六种挺水植物对水位梯度的响应研究

选择花菖蒲(Iris ensata var.hortensis)、泽苔草(Caldesia parnassifolias)、黄花鸢尾(Iris pseudacorus)、美人蕉(Canna indica)、再力花(Thalia dealbata)、水葱(Scirpus tabernaemontani)共6种常见挺水植物,研究了不同水位梯度(-5～150 cm)对6种挺水植物外伤症状、株高、分株数、存活率、发芽率、叶绿素(Chl)、超氧化物歧化酶(SOD)、丙二醛(MDA)等生理指标的影响。结果表明:(1)除黄花鸢尾出现一定外伤症状外,其余5种挺水植物在不同水位条件下生长较好,有较高存活率和发芽率。(2)花菖蒲在水位30 cm、美人蕉在60 cm、再力花和水葱在100 cm均有较高的株高、分株数、存活率和发芽率。(3)花菖蒲、泽苔草、黄花鸢尾的叶绿素含量在水位-5～0 cm达到最大,水位升高,含量下降;与之相反,美人蕉在水位90 cm、再力花和水葱在水位100 cm时叶绿素含量最高。(4)6种挺水植物在水淹胁迫的水深梯度下,产生了不同程度的SOD。实验前期(10 d),不同水位梯度下6种挺水植物叶片SOD活性出现不同程度下降,随着对不同水位梯度环境的适应,SOD开始回升;花菖蒲(-5～45 cm)、美人蕉(-5～90 cm)在水淹与干旱处理下,叶片SOD活性均高于零水位;再力花和水葱随着水位(-5～100 cm)降低SOD活性升高,水位-5 cm时达到最高,分别提高了40.57%和63.79%;泽苔草在各水位下(-5～45 cm)SOD最终与零水位基本持平;黄花鸢尾各水位下保持稳步上升趋势。(5)6种挺水植物在实验前期不同水位梯度MDA含量均有所提升,中后期呈现下降态势。综合各项指标分析,泽苔草适应各水位胁迫,花菖蒲和黄花鸢尾在低水位生长较好,美人蕉、再力花和水葱能较好地适应高水位环境,6种植物均可用于滨水带生态修复。本研究为湿地生态修复植物选择、水生植物生长水位联动控制提供了科学依据。

Response of Six Emergent Plants to Water Level Stress

Iris ensata var. hortensis, Caldesia parnassifolias, Iris pseudacorus, Canna indica, Thalia dealbata and Scirpus tabernaemontani are emergent plants commonly selected for riparian ecosystem conservation and wetland restoration. In this study, we investigated growth parameters of the six plants at different water depths (-5~150 cm), focusing on external damage, plant height, ramet number, survival rate, germination rate and the chlorophyll content, SOD activity and MDA content of leaves. The aim of the study was to determine the influence of water stress on the growth and reproduction of emergent plants. From July 16 to September 28, 2016, a pot experiment was conducted that simulated the natural habitat. The plants were divided into three groups according to preferred water depth. Five water depths were set for each group: 45 cm, 30 cm, 15 cm, 0 cm and -5 cm for Iris ensata var. hortensis and Caldesia parnassifolias; 90 cm, 60 cm, 30 cm, 0 cm and -5 cm for Iris pseudacorus and Canna indica; 150 cm, 100 cm, 50 cm, 0 cm and -5 cm for Thalia dealbata and Scirpus tabernaemontani. The control group was planted at a depth of 0 cm. During the experiment, water level was adjusted at 9:00 and 17:00 each day and SOD activity and MDA content were measured at 10-day intervals. Plant height, external damage, ramet number, survival rate, germination rate and chlorophyll content were determined at the end of the experiment. The study yielded five primary findings: (1) Except for Iris pseudacorus, the plants showed high tolerance to water level stress and had high survival and germination rates in all treatments. (2) The optimal water depth, based on plant height, ramet number and rates of survival and germination, was 30 cm for Iris ensata var. hortensis, 60 cm for Canna indica and 100 cm for Thalia dealbata and Scirpus tabernaemontani. (3) Maximum chlorophyll content in Iris ensata var. hortensis, Caldesia parnassifolias and Iris pseudacorus occurred at -5 to 0 cm and decreased with water depth. Maximum chlorophyll content occurred at 90 cm for Canna indica and at 100 cm for Thalia dealbata and Scirpus tabernaemontani. (4) SOD activity in all six species initially decreased (day 10) and then gradually increased. SOD activity in Iris ensata var. hortensis and Canna indica in waterlogged and drought treatments was higher than in the control group. SOD activity in Thalia dealbata and Scirpus tabernaemontani increased as water level decreased, with the highest SOD activity at -5 cm. The SOD activity of Caldesia parnassifolias did not differ significantly from the control group for any treatment. SOD activity in Iris pseudacorus increased gradually at different water depth treatments. (5) The MDA content of all plants in all treatments increased early in the experiment and then decreased. In conclusion, all six plants can be used for ecological restoration of riparian zones; Caldesia parnassifolias tolerates different water levels, Iris ensata var. hortensis and Iris pseudacorus grow better at low water levels and Canna indica, Thalia dealbata and Scirpus tabernaemontani are adapted to higher water levels. This study provides a scientific basis to support riparian conservation and improve plant selection for wetland restoration.