Hu Hui, Bao Weikai, Huang Long, Li Fanglan
Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
Henan Key Laboratory of Water Pollution Control and Rehabilitation Henan University of Urban Construction Pingdingshan China.
Ecol Evol. 2024 Feb 7;14(2):e10889. doi: 10.1002/ece3.10889. eCollection 2024 Feb.
Fine root (diameter < 2 mm) distribution influences the potential for resource acquisition in soil profiles, which defines how plants interact with local soil environments; however, a deep understanding of how fine root vertical distribution varies with soil structural variations and across growth years is lacking. We subjected four xerophytic species native to an arid valley of China, , , , and , to increasing rock fragment content (RFC) treatments (0%, 25%, 50%, and 75%, v v) in an arid environment and measured fine root vertical profiles over 4 years of growth. Fine root depth and biomass of woody species increased with increasing RFC, but the extent of increase declined with growth years. Increasing RFC also increased the degree of interannual decreases in fine root diameter. The limited supply of soil resources in coarse soils explained the increases in rooting depth and variations in the pattern of fine root profiles across RFC. Fine root depth and biomass of the non-woody species () in soil profiles decreased with the increase in RFC and growth years, showing an opposite pattern from the other three woody species. Within woody species, the annual increase in fine root biomass varied with RFC, which led to large interannual differences in the patterns of fine root profiles. Younger or non-woody plants were more susceptible to soil environmental changes than the older or woody plants. These results reveal the limitations of dry and rocky environments on the growth of different plants, with woody and non-woody plants adjusting their root vertical distribution through opposite pathways to cope with resource constraints, which has management implications for degraded agroforest ecosystems.
细根（直径<2毫米）分布影响土壤剖面中资源获取的潜力，这决定了植物与当地土壤环境的相互作用方式；然而，目前缺乏对细根垂直分布如何随土壤结构变化以及在不同生长年份间变化的深入了解。我们将中国干旱河谷原生的四种旱生植物，[植物名称1]、[植物名称2]、[植物名称3]和[植物名称4]，置于干旱环境中，进行增加岩石碎片含量（RFC）的处理（0%、25%、50%和75%，体积比），并在4年的生长过程中测量细根垂直剖面。木本植物的细根深度和生物量随RFC增加而增加，但增加幅度随生长年份下降。RFC增加还加大了细根直径年际减小的程度。粗质地土壤中土壤资源的有限供应解释了生根深度的增加以及不同RFC水平下细根剖面模式的变化。土壤剖面中非木本植物（[植物名称4]）的细根深度和生物量随RFC和生长年份增加而减少，呈现出与其他三种木本植物相反的模式。在木本植物中，细根生物量的年增加量随RFC变化，导致细根剖面模式存在较大的年际差异。较年轻或非木本植物比年长或木本植物对土壤环境变化更敏感。这些结果揭示了干旱多石环境对不同植物生长的限制，木本和非木本植物通过相反途径调整其根垂直分布以应对资源限制，这对退化的农林生态系统管理具有启示意义。
