升温及淹水条件下土著与外来盐沼植物的生长和光合特征比较

Comparison of growth and photosynthesis characteristics of native and exotic salt marsh vegetation under elevated temperature and waterlogging conditions

针对我国海岸带典型土著植物芦苇(Phragmites australis)和外来物种互花米草(Spartina alterniflora),研究了其在升温(约升高3℃)和淹水(浅淹水和深淹水)条件下的生长和光合特性.结果显示,升温处理增加了不淹水和浅淹水条件下的芦苇株高、叶面积、最大光合速率与表观量子效率,而对深淹水条件下的芦苇影响较小.深淹水处理下芦苇株高最高,但叶面积最小,体现了其形态适应性.深淹水处理显著降低了生长季中期与后期的芦苇光合和叶绿素荧光参数.升温和淹水处理均提高了互花米草的生长、光合和叶绿素荧光参数,且升温条件下的增加程度较芦苇高,各生长阶段不同淹水处理之间没有显著差异.方差分析表明,升温和淹水处理对芦苇生理生态参数的影响显著程度具有季节差异性,淹水处理的影响更为显著,并存在因子交互作用.升温处理对互花米草光合参数有显著影响,而淹水处理的影响不显著.因此,外来物种可能比土著物种更能适应未来气温升高和海平面上升的环境条件.

Growth and photosynthesis characteristics of native Phragmites australis and exotic Spartina alterniflora,the dominant salt marsh species in China’s coastline,grown under elevated temperature and waterlogging conditions,were investigated.The results showed that elevated temperature increased the shoot height,leaf area,maximum rate of photosynthesis,and the apparent quantum yield of P.australis under non-waterlogging(Non-W)and shallow-waterlogging(S-W)conditions.However,the effect was negligible for the growth and photosynthesis parameters of P.australis in deep-waterlogging(D-W)conditions.The shoot height of P.australis reached a maximum,but the leaf area was lowest in a D-W state,indicating morphological adaption to waterlogging.D-W conditions significantly decreased the photosynthesis and chlorophyll fluorescence parameters of P.australis during the middle and later growth periods,compared to Non-W and S-W condi-tions.Both temperature elevation and waterlogging increased the growth,photosynthesis and chlorophyll fluorescence parameters of S.alterniflora,and the degree of increase under elevated temperature was greater than that of P.australis.Differences in growth and photosynthesis of S.alterniflora between the waterlogging treatments were not notable throughout the growing period.Analysis of variance showed that the effect of elevated temperature on the eco-physiological characters of P.australis was season-dependent,and the impact of waterlogging treatment was more notable with some interaction between the treatments.The effect of temperature elevation on photosynthesis parameters of S.alterniflora was notable,but not for the waterlogging treatment.We suggest that anticipated climate warming and rises in sea level might be beneficial to the exotic marsh species.