Preliminary Study On Allelopathy Of Amaranth (Amaranthus Tricolor L.)

The application of allelopathy in agriculture is very extensive.The influence of plant allelopathy should be considered on crop rotation,intercropping,and continuous cropping.Foliage vegetables are the indispensable vegetable in daily life for human,such as amaranth,non-heading Chinese cabbage,head cabbage,lettuce,baby cabbage and radish.However there is little study on allelopathy between foliage vegetables.In this study,amaranth was treated as a donor,while non-heading Chinese cabbage,head cabbage,lettuce,baby cabbage and radish were chosen as the receptors.The effects of aqueous extracts was analyzed on different parts of amaranth and cultured soil by bioassay in laboratory.At the same time,a further study on the allelopathy effects of aqueous extracts of amaranth on non-heading Chinese cabbage was completed The results were as follows:The inhibition effect of soil water extracts of amaranth on on non-heading Chinese cabbage seed germination is stronger than on head cabbage.The degree of inhibition was:the second growth period of 90 days>a growth period of 30 days.The minimum impact was on the seedling fresh weight,the second was on seedling height,the influence on root length was most obvious.The concentration of 0.05g/mL from soil in a growth period of 30 days for amaranth showed inhibitory effect on root length of lettuce,other soil water extracts promoted root growth for lettuce.Overall,the degree of inhibition was baby cabbage>head cabbage>non-heading Chinese cabbage>radish.Compared to aqueous extract from stem and root of amaranth,the inhibition influence of aqueous extract from leaf of amaranth on the germination rate of five receptors is the most obvious.The seed germination of five receptors were inhibited by aqueous extracts from leaf of amaranth when the concentration was 0.1g/mL.The higher the concentration of aqueous extracts,the stronger inhibition on vegetable seed germination.But when the concentration was 0.125g/mL,the seed germination of five vegetable receptors was more obviously higher than that of the concentration of 0.1g/mL.The inhibition of aqueous extract from root,stem and leaf of amaranth on the germination rate of non-heading Chinese cabbage and head cabbage were the most obvious.The influence of aqueous extract from leaf of amaranth on root length,seedling height and seedling fresh weight of five vegetables were more obvious than that of the aqueous extract from root and stem of amaranth.When the treat concentration was 0.1g/mL and 0.125g/mL,the growth of non-heading Chinese cabbage,head cabbage and baby cabbage have completely stopped.For the root length of five vegetables lower concentration showed promotion effect,while higher concentration showed inhibition effect when aqueous extract from leaf of amaranth was at or less than 0.075g/mL.The plant height of head cabbage was stimulated,and the plant height of baby cabbage was inhibited at or less than 0.075g/mL of aqueous extract from leaf of amaranth.The seedling fresh weight of five vegetables was stimulated at or less than 0.075g/mL of aqueous extract from leaf of amaranth.Meanwhile,the seedling fresh weight of radish and lettuce were inhibited at 0.1g/mL and 0.125g/mL.The influence of aqueous extract from stem of amaranth on the root length of five receptors were inhibited.The root length of head cabbage was stimulated at or less than 0.05g/mL of aqueous extract from stem of amaranth,and inhibited at or higher than 0.075g/mL.The root length of non-heading Chinese cabbage and lettuce was stimulated at or less than 0.05g/mL of aqueous extract from root of amaranth,and inhibited at or higher than 0.075g/mL.The root length of head cabbage was stimulated at or less than 0.025g/mL of aqueous extract from root of amaranth,and inhibited at or higher than 0.05g/mL.The root length of radish was stimulated at or less than 0.1g/mL of aqueous extract from root of amaranth,and inhibited at 0.125g/mL.The root length of non-heading Chinese cabbage was stimulated at 0.025g/mL of aqueous extract from whole plant of amaranth,and was inhibited at or higher than 0.05g/mL.The leaf length and leaf width of non-heading Chinese cabbage were stimulated at five concentration of aqueous extract from whole plant of amaranth,and the higher concentration of aqueous extracts,the stronger inhibition on leaf length and width.Compared to the concentration of 0.1g/mL of aqueous extract from whole plant of amaranth,the promoting effect was weak on leaf length and width of non-heading Chinese cabbage at 0.125g/mL.The fresh weight up cotyledons section of non-heading Chinese cabbage was inhibited by aqueous extract from whole plant of amaranth with the increased of concentration.The fresh weight down cotyledons section of non-heading Chinese cabbage was stimulated with the increase of concentration.Compared to the concentration of 0.1g/mL of aqueous extract from whole plant of amaranth,the promoting effect was weak on the fresh weight down cotyledons section of non-heading Chinese cabbage at 0.125g/mL.