低磷胁迫下不同杉木家系根系觅磷能力分析

Root foraging ability for phosphorus of different Chinese fir family seedlings under low phosphorus supply

选择杉木种子园9个半同胞家系种子培育的幼苗作为研究对象,通过室内模拟磷胁迫盆栽试验,从根系增生觅磷能力角度比较分析不同家系杉木幼苗在低磷胁迫下根系形态指标生长的差异,结合苗高、地径和根冠比等生长指标,利用隶属函数法并结合权重进行综合评价,旨在筛选出具较强觅磷能力的杉木优良种质材料.结果表明:供磷处理和家系对杉木幼苗根体积、根生物量和根冠比的影响均存在明显的交互作用,而对苗高、地径、根长和根表面积的影响无明显交互作用.从单个因素来看,家系对杉木苗高、地径和根系形态指标的影响均达显著水平;供磷处理对根系指标和地径的影响均达显著水平,而对苗高的影响不显著.轻度与重度磷胁迫下,杉木家系地径增量比正常供磷处理显著降低22.9%和25.4%,且这两种低磷胁迫处理均明显促进根长、根体积、根生物量和根冠比等指标的增加.综合评价结果表明低磷环境中, 25号、20号和41号家系杉木根系觅磷能力较强,有利于对土壤磷斑块的觅食,从而维持地上部的正常生长.

To analyze the root morphological growth of Chinese fir seedlings under phosphorus(P)stress, an indoor pot experiment was conducted on seedlings of 9 half-sib families originated from Chinese fir seed orchard. Then comprehensive evaluation was conducted based on seedling growth indexes(e.g., height, root collar diameter and root to shoot ratio)using membership function method and method of weighting so as to select elite Chinese fir families with root strong foraging ability for P. The results showed that P supply and family exerted significant interactive effect on root volume and biomass and root to shoot ratio of Chinese fir seedlings, but not on seedling height, and the collar diameter, length and surface area of root. According to single factor ananlysis, seedling height, diameter and root morphological indexes varied significantly among different families. While P supply had significant effect on root morphological indexes and root collar diameter, but not on seedling height. Increments on root collar diameter dropped by 22.9% and 25.4% respectively under mild and severe P stress conditions than the control, but the length, volume, and biomass of root and root to shoot ratio remarkedly increased under both P stress conditions. Comprehensive evaluation showed that families No.25, 20 and 41 were elite Chinese fir with strong P foraging ability.