Exogenous Nitric Oxide Eases The Allelochemical Stress Mechanism Of Eupatorium Adenophorum Extracts On Seed Germination And Seedling Growth Of Wheat

As the third largest grain crops in our country,wheat provides people with important energy and protein.During the process of wheat production,weeds is a common hazard.For a long time,chemical pesticide has been used to prevent and control weeds.It not only pollutes the environment,but also threatens the safety of wheat products.Eupatorium adenophorum Spreng has natural active substance to curb the growth of plants.It is of great significance to apply it in the research and development of new types of botanical herbicides for the green prevention and control of triticeae weeds.Extractive from Eupatorium adenophorum Spreng will control the weeds,however,it will definitely affect the growth of triticeae crops.It requires further study on how to ease the harm of crofton weed on triticeae crops.Exogenous NO is vital for the adjustment of plant growth and development and its response to adverse situation.However,the harm mechanism of exogenous NO in easing the Eupatorium adenophorum Spreng extracts on the seed germination and seedling growth of triticeae crops is still unclear.In this study,using Shanxi Wheat No.98 as studying material,that exogenous NO can ease the allelopathy stress mechanism of Eupatorium adenophorum Spreng extracts on the seed germination and seedling growth in the early stage has been analyzed.The results are as follows:1.Eupatorium adenophorum Spreng extracts has allelopathy stress on the seed germination and seedling growth of wheat.The higher the concentration of the extractive is,the stronger the allelopathy stress.Stress treatment of the weed by 400 mg·L-1 extractive aqueous solution shows that the germination potential,germination rate,germination index,and vigor index has obviously decreased compared with that of the control group.The dry and fresh weight of the seedling,seedling length,and main root length and so on are distinctly smaller than that of the control group.2.Use 0.5 mmol·L-1 sodium nitroprusside(SNP)to trigger germination.It can distinctly ease the allelopathy stress of Eupatorium adenophorum Spreng extracts on the seed germination and seedling growth of wheat.Stressed by 1200 mg·L-1 Eupatorium adenophorum Spreng extracts and treated by NO,the germination potential,germination rate,germination index,and vigor index are respectively 166.67%,5.71%,29.99%,and 63.96%higher than that treated by ionized water.And the seedling length,seedling fresh and dry weight are respectively 32.76%,25.95%and 27.98%higher than that treated by ionized water.Among them,significant difference has been seen for the germination potential,germination index,vigor index and fresh and dry seedling weight.3.Eupatorium adenophorum Spreng extracts has allelopathy stress on the root border cell(RBC)of wheat seedlings and cause apoptosis,death and thickened mucilage on a large scale.Under the allelopathy stress of Eupatorium adenophorum Spreng extracts using NO to treat the seeds will distinctly lower the apoptosis and death rate of the root border cell,respectively 44.42%and 47,81%lower than that treated by ionized water.And the thickness of mucilage is lowered by 42.71%.Theses all reach the level of significant difference.4.After treated by NO,the impact of Eupatorium adenophorum Spreng extracts on the seed germination and seedling growth of wheat can be effectively eased.The possible mechanism is that:the treatment by NO has enhanced the tolerance of wheat seeds against the allelopathy mechanism of the extractive and the apoptosis and death rate of root border cell of the seedling will be lowered.More active root border cells can avoid the harm of the allelopathy stress harm by the extractive,so the root can develop and grow normally.This study has provided some theoretical basis for the application of Eupatorium adenophorum Spreng extracts and exogenous NO to the green production of wheat.