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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