Root traits variations of subtropical evergreen tree Ligustrum lucidum and their adaptation to soil moisture and nutrient condition stress

Abstract

Aims In the face of extreme drought and increased soil erosion brought about by global changes, the physiological changes and response mechanisms of plant root systems to environmental stresses are understood by taking the example of suitable plants in typical karst areas that are subject to the dual stresses of drought and soil infertility. Methods We collected roots and soils of representative woody plants (Ligustrum lucidum) in sandy shale and limestone regions with different degrees of rock desertification, correlated root functional traits with soil physical and chemical characteristics, and then concluded the root resource utilization strategy of a representative woody plant. Results Soil moisture and nutrients in limestone areas are lower than those in sand shale areas. With the increase of rocky desertification, soil nutrients, and water content showed a significant decreasing trend. The diameter and volume of roots in sand shale areas are higher than those in limestone areas, and there are two kinds of resource utilization methods for root formation. Conclusions Root functional traits of Ligustrum lucidum adopt an active resource acquisition strategy in the limestone area but a conservative resource acquisition strategy in the sand shale area. The variability of root functional traits increased with the deterioration of soil moisture and nutrient conditions which was induced by deteriorative karst rocky desertification degree. Soil moisture variability affects plant root functional traits in the long term, and soil nutrients are a major influence on the variability of plant root functional traits.