摘要
植物根序和径级不仅反映细根的形态结构,而且能反映根系的一些生理特征,如细根寿命和周转等。该文以二年生油松(Pinus tabulaeformis)幼苗根系为研究对象,系统比较了根序分类方法和径级分类方法在描述根系特征上的优缺点,探索了两者之间的内在联系。结果表明:二年生油松幼苗最多可包括6级根序,直径的变化范围为0.169–3.877mm。按根序划分,I–VI级根序的总根长和总根表面积主要集中在前3级根序,这3级根序的根占总根长的78.77%和总根表面积的62.72%。前3级根序的比根长是后3级根序比根长的1.3–3.0倍,比根面积是后3级比根面积的1.0–1.5倍。按常用的径级(以0.5、1.0、1.5和2.0mm为阈值)划分方法,油松幼苗大部分根系直径≤1.5mm,此区间细根的根长和根表面积占总根长的93.76%和总根表面积的84.35%。直径≤1.5mm的细根平均比根长是>1.5mm细根比根长的3–7倍,比根面积的1.5–3.0倍。由于油松根序和径级之间有显著的指数关系,依据径级最大程度反映根序的原则,提出了新的径级划分方法,即以0.4、0.8、1.3和2.0mm为阈值对油松幼苗根系径级重新进行划分。此时,上述区间可分别包括I级、II级、III级、IV级、V级根序中根尖数的93.22%、86.37%、75.96%、70.47%和76.67%。同时也可分别涵盖各径级根长的89.34%–70.83%、根面积的86.01%–76.12%以及体积的87.73%–76.12%。此时,根系不同径级与根序之间可以建立起良好的对应关系。这些结果表明,通过合理划分径级区间可以较好地反映根序特征。
Aims Our objectives were to： 1） compare the advantages and disadvantages of the root order and diameter classes in the description of root morphology characteristics and 2） explore the inherent connection between them. Methods We excavated 2-year-old Pinus tabulaeformis seedling roots in Zhouzhi County, Shaanxi Province, China. Individual roots were dissected according to the branching order, starting from the distal end of the root system that was numbered as the first order and then increasing sequentially with each branch from the first order roots to higher order ones. Following dissection, fine root samples were scanned by the Win-RHIZO system to analyze root length, specific root length, specific root surface area, diameter and tips. Fine root samples were then oven-dried at 65 °C to a constant weight to determine weight. Important findings Six root orders were included, with diameters that ranged from 0.169 to 3.877 mm. The summed length and surface area of the first three orders accounted for 78.77% and 62.72% of the totals, respec-tively. The specific root length and specific root area of the first three orders are 1.3–3.0 times and 1.0–1.5 times that of as the other orders. Based on diameter classes of ≤0.5, 0.5–1.0, 1.0–1.5 and 1.5–2.0 mm, most root di-ameters of P. tabulaeformis seedling were 1.5 mm. The summed length and surface area of this diameter range accounted for 93.76% and 84.35% of the totals, respectively. The specific root length and specific root area of roots 1.5 mm in diameter were 3.0–7.0 times and 1.5–3.0 times as large as roots 1.5 mm. For the exponential relationship between root orders and diameters and based on diameters’ maximum ratio reflecting root orders, a new diameter classification was proposed： ≤0.4, 0.4–0.8, 0.8–1.3 and 1.3–2.0 mm. As a result, the above intervals might represent the I, II, III, IV and V root orders in number of root tip of 93.22%, 86.37%, 75.96%, 70.47% and 76.67%, root length of 89.34%–70.83%, root area of 86.01%–7
出处
《植物生态学报》
CAS
CSCD
北大核心
2010年第12期1386-1393,共8页
Chinese Journal of Plant Ecology
基金
国家自然科学基金项目(408701150)
中国科学院"西部之光"人才项目资助
关键词
油松
根系特征
根系径级
根系生态学
根序
Pinus tabulaeformis
root characteristic
root diameter classification
root ecology
root order
