基于光合参数探讨四种藓类作水族箱植物的应用潜力

摘要

水生藓类植物适宜作为水簇箱植物，许多半水生藓类植物同样能够生长于水体环境中.中国东部地区的水生藓类植物种类不多，陆生藓类植物能否应用于水族箱中？为了回答这一问题，需要阐明陆生藓类植物对水体环境的适应能力.该研究测定了匐枝青藓(Brachythecium procumbens )，弯叶灰藓(Hypnum hamulosum )、白发藓(Leucobryum glaucum)和虎尾藓(Hedwigia ciliata)在与它们的自然生境相似条件下以及沉水环境下的光合参数，并应用直角双曲线模型拟合了它们的光－光合响应曲线.结果表明：这四种藓类植物在最大净光合速率(Pn)、光饱和点(LSP )和光补偿点(LCP )上存在很大差异.它们的最大净光合速率、光饱和点和光补偿点的变异范围分别为122．575~19．099μmol CO2•kg-1 DW•s-1、1166．00~670．030μmol•m-2•s-1和85．000~5．3μmol•m-2•s-1.在沉水环境中生长30 d后，匐枝青藓、弯叶灰藓和白发藓的最大净光合速率分别是对照的110．78％、80．84％和109．63％，说明在实验周期里这三种藓类植物能够在水体环境中生存，而虎尾藓在水体中浸泡20 d后，其最大净光合速率仅为对照的5．25％，反映出该种植物并不适应水体环境.综上可知，四种藓类植物的光合速率与其形态结构和原生境条件有很大的关系，虽然匐枝青藓、弯叶灰藓和白发藓主要分布于陆生环境，但作为水族箱植物也具有一定的应用潜力.%Aquatic mosses could be used as aquarium plants,many semi-aquatic mosses are also able to grow in aquar-ia.In eastern China,there are few aquatic mosses.Is it possible to use some terrestrial mosses in aquaria? In order to answer the question,we elucidated the adaptability of focal terrestrial mosses to water environment.In the present work,we measured the photosynthetic parameters of four terrestrial mosses including Brachythecium procumbens, Hypnum hamulosum,Leucobryum glaucum,and Hedwigia ciliata under conditions similar to their natural habitats and those after their submersion in water.We also made their photosynthetic light-response curves by using rectangu-lar hyperbolic model.We found significant differences among their maximum net photosynthesis rate (Pn),light sat-uration point (LSP),and light compensation point (LCP).The variation ranges of their maximal Pn,LSP and LCP were from 122.575 to 19.099μmol CO2•kg-1 DW•s-1 ,from 1 166.00 to 670.030μmol•m-2•s-1 ,and from 85.000 to 5.3 μmol•m-2•s-1 ,respectively.After Brachythecium procumbens,Hedwigia hamulosum and Leucobryum glaucum had been submerged in water for 30 d,their maximal Pn were 110.78%,80.84% and 109.63% of the con-trol,respectively,indicating that these three mosses are able to survive in water during the experimental period.While submerged in water for 20 d,Hedwigia ciliata had only 5.25% net photosynthetic rate of the control,revealing that H .ciliate is not able to grow in aquatic environment.We also discussed the relationships of their photosynthesis with their morphological structure and habitat conditions.Our analyses showed that Brachytheciumprocumbens,H.ham-ulosum and Leucobryum glaucum,though distribute in terrestrial habitats in the field,were three potential aquarium plants.