Inhibitory Effects Of Harlequin Glorybower(Clerodendrum Trichotomum) Extract On Growth Of Water Hyacinth(Eichhornia Crassipes)

Water hyacinth (Eichhornia crassipes) is an invasive aquatic weed which has resulted in enormous ecological and economic consequences in China, the research of biological control with native species on water hyacinth has both theoretical meaning and applied value.Water hyacinth was introduced as an ornamental plant from Japan to Taiwan in1901. Although water hyacinth has many use values, the growth and reproduction of water hyacinth are rapid. It is easy to flooded, damage the aquatic ecosystem, block rivers, affect transport and water power generation, that have brought major ecological pollution and economic losses.Currently, water hyacinth is widely distributed in China’s nineteen provinces, autonomous regions and municipalities, more than ten provinces and cities are in the dangers of water hyacinth. Every year, huge investment of human, material and financial resources are used to control water hyacinth in China. The main methods of water hyacinth control are artificial fishing, chemical control and biological control. Biological control of water hyacinth is considered to be a feasible, safe and sustainable control measure. The research of biological inhibitors prepared by native species which is use to control the growth and reproduction of water hyacinth has important significance and practical value.This study was to explore inhibition effects of harlequin glorybower (Clerodendrum trichotomum) water extract on water hyacinth growth and analyze its inhibition mechanism with measuring chlorophyll, catalase and malondialdehyde.The results showed that health leaf proportion of water hyacinth which was sprayed with the extract was significantly lower than the blank group and control group (P=0.000<0.01), less than1%, and the death leaf proportion of water hyacinth was significantly higher (P=0.000<0.01), more than90%, chlorophyll of leaves from treated groups was decreased (P=0.014<0.05), catalase activity was enhanced (P=0.035<0.05), malondialdehyde was significantly increased (P=0.001<0.01). The extract of harlequin glorybower effected on leaves of water hyacinth, so that chlorophyll content was decreased, reactive oxygen was accumulated to damage biofilm system, resulting in leaves dry rot and decay. The extract of harlequin glorybower effectively inhibited the growth of water hyacinth, which provided a new biological approach to water hyacinth control.