Data from: Female Salix viminalis are more severely infected by Melampsora spp. but neither sex experiences associational effects

Associational effects of plant genotype or species on plant biotic interactions are common, not least for disease spread, but associational effects of plant sex on interactions have largely been ignored. Sex in dioecious plants can affect biotic interactions with herbivores and pollinators; however, its effects on plant–pathogen interactions are understudied and associational effects are unknown. In a replicated field experiment, we assessed Melampsora spp. leaf rust infection in monosexual and mixed sex plots of dioecious Salix viminalis L. to determine whether plant sex has either direct or associational effects on infection severity. We found no differences in Melampsora spp. infection severity among sexual monocultures and mixtures in our field experiment. However, female plants were overall more severely infected. In addition, we surveyed previous studies of infection in S. viminalis clones and reevaluated the studies after we assigned sex to the clones. We found that females were generally more severely infected, as in our field study. Similarly, in a survey of studies on sex-biased infection in dioecious plants, we found more female-biased infections in plant–pathogen pairs. We conclude that there was no evidence for associational plant sex effects of neighboring conspecifics for either females or males on infection severity. Instead, plant sex effects on infection act at an individual plant level. Our findings also suggest that female plants may in general be more severely affected by fungal pathogens than males.

植物基因型或物种对生物互作的关联效应（associational effects）普遍存在，在病害传播方面尤为如此，但植物性别对互作的关联效应却在很大程度上被忽视。雌雄异株植物（dioecious plants）的性别可影响其与植食动物和传粉者的生物互作；然而，目前对其在植物-病原物互作中的效应研究仍较为不足，且相关关联效应尚不明确。本研究通过重复田间试验，在雌雄异株欧杞柳（Salix viminalis L.）的单性样地与混性样地中评估了栅锈菌属（Melampsora spp.）的叶锈病感染情况，以明确植物性别对病害严重度是否存在直接效应或关联效应。田间试验结果显示，不同性别的单作样地与混作样地间，栅锈菌属的病害严重度并无显著差异，但总体而言雌株的感染严重度更高。此外，我们调研了此前关于欧杞柳无性系感染情况的研究，并在为这些无性系标注性别后重新评估了相关数据，结果与本田间试验一致，发现雌株普遍感染更为严重。同样，在一项针对雌雄异株植物性别偏向性感染的研究调研中，我们发现植物-病原物互作组合中更多表现为雌株偏向性感染。本研究结论表明，并无证据显示邻体同种植株的性别对雌株或雄株的病害严重度存在关联效应。换言之，植物性别对感染的影响仅作用于个体植株层面。本研究结果还提示，总体而言雌株受真菌病原物的感染严重程度可能高于雄株。