浅水高光环境对沉水植物光叶眼子菜生态修复效果的影响

Impacts of Shallow Water and High Light Environments on Ecological Restoration Effect of a Submerged Plant Potamogeton Lucens

为研究高光照对沉水植物的抑制作用,选取沉水植物光叶眼子菜为实验材料,测定5个不同光照强度(全光照的100%、75%、50%、30%和15%)对光叶眼子菜叶片中的碳、氮、磷含量和叶绿素a、叶绿素b、叶绿素(a+b)含量,植株根、茎、叶重量,植株单重,以及植株相对生长率、分蘖数、根长和株高的影响。实验结果显示,所测定的14个指标对光照强度的响应模式不同,即:1)根长和株高随光照强度的下降而升高,2)随着光照强度的下降,叶片中的叶绿素a、叶绿素b、叶绿素(a+b)含量、磷含量、碳含量,以及叶片重量均表现为先上升再下降的趋势,3)不同光照强度对植株根重、茎重、植株单重、相对生长率、分蘖数、植物叶片中的氮含量均无显著影响。结果表明:光叶眼子菜叶重、碳含量、磷含量、根长、株高和叶绿素含量都可能受到强光抑制的影响,而且这些指标比其他测定指标对强光抑制的反应更敏感;强光抑制作用主要抑制植物地上部分的生长,而对植物地下部分的影响较小。因此,在富营养化湖泊水体中进行沉水植被生态恢复工程时,应当尽量避免强光的作用,以提高沉水植物的生态功能。

In order to study the inhibitory effect of light on submerged plants,the submerged plant Potamogeton lucens was selected as the experimental material.The effects of five different light gradients(100%、75%、50%、30%and 15%of full light)on carbon content,nitrogen content and phosphorus content,chlorophyll a content,chlorophyll b content,chlorophyll(a+b)content,root mass,stem mass and leaf mass,plant mass,relative growth rate,tiller number,root length and plant height of P.lucens were measured.The results indicated that the 14 measured indices of P.lucens responded differently to the light gradient:1)root length and plant height of P.lucens increased with the decreasing light intensity;2)chlorophyll a content,chlorophyll b content,chlorophyll(a+b)content,leaf mass,phosphorus content and carbon content in leaves of P.lucens initially increased and then decreased with decreasing light intensity;3)the root mass,stem mass,plant total mass,relative growth rate,ramet number,leaf nitrogen content of P.lucens were not significantly impacted by light irradiance.The results indicated that high light intensity significantly inhibited the growth of P.lucens,particularly affecting root length,plant height,the contents of chlorophyll a,chlorophyll b,chlorophyll(a+b),leaf mass,carbon content and phosphorus content in leaves,which were more sensitive to high light inhibition than the other indices.Additionally,the results suggested that high light inhibition mainly affects the above-ground parts of the plant while having a lesser impact on the below-ground parts.Therefore,when conducting submerged aquatic vegetation restoration programs in eutrophic lakes,efforts should be made to avoid the negative effects of high light to enhance the ecological functions of submerged plants.