Isolation And Identification Of Allelochemicals In Different Pea Cultivation Substrates And Study On Biological Effect

In the process of industrial production,the phenomenon that pea continius cropping die has become serious gradually.The research showed that the important reason of death in pea continius cropping is Autotoxicity.A variety of allelochemicals excreted by pea root having an effect on the pea will be.In order to know the influence of allelochemicals excreted by pea root on the death of pea continius cropping,this study took compound excreted by the “Long Wan NO.1”as research object.The GC-MS method was used to identify the type of compound of pea root exudates in different culture medium,and study the difference of pea root exudates between rotational cropping and continuous cropping twice in the same culture medium.The culture medium without root exudates was served as blank control,the germination potential,germination percentage,root / shoot ratio,chlorophyll content,root activity and SOD,CAT,MDA activity of four kinds of crops were tested in pea root exudates with 5 different concentration gradients of 2,4-2 tertiary butyl phenol and 2,6-butylated hydroxytoluene.The results are as follows:1.Secretions can be extracted from dichloromethane were alcohols,aldehydes,lipids,benzene hydrocarbons etc.In the experiment,only three kinds of culture medium agar,MS and soil cultivation were compared.The two allelochemicals 2,4-DB and 2,6-DM were compared for biological detection based on articals.2.In the culture medium containing only agar,the continuous cropping compounds of exudates were more than that of rotation.In the MS culture medium,the total species of compounds were almost same in rotational cropping and continuous cropping,but the type changed.Compounds of rotation were more than that of continuous cropping based on soil culture.3.When bioassaying the peas,mung beans,wheat and corn,the germination potential,germination rate and root / shoot ratio of four crops were statistically analyzed.The result shows: if the concentration of two kinds of exudates was in the range of 0-5 mmol·L^-1,it can promote the germination of pea and mung bean seeds when the concentration of allelochemicals is 0-2 mmol·L^-1,and inhibit the germination of seed when the concentration of allelochemicals is 3-5 mmol·L^-1.With the increase of the concentration of two kindsallelochemicals,the germination potential and germination rate of corns and wheat seeds increased gradually,and the adverse effect of two kinds of exudates on wheat and maize were greater than those of pea and mung bean in the growth of the root system.4.In the detection of chlorophyll,when the concentration of allelochemicals was 0-5 mmol·L^-1,chlorophyll content of pea and mung bean increased with the increase of allelochemicals in range of 0-2 mmol·L^-1 of 2,4-DB,and chlorophyll content of the two crops decreased with the increase of allelochemicals in range of 3-5 mmol·L^-1 of 2,4-DB.When the concentration of 2,6-DM was in the range of 0-3 mmol·L^-1,chlorophyll content increased with the increase of concentration.When this concentration was 4-5 mmol·L^-1,chlorophyll content of the four crops decreased.When the concentration of two allelochemicals was in the range of 0-5 mmol·L^-1,the chlorophyll content of maize and wheat decreased.5.When the concentration of two kinds of exudates was in the range of 0-5 mmol·L^-1,the root activity of the four crops showed a downward trend.6.Within the concentration range of 0-5 mmol·L^-1 of two kinds of exudates,the effects of SOD,CAT and MDA on the four kinds of crop seedlings were as follows: when allelochemicals concentration was 0-2 mmol·L^-1,SOD enzyme activity increased with the increase of concentration,and SOD enzyme activity decreased when allelochemicals concentration increased to 3-5 mmol·L^-1.When allelochemicals concentration was 0-3 mmol·L^-1,CAT activity and MDA content were increased in pea and mung bean seedlings,and enzyme activity decreased when this concentration was 3-5 mmol·L^-1.When allelochemicals concentration was 0-5 mmol·L^-1,enzyme activity and MDA content were decreased in wheat and maize with the increase of concentration.