory of Ministry of Education, Si-no-U.S. Research Centers for Sustainable Grassland and Livestock Management, Lanzhou 730070, China
  • Received:2015-06-29 Revised:2015-09-30 Online:2016-07-20 Published:2016-07-20

摘要: 以东祁连山高寒杜鹃灌丛草地建群种-千里香杜鹃为对象,研究了灌丛基部和灌丛间千里香杜鹃及其他植物根系生物量水平与垂直分布特征,以及不同生育期的动态规律。结果表明,随土层的深入,千里香杜鹃地下粗根、细根生物量,以及群落其他植物的地下活根及死根生物量均随土层的深入显著降低,千里香杜鹃地下细根生物量的90%分布在0~20 cm的土层中,千里香杜鹃灌丛基部生物量大于灌丛间。千里香杜鹃细根生物量在萌动期和休眠前相对较低,从6月份开始进入快速增长期,7月达最大;表层峰值的出现总是早于深层,而灌丛间峰值早于灌丛基部,灌丛间细根变幅活跃。群落其他植物地下生物量从萌动初开始下降,7月达最低,8月出现小幅增长后开始下降,在生长季末呈现较大幅度增长;随土层加深,死根生物量比例增加,7, 8月份0~10 cm层土壤中千里香杜鹃活根占总生物量的比值最大,此时,群落活根总量接近或大于死根,但年平均群落死根量大于活根,深层动态升降的出现滞后于表层。

Abstract: Rhododendron thymifolium is a dominant species in alpine azalea shrub land in Eastern Qilian Mountains. The horizontal and vertical distribution of root biomass for R. thymifolium and of other associated plant species were measured under the shrub canopy and in the gaps between plants of R. thymifolium, and seasonal trends were monitored. Coarse and fine-root biomass, and other species root biomass decreased with increasing soil depth. For R. thymifolium, 90% of fine root biomass was located in the 0-20 cm soil layer, and root biomass under the shrub canopy was greater than that in the between-plant gaps. The fine-root biomass of R. thymifolium was less during the germination period and pre-dormancy periods; the fine roots grew rapidly from June, and reached peak values in July. Peak values always occurred earlier in the surface layer than in the deep layer, and roots in gap areas appeared earlier than those in the shrub canopy area. Gaps between shrubs were regions of active fine root growth. Root biomass of other species began to decline from the sprout period, and was low in July, then reached a maximum at the end of the growing season. The annual average dead root biomass was greater than live root biomass, the dead∶live root biomass ratio increased with soil depth.