放牧强度和短期休牧对青藏高原东部高寒草甸优势物种根系分泌速率的影响  

The effects of grazing on root exudates of dominant species in an alpine meadow of the eastern Tibetan Plateau

作　　者：陈冬明[1,2] 孙庚[2] 郑群英[3] 张楠楠[2] 冉启凡 史长光[3] 徐良英[5] 曾凯[1] 刘琳[1] 

机构地区：[1]四川农业大学动物科技学院草学系,成都611130 [2]中国科学院成都生物研究所中国科学院山地生态恢复与生物资源利用重点实验室生态恢复与生物多样性保育四川省重点实验室,成都610041 [3]四川省草原科学研究院,成都610097 [4]重庆市畜牧科学院,荣昌4024605 [5]九寨沟风景名胜区管理局,九寨沟623402

出　　处：《应用与环境生物学报》2016年第4期555-560,共6页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31500346;31350110328);四川省科技厅项目(2014HH0017;2015HH0025;2015JY0231;2016HH0082);中国科学院"西部之光"项目和中国科学院成都生物研究所青年研究员项目资助~~

摘　　要：根系分泌物是调节土壤养分循环的关键物质,对土壤微生物生理活性和有机物分解等土壤生态过程有关键影响.为了解放牧条件下根系分泌物分泌速率和变化规律,在放牧管理试验样地上,采用原位草本根系分泌物收集法,在生长旺季测定不同放牧强度(不放牧、轻度放牧、重度放牧)和放牧停止后1 d和21 d取样(视为短期休牧)青藏高原高寒草甸优势物种垂穗披碱草(Elymus nutans)的根系分泌速率.结果显示:放牧条件下,垂穗披碱草在生长旺季正午的根系分泌平均速率(以C计)为851.29μg g^(-1) h^(-1).放牧停止后1 d,不放牧、轻度放牧和重度放牧的根系分泌速率无显著差异;而放牧停止后21 d,轻度放牧的根系分泌速率[(1 032.33±53.63)μg g^(-1) h^(-1)]和地上生物量增量显著高于不放牧,重度放牧则与不放牧差异不显著.本研究表明,轻度放牧和适当短期休牧能够增加根系分泌速率,并可能通过正反馈作用刺激植物地上补偿生长.Root exudates are the key substances in regulating soil nutrient cycling, and they have pivotal impacts on soil microbial activity and organic matter decomposition. This paper aimed to clarify secretion rates and changes of root exudates under grazing condition. We conducted a grazing management experiment and adopted in situ method to measure root exudates of the dominant species Elymus nutans under different grazing intensities （no grazing, light grazing, heavy grazing） and different days after grazing stopped （1 day and 21 day） during the peak growing season in an alpine meadow of the eastern Tibetan Plateau. The results showed an average rate of root exudates orE. nutans as 851.29 μg · g-1 root h-1 during the peak growing season. The rate of root exudates was significantly higher in light grazing than no grazing, but there was no significant difference between heavy grazing and no grazing. The rate of root exudation 1 day after grazing showed no significant difference from that of no grazing, while the rate was significantly higher in 21 day after grazing than in 1 day after grazing and the no grazing. This study showed that both light grazing and rest grazing could enhance the rate of root exudation, therefore beneficial to maintenance of soil fertility in an alpine meadow ecosystem.

关 键 词：根系分泌物 放牧强度 垂穗披碱草 高寒草甸 野外原位根系分泌物测定法 

分 类 号：S812[农业科学—草业科学]