[Effects of livestock wastewater on seedlings of two mangrove species].

Effects of livestock wastewater on growth and physiology of seedlings of two mangrove species (Kandelia candel and Bruguiera gymnorrhiza) in greenhouse pot-cultivation systems were studied under different salinity conditions. In terms of stem height, stem basal diameter, leaf production, maximum leaf area and relative growth rate, livestock wastewater enhanced the growth of Kandelia candel and Bruguiera gymnorrhiza, The effects of salinity and livestock wastewater on biomass partitioning were significant for Bruguiera gymnorrhiza, but not for Kandelia candel. Under livestock wastewater application, the chlorophyll a and b contents of Bruguiera gymnorrhiza leaves increased, but the electric conductance had no significant variation. Wastewater increased the leaf electric conductance of Kandelia candel, but had no significant effects on its chlorophyll a and b contents. Under the two salinity conditions, there was no significant difference in root activity of both species. The POX activity increased in the stem and root of Kandelia candel under the two salinity conditions, while decreased in the root of Bruguiera gymnorrhiza under freshwater condition, and increased under seawater condition. The SOD activity of Bruguiera gymnorrhiza decreased, but for Kandelia candel, it had no significant change.