Patterns and drivers of plant sexual systems in the dry-hot valley region of southwestern China

Sexual systems play important roles in angiosperm evolution and exhibit substantial variations among different floras. Thus, studying their evolution in a whole flora is crucial for understanding the formation and maintenance of plant biodiversity and predicting its responses to environmental change. In this study, we determined the patterns of plant sexual systems and their associations with geographic elements and various life-history traits in dry-hot valley region of southwestern China, an extremely vulnerable ecosystem. Of the 3166 angiosperm species recorded in this area, 74.5% were hermaphroditic,13.5% were monoecious and 12% were dioecious, showing a high incidence of diclinous species. Diclinous species were strongly associated with tropical elements, whereas hermaphroditic species were strongly associated with temperate and cosmopolitan elements. We also found that hermaphroditism was strongly associated with showy floral displays, specialist entomophily, dry fruits and herbaceous plants.Dioecy was strongly associated with inconspicuous, pale-colored flowers, generalist entomophily, fleshy fruits, and woody plants, whereas monoecy was strongly associated with inconspicuous, pale-colored flowers, anemophily, dry fruits, and herbaceous plants. In addition, hermaphroditic species with generalist entomophily tended to flower in the dry season, whereas diclinous species with specialist entomophily tended to flower in the rainy season. However, independent of sexual systems, plants that produce dry fruits tended to flower in the rainy season and set fruits in the dry season, but the opposite pattern was found for fleshy fruit-producing plants. Our results suggest that in the dry-hot valleys, plant sexual systems are associated with geographic elements as well as various life-history traits that are sensitive to environmental change.

苹果果袋封口装置设计

文章在分析水果套袋封口过程中遇到问题的基础上,自主研发了一种新型封口装置。该装置利用菱形连杆机构带动夹紧机构的平行收缩,使夹紧机构向中心靠拢封口,采取橡胶封口块保护果柄,使用转刀切除多余幼果,封口后利用弹簧本身弹力变化恢复至原始位置,以满足自动封口的要求。

Patterns of plant sexual systems in subtropical evergreen broad-leaved forests in Ailao Mountains, SW China

Aims Sexual systems influence many components of the ecology and evolution of plant populations and have rarely been documented in subtropical evergreen broad-leaved forests(SEBLF).Here we report frequency distribution and ecological correlates of plant sexual systems in SEBLF at Ailao Mountains,and compare our results with that of tropical and cool temperate forests.Methods We examine the sexual systems of 703 species of woody angiosperms belonging to 103 families and 296 genera based on a comprehensive survey of SEBLF at Ailao Mountains Natural Reserve.Information of plant sexual systems and ecological traits were mainly based on published literatures and specimens as well as our field observations.The associations between plant sexual system and ecological traits were assessed with chi-square tests.Important findings Among these species,60.2%were hermaphroditic,15.8%were monoecious and 24.0%were dioecious.The percentage of dioecious sexual system among tree species(22.2%)in SEBLF was comparable to those of tropical tree floras,but much higher than those of temperate forests at North America.The percentage of monoecious sexual system among tree species(30.1%)in SEBLF was higher than that of tropical tree floras,but much lower than those of temperate forests at North America.Monoecy was significantly associated with the tree growth form and was relatively common in temperate genera.Dioecy was significantly associated with fleshy fruits and monoecy was significantly associated with dry fruit type in SEBLF.The high percentage of diclinous sexual systems(monoecy and dioecy)in SEBLF may be associated with the origin of the flora and the prevalence of relatively small inconspicuous flowers of the forests in the Oriental Region.