Studies On Allelochemicals Of Pinellia Ternate And Their Rotations With Different Crops

Pinellia ternata is an annual plant of Pinellia in Araceae and has too serious continuous cropping obstacles to be replayed,which seriously restricts the production and development.In order to improve the land utilization efficiency,explore its the benefits of two crop rotation mode and the mitigation effect of continuous cropping obstacles.Taking Pinellia ternata as the research object of the experiment,mainly studied the effects of rotation mode of two crops a year on growth physiology,yield and quality of Pinellia ternata,analyzed the effects of rotation mode of two crops a year on soil nutrients,enzyme activities,microbial community structure and allelochemicals,and also compared the economic,social and ecological benefits of rotation mode of two crops a year.It provided a new planting mode for Pinellia ternata cultivation and an effective measure for alleviating continuous cropping obstacles.The main results are as follows:1.Effects of rotation on the growth and physiology of Pinellia ternata.The results showed that the emergence rate of Pinellia ternata in rotation was higher than that in continuous cropping,and the emergence rate of Pinellia tuber in rotation was85% higher than that in continuous cropping,and the SPAD value and net photosynthetic rate of rotation Pinellia ternata were also higher than that of continuous cropping.However,the contents of MDA,proline,soluble sugar and soluble protein in rotation Pinellia ternata were lower than those in continuous cropping Pinellia ternata,and the Pinellia ternata with the rotation of broad bean in each period was significantly lower than that of continuous cropping.2.The yield,quality and benefit of Pinellia ternata under rotation were higher than those under continuous cropping.Compared with continuous cropping of Pinellia ternata,the total yield of rotation of pea,broad bean,green vegetables and alfalfa increased by 108.14%,172.06%,139.94% and 59.44%,while continuous cropping decreased by 64.65% compared with continuous cropping of Pinellia ternata;rotation also increased the first-class and second-class commodity rate of Pinellia ternata,and the third-class was the highest.The quality of Pinellia ternata in rotation and continuous cropping reached the standard of Chinese Pharmacopoeia,but the extract and succinic acid of Pinellia ternata in rotation were higher than those in continuous cropping.The results of benefit analysis showed that the economic,social and ecological benefits of rotation Pinellia ternata per unit area in one year were also higher than that of continuous cropping,but the economic benefit of continuous cropping is loss.Among them,the benefit of rotation broad bean reached 4210 yuan per mu,which was only 9.66% lower than that of continuous cropping Pinellia ternata.At the same time,the ratio of output to investment was 2.77 times of continuous cropping Pinellia ternata.The results indicated that Broad bean rotation was the best rotation mode in Pinellia pinellia field production.3.After the rotation of Pinellia ternate with cash crop,the soil physical and chemical properties were also affected.For example,(1)the nutrient of rotation soil is higher than that of fallow soil after stubble.The contents of organic matter,available nitrogen,available potassium and available phosphorus in rotation soil were higher than those in fallow soil after stubble.The contents of organic matter,available nitrogen and available phosphorus in rotation broad bean soil were 1.07,1.09 and 1.58 times significantly higher than those in fallow soil after stubble.(2)The enzyme activity of rotation soil was higher than that of fallow soil after stubble.The activities of polyphenol oxidase,catalase,urease,acid phosphatase and sucrase in rotation soil were higher than those in fallow soil after stubble.Except the sucrase,the activities of other enzymes in rotation pea,broad bean and green vegetable soil were significantly different from those in fallow soil after stubble,and the order was: rotation broad bean > rotation green vegetable > rotation pea.4.After the rotation of Pinellia ternate with cash crop,it also affected the soil microorganism.The bacterial 16 S V3 + V4 and fungal ITS1 regions were sequenced using Illumina PE 300 platform.The results showed that compared with fallow after stubble,rotation significantly increased the richness and diversity of soil bacterial community,and rotation of broad bean and green vegetables also increased the diversity of fungal community.In terms of bacteria,the relative abundance of Acidobacteria,Proteobacteria,Myxococcota,Planctomycetota and Gemmatimonadota in pea and broad bean rotation soil was higher than that in fallow soil,and the abundance of dominant bacteria in rotation soil was more uniform at the level of genus classification.In terms of fungi,the relative abundance of Basidiomycota in rotation soil was higher than that in fallow soil,but Ascomycota was lower than that;the relative abundance of Solidocozyma in rotation soil was higher than that in fallow soil,while the Saitozyma in rotation soil was lower than that.Further principal component analysis also showed that the composition of soil microbial community was different between fallow and rotation,and the composition of soil microbial community was more similar between rotation and non planting Pinellia ternata.5.Twenty one compounds were identified by GC-MS,and benzoic acid and vanillin,which were reported as allelochemicals,were relatively high.The relative content of benzoic acid and vanillin in rotation soil was significantly lower than that of the fallow soil after stubble,and the soybean in rotation was 52.83% and 46.77%lower than it.It is speculated that benzoic acid and vanillin may be allelochemicals that cause continuous cropping disorder of Pinellia ternata.