哀牢山湿性常绿阔叶林地生、树干及树枝 附生苔藓生活型组成及其水分特性

为探讨林内不同垂直高度生境下及不同生活型苔藓植物水分特征的差异,该文对哀牢山湿性常绿阔叶林内地生苔藓、林下树干附生和林冠层树枝附生苔藓优势或常见种的生活型组成、持水力、失水特征和水分利用效率进行了研究。结果表明:地生、树干附生和树枝附生苔藓植物类群分别以交织型、扇型、悬垂型苔藓植物占据优势;地生、树干附生、枝条附生苔藓植物的饱和持水率分别为476%DW、210.98%DW、238.95%DW;地生苔藓植物的持水率和失水速率均高于附生苔藓,树干附生苔藓植物持水率低于树枝附生苔藓,而失水速率高于树枝附生苔藓。在不同生活型苔藓的水分特性上,交织型苔藓具有较高的持水率和失水速率,保水性能较弱,其次为悬垂型苔藓,扇型苔藓的持水率最小,失水速率也较快;地生和树干附生苔藓的水分利用效率均显著高于树干附生苔藓,交织型和扇型苔藓的水分利用效率显著高于悬垂型苔藓。在三种生境下,地生苔藓持水力高,水分利用效率较高而保水能力低;枝条附生苔藓持水力低,水分利用效率低而保水能力较高;树干附生苔藓水分利用效率较高而持水力和保水能力均较差。因此,不同生境下苔藓植物生活型组成及其水分变化特性在一定程度上反映了它们对不同生境的适应策略。

Life-form composition and water characteristics of terrestrial, bole and branch epiphytic bryophytes in a moist evergreen broad-leaved forest in Ailao Mountains

In order to explore ecological adaptation strategies of bryophytes for different water conditions, we determined the water loss characteristics during natural desiccation and water use efficiency of dominated or common bryophyte species from terrestrial, trunk and branch in a moist evergreen broad-leaved forest in Ailao Mountains. Our results demonstrated that weft, fan and pendant life-forms were dominated in terrestrial, bole epiphytic and branch epiphytic bryophytes respectively. Bryophytes from different microhabitats exhibited great variances of water-holding capacity and water loss rate: Water-holding capacity of bryophytes from three microhabitats was 476%DW, 210.98%DW and 238.95%DW respectively; Water-holding capacity and water loss rate of terrestrial bryophytes were higher than these of the trunk- and branch-dwellers. Compared with branch-dwellers, the bole epiphytic bryophytes had lower water-holding capacity and higher water loss rate. Water holding capacity and water loss rate of bryophytes among different life-forms also exhibited significant differences: Weft life-form bryophytes exhibited higher water-holding capacity and higher water loss rate, indicating their weaker water retention capacity, followed by pendant bryophytes, and fan bryophytes had lowest water holding capacity and highest water loss rate. Water use efficiency of terrestrial bryophytes and bole epiphytic bryophytes were significantly higher than branch-dwellers. Weft and fan life-form bryophytes had higher water use efficiency than that of pendant bryophytes. The results indicated that water-holding capacity and water use efficiency of terrestrial bryophytes was higher while water retention capacity was poor; Water retention capacity of branch-dwellers was higher while water-holding capacity and water use efficiency was lower; Water use efficiency of trunk-dwellers was higher while both water-holding capacity and water retention capacity was poor. Life-form composition and water characteristics of bryophytes from terrestrial bryophytes, bole and branch epiphytic bryophytes indicated their adaptation strategies to different habitats to a certain extent. The results would provide a scientific reference for elucidating hydrological features of bryophytes under different microhabitats, and understanding ecological adaptation strategies of bryophyte.