Mating strategies of Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae): a mixed mating system with inbreeding depression.

Abstract

Plant reproductive ecology is one of the research hotspots in ecology. With the increasing attention paid to the conservation of plant diversity, the research on reproductive characteristics and flowering biological characteristics of more species has attracted more attention. However, plant reproduction is affected by multiple interacting factors such as pollen limitation and resource availability. Vitex. negundo var. heterophylla (Franch.) Rehder (Lamiaceae) is a basilic species for water and soil conservation. Previous studies have revealed its mating system by the biological characteristics of flowering and SSR markers, but its reproductive strategies remains to be further studied.We evaluated reproductive success through artificial pollination to explore the reproductive characteristics of V. negundo var. heterophylla for the first time.From the results of fruit set, there is a mixed mating system dominated by outcrossing in V. negundo var. heterophylla accompanied by self-compatibility, and it cannot carry out autonomous selfing. Our data shows the pollinator-mediated interaction in the success of reproduction, whereas the effect of anemophily is very weak. And the seed germination rate of inbred line progenies was lower than that of hybrid progenies, which is suspected to be caused by inbreeding depression. The research will provide a scientific information for the protection and conservation of V. negundo var. heterophylla from the point of view of reproduction. In parallel, the results are necessary to protect zoophily in the background of insect decline.