不同土壤水分下刺槐和油松的生理特征

The physiological characteristics of Robinia pseudoacacia and Pinus tabulaeformis seedlings under different soil water contents

在适宜土壤水分(70%θf)、中度干旱(55%θf)和严重干旱(40%θf)3种土壤水分条件下研究了黄土高原常见造林树种刺槐(RobiniapseudoacaciaL.)和油松(PinustabulaeformisCarr.)的生长及水分利用特性。结果表明:干旱胁迫使2树种的成活率、干物质累积和光合速率均显著下降。在适宜水分下刺槐的单叶水分利用率(WUE)最高,严重干旱下最低。刺槐和油松的枝条快速生长期主要集中在3-6月,在中度干旱条件,2个树种均可良好生长;在严重干旱下2个树种的生长均受到显著抑制,但刺槐受影响较大,油松受影响较小。在3种土壤水分条件下刺槐耗水量、生物量及水分利用率均显著高于油松。2树种在中度干旱下的总WUE最高,严重干旱下最低。刺槐属于高耗水树种,油松属于低耗水树种,油松的耐旱性强于刺槐。研究结果表明,刺槐在黄土高原缺水地区不适宜大面积栽植,只能用于水分条件较好的立地条件下造林。油松应尽可能在含水量较高的阴坡或沟坡地带造林。

Under fitted soil water content (70% θ_(f)), medium drought (55% θ_(f))and serious drought (40% θ_(f)),the growth and water use characteristics of Robinia pseudoacacia L. and Pinus tabulaeformis Carr. were studied. The results showed that survival rate, photosynthesis rate and biomass accumulation of two tree seedlings decreased significantly with the soil water content decrease. The water use efficiency of R. pseudoacacia leaves was the highest in fitted soil water content, it was the lowest under serious drought. Season of fast branch growth of two tree seedlings was mainly in March-June. Two tree seedlings all grew well under favorable soil water content and medium drought, their growth were all significantly inhibited under serious drought. The total water consumption, biomass and water use efficiency of R. pseudoacacia were significantly higher than that of P. tabulacformis under the three soil water contents. The total water use efficiency of the two tree seedlings was the highest at medium drought, that was the lowest under serious drought. The water consumption of R. pseudoacacia was higher than that of P. tabulaeformis. The ability of drought resistance of P. tabulaeformis was higher than that of R. pseudoacacia. R. pseudoacacia did not have the character of drought resistance plants, so it was not fit to plant widely in loess plateau area and only fit to favorable soil water condition. P. tabulaeformis should be planted in areas of high soil water content , such as shady slopes, gaps,channels, etc.