Study On Allelopathy Mechanism Of Natural Meadow Poisonous Plants Oxytropis Ochrocephala

Gansu provence is China's important grassland distribution provinces,the grassland area of Gansu provence is 179.4206×104hm2,and it accounts for the national 39.4%[119].One of the reason that leaded the pasture degeneration is that poisonous plant breed and spread.The allelochemicals that released into the environment with the growth of poisonous plant has strong allelopathic actions and could inhibit the growth and development of herbage,So the allelochemicals of poisonous plant leaded the pasture degeneration.If the weeding active substances,insecticidal activity material and sterilization sex material can be found from the poisonous plant , the poisonous plant could be used effectively and the hazard of poisonous plant would into benefit.Regarding Oxytropis Ochrocephala in Tian Zhu Natural Meadow collected as donor plant and Avena sativa,Brassica campestris as receptor plants,the allelopathy mechanism of Oxytropis Ochrocephala was studied in this paper.The purpose of the research was made clear the allelopathy mechanism of Oxytropis Ochrocephala and to provide a theoretical basia for developing the new biological herbicide and plant growth regulator, reasonably and effectively using poisonous plant resources.The main results were showed as follows:1. Influence of water extraction liquid of Oxytropis Ochrocephala.on the seed germination and seedling growth of receptor plants.By means of indoor Petri dish bioassay and pot-culture method and biochemical analysis, the allelopathy of water extraction liquid of Oxytropis Ochrocephala.on the seed germination and seedling growth of receptor plants.ware stidied, The results showed that the water extraction liquid of Oxytropis Ochrocephala.remarkably inhibited the seed germination and the growth of receptor plants.The allelopathy of Oxytropis Ochrocephala. water extract showed that low concentration promoted the seed germination and seedling growth of receptor plants. and the inhibition increased with increasing concentration.The sensitive degree of different parts of receptor plants to Oxytropis Ochrocephala. water extract was different, the roots more sensitive than stems and leaves.2. Influence of water extraction liquid of Oxytropis Ochrocephala. on the root structure and mitosis of receptor plants.Oxytropis Ochrocephala. water extract has a significant effect on roots and hair of receptor plants seedings with different concentration and time treatments. Micrographs showed that water extraction liquid of Oxytropis Ochrocephala. remarkably inhibited the growth of roots hair and reduced the roots hairs number and length.The inhibition to roots hair growth of Avena sativa stronger than Brassica campestri.We looked at the paraffin section of roots under microscope and found that high concentration of Oxytropis Ochrocephala. water extract has a remarkably effect on the root structure of receptor plants,The water extraction liquid of Oxytropis Ochrocephala.leaded the cells of root cap to deformation and the cell layer was not obviou;We also found that Oxytropis Ochrocephala. water extract inhibited the mitotic and delay the mitotic time.3. Influence of water extraction liquid of Oxytropis Ochrocephala. on physiological and biochemical indexesAllelopathic effect of Oxytropis Ochrocephala. water extract on physiological and biochemical indexes of receptor plants were bioassayed,The results showed that Oxytropis Ochrocephala. water extract has a significant allelopathic effect on root vigor and Membrane permeability of receptor plants seedlings.The inhibition of Oxytropis Ochrocephala. water extract to root vigor and the harm to membrane permeability were increased with increasing concentration.The content of soluble MDA was increased and the content of soluble sugar,the content of soluble protein,chlorophyll a and chlorophyll b were reduced with the concentration of Oxytropis Ochrocephala. water extract and the treattime prolonging.The activity of POD,CAT,SOD and PPO were inhibited by the water extraction liquid of Oxytropis Ochrocephala.and the activity of PAL was increased,the content of nucleic acid was reduced too.Compare the allelopathic effect of Oxytropis Ochrocephala. water extract to diffierent receptor plants and diffierent parts of receptor plants,the results showed that allelopathic effect of Oxytropis Ochrocephala. water extract to Avena sativa was stronger than Brassica campestris,and to roots of receptor plants was stronger than stem and leaf.