柠条（Caragana korshinskii）、花棒（Hedysarum scoparium）根系生长对土壤含水量的响应

doi:10.7522/j.issn.1000-694X.2025.00321

摘要/Abstract

摘要：

在荒漠生态系统中，土壤水分的时空异质性是制约植物生长与分布的关键因子。然而，目前关于植物根系结构如何响应水分条件变化的机制尚不明确，尤其缺乏针对荒漠灌木通过调节根系生长与分布以适应土壤水分动态的系统研究。本研究以甘肃临泽县北部绿洲-荒漠过渡带为研究区域，采用微根窗与土壤水分自动观测系统相结合的方法，在2022—2024年生长季，对柠条（Caragana korshinskii）和花棒（Hedysarum scoparium）的细根的垂直分布与伸长率进行了连续观测。结果表明：（1）花棒和柠条细根分布在垂直方向上均呈先增多后减少的趋势，占比最大值分别在34~69 cm和52~86 cm土层处。降水量仅80 mm左右的枯水年，花棒细根有向浅层土壤聚集的趋势，且浅层细根占比大于深层，而柠条各层细根占比始终保持稳定且深层细根占比大于浅层。（2）两个物种细根伸长率在垂直方向上均先增大后减小，且大部分观测期内柠条细根伸长率大于花棒；3年观测期中，平水年两个物种细根伸长率显著高于枯水年。（3）两物种的根系伸长率具有显著的季节变化特征，各土层的伸长率峰值都出现在秋季。土壤含水量分别能解释花棒和柠条细根伸长率19%~37%和41%~75%的变异。物种根系分层差异为荒漠地区植物配置提供了理论依据。

关键词: 荒漠灌木, 细根分布, 伸长率, 土壤含水量

Abstract:

In desert ecosystems， spatiotemporal heterogeneity of soil moisture is a key limiting factor constraining plant growth and distribution. However， the mechanisms by which plant root system architecture responds to changes in water availability remain unclear， particularly lacking systematic research on how desert shrubs regulate root growth and distribution to adapt to soil moisture dynamics. This study was conducted in the oasis-desert ecotone north of Linze County， Gansu Province. Using a combination of minirhizotron and automated soil moisture monitoring systems， continuous observations were made on the vertical distribution and elongation rate of fine roots of Caragana korshinskii and Hedysarum scoparium during the growing seasons from 2022 to 2024. The results showed that：（1） The vertical distribution of fine roots for both species exhibited an initial increase followed by a decrease， with the maximum proportions occurring at soil depths of 34-69 cm for H. scoparium and 52-86 cm for C. korshinskii. In a dry year with approximately 80 mm of rainfall， fine roots of H. scoparium tended to concentrate in shallower soil layers， with a higher proportion in shallow layers than in deep layers. In contrast， the proportion of fine roots of C. korshinskii remained stable across layers， with a consistently higher proportion in deep layers than in shallow layers. （2） The fine root elongation rates of both species initially increased and then decreased with soil depth. In most observation periods， the elongation rate of C. korshinskii was greater than that of H. scoparium. Over the three-year observation period， the fine root elongation rates of both species were significantly higher in normal-water years than in dry years. （3） Both species exhibited significant seasonal variation in fine root elongation rate， with peak values in all soil layers occurring in autumn. Soil water content explained 19%-37% of the variation in fine root elongation rate for H. scoparium and 41%-75% for C. korshinskii. The differences in root stratification between species provide a theoretical basis for plant species selection and arrangement in desert regions.

Key words: desert shrubs, fine root distribution, root elongation rate, soil water content

中图分类号:

Q945

陈炫廷, 周海, 杨淇越, 任珩, 顾虎利, 范明彦. 柠条（Caragana korshinskii）、花棒（Hedysarum scoparium）根系生长对土壤含水量的响应[J]. 中国沙漠, 2026, 46(1): 252-261.

Xuanting Chen, Hai Zhou, Qiyue Yang, Heng Ren, Huli Gu, Mingyan Fan. Responses of root growth to soil moisture in Caragana korshinskii and Hedysarum scoparium[J]. Journal of Desert Research, 2026, 46(1): 252-261.

图/表 5

图1 2022—2024年试验样地气象状况

Fig.1 Meteorological conditions at the study site from 2022 to 2024

图2 2022—2024年试验样地土壤含水量动态

Fig.2 Dynamics of soil water content in the experimental plot from 2022 to 2024

图3 两种荒漠植物不同土层处细根总根长占比动态

Fig.3 Temporal dynamics of the proportional fine‐root length in different soil layers for the two shrub species

图4 不同土壤深度下两种荒漠植物细根伸长率动态注:不同小写字母表示相同物种不同土层间差异显著(P<0.05)；*表示两个物种差异显著(P<0.05);**表示两个物种差异极显著(P<0.01)

Fig.4 Fine‐root elongation rate of the two species across soil depths

图5 不同土壤深度下两种荒漠植物细根伸长率与土壤含水量的线性关系

Fig.5 Liner relationships between fine-root elongation rates of two shrub species and soil water content at different soil depths

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