The Study On Allelopathy Of Trifolium Repens L. To Raspberry

Raspberry belongs to Rubus L.of Rosaceae.It is a kind of bacca plants developping very quickly throughout the world nowadays.The fruits have beautiful color,good taste,abundant nutrition, especially the contents of V_E and SOD are the highest of all fruits.It proved that the raspberry fruits are potential benefits to people's health.So raspberry is called the third generation fruit.The fruits not only can be eaten directly but also exploited in many fields including medication,dressing, health care,and food process.Raspberry is a kind of important bacca plants cultivated in many countries.The fruit and the processed products are very popular in the world,especially in the European and American market. Therefore,big profits must be achieved from exploitation and seedling cultivation.At present, raspberry is mainly concentrated in the Northwest and the North China,and it is not yet formed scale cultivation in others regions in our country.The phenomenon,plants or microorganism can produce any direct or indirect,beneficial or bad effect on other plants or microorganism through releasing some special chemical compound(allelochemical)into circumstance is called allelopathy.Allelopathy is a very common and important ecological mechanism in nature.The research on plant allelopathy deeply is important on knowing the structure and succession of plant community,logical application of agricultural cultivation system,measures of biology-weed and exploitation new type pesticide.White clover(Trifolium repens L.)is a vivacious and leguminous plant.White clover was planted widely in the orchard nowadays.It can enhance the soil fertility,control weed,enhance the ability of biological controlAllelopathy exists in the nature universally.ln cultivation the problem must be considered that how to make use of the mechanism of allelopathy to make the best of beneficial allelopathy and remove harmful allelopathy between plants and between plants and microorganism,and to combine the environmental control with biological control in orchard ecosystem.At present the research on the problem is rarely reported.In order to investigate the allelopathic potential of the different concentration aqueous extracts of Trifolium repens L.and the effects of applying aqueous extracts of Trifolium repens L.on the growth of raspberry and the environment of rhizosphere soil,the experiment were conducted with raspberry as acceptor.The study was expected to provide scientific theory for improving the quality and the production of the raspberry,applying the allelopathy of Trifolium repens L.in the orchard and biology-weeding and so on.The main results are showed as follows.1.Planting Trifolium repens L.and Paspalum notatum Flugge could promote the growth of raspberry,improve the photosynthesis of raspberry and the content of N,P,K,increase the activity of membrane protective system.And the effect of Trifolium repens L.was notable.So it was concluded that Trifolium repens L.was the best orchard grass species.2.Trifolium repens L.and Paspalum notatum Flugge could notably promote the growth of raspberry in vitro,and the promotion effect of Trifolium repens L.was notable.It was concluded that intercropping grass species could produce the allelopathy to raspberry.3.The allelopathic effects of the different concentration aqueous extracts of Trifolium repens L.were studied on Raphanus sativus and Brassica chinensis.The results showed that the different concentration aqueous extracts of white clover(Trifolium repens L.)promoted or inhibited the germination rate of seeds,the fresh weight of the acceptors,the growth of the plants obviously.The experiment showed that white clover existed obviously allelopathy.4.Allelopathy of the different concentration aqueous extracts of white clover for Raphanus sativus from strong to feeble is:20%＞10%＞5%＞50%＞100%;but for Brassica chinensis is 20%＞10%＞50%＞5%＞100%.Therefore,it was concluded that the allelopathy of white clover(Trifolium repens L.)was different with different concentration.The stimulative effect was found with low concentration extracts of white clover.However,inhibitory effect was appeared in high concentration extracts.5.Applying the aqueous extracts of Trifolium repens L.into MS culture medium,research on the effects of the extracts of Trifolium repens L.on the growth of raspberry seedling in vitro was conducted.The results showed that the aqueous extracts could promote the growth of raspberry seedling obviously.The stimulative effect was most significantly when the concentration of the aqueous extracts is 20%.And the inhibition rate increased with the concentration of the aqueous extracts increasing.The treatment with the water extracts of white clover was notably inhibited in the concentration of 100%.The experiment showed that the allelochemical existed in the aqueous extracts of Trifolium repens L..And the allelochemical had the stimulative effect with low concentration extracts and inhibitory effect with high concentration extracts.6.Raspberry seedling transplanted from MS culture medium was treated by the aqueous extracts of white clover.By comparison of the treatments' product of photosynthesis,the activity of membrane protective system,the activity of root system and so on,it showed that the concentration of 10%and 20%were the best concentration level.However,the treatment of 100%inhibited physiological index of raspberry seedling obviously.7.The irrigation of the different concentration aqueous extracts of Trifolium repens L.reduced or enhanced the soil enzyme activities in raspberry rhizosphere soil.The treatment with irrigating the concentration of 10%enhanced the activities of polyphenoloxidase and catalase in the soil.The treatment of 20%enhanced the activities of saccharase and acid ahosphatase in the soil.But the concentration of 100%could notably inhibit the soil enzyme activities in raspberry rhizosphere soil.The results showed that the low concentration extracts of Trifolium repens L.could promote the absorpotion of mineral nutrition,the growth of raspberry seedlings and so on.8.The allelochemical existed in the aqueous extracts of Trifolium repens L.,and the allelochemical had concentration effects.Therefore,the sod-culture cultivation in the orchard should notice the planting consistency.