土壤水分胁迫对红砂幼苗细根形态和功能特征的影响

通过盆栽人工模拟干旱试验,研究了土壤水分胁迫对红砂幼苗细根形态及功能的影响。结果表明:(1)随胁迫程度的加剧红砂幼苗细根直径和体积呈减小趋势,而根长、比根长、表面积、比表面积均呈增大趋势,表明在胁迫条件下,红砂幼苗细根可通过根长、比根长、表面积、比表面积的增加与直径和体积的减小来适应逆境胁迫。随根序的升高红砂幼苗细根直径呈增大趋势,而根长和比根长表现出减小趋势,比表面积呈先升高后降低的趋势。(2)随胁迫程度的加剧红砂幼苗细根全C含量呈降低趋势,而全N含量先呈明显的降低趋势,后呈升高趋势,表明在中度胁迫下红砂幼苗细根呼吸作用明显降低。随根序的升高红砂幼苗细根全C含量呈增加趋势,而全N含量呈下降趋势,表明红砂幼苗较低级根序具有较强的呼吸作用与代谢活性。(3)红砂幼苗细根根长与全C含量之间呈极显著正相关关系;直径与全C含量之间呈显著正相关关系;比根长与C含量呈显著负相关关系。

Effect of Soil Water Stress on Fine Root Morphology and Functional Characteristics of Reaumuria Soongorica

A pot experiment was conducted to study the effects of soil water stress in whole growth period on fine root morphology and function of Reaumuria soongorica. The results were as followings:(1) The diameter and volume decreased with the increasing of soil water stress, on the contrary, with the increasing of soil water stress, root length, specific root length(SRL), surface area and specific root surface area(SRA) increased, which indicated that under soil water stress conditions, fine root of R. soongorica seedling could adapt stress by the increasing root length, SRL, surface area and SRA and reducing the diameter and volume. The diameter increased with the rise of root order, root length and SRL increased, while SRA firstly increased and then reduced.(2) Total C content decreased with the increasing of soil water stress, while with soil water stress increasing total N content first decreased significantly and then showed the increasing tendency, which indicated that respiration of fine roots of R. soongorica seedling was restrained under medium soil water condition. Total C content increased with the rise of root order, total N content decreased, which indicated that the low roots have stronger respiration and metabolic activity.(3) The root length had a highly significant positive correlation with C content. The diameter had a significant positive correlation with C content. The SRL was negatively correlated with C content.