杭州人工湿地与西溪湿地4种植物光合生理生态比较

A Comparison of the Physioecological Characteristics of Four Kinds of Plants between A Constructed Wetland and Xixi Wetland

比较了夏季杭州植物园观鱼池人工湿地和西溪湿地的4种植物,鸢尾(Iris tectorum)、菖蒲(Acorus cala-mus)、美人蕉(Canna indica)和旱柳(Salix matsudana)的生理生态差异。测定了植物的光饱和曲线,蒸腾速率(Tr),计算了表观光量子效率(AQY)、水分利用效率(WUE)和呼吸速率(Rd)等生理参数。研究发现,夏季人工湿地植物的生长状态优于西溪湿地的植物,最大光合速率和蒸腾速率都是人工湿地大于西溪湿地,而呼吸速率则是西溪湿地大于人工湿地。人工湿地为净化鱼池水的沙基质结构以及间歇式供水条件在净化富营养化水的同时也为其中生长的植物创造了好于自然湿地的生长环境。

Constructed wetland has been proven efficient technology for both wastewater treatment and rescue of water resources. Compared with conventional treatment systems, it is economical, and easily operated and maintained. An integrated vertical flow constructed wetland was built in Hangzhou Botanical Garden, Zhejiang province, P. R. China, to purify eutrophic water from Jade fish -seeing pond. In order to assess the growth state of the plant in the constructed wetland, we studied the differences of physioecological characteristics of plants between a constructed wetland and Xixi wetland. Four species were growing both in both sites, including Iris rectorum, Acorus calamus, Canna indica, Salix matsudana. The plant physiological indices, such as photosynthetic curves, the transpiration rate （Tr） and the photosynthetic rate （Pn） under,photo synthetically active radiation （PAR） 1 000 μmol/（m^2·s） were tested. Through the photosynthetic curves, the light compensation point （ LCP）, light saturation point （ LSP）, dark respiration rate （Rd）, apparent quantum yield （AQY） and the maximum photosynthetic rate （Pmax） were calculated. Through the Tr and Pn, the water- use -efficiency （WUE） was calculated. The photosynthesis of the plants iri the constructed wetland was better than that in the Xixi wetland. The LSP values of the plants were ones of constructed wetland more than those of Xixi wetland, implicated that theplants in Xixi wetland need more light to achieve the optimal photosynthetic point. The Pmax of plants in the constructed wetland was higher than those in the Xixi wetland. It is because （a） the constructed wetland with the sand base structure was draftier than the Xixi wetland （b） the intermittent water supply compensated the water loss defect, especially during the droughty season. Those two features kept the plant growing well. The results showed that Rd values of plants in Xixi wetland were more than those in constructed wetland plants, implicating that the plants in Xixi wetland need to consume more energy to maintain their normal physioecological state. The temperature of the environment can be a possible reason for the Rd difference as the temperature in constructed wetland is higher than the Xixi wetland. To some extent having low Rd is benefit for biomass accumulation. The WUE of Acorus calamu and Canna indica in constructed wetland was more than that in Xixi wetland, while the Iris tectorum and Salix matsudana had complicated cases. The plants in the constructed wetland didnt show lower WUE than those in Xixi wetland, implying that the environment of the constructed wetland was suitable for the plants keeping a high WUE. This is benefit for the water circulation in the constructed wetland - Jade - fish - seeing - pond system. The order of the four species of Pmax and AQY were similar, that is, Salix matsudana 〉 Canna indica 〉 Acorus calamu 〉 Iris tectorum. This phenomenon implied that the plant with the high photosynthetic capacity had the high transpiration rate. Furthermore, those kinds of plants had the better capacity of purify the wastewater, and can be appropriate plants planted in the constructed wetland. It is found that the water supply system with sand base and the shade environment are suitable for plants growing. Especially in July, plants＇ growing would be affected negatively by the strong sum radiations, and the declining of the soil and air moisture. The plants can conquer the water deficiency in the constructed wetland system.