人工湿地污水处理系统3种红树植物生理生态特性

Studies of eco-physiological characteristics of three mangrove species in constructed wetland sewage treatment system

研究了淡水条件下潜流型人工湿地污水处理系统中红树植物海桑、桐花树和木榄的生理生态特性。一年后,海桑、桐花树和木榄株高增长量分别为134、32cm和21cm,基径增长量分别为18.2、14.3mm和12.9mm,生物量增长量分别为747、113g/株和55g/株,表明海桑生长最快,桐花树次之,木榄最慢。从2004年1月至12月,海桑、桐花树和木榄各项生理指标的平均值分别为:叶片总叶绿素含量1.91、1.26、0.91mg/gFW,叶绿素a含量1.44、0.93、0.64mg/gFW,叶绿素b含量0.5、0.34、0.17mg/gFW,净光合速率9.67、6.39、3.57μmolCO2/(m2·s),蒸腾速率54、38、24mmolH2O/(m2·s),气孔导度285、222、110mmolH2O/(m2·s),电解质渗出率10.2、12.9、13.5%和SOD活性447、396、386U/gFW。结果表明光合作用和水分代谢海桑>桐花树>木榄,植物受伤害程度海桑<桐花树≈木榄。另外,3种红树植物全年的生理生态特征的变化规律基本相似,4～10月份生长较快,大部分生理指标维持高水平,1～3月份和11～12月份由于温度较低,生长比较慢,大部分生理指标处于较低水平。综合比较一年来人工湿地中3种红树植物的各项生理生态特征,结果显示海桑好于桐花树,桐花树好于木榄。

Mangroves are diverse communities of tropical to subtropical trees and shrubs growing in the intertidal zone. Pollution eco physiology and purifying effect of mangrove under seawater condition have been widely investigated. Only few studies related to mangrove wetlands under freshwater condition have been conducted. The objective of this study is to investigate the eco-physiological characteristics of three mangrove species, i. e. Sonneratia caseolaris （Sc）, Aegiceras corniculatum （Ac） and Bruguiera gymnorrhiza （Bg） in subsurface flow constructed wetland sewage treatment system under freshwater condition. The experiment was conducted in South China Normal University, Guangdong Province of China, from January to December 2004. One-year seedlings of mangroves were obtained from Futian Nature Reserve, Shenzhen Bay. The constructed wetland, with 2 m in length, 2 m in width and 0.6 m in depth, was planted with mangrove at a density of 30 plants per wetland bed. Wetland systems received sewage once a week. Plant height, basal diameter, biomass, SOD activity were measured once a month, while chlorophyll content, photosynthetic rate, transpiration rate,stomatal conductance, electrolyte leakage were measured once a week. The results showed that growth rate of the three species are different. Stem height increment of Sc, Acand Bgwere 134, 32 and 21cm, respectively. Basal diameter increment was 18.2, 14.3, 12.9 mm, respectively. Biomass increment were 747, 113, 55 g/plant, respectively. The growth rate of three species was in the order of Sc〉Ac〉Bg. Average value of physiological characteristics of the three mangrove species were obtain according to the values of all treatment months. Total chlorophyll content of Sc, Ac and Bg were 1.91, 1.26, 0.91 mg/gFW,respectively. Chlorophyll a content were 1.44, 0.93, 0.64 mg/gFW, while chlorophyll b content were 0.5, 0.34, 0.17 mg/gFW, respectively. Net photosynthetic rate were 9.67,6.39, 3.57μmolCO2/（m^2·s）,and transpiration rate were 54, 38, 24 mmol H2O /（m^2·s）. stomatal conductance were 285,222, 110 mmol H2O/（m2·s）. Electrolyte leakage were 10.2, 12.9, 13.5%.SOD activities were 447, 396, 386 U/g FW.The results indicated that photosynthesis and water metabolism showed a sequence of Sc〉AC〉Bg, and Sc had a better resistance to sewage stress. The changes of eco-physiological characteristics of the three mangrove species during one year were similar. All of the three mangrove species maintained high growth rate and physiological characteristics from April to October, but had low growth rate and physiological characteristics from January to March and from November to December. In conclusion, three mangrove species, i.e. Sonneratia caseolaris, Aegiceras corniculatum and Bruguiera gymnorrhiza are adaptable of subsurface flow constructed wetland sewage treatment system under freshwater condition. According to the ecophysiological characteristics, Sc was better than Ac, and Ac was better than Bg.