不同种源杉木细根根序及碳氮计量的比较分析

Comparison of fine root morphology and carbon and nitrogen content in Chinese fir from different provenances

为分析不同种源杉木人工林细根根序形态和碳氮计量的差异,选取福建三明莘口教学林场38年生8个不同种源的杉木林为研究对象,采用根序分级法进行不同种源细根根序形态的调查,并对其碳氮含量进行测定,比较不同种源杉木细根根序形态及碳氮计量的差异。研究表明:不同种源杉木细根根序形态存在差异。四川芦山、四川彭县的北带种源以及湖北竹溪的中带偏北种源的比根长、比表面积和组织密度总体上小于贵州剑河、浙江金华、安徽休宁和湖南会同等中带种源,南带广东郁南杉木根序形态指标较低;随着根序级别的递增,不同种源杉木比根长、比表面积均呈下降趋势,而细根平均直径、组织密度、C含量及C/N则随着根序级别的增加而增加;不同种源杉木根系的C、N含量变化没有明显规律,但C/N总体上随着杉木种源所在的纬度下降而增加。

The 38-year-old Chinese fir forests from eight different provenances in Xinkou Teaching Forest Farm,Sanming,Fujian Province were selected as the research objects for the analysis of the differences in fine roots in Chinese fir plantations which from different provenances,through the measurement of morphology,carbon,and nitrogen.The root order morphology of fine roots from different provenances was investigated by root order classification method,and the carbon and nitrogen content of fine roots was determined.The results showed that fine root order morphology of Chinese fir from different provenances was different.The specific root length,specific surface area and tissue density of Chinese fir in the northern provenances of Lushan and Pengxian in Sichuan and the middle belt to the north provenances of Zhuxi in the Hubei Province,were generally smaller than those of Jianhe in Guizhou,Jinhua in Zhejiang,Xiuning in Anhui,and Huitong in the Hunan Province,which were from the middle belt.The morphological indices of root order of Chinese fir in the southern zone of Guangdong Province were low.The specific root length and specific surface area of Chinese fir from different provenances decreased with an increase in root order,but the average diameter,tissue density,C content,and C/N ratio of fine roots increased with an increase of root order.The C and N content in the roots of Chinese fir from different provenances had no obvious pattern,but the C/N ratio increased with a decrease in the latitude of Chinese fir provenance.