The Spatial Patterns Of Sexual Reproduction In Sagittaria Trifolia

Successful reproduction is the basis of population maintenance and dispersal,which affects the species' distribution in time and space.In the process of plant reproduction,different habitat conditions affect the level of reproduction.Especially for widely distributed plant species,the most typical environmental factors are light(abiotic factor)and pollinator(biotic factor).Meanwhile,different positions of plants in the population also affect the success of plant reproduction.For example,populations of small-scale and irregular shapes increase the proportion of edge plants in the population,which affects pollinators' foraging behavior and leads to variations in reproduction.Sagittaria trifolia,a widely distributed and insect pollinated herb,was selected as the research material.In order to explore the mating distance and the number of mates of S.trifolia among different habitats and positions within populations,we set up common gardens of three habitats,namely net area,shade area and open area,and differentiate edge and internal plants in the experimental array.The results showed that the mating distance and mate diversity in the net area were significantly lower than those in the shade and open areas.The frequency of selfing was higher in net area,which was mainly affected by the range of activities and foraging behavior of ants,the main pollinators in net area.The mating distance in the shade area was longer than that in the open area,which indicated that the shade area was strongly affected by light,and the density of flowering plants was low.In such scenario,pollinators needed to fly long distances,so as to increase gene exchange between distant plants.In terms of mate diversity,the shade area was significantly lower than the open area,which may be due to fewer pollinator visits caused by lower flowering density and thus decreased attraction to pollinators.The main pollinators of the two areas were also different.Bee was the main pollinator in the open area,enjoying short and fast foraging behavior,which made the efficiency of pollen transmission higher.Hoverfly,the main pollinator in the shade area,mostly stay on flowers and hover between flowers,and their procrastination behavior might have aggravated the decline of number of mates in this area.The mating distance of edge plants was longer than that of internal ones,and their mate diversity was lower than that of internal ones.The difference of mating distance may be due to fewer individuals adjacent to the edge plants,and their pollen needs to be transferred at long distances to be successful in reproduction.The difference in the number of mates may be related to the visiting frequency of pollinators.The population edge may act as a channel for pollinators to enter the population and the visiting frequency is low,while the visiting frequency of internal plants is increased due to longer stay and repeated visits,resulting in the increase of pollen recipients.In conclusion,I studied the mating distance and mate diversity of S.trifolia of different habitats and positions in populations,and revealed the effects of habitat heterogeneity and habitat fragmentation on the spatial patterns of plant reproduction.This research deepens our understanding of the impact of habitat on plant reproduction under the pressure of global change,and provides empirical support for the study of plant reproductive ecology with deteriorated environments.