Research On Pre-dispersal Seed Predation And The Influencing Factors Of Songnen Grassland Plants

Seed predation is a common phenomenon of all the biota plants in the world,which affects the population dynamics and community structure of plants.Seed predation is influenced by different biological and abiotic factors.Most previous researches focus on forest ecosystem and woody plant seeds,and lack of research on the relationship between seed predation and plant characteristics and seed characters of herbaceous plants.The study discussed the factors influencing predation of plant seeds in Songnen grassland from the aspects of environmental factors,plant groups,plant characteristics,seed characters and seed defense characteristics.In order to supplement and enrich the research theory of animal and plant relationship and biodiversity,to provide important information and basis for the protection of wild germplasm resources and the formulation of crop pest control policy and measures,and to provide reference for the biological control of weed species and invasive species.In this study,the seed of 100 species was collected from common seed bearing herbs in Songnen grassland.20 individuals of plants with mature seeds were collected as repeat.Through the seed predation rate,plant height,plant dry weight,seed production,seed size,protective tissue weight percentage,seed coat thickness,crude fat content percentage,total phenols content,total carbon content,total nitrogen content and total phosphorus content.The comprehensive analysis of the factors affecting seed predation by using structural equation model.The main results are as follows:Besides the species without seed predation,there are significant differences in seed predation rate in different years.The seed predation rate in 2019 is about 1.5 times of that of 2020,and it is also proved that the seed predation rate is negatively correlated with rainfall.And the seed predation rate is positive correlated with water evaporation In addition,the predation rate of seeds is not related to the life style of plants.But the rate of seed predation was significantly different among different families,and the seed predation rate of Legume plants was significantly higher than that of other families,about 2.9 times the average of the other 7 families.The predation rate of seeds was not correlated with plant height,dry weight,seed production,seed volume and empty flat rate in plant characteristics and seed characters,but only positively correlated with seed size.In addition,the seed predation rate was significantly related to the fruit type,and the seed predation rate of pod was significantly higher than that of other fruit types,about 20.6 times the average of the other fruit types.In the defense characteristics,there was no significant linear relationship between the predation rate and the weight ratio of the protected tissue,the fat content,the total phenol and the total carbon content,and was positively correlated with the thickness of seed coat,the total nitrogen and the total phosphorus content.The results show that the fruit type,seed coat thickness,total nitrogen content and total phosphorus content are the key factors affecting pre-dispersal seed predation.The total nitrogen content is the most important factor affecting seed predation,and the chemical defense characteristics are the most important factors.In addition,the factors influencing each other interact with each other and act on the results of seed predation.