叶异形水生植物不同发育阶段叶片的结构和无机碳获取策略

Leaf structure and inorganic carbon acquisition strategies of heteroblastic aquatic plants at different stages of development

以睡莲(Nymphaea tetragona Georgi)、萍蓬草(Nuphar pumila(Timm)de Candolle)、条叶萍蓬草(Nuphar sagittifolia Pursh)、眼子菜(Potamogeton distinctus A.Bennett)、南方眼子菜(Potamogeton octandrus Poir)和泽泻(Alisma plantago-aquatica L.)6种叶异形水生植物为材料,对它们的叶绿素含量、气孔性状、解剖结构和HCO_(3)^(-)利用等指标进行分析,比较了两种不同发育阶段叶片结构和无机碳获取策略的差异。结果显示,幼态叶比成熟叶的叶片更薄,具有更少的细胞层数,幼态叶上下表面均不具备气孔,而成熟叶上表皮有气孔。说明幼态叶在结构上增加细胞比表面积,增加水下吸收无机碳的能力,而成熟叶的结构能更好地吸收大气中的CO_(2)。pH-drift分析结果证明,幼态叶具有更高获取水下无机碳的能力,以适应沉水环境。本研究还发现眼子菜和南方眼子菜的幼态叶可以利用水体中HCO_(3)^(-)为额外碳源,更有利于其在沉水环境中生长。研究结果阐明了叶异形水生植物不同发育阶段叶片结构和利用无机碳获取策略对水下和气生环境的适应性。

Six heteroblastic aquatic plants,i.e.,Nymphaea tetragona Georgi,Nuphar pumila(Timm)de Candolle,Nuphar sagittifolia Pursh,Potamogeton distinctus A.Bennett,Potamogeton octandrus Poir,and Alisma plantago-aquatica L.,were studied and their chlorophyll content,stomatal traits,anatomical structure,and HCO_(3)^(-) utilization were analyzed,the differences between leaf structure and inorganic carbon acquisition strategies at different developmental stages were compared.Results showed that the juvenile leaves were thinner and had fewer cell layers than the mature leaves.The upper and lower surfaces of the juvenile leaves did not contain stomata,whereas the upper epidermis of the mature leaves did contain stomata.Thus,the juvenile leaf structure showed increased cell surface area and the ability to absorb inorganic carbon underwater,while the mature leaves structure better absorbed CO_(2) from the atmosphere.Results from pH-drift analysis indicated that the juvenile leaves exhibited better acquisition of underwater inorganic carbon as an adaptation to the submerged environment.In addition,the juvenile leaves of P.distinctus and P.octandrus used HCO_(3)^(-)in the water as an additional carbon source,which was beneficial for growth in the submerged environment.These results elucidate the leaf structure of heteroblastic aquatic plants at different stages of development and the adaptability of inorganic carbon acquisition strategies to the submerged and aerial environments.