摘要:水、盐条件是盐沼生态系统最重要的环境因子，直接影响着植物的生长和繁殖。以莫莫格湿地优势植物三江藨草（Scirpus nipponicus）为研究对象，探究不同水盐条件及其交互作用对湿地植物三江藨草功能性状和生物量分配格局的影响，以期加深对湿地盐渍化背景下内陆盐沼植物生态适应对策的了解，为指导湿地水盐管理和植被生态恢复提供基础数据。实验采用室内模拟控制水盐条件的方法，设置盐度（300、1000、2000、3000、4000 mg/L和5000 mg/L）和水位（-10，0，20，40，60 cm和80 cm）各6个梯度处理，结果表明，三江藨草株高变化仅受水位处理的影响（P<0.05），随水位的升高株高呈现先增加后下降的趋势；株数变化仅受盐度处理的影响，并且受水位的限制，适宜盐度能促进浅水域植株分株数增加；水位、盐度和二者的交互作用对三江藨草生物量积累及其分配均产生显著影响，随着水位和盐度的升高，三江藨草球茎、地下、地上和单株总生物量均呈先增加后降低的趋势；生物量分配受水盐交互作用较明显，在1000、2000 mg/L和3000 mg/L盐度处理时，随着水位升高球茎生物量分配和地下生物量分配增加，地上生物量分配减少。综合三江藨草的生长特征和生物量累积，认为其在40-80 cm水位和1000-3000 mg/L盐分处理环境中生长状态较好，适宜的盐分处理可以增加三江藨草对水深的耐受程度。



Abstract:Hydrology and salinity are the most important environmental factors in the salt marsh ecology system, they directly affect the growth and reproduction of wetland plants. In order to better understand the ecological adaptation strategies of saltmarsh plants under the background of salinization of wetlands, and to provide theoretical and technical support for water-salt manipulation and wetland vegetation restoration, the Scirpus nipponicus was selected as the experimental material to study the effects of water levels and salinity on its growth traits and the biomass allocation in Momoge National Nature Reserve. The tested soil was collected in June 2019 from the study area, its salinity was 0.512 ±0.0038 g/L. The S.nipponicus seedlings were cultivated outdoors for 3 weeks before the experiment. We carried out a controlled experiment with six levels of salinity (300, 1000, 2000, 3000, 4000 mg/L and 5000 mg/L) and six water levels(-10, 0, 20, 40, 60 cm and 80 cm). The salinity was controlled by mixing NaCl with NaHCO₃ (molar ratio was 2:1), and the water level was controlled by platforms of different heights. The experiment lasted for 60 days. The individual height and ramet number were determined directly. The biomass of tuber, and the underground, aboveground parts and total biomass were determined after drying to constant weight at 65℃. The biomass allocation indexes included tuber biomass allocation (tuber biomass/total biomass), underground biomass allocation (underground biomass/total biomass), and aboveground biomass allocation (aboveground biomass/total biomass). The results showed that the water level significantly affected individual height (P<0.05), individual height increased first and then decreased with water level increasing. The ramet number was significantly affected by salinity, and it was limited by water level. The ramet number in shallow water increased at the appropriate salinity. The water level, salinity and their interaction significantly affected the biomass accumulation and allocation of S.nipponicus. The biomass of tuber, and the underground, aboveground parts and total biomass all increased first and then decreased with water level and salinity increasing. The total biomass was higher (3.24-3.71 g) at the salinity of 1000-3000 mg/L and the water level of 80 cm. The biomass allocation was significantly affected by water level-salinity interaction. At the salinity of 1000, 2000 mg/L and 3000 mg/L, the tuber biomass allocation and underground biomass allocation increased and the aboveground biomass allocation decreased with the water level increasing. This suggested that S.nipponicus focused on asexual reproduction to adapt to rising water levels. In summary, S.nipponicus grew well at the water level of 40-80 cm and the salinity of 1000-3000 mg/L. The tolerance of S.nipponicus to the water level increased at the appropriate salinity, while the threshold reduced at high salinity.





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