落叶松不同根序细根可溶性糖和淀粉浓度的差异和季节动态

非结构性碳水化合物是植物光合作用与生长利用之间主要的中间贮存物,在植物的生长和代谢过程中起着十分重要的作用。为了揭示落叶松(Larix gmelinii)根系根序间非结构性碳水化合物的分配及季节变化规律,探讨根系内可溶性糖和淀粉间的关系。本研究以落叶松根系为研究材料,在5~10月采集根系样品,采用根序法将细根分为1、2、3、4和5级,采用苯酚—浓硫酸方法和酶解法分别测定可溶性糖和淀粉浓度。结果表明:可溶性糖浓度在根序、月份及其交互差异性显著(P<0.001),1~5级根可溶性糖浓度的变化范围分别为4.42%~14.90%,4.35%~16.40%,5.67%~19.70%,5.91%~33.10%,6.95%~37.80%,不同根序可溶性糖浓度最大值均出现在7月。根序间淀粉浓度差异性不显著(P>0.05),月份间根系淀粉浓度差异显著(P<0.001),变化范围为23.36%~48.65%;淀粉浓度5~7月下降,随后上升,从8月份达到峰值,10月与5月差异不显著。研究结果可为阐明落叶松根系碳水化合物代谢和生长适应对策提供数据基础,对理解植物细根系统内部结构及功能异质性提供数据支撑。

Differences and Seasonal Dynamics of Soluble Sugar and Starch Concentrations in Fine Roots with Different Root Orders of Larix gmelinii

Non-structural carbohydrate was the main intermediate storage between photosynthesis and growth of plants,and played an important role in the growth and metabolism of plants.To explore the distribution and seasonal variation of non-structural carbohydrates and the relationship between soluble sugar and starch in roots.The root sample of Larix gmelinii was collected from May to October in 2018, and the samples were divided into 1,2,3,4,and 5 rank by root order method.The concentration of soluble sugar and starch were measured using the phenol-sulfuric acid method and enzmatic hydrolysis method respectively.The results showed that the concentration of soluble sugar was a significant difference between root order,month,and their interaction(P<0.001).The concentration of soluble sugar in 1-5 orders ranged from 4.42%~14.90%,4.35%~16.40%,5.67%~19.70%,5.91%~33.10% and 6.95%~37.80%,respectively.There was no significant difference in the concentration of starch among different root orders(P>0.05).However,the concentration of starch was a significant difference among months(P<0.001).It was ranged 23.36%~48.65% and decreased from May to July,and then increased,peaked in August,and there was no significant difference between October and May in 2018.The results could provide data for explaining the carbon metabolism and growth adaptation strategies of roots and understanding the internal structure and functional heterogeneity of fine root system.