Subjects: Biology >> Botany >> Applied botany submitted time 2018-10-26 Cooperative journals: 《广西植物》
Abstract：附生苔藓在维持森林生态系统水分和养分循环中发挥着重要的生态作用。然而，由于访问技术的限制，附生苔藓多样性及其在林冠三维空间中的分布格局却鲜为人知。本研究首次借助林冠塔吊调查了西双版纳国家级自然保护区龙脑香热带雨林样地内69棵树13个垂直高度上的附生苔藓植物，通过统计不同垂直高度上的苔藓物种及其生活型，并利用典范相关分析法（CCA）和物种指示法对该区域附生苔藓植物沿宿主垂直梯度上的微生境偏好及其指示作用进行了分析。结果表明：该龙脑香热带雨林69棵树上共记录到隶属于25科60属的90种附生苔藓，其中细鳞苔科物种数最多，占比达25.6%。13个垂直高度上共划分出三种生态类型：喜阳苔藓(＞45m散生巨树的垂直高度上)，喜阴苔藓(＜15m的乔木树干上)，广布苔藓（通常广泛分布于各个宿主垂直高度上，生态位宽），并筛选出对微生境有特殊偏好的17种苔藓指示种（IndVal ≥ 0. 7，P ＜ 0. 05）。随宿主垂直高度的升高，扇型和交织型的苔藓占比降低，悬垂型苔藓占比先升高后降低，细平铺型和粗平铺型的苔藓占比升高。大气湿度、水汽压、胸径以及树皮粗糙度对附生苔藓生活型的分布偏好具有显著影响。总之，沿宿主垂直高度上的附生苔藓对微环境变化在生活型和形态结构上有着不同的响应方式，而同一种生态型的苔藓群落有相似的适应机制。因此，在森林林冠生境变化的监测和管理中，对微生境具有明显偏好的附生苔藓物种或生活型可作为有效的指示材料。
Subjects: Biology >> Botany >> Applied botany submitted time 2018-09-07 Cooperative journals: 《广西植物》
Abstract： Bryophytes are typically poikilohydric plants and water availability for growth of bryophytes is particularly important. 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 18 dominated or common bryophytes species from terrestrial, trunk and branch in a moist evergreen broad-leaved forest in Ailao Mts. 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 variance 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 holdingcapacityandwaterlossrateofbryophytesamongdifferent life-formsalso exhibitedsignificantdifferences: 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 bryophytesindicated theiradaptation strategies to different habitats toa certain extent. The resultswould providea scientific basis ofelucidating hydrological features ofbryophytes under different microhabitats, and understanding ecologicaladaptationstrategiesofbryophyte.
Subjects: Biology >> Botany >> Applied botany submitted time 2018-07-23 Cooperative journals: 《广西植物》
Abstract： Stoichiometric homeostasis is one of the core concepts of ecological stoichiometry. It refers to the ability of an organism to maintain a given elemental composition in the body despite variation in the elemental composition of its environment or diet. It reflects the net outcome of many underlying physiological and biochemical adjustments as organisms respond to their surroundings. The homeostatic index (H) of plant can be estimated by measuring the nitrogen and phosphorus contents and N:P ratio in plant and soil. In general, the homeostasis of plants is weaker than that of animals, with a larger variety of homeostasis. Stoichiometric homeostasis is an important mechanism in maintaining ecosystem structure, function, and stability. The homoeostatic species tend to have high and stable biomass; and ecosystems dominated by more homoeostatic species have higher productivity and greater stability. Therefore, the homeostasis is considered to be an important index to measure species competitiveness. Studies of stoichiometric homeostasis of plant will help us to understand the adaptation strategies and ecological adaptability of plants to the environment, as well as the relationship between plant ecological stoichiometry homeostasis and ecosystem functions. However, there are few studies on the internal stability of plant ecological stoichiometry. Previous research showed that the stoichiometric homeostasis characteristics of different plant species or functional groups were different. There were differences in stoichiometric homeostasis among different growth stages, different organs of the same species, as well as different nutrient elements. This paper reviews the concept of stoichiometric homeostasis, the estimation of plant homeostatic index (H), the stoichiometric homeostasis characteristics of different plant species or functional groups, different organs and growth stages and different elements, as well as linking plant stoichiometric homoeostasis with ecosystem structure, functioning and stability. Based on the obtained achievements and the current study, we put forward some perspectives of plant stoichiometric homoeostasis for future research to be conducted with an aim to promote this discipline of research in China.
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