摘要
根系分叉数和连接长度影响植物根系分布格局,二者的权衡关系对理解植物根系构型的生态适应策略有重要意义。利用Arc GIS建立研究区域的数字高程模型,并提取坡向数据,采用全根挖掘和Win-RHIZO根系分析仪相结合的方法,研究了祁连山北坡高寒退化草地不同坡向甘肃臭草(Melica przewalskyi)根系分叉数与连接长度间的关系。结果表明:随着坡向由北坡向东坡、西坡、南坡转变,草地群落的密度、高度、地上生物量和土壤含水量逐渐减小,甘肃臭草种群的密度、高度以及根系连接长度呈逐渐增大的趋势、分叉数逐渐减小;不同坡向甘肃臭草根系分叉数与连接长度间的相关性存在差异(p<0.05),在南坡和北坡甘肃臭草根系分叉数和连接长度之间存在极显著的负相关关系(p<0.01),在东坡和西坡二者之间存在显著的负相关关系(p<0.05),甘肃臭草分配给根系分叉数与连接长度的资源间存在着"此消彼长"的权衡关系。不同坡向甘肃臭草根系分叉数和连接长度的资源配置模式反映了植物根系功能性状对环境的响应和适应,以及根系构型构建的投资权衡机制。
Aims The number of root forks and link length influence distribution patterns of plant roots.The trade-off between root forks and link length has an important meaning for comprehending ecological adaptation strategy of root architecture.Our objective was to study the relationship between root forks and link length of Melica przewalskyi population in response to slope aspects in the northwest of China.Methods The study site was located in a degraded alpine grassland on the northern slope of Qilian Mountains,Gansu Province,China.Survey and sampling were carried out in 80 plots that were set up along four aspect transects of a hill with 20 m distance between adjacent plots.A handheld GPS was used to record latitude,longitude and altitude of each plot.Arc GIS was used to set up digital elevation model（DEM） to extract the information of elevation,aspect,and slope for each plot.The traits of plant communities were investigated and three individual samplings of M.przewalskyi were collected randomly in each plot.The samples were cleaned and divided into different organs.The roots were scanned with the Win-RHIZO for measurements of root forks and link length in laboratory,and biomass of different organs was measured after being dried at 80 °C in an oven.The 240 plots were categorized into groups of north,east,west and south aspects of slopes,and the linear regression analysis was then used to examine the trade-off relationship between root forks and link length in different groups.Important findings With a change of the aspect from north to east,west and south,the density,aboveground biomass,height and soil moisture content of the plant community displayed a pattern of steadily declining,while the density,height,root link length of M.przewalskyi increased,and the root forks decreased.The number of root forks was negatively correlated with the link length in all aspects,but the relationship varied along the aspect gradient（p〈0.05）.There was a highly significant negative correlation（p〈0.01） between the root forks and linklength on north slope and south slope,whereas less significant（p〈0.05） on the east slope and west slope,all indicating a trade-off relationship between the root forks and link length.Consequently,the patterns of resource allocation between root forks and link length in different slope habitats reflected the response and adaption of plant root functional traits to their biotic and abiotic environments and the investment balance mechanism for root architecture construction.
出处
《植物生态学报》
CAS
CSCD
北大核心
2015年第6期577-585,共9页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(41461013和9112-5014)
