高寒退化草地星毛委陵菜根系分叉数和连接长度的关系  

Trade-off between root forks and link length of Potentilla acaulis in degraded alpine grassland

作　　者：张伟涛 赵成章 宋清华 王继伟 王建良 姚文秀 李群 

机构地区：[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　　处：《生态学报》2017年第24期8518-8525,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金(41461013,91125014);甘肃省生态学重点学科

摘　　要：根系分叉数和连接长度影响着植物根系的空间分布和资源获取,二者的权衡关系有助于深层次的理解植物根系构型的生态适应性。在祁连山北坡高寒退化草地,设置未退化(T_1)、轻度退化(T_2)、中度退化(T_3)和重度退化(T_4)4个退化梯度样地,采用全根挖掘和Win-RHIZO根系分析仪相结合的方法,研究了星毛委陵菜(Potentilla acaulis)根系分叉数和连接长度之间的关系。结果表明:随着天然草地退化程度的加剧,草地群落的密度、高度、盖度、地上生物量和土壤含水量逐渐减小,土壤紧实度不断增大,星毛委陵菜种群的密度、高度、盖度、地上和地下生物量、根冠比和根系连接长度逐渐增大,分叉数呈相反的变化趋势;不同退化草地星毛委陵菜根系分叉数与连接长度之间的相关性存在差异(P<0.05),在未退化(T_1)和重度退化(T_4)草地星毛委陵菜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),在轻度退化(T_2)和中度退化(T_3)草地二者之间存在显著的负相关关系(P<0.05)。随着天然草地的退化,星毛委陵菜选择减小根系分叉数和增大根系连接长度的构型构建模式,反映了植物不同功能性状间生物量分配的权衡机制。Root forks and link length influence spatial distribution and resource retrieval of plant roots. The trade-off between root forks and link length has a significant effect on ecological adaptation of root architecture. This study used the MaChangtan grassland in eastern SuNan country on the northern slope of Qilian Mountains in Northwest China （38°47＇22.1＂-38°52＇11.4＂ N, 99°45＇11.7＂-99°57＇41.2＂ E） as a study field. The altitude is 2610-2632 m, the average annual temperature varies within a range of 1-2℃, the annual precipitation is 270-350 mm, the climate is continental and vertical, the soil is composed primarily of mountain chestnut soil, and the dominant native vegetation is mainly perennial grasses and forbs. In August 2014, the density, height, coverage, and species of the plants in the community were recorded, which were from 1 m×1 m grids in four kinds of degradation gradients in six replicates, SC-900 Soil Compaction Meter was used to measure soil compaction （at 0-10 cm, 10-20 cm, and 20-30 cm） in each grid （five replicates）, and the average compaction of the entire 0-30 cm depth was used to represent the degradation gradient. According to detailed community study, population characteristics of Stipa krylovii and grassland stocking rate （2004-2013）, we defined as：no degradation （〉 90%）, light degradation （98%-115%）, moderate degradation （120%-131%）, and heavy degradation （135%-156%）. Then, the method of whole root system excavation was used to dig soil cores （30×30×50 cm） from 30 cm×30 cm grids in all four kinds of degradation gradients （240 in all）, and sieved it （bore diameter=0.25 mm） to clean and select Potentilla acaulis in a nearby river. Meanwhile, we used stratified sampling （0-50 cm）, where each layer of soil was 10 cm, with an auger （diameter=4 cm）, to collect soil in every layer and the total depth. In the laboratory, the roots divided from P. acaulis were scanned with Win-RHIZO to measure its root forks and link l

关 键 词：星毛委陵菜 根系分叉数 根系连接长度 根系构型 权衡关系 祁连山北坡 

分 类 号：Q948[生物学—植物学]