Effects Of Water And Nitrogen Conditions On Asexual Reproduction And Sexual Reproduction Traits And Their Relationship In Leymus Chinensis

Grassland productivity is an important indicator reflecting its function.In the grassland ecosystem dominated by perennial clonal plants,asexual reproduction is the basis and foundation of above-ground vegetation change,population renewal and productivity formation.In the arid and semi-arid ecosystems,asexual reproduction are driven and restricted by water and nitrogen.At present,there are few studies on the response of asexual reproduction and sexual reproduction to water and nitrogen in arid and semi-arid regions,especially the lack of water and nitrogen conditions on the relationship between them.In this paper,based on the research on the grassland establishment in Northeast China,Leymus chinensis,the anaerobic reproductive traits of Leymus chinensis were further analyzed based on the study of the response of asexual reproduction traits to water and fertilizer conditions through different treatments of nitrogen fertilizer,water and water and fertilizer.The relationship between sexual reproduction traits,clarifying the relationship between the asexual reproduction and sexual reproduction of semi-arid grasses and grasses,and how to improve the productivity of grassland under the change of the “two major” driving factors.In the future,grassland science management will provide strong theoretical and practical basis.The study found:(1)Nitrogen application,watering and water-nitrogen coupling treatment can affect the changes of asexual reproduction traits of Leymus chinensis.The water and nitrogen treatment conditions are conducive to the increase of total plant density and asexual reproduction density,especially in the asexual reproduction period.Nitrogen application,watering and water-nitrogen coupling treatment can improve the biomass and vegetative propagation biomass of Leymus chinensis,and the water and nitrogen coupling treatment in the three treatments is better than watering and nitrogen application treatment.(2)Nitrogen application,watering and water-nitrogen coupling treatment can affect the changes of sexual reproduction characteristics of Leymus chinensis.Water and nitrogen treatments can significantly increase the seed yield of Leymus chinensis,and the effect is most significant under the conditions of water and nitrogen coupling treatment.The water and nitrogen treatment in the same year could significantly increase the number of florets,the number of sturdy grains and the seed setting rate and 1000-grain weight(P<0.05),but had no significant effect on the number of headings and heading rate of Leymus chinensis.(3)Under the condition of water and nitrogen treatment,the total bud density and total plant density of Leymus chinensis and the total density of asexual reproduction were not correlated with the number of heading per unit area;the total daughter shoots density and the asexual reproduction density after seed harvesting was significantly positively correlated with the number of sturdy grains.The growth rate of the grain number was larger than that of them.The asexual reproduction biomass of Leymus chinensis under the condition of water and nitrogen was correlated with the seed yield at the maturity stage and the post-fruit vegetative stage,but the increase in seed yield was greater than that in asexually production biomass.In summary,nitrogen application,watering and water-nitrogen coupling treatment conditions can promote the development of asexual reproduction productivity,and significantly improve sexual reproduction productivity,the best effect under water and nitrogen coupling conditions.It can be seen that although Leymus chinensis has the ecological characteristics of asexual reproduction and weak sexual reproduction,but when the water and nitrogen are sufficient in the habitat,both can be compensated.This provides strong evidence for the restoration of grassland productivity and the scientific management of grassland.