不同建群时间下互花米草种群生长及生物量分配

Growth and biomass allocation of differently-aged populations of Spartina alterniflora

采用"空间代替时间"的方法,研究具有不同建群时间的互花米草种群生长及生物量分配特征。结果表明:种群高度生长从建群2a到16a呈下降趋势,6a和16a均显著低于2a(P<0.05);密度、总生物量及地上生物量从建群2a到16a均呈下降趋势,16a显著低于2a(P<0.05);地下生物量、根冠比随建群时间延长先增长后降低,但前者16a显著低于2a(P<0.05);同化器官生物量不随建群时间变化,而非同化器官生物量随建群时间延长而减少,6a和16a均显著低于2a(P<0.05);须根和根状茎生物量随建群时间延长先增大后减小。结果显示建群16a后种群呈衰退态势,探究其原因将有助于我国互花米草的管理与控制。

Growth and biomass allocation of differently-aged populations of Spartina alterniflora were studied by methodology of ＂spatial for temporal gradient＂.The results showed that：the height growth of Spartina alterniflora populations presented a downward trend with the increase of population age,and the height growth of 6 and 16 years old populations were significantly lower than that of 2 years old population（P0.05）;the density,total biomass and above-ground biomass of populations decreased with the increase of population age,with significant difference between those of 16 and 2 years old populations（P0.05）;the below-ground biomass and root-shoot ratio increased in the first few years followed with reducing thenafter,and the below-ground biomass of 16 years old population was significantly lower than that of 2 years old population（P0.05）;the assimilative organic biomass didn＇t change with population age,while non-assimilative organic biomass reduced with increase of population age with those of 6 and 16 years old populations being significantly lower than that of 2 years old population（P0.05）;the fibrous roots and rhizome biomass increased in the first few years followed with reducing.All the results indicated that the 16 years old population of Spartina alterniflora presented a declining trend and more understanding of the declining reasons will be helpful to the management and control of Spartina alterniflora in China.