铺地榕对不同土壤磷营养水平的生理生态学响应

磷矿废弃地的形成在破坏植被和景观的同时,还导致水土流失和水体富营养化等不良环境影响.本文通过控制实验研究了铺地榕Ficus tikoua对不同土壤磷营养水平的生理生态学响应,以求在揭示植物对高磷条件生态响应的机理上,为磷矿弃地的生态恢复筛选适宜的先锋物种.结果显示,在磷处理质量浓度为0～360 mg·L~(-1)范围内,铺地榕的净光合速率、蒸腾速率、气孔导度、叶绿素质量分数、可溶性糖和根系生长的相关参数随着磷处理质量浓度的增加而增加,其后则显示出逐渐减少的趋势.植物的光饱和曲线和二氧化碳饱和曲线显示,该物种的光饱和点和二氧化碳饱和点分别为800 μmol·m~(-2)·s~(-1)和1 000 μmol·mol~(-1),表明该物种具有较强的光合性能,且是一种喜阳植物.该物种各器官对磷的吸收能力依次为根>茎>叶,实验中植物体的磷质量分数最高达到植物干物质量的1.13%左右.综合分析表明,铺地榕对土壤磷营养的适应范围较广,吸收固定能力强,是一种潜在的可用于磷矿废弃地治理的先锋物种.

Ecophysiological response of Ficus tikoua to different soil phosphorous content

Three Gorges region is rich in mineral resources, especially in phosphate mineral resources. Mining wastelands not only damaged local ecosystem, but also caused the loss of water and soil, and river eutrophication in the Three Gorges region. In order to reveal the mechanism of plant species' adaptation to high soil phosphorous content and select appropriate pioneer species for waste-land restoration, the ecophysiological response of Ficus tikoua seedlings to different soil phosphorous level were studied in this paper through control experiment. Results showed that P_n, T_r, G_s ChL soluble sugar and some parameters related with root growth in-creased when phosphorous treatment ranged from 0～360 mg·L~(-1), and then decreased gradually with the increase of phosphorous treatment concentration. The light saturation curve and carbon dioxide saturation curves of the species demonstrated that its light saturation point and carbon dioxide saturation were about 800 μmol·m~(-2)·s~(-1) and 1 000 μmol·mol~(-1) respectively, which indicated the Ficus tikoua preferred growing in sunny condition. The ability of organs absorbing and storing phosphorus was root> stem> leaf. The highest phosphorus content of plants reached 1.13 % in the experiment. All of these suggested that Ficus tikouat has good absorption ability and can adapt to a wide range of soil phosphate. Ficus tikouat is a potential pioneer species which can be used to restore the phosphorous mining wasteland.