典型喀斯特山区优势树种钙吸收能力的海拔分异特征研究

Differentiation Characteristics of Calcium Bioabsorption Capacity of Dominant Tree Species with Altitude in Typical Karst Mountain Area

为探明典型喀斯特石漠化地区优势乔木种的钙吸收能力随海拔上升的变化规律及其影响因素,从而有效指导土壤养分的合理利用和生态修复中树种的选择,以贵州花江石漠化治理示范区为研究区域,4种典型树种(香椿Toona sinensis、翅荚香槐Cladrastis platycarpa、构树Broussonetia papyrifera、栾树Koelreuteria paniculata)为研究对象,通过野外调查采集不同海拔的叶片及其土壤,进行植物-土壤总钙和理化性质的分析,对土壤和叶片钙素含量在不同海拔的差异性及其与环境因子的相关性进行研究。结果表明:(1)香椿和构树叶片及各树种土壤钙素含量随海拔变化有显著差异(P<0.05),香椿和栾树在500 m处富钙能力最强(38.99 g·kg^(−1)和44.72 g·kg^(−1)),翅荚香槐和构树分别在900 m处和1100 m处最强(41.42 g·kg^(−1)和51.21 g·kg^(−1));(2)香椿和翅荚香槐对土壤钙素的吸收能力在900 m处最大(2.72和1.07),可作为西南石漠化地区中高海拔处植被恢复的先锋树种;栾树和构树在500 m处最大(0.79和0.82),可作为低海拔处植被恢复的先锋树种;(3)海拔差异引起的土壤钾、钠、有机质含量的变化很有可能是影响树种钙生物吸收能力的重要原因,也是树种改变对高钙环境适应策略的关键因素之一。研究结果有助于深入了解不同优势树种在西南喀斯特高钙环境中的适应特性。

To investigate the variety of calcium absorption coefficient of predominant tree species with expanding height in the typical karst rocky desertification area and its impacting factors, four normal tree species(Toona sinensis, Cladrastis platycarpa,Broussonetia papyrifera and Koelreuteria paniculata) were chosen as the study objects in Huajiang rocky desertification control demonstration area of Guizhou Province, and the leaves and sub-tree soils were gathered at various elevations for the assurance of total calcium and physical and chemical properties, and the inconstancy of soil and leaf calcium substance at various heights and their relationship with natural elements were researched by measurable examination and connection investigation. The results showed that,(1) there were significant differences(P<0.05) in leaf calcium content of Toona sinensis and Broussonetia papyrifera and soil calcium content of understory of each tree species with altitude, and the calcium enrichment capacity of Toona sinensis and Koelreuteria paniculata was strongest at 500 m(38.99 g·kg-1 and 44.72 g·kg-1), that of Cladrastis platycarpa was strongest at 900 m, and that of Koelreuteria paniculata was strongest at 1 100 m(41.42 g·kg-1 and 51.21 g·kg-1).(2) The absorption capacity of Toona sinensis and Cladrastis platycarpa on soil calcium is the largest at 900 m(2.72 and 1.07), which can be selected as a pioneer tree species to afforestation at middle and high altitude in the study area;The absorption capacity of Koelreuteria paniculata and Broussonetia papyrifera on soil calcium is the largest at 500 m(0.79 and 0.82), which can be selected as a pioneer tree species to afforestation at low altitude in the study area.(3) The change of potassium, sodium and organic matter content caused by altitude difference is likely to be an important factor affecting the calcium bioabsorption capacity of tree species, and also one of the key factors for tree species to change their adaptation strategies to high calcium environment. The results are helpful to understand the adaptation characteristics of different dominant tree species in karst high calcium environment.