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生态学杂志 ›› 2010, Vol. 29 ›› Issue (12): 2365-2372.

• 研究报告 • 上一篇    下一篇

沿海防护林四个树种根系分布对盐胁迫的响应

孙洪刚,陈益泰   

  1. 中国林业科学研究院亚热带林业研究所| 浙江富阳 311400
  • 出版日期:2010-12-08 发布日期:2010-12-08

Root growth patterns of four coastal shelter forest tree species in response to salt stress.

SUN Hong-gang, CHEN Yi-tai   

  1. Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang 311400, Zhejiang, China
  • Online:2010-12-08 Published:2010-12-08

摘要: 研究盐分胁迫下植物根系的分布及生长特性对沿海防护林树种的筛选具有重要意义。以8年生女贞(Ligustrum lucidum)、洋白蜡(Fraxinus pennsylvanica)、木麻黄(Casuarina equiestifolia)和墨西哥落羽杉(Taxodium mucronatum)等4个亚热带沿海防护林树种为对象,对
其根系生长特性与土壤盐度关系、根系生物量分配格局、功能根的分布特征以及根系的比根长和根长密度进行了比较。结果表明:1)土壤盐分对植物根系垂直生长与分布具有强烈的制约作用,根系的水平伸展能力与树种根系垂直生长呈负相关;2)不同树种适应盐分胁迫能力不同,导致各自功能根的生物量分配格局差异;3)根径级越小,其吸收水分和营养物质的能力越强;根径级越大,固定和支持植株的能力越强;4)墨西哥落羽杉盐分阈值>0.45%,根系垂直分布在0~95 cm的土层中,具有良好的抗台风和耐盐土能力;木麻黄和洋白蜡2个树种的主根系长度分别为25 cm和29 cm,支撑根的比例分别为87.2%和56.3%,因此也具有一定的抗台风能力,可以栽植在盐度<0.36%的沿海滩涂上;女贞盐分阈值<0.21%,垂直根系为20 cm,支撑根比例51.0%,不适合栽植于高盐分的台风分布地理区域。

关键词: 杨树无性系, 渗透胁迫, 光合作用光抑制, 活性氧, 保护酶

Abstract: Taking 8-year old subtropical coastal shelter forest tree species Ligustrum lucidum, Fraxinus pennsylvanica, Casuarinn equiestifolia, and Taxodium mucronatum as study objects, this paper investigated their root growth characteristics with relation to soil salt content, and compared the root biomass pattern, functional root distribution percentage, specific root length, and root length density among the four tree species. The results indicated that soil salt content was the most important factor limiting the vertical root growth, and the latter had a negative relationship with horizontal root growth. The test tree species had different salt-tolerance characters, resulting in the difference of their functional root biomass pattern. The smaller the lateral root diameter, the larger the lateral root water- and nutrient absorbing capacity; the larger the lateral root diameter, the stronger the capacity of the lateral roots in anchoring and supporting plant. For T. mucronatum, its salt threshold was > 0.45%, and its vertical root distribution was at the soil depth of 0-95 cm, which resulted in a good capability to resist typhoon and soil salt stress. For C. equiestifolia and F. pennsylvanica, their tap root length was 25 cm and 29 cm, and their anchor root occupied 87.2% and 56.3%, respectively. These two tree species had definite capability to resist typhoon, and could be planted on the coastal tidal flat with salt content < 0.36%. For L. lucidum, its salt threshold was < 0.21 %, tap root length was 20 cm, and anchor root occupied 51.0%, suguesting that it was not adaptable to plant in the coastal areas with high salt content and typhoon.

Key words: Poplar clone seedlings, Osmotic stress, Photo inhibition of photosynthesis, Reactive oxygen species, Protecting enzymes