Effects Of Allelochemicals And Aqueous Extracts Of Bermudagrass On Seed Germination And Seedling Growth Of Alfalfa And Dodder

Allelopathy is an important and complex factor in the natural and artificial ecosystem, the systematic study of Allelopathy can enhance the understanding of the structure of natural ecosystem, formulate a reasonable way of cultivation and farming systems, control pest and disease, Regulate plant growth and protect the environment. Bermudagrass (Cynodon dactylon) is widely distributed in China and is a fine lawn grass and pasture resources. The research of allelopathy of bermudagrass is still not enough, this paper focused on the effects of allelochemicals and aqueous extracts of bermudagrass on seed germination and seedling growth of alfalfa and dodder. The main contens are as follows:1. The experiment studied the effects of seed germination and seedling growth of alfalfa and dodder under allelochemicals: ferulic acid, p-Hydroxybenzoic acid, cinnamic acid and coumarin. The concentration of four allelochemicals were used in four degrees: 50, 100, 200 and 400 mg/L. The results showed that the four allelochemicals had significant allelopathic effects on seed germination and seedling growth. In high concentrations(200, 400mg/L), the inhibition effects on seed germination showed that coumarin>cinnamic acid> ferulic acid>p-Hydroxybenzoic acid. In low concentrations, cinnamic acid, ferulic acid and p-Hydroxybenzoic acid had a certainly stimulating effect. The inhibition effects on seedling growth showed that coumarin>cinnamic acid>p-Hydroxybenzoic acid>ferulic acid.2. Four allelochemicals in different random combination had obvious composition effect, The results showed that different random combination had significant allelopathic effects on seed germination and seedling growth, and the effects were significant related with the kinds of allelochemicals and their concentrations, and their inhibition effect reduced as the concentration reduced.3. Choosing bermudagrass in different growth stages as donor plant, and allelopathy effect of extracts of bermudagrass on seed germination and seedling growth of the receptor were studied. The concentration of extracts of bermudagrass were used in five degrees: 2.5, 5, 10, 20 and 40DWg/L. The results showed that the extracts of bermudagrass had no impact on seed germination percentage, the seed germination index of receptor gradually improved as the concentration of extracts gradually reduced. Extracts of bermudagrass had stimulating effect on seedling growth of the receptor, the length and fresh weight of receptor seedling gradually reduced as the concentration of extracts gradually reduced. In the same concentration, the stimulating effect on seedling growth of the extracts of stem and leaf was stronger than the extracts of root.4. Planting bermudagrass in greenhouse to study the allelopathy of bermudagrass under different environmental stress. The results showed that the effects of extracts of bermudagrass under different environmental stress was similar to the effects of extracts of bermudagrass in different growth stages. Compared to extracts of bermudagrass under no environmental stress, the receptor seed germination index had increased by root extracts of bermudagrass under different environmental stress; reduced by stem and leaf extracts of bermudagrass under different environmental stress. The effects of extracts on receptor seedling growth were no significantly difference between under different environmental stress and under no environmental stress.The study of allelopathy of bermudagrass was preliminary on this paper, and it would establish a base for further research on allelopathy of bermudagrass, such as the allelopathy mechanism of bermudagrass, the separation, extraction and identification of allelochemicals in bermudagrass.