PDF(Pubmed)
Abstract：
The responses of rare plants to environmental stressors will determine their potential to adapt to a rapidly changing climate. We used a common garden approach to evaluate how six populations of the annual San Diego thornmint (Acanthomintha ilicifolia Lamiaceae; listed as endangered in the state of California and as threatened by the US Fish and Wildlife Service) from across the species range respond in terms of growth (biomass, height, and width) and reproduction (seed production, floral production, and next generation seed viability) to experimental differences in water availability. We found a significant irrigation-by-population interaction on the aboveground growth, wherein the differences in the magnitude and direction of treatment did not correlate directly with climate variables in natural populations. With respect to reproduction, the low-irrigation treatment produced more seeds per plant, more reproductive individuals, and a larger proportion of viable seed in most, but not all, populations. The seed production and the effect of irrigation on seed production correlated positively with rainfall at wild source populations. These results suggest that Acanthomintha ilicifolia responds to water limitation by creating more and higher-quality seed, and that plants locally adapted to a higher annual rainfall show a greater plasticity to differences in water availability than plants adapted to a lower annual rainfall, a finding that can inform the in situ demographic management and ex situ collection strategy for Acanthomintha ilicifolia and other rare California annuals.
摘要：
稀有植物对环境压力的反应将决定它们适应快速变化的气候的潜力。我们使用一种常见的花园方法来评估年度圣地亚哥薄荷的六个种群（ActhanthominthailicifoliaLamiaceae；在加利福尼亚州被列为濒危物种，并受到美国鱼类和野生动物服务局的威胁）在整个物种范围内的生长（生物量，高度,和宽度)和繁殖(种子生产，花卉生产，和下一代种子的生存力）与水利用率的实验差异。我们发现在地上生长上存在显著的灌溉-种群相互作用，其中处理的大小和方向的差异与自然种群的气候变量没有直接相关。关于繁殖，低灌溉处理每株植物产生更多的种子，更多的生殖个体，大多数有活力的种子比例更大，但不是全部,人口。野生源种群的种子产量和灌溉对种子产量的影响与降雨呈正相关。这些结果表明，刺槐通过创造更多和更高质量的种子来响应水分限制，当地适应较高年降雨量的植物比适应较低年降雨量的植物对水资源供应差异表现出更大的可塑性，这一发现可以为刺果和其他罕见的加州年鉴的原位人口管理和异位收集策略提供信息。
