Satyanti Annisa, Guja Lydia K, Nicotra Adrienne B
Division of Ecology and Evolution, Research School of Biology, Building Number 46, The Australian National University, Canberra, ACT, Australia.
Center for Plant Conservation-Botanic Gardens, Indonesian Institute of Sciences, Jalan Ir. Haji Juanda 16003, Bogor, Indonesia.
Oecologia. 2019 Feb;189(2):407-419. doi: 10.1007/s00442-018-04328-2. Epub 2019 Jan 2.
Plant establishment and subsequent persistence are strongly influenced by germination strategy, especially in temporally and spatially heterogeneous environments. Germination strategy determines the plant's ability to synchronise germination timing and seedling emergence to a favourable growing season and thus variation in germination strategy within species may be key to persistence under more extreme and variable future climates. However, the determinants of variation in germination strategy are not well resolved. To understand the variation of germination strategy and the climate drivers, we assessed seed traits, germination patterns, and seedling establishment traits of Oreomyrrhis eriopoda from 29 populations across its range. Germination patterns were then analysed against climate data to determine the strongest climate correlates influencing the germination strategy. Oreomyrrhis eriopoda exhibits a striking range of germination strategies among populations: varying from immediate to staggered, postponed, and postponed-deep. Seeds from regions with lower temperature variability were more likely to exhibit an immediate germination strategy; however, those patterns depended on the timescale of climatic assessment. In addition, we show that these strategy differences extend to seedling establishment traits: autumn seedlings (from populations with an immediate or staggered germination strategy) exhibited a higher leaf production rate than spring seedlings (of staggered or postponed strategy). Our results demonstrate not only substantial within-species variation in germination strategy across the species distribution range, but also that this variation correlates with environmental drivers. Given that these differences also extend to establishment traits, they may reflect a critical mechanism for persistence in changing climate.
植物的定植及后续存活受到萌发策略的强烈影响，尤其是在时空异质性环境中。萌发策略决定了植物使萌发时间和幼苗出土与有利生长季节同步的能力，因此物种内萌发策略的变化可能是在更极端和多变的未来气候条件下持续存在的关键。然而，萌发策略变化的决定因素尚未得到很好的解析。为了了解萌发策略的变化及气候驱动因素，我们评估了分布范围内29个种群的绵毛山茉莉的种子性状、萌发模式和幼苗定植性状。然后将萌发模式与气候数据进行分析，以确定影响萌发策略的最强气候相关因素。绵毛山茉莉在不同种群间表现出显著的萌发策略范围：从即时萌发到交错萌发、延迟萌发和深层延迟萌发。来自温度变异性较低地区的种子更有可能表现出即时萌发策略；然而，这些模式取决于气候评估的时间尺度。此外，我们表明这些策略差异还延伸到幼苗定植性状：秋季幼苗（来自即时或交错萌发策略的种群）的叶片生产速率高于春季幼苗（交错或延迟策略）。我们的结果不仅证明了整个物种分布范围内萌发策略存在显著的种内变异，还表明这种变异与环境驱动因素相关。鉴于这些差异也延伸到定植性状，它们可能反映了在气候变化中持续存在的关键机制。
