延安公路山辽东栎林优势植物水分适应性及适应类型分析

以陕西省延安公路山辽东栎林群落为对象,测定林内外不同状态下12种优势植物的水势日进程、自然饱和亏、临界饱和亏等水分利用参数,分析它们在林内和林外孤立木状态下的水分利用多样性和水分平衡策略,以揭示辽东栎群落水分利用多样性在群落持续发育中的作用.结果表明:(1)在林内或林外12种优势植物的水势日变化趋势基本一致,一天内每一时段物种间水势值跨度不同,林内种间水势跨度为0.85～1.93 Mpa,林外种间水势跨度为0.6～1.83Mpa;林内物种间日最低水势(-1.43～-3.05 Mpa)及临界饱和亏(63.12%～92.59%)变幅较大;各优势植物水势日进程与气象因子显著相关.(2)林内外各时段物种间水势跨度不同,14:00和17:00林外物种间水势跨度大于林内;12种植物的水势日变化与林内有显著差异(P<0.05),且在林内和林外环境下水分参数具有相似变化趋势.(3)根据黎明前水势、日最低水势、自然饱和亏、临界饱和亏将辽东栎林内12种优势植物水分利用策略聚类分为 4个水分适应类型,每个适应类型具有特殊的水分适应方式.可见,辽东栎群落内12种优势植物的水分利用参数及其对环境适应表现出多样性特点,为该群落持续发育奠定了基础.

Analysis of Water Adaptation Characteristics and Adapted Patterns of Dominant Species in Quercus liaotungensis Forest of Gonglu Mountain,Yan'an

In order to elucidate the water utilization diversity in the role of the sustainable development of Quercus liaotungensis community.In August,plant water relation indexes,including the daily process of water potential,the natural water saturation deficiency (n.w.s.d.) and the critical water saturation deficiency (c.w.s.d.) of 12 dominant species of Quercus liaotungensis forest in Yan'an Gonglu mountain were determined.By statistics and analysis the different of water utilization diversity and water balance strategy among these plants growing in and out of forest.The results show that:(1)Inside or outside forest,the changes of water potential daily course of 12 dominant species are almost the same format;the span of water potential measured in each period was different among these plants.In a day,the span of water potential among these plants inside forest was from 0.85 to 1.93 Mpa,and outside forest was from 0.6 to 1.83 Mpa.The dominant species' daily process of water potential was highly relevant to the meteorological factors.The span of daily minimum water potential (Daily Ψw_(min)) (from -1.43 to -3.05 Mpa) and the c.w.s.d (from 63.12% to 92.59%) was the larger among other water relation indexes in forest.(2)The values of water potential measured in each period of the 12 dominant species' daily process of water potential were significantly different among these plants growing out of forest (P<0.05).The span length of water potential at 13:00 and 17:00 out of forest were bigger than that inside forest.There was similar change trend in water relation indexes among these plants in-versus out of the forest.(3)The strategies of the 12 species divided into 4 types by cluster analysis which identified significant patterns associated with 4 water indexes (including the predawn water potation(PΨw),the daily minimum water potential (DΨw_(min)),the natural water saturation deficiency (n.w.s.d),the critical water saturation deficiency (c.w.s.d)) in forest.Each of these types has a distinct water balance mechanism and parameter-adjusting pattern.The diversity of plant water relation indexes and adaptation to the environment was the basis of community sustainable development.