目的:抗旱性状的种内变异,比如干旱逃生,在野外似乎很频繁,ruderalforb物种。了解这些特征是如何在整个景观中排列的,特别是与气候有关,对于开发荒地恢复计划的forbs至关重要。使用forbs是维持生物多样性和生态服务的必要条件。
方法:使用来自95个野生的6074个温室种植的Chaenactisdouglasii幼苗,整个美国西部的种子来源的人口,我们使用流式细胞术记录了螺栓现象和估计的基因组大小。混合效应回归模型用于评估种子起源的气候是否可以预测抽苔物候和基因组大小。
结果:螺栓连接的变化,反映年度与这个物种的常年寿命,在8.7%的植物中观察到,与螺栓植物不成比例地发生在温暖的地方,干旱气候。热量和干旱增加的人群与观察到的螺栓固定呈正相关(r=0.61,p<0.0001)。总寿命变化(61%)的约三分之一(22%)归因于种子源气候和年度热湿指数,干旱的程度。基因组大小对抽动没有显著影响。本世纪中叶(2041-2070)的预计气候模型支持年寿命的增加。
结论:我们的分析支持干旱逃逸,C.douglasii的押注对冲策略。暴露于更干旱的人群中,年寿命的个体比例更高。导致年寿命的干旱逃逸可能会影响种子的繁殖和部署方式,以进行基于气候的恢复。
OBJECTIVE: Intraspecific variation in drought resistance traits, such as drought escape, appear to be frequent within wild, ruderal forb species. Understanding how these traits are arrayed across the landscape, particularly in association with climate, is critical to developing forbs for wildland restoration programs. Use of forbs is requisite for maintaining biological diversity and ecological services.
METHODS: Using 6074 greenhouse-grown Chaenactis douglasii seedlings from 95 wild, seed-sourced populations across the western United States, we recorded bolting phenology and estimated genome size using flow cytometry. Mixed-effects regression models were used to assess whether climate of seed origin was predictive for bolting phenology and genome size.
RESULTS: Variation in bolting, reflecting an annual vs. perennial lifespan in this species, was observed in 8.7% of the plants, with bolting plants disproportionately occurring in locations with warm, arid climates. Populations with increasing heat and aridity were positively correlated with observed bolting (r = 0.61, p < 0.0001). About one-third (22%) of the total (61%) lifespan variation was attributed to seed source climate and annual heat moisture index, a measure of aridity. Genome size had no significant effect on bolting. Projected climate modeling for mid-century (2041-2070) supports an increasing occurrence of annual lifespan.
CONCLUSIONS: Our analyses support a drought escape, bet-hedging strategy in C. douglasii. Populations exposed to greater aridity exhibited a higher proportion of individuals with an annual lifespan. Drought escape leading to an annual lifespan can affect how seeds are propagated and deployed for climate-informed restoration.