Study On The Allelopathic Effects Of Six Forage And Rhizosphere Soil Water Extracts On Invasive Plants Of Cenchrus Incertus

The invasion of alien organisms has had a serious impact on the global ecology,economy,humans and animals.The use of allelopathy between plants and plants to curb the spread of invasive alien plants from the perspective of ecological control has been a research hotspot in recent years.C.incertus,is a serious invasive weed in the sandy areas of Horqin,posing a double challenge to the local economy and ecology,and biological control is of great concern because it does not cause new environmental problems.In this study,we used indoor Petri dish method and pot control test method to investigate the effects of water extracts of stems,leaves,roots and inter-root soil of six forage grasses,alfalfa,oat,sheep grass,huckleberry,grass mullein and sodawan,at different concentrations(100,50,25,12.5 and 0 g/L)on seed germination,seedling growth,and seedling enzyme activity and osmoregulatory substances of the six forage grasses and their inter-root soil.We investigated the effects of six forage grasses and their inter-root soil water extracts on seed germination,seedling growth,seedling enzyme activity and osmoregulatory substances,and clarified the comprehensive chemosensory effects of six forage grasses and their inter-root soil water extracts on seeds and seedlings of C.incertus,so as to provide a theoretical basis for biological control of C.incertus.The results of the study are as follows.1.6 kinds of forage grass stems,leaves,roots and rhizosphere soils of different centrations of water immersion solution have a certain allopathic effect on the germination of C.incertus,but the effect is different.Among them,under the treatment of stem and leaf water immersion solution,the oat 100 g/L treatment group had the strongest inhibitory effect on the germination rate,root length and bud length of C.incertus seeds,and the allelopathic effect index(IR)was-0.38,-0.56 and-0.73,respectively.Under the treatment of root water leaching solution,the oat 100 g/L treatment group had the strongest inhibition effect on the germination rate and root length of C.incertus,with a chemotic effect index(IR)of-0.40 and-0.67,respectively,while under the treatment of rhizosphere soil leaching solution,the 100 g/L treatment group of Oats had the strongest inhibition of the germination of C.incertus seeds.2.6 kinds of forage grass stems,leaves,roots and rhizosphere soil different centrations of water immersion solution on the growth index of C.incertus seedlings had two different effects on the growth index of C.incertus seedlings,among which,under the treatment of stem and leaf water leaching solution,the 100 g/L treatment group of leymus chinensis had the strongest inhibition effect on the leaf area and plant height of C.incertus seedlings,with a chemotic effect index(IR)of-0.43 and-0.47,and under the treatment of root water leaching solution,the 100 g/L treatment group of grass and Melilotus officinalis had the strongest inhibitory effect on the leaf area and fresh weight of C.incertus seedlings.The allelopathic effect index(IR)was-0.51 and-0.87,and under the treatment of rhizosphere soil water immersion,the alfalfa 100 g/L treatment group had the strongest inhibition effect on plant height,and the allein effect index(IR)was-0.62,while the leaf area and plant height of 100 g/L were the strongest inhibitors on leaf area and plant height,respectively.3.Under the treatment of different concentrations of water leaching solution of 6 kinds of pasture grasses and their rhizosphere soils,the content of malondialdehyde(MDA)in C.incertus seedlings was treated with 100 g/L of water extract from Astragalus laxmannii Jacquin root,leymus chinensis rhizosphere soil and alfalfa stem and leaf extract,which had a higher degree of rise,and peroxidase(POD),The changes in the activities of catalase(CAT)and superoxide dismutase(SOD)showed a trend of gradually increasing with the increase of the concentration of the water extract or increasing first and then decreasing,of which the change trend of catalase(CAT)activity was basically consistent with the change of malondialdehyde(MDA)content.Under the treatment of forage and rhizosphere soil water extract,the two osmotic regulatory substances proline(Pro)and soluble sugar(SS)responded to the changes in the concentration of stems and leaves and root water extracts of Alfalfa,Astragalus laxmannii Jacquin,and Melilotus officinalis.4.The comprehensive allelopathic effect index(SE)of different kinds of forage stem and leaf water immersion solution on tribulus sativa sativa was that,except f or the alfalfa treatment group,the rest of the treatment groups gradually increased with the increase of concentration,and the comprehensive order of allelopathy unde r the maximum treatment concentration was oat>alfalfa>leymus chinensis>beard bran ch >Astragalus laxmannii Jacquin>Melilotus officinalis;the allelopathic effect of differ ent kinds of forage root water immersion solution on the C.incertus was that,in a ddition to the water immersion treatment of each concentration of leymus chinensis,the overall performance of the treatment of the other five treatments was low co ncentration promotion.High concentration inhibition,under the maximum treatment concentration,the order is alfalfa>Astragalus laxmannii Jacquin>oats>leymus chinensi s >Melilotus officinalis > Lespedeza bicolor Turcz;the comprehensive effect of diffe rent kinds of forage rhizosphere soil water extract on C.incertus is the combination of the Lespedeza bicolor Turcz>leymus chinensis>alfalfa>Melilotus officinalis >oat>Astragalus laxmannii Jacquin,and the treatment of low concentration of water imme rsion extract of leymus chinensis and sand wang and beard branch is to promote th e effect,and the inhibition effect is gradually enhanced under other treatments with the increase of the treatment concentration.In summary,the comprehensive allelopathic effect index of the six forage rhizosphere soil water leaching solution treatment was much higher than that of the stem,leaf and root water leaching solution treatment,and the sensitivity of C.incertus to the rhizosphere soil leaching solution of the bearded twig was higher.