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琵琶柴根系分叉数与连接长度权衡关系的坡向差异

郑慧玲,赵成章**,段贝贝,冯威,徐婷,韩玲   

  1. (西北师范大学地理与环境科学学院,甘肃省湿地资源保护与产业发展工程研究中心, 兰州 730070)
  • 出版日期:2015-10-10 发布日期:2015-10-10

Differences of tradeoff relationship among root forks and link length in Reaumuria soongorica on slopes of different aspects.

ZHENG Hui-ling, ZHAO Cheng-zhang**, DUAN Bei-bei, FENG Wei, XU Ting, HAN Ling   

  1. (Research Center of Wetland Resources Protection and Industrial Development Engineering of Gansu Province, College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China)
  • Online:2015-10-10 Published:2015-10-10

摘要: 权衡关系是生活史对策理论的基础,根系分叉数和连接长度的权衡关系对理解植物在不同生境下的表型可塑性有重要意义。利用ArcGIS建立研究区域的数字高程模型(DEM),采用全根系挖掘法,研究了祁连山北坡荒漠草原不同坡向琵琶柴(Reaumuria soongorica)根系分叉数和连接长度间的关系。结果表明:随着坡向由南坡转向西坡、东坡、北坡,草地群落密度、盖度、高度和土壤含水量呈逐渐增加的趋势,琵琶柴种群的高度、根冠比以及根系连接长度呈逐渐减小趋势,比根长和分叉数逐渐增加;不同坡向琵琶柴根系分叉数和连接长度的相关性存在差异,在南坡和北坡琵琶柴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);琵琶柴根系分配给根系分叉数和连接长度的资源间存在着“此消彼长”的权衡关系。不同坡向琵琶柴根系合理权衡连接长度和分叉数的资源配置模式,反映了异质生境中资源多重竞争下琵琶柴生物量分配机制和提高种群适应性的策略。

关键词: 萌芽期, 苹果, 氮水平, 氮去向, 新梢旺长期, 土壤氮库盈亏

Abstract: Tradeoff is the basis of life history strategy theory. Elucidation of the tradeoff between root forks and link length is important for understanding the phenotypic plasticity of plants under different habitat conditions. By using the ArcGISestablished regional digital elevation model (DEM), this paper studied the tradeoff relationship between root forks and link length of Reaumuria soongorica at different slope aspects in a desert grassland on the northern slope of Qilian Mountains, Northwest China with the method of whole root system excavation. The results showed that the plant community density, cover, height and soil moisture content displayed a pattern of gradual increase, and the height, rootshoot ratio and root link length of R. soongorica displayed a pattern of gradual decrease, while the specific root length and root forks increased gradually with the slope aspect turned from south to west, east and north. The relationship between root forks and link length varied with the slope aspect: there was a highly significant negative correlation between the root forks and link length at north slope and south slope (P<0.01), whereas the correlation reached a significant level at the east slope and west slope (P<0.05). There was a tradeoff in resource allocation between the root forks and link length. The resource allocation mode in roots by reasonable tradeoff between root forks and link length with changes in slope aspect of habitat reflected the mechanism of biomass allocation and the adaptation strategy of R. soongorica populations under conditions of multiple competitions for resources in diverse habitats.

Key words: nitrogen fate, new shoot growing stage, apple tree, soil nitrogen budget, nitrogen level, germination stage