Although plant-plant interactions have been intensively studied, few studies examined sex-related neighbor interactions in dioecious plant species. Here, we investigated the sexual diffe-rences in biomass accumulation, and analyzed the sexual neighbor effects and yields of sexual combination in Populus cathayana seedlings under the treatments of inter- and intra-sex neighbors and soil sterilization. The results showed that biomass accumulation of P. cathayana decreased in both of sexes when grown with an intra-sex neighbor. Females increased biomass accumulation under non-sterilization condition when grown with an inter-sex neighbor. Soil sterilization decreased biomass accumulation in both sexes of these plants, especially for females. Soil sterilization treatments did not significantly affect intra-sex interactions, but neutralized the positive effects in females and led the effects in males to turn from neutral to negative in inter-sex neighbors. The highest biomass in female-male combination under non-sterilization condition and the lowest biomass in male-male combination under sterilization condition were observed among combinations. These results indicated that the growth of female and male P. cathayana differed in their responses to their sexual neighbors, and that such neighbor effects were affected by soil microorganism. Our results could contribute to improve the productivity of poplar plantations in silviculture.
尽管植物邻体关系受到广泛关注,但关于雌雄异株植物性别间邻体关系的研究还较少。本研究比较了雌、雄青杨幼苗生物量的积累对其邻株性别和土壤灭菌的响应差异,并分析了性别间的邻体效应关系及不同性别混栽下生物量的差异。结果表明: 同性邻株模式降低了青杨雌株或雄株生物量的积累,而异性邻株模式在未灭菌条件下促进了雌株的生物量积累;土壤灭菌抑制了雌雄株生物量的积累,尤其是雌株;灭菌对同性邻体效应无显著影响,但异性邻株对雌株的效应由正相关关系变为中性相关,对雄株的效应由中性关系变为负相关;在所有组合中,未灭菌下的雌雄组合生物量最高,而灭菌下的雄雄组合生物量最低。雌雄青杨的生长对邻株性别的响应不同,且邻体效应受土壤微生物的影响。研究结果可为高产杨树人工林的栽培提供支撑。.
Keywords: Populus cathayana; dioecy; plant neighbor effect; soil microorganism.