盐碱胁迫对三江藨草幼苗功能性状的影响

Effects of salt-alkaline stress on functional traits of Scirpus nipponicus seedlings

盐碱作为盐碱湿地生态系统的重要环境因子之一,影响着湿地植物的定植、生长和繁殖.以莫莫格盐碱湿地常见植物三江藨草(Scirpus nipponicus)为研究对象,设置了盐度(25,100,200 mmol/L)和pH值(7.79±0.06,9.42±0.02,10.40±0.01)各3个梯度处理,及1个空白处理作为对照,探讨不同盐碱胁迫及其交互作用对湿地植物三江藨草幼苗功能性状和生物量分配格局的影响.结果显示,盐碱胁迫对三江藨草幼苗生长、生物量积累及其分配均产生显著影响(P<0.05).与空白处理相比,随着盐碱胁迫的升高,三江藨草幼苗株高、分株数、球茎数等功能性状,以及根、根茎、球茎、地下、地上生物量和总生物量等均呈现先增加后降低的趋势;三江藨草幼苗在盐度和pH分别为25 mmol/L和7.79(±0.06)时生长最好,在盐度和pH分别为200 mmol/L和10.40(±0.01)时,植株全部死亡;盐碱胁迫对三江藨草幼苗生物量分配具有显著影响(P<0.05),随着盐碱胁迫增强,根和地上生物量分配增加,而球茎生物量分配减少,根茎生物量在25 mmol/L盐度处理下分配减少,在其他盐度处理下分配则增加.本研究表明碱胁迫对植物的伤害强于盐胁迫,湿地土壤的碱化对三江藨草的生长更为不利.

Salt-alkaline stress is a key environmental factor affecting seedling establishment,growth,and reproduction of hygrophytes in salt-marsh ecosystems.This paper aims to understand the effects of saltalkaline stress on growth traits and biomass allocation of Scirpus nipponicus seedlings in Momoge National Nature Reserve.We conducted a common garden experiment with three levels of salinity(25,100,and 200 mmol/L)and three levels of pH(7.79±0.06,9.42±0.02,and 10.40±0.01)with one control.Results indicate that salt-alkaline stress has a significant effect on growth traits,biomass accumulation,and biomass allocation of S.nipponicus seedlings(P<0.05).With increasing salt-alkaline stress,individual height,ramet number,tuber number,and the biomass of roots,rhizomes,tubers,belowground parts,aboveground parts,and total biomass all increased firstly and then decreased compared with the control.The optimum salinity concentration and pH was 25 mmol/L and 7.79(±0.06),respectively.The S.nipponicus seedlings would not survive at the S3A3(salinity and pH:200 mmol/L and 10.40(±0.01),respectively)treatment.The effects of salt-alkaline stress on the root,rhizome,tuber biomass allocation and aboveground biomass allocation were all significant(P<0.05).With increasing salt-alkaline stress,root and aboveground biomass allocation increased but tuber biomass allocation decreased.At salinity levels of 25 mmol/L,rhizome biomass allocation decreased but increased under other salinity treatments.Alkaline stress was more severe than salt stress,indicating that the alkalization of soil is more detrimental to the growth of S.nipponicus.