Sandamal Salinda, Tennakoon Asanka, Wijerathna Parakkrama, Zhang Hong-Xiang, Yu Wen-Hao, Qiang Cheng-Gen, Han Jing-Dan, Zhang Fu-Min, Ratnasekera Disna, Ge Song
Institute of Botany State Key Laboratory of Systematic and Evolutionary Botany, Chinese Academy of Sciences, 100093, Beijing, China.
University of Chinese Academy of Sciences, 100049, Beijing, China.
Sci Rep. 2024 Dec 28;14(1):31126. doi: 10.1038/s41598-024-82383-x.
Phenological and morphological variation are widely viewed as a pivotal driver of ecological adaptation and speciation. Here, we investigate variation patterns of flowering phenology and morphological traits within and between O. rufipogon and O. nivara populations in Sri Lanka by incorporating the in situ observation in natural habitats and manipulative experiments in the common gardens. First, we observed varying degrees of phenological variation under different temporal and spatial conditions, suggesting that flowering phenology of two Oryza species varied depending on both environments and management practices. Particularly, the Sri Lankan O. nivara exhibits high plasticity in flowering phenology, implying that O. nivara might not be an annual in the strict sense. Second, the observation that flowering time of the two species overlapped suggests that the primary factor to maintain the species divergence in Sri Lanka may not be flowering time but rather environments. Third, our selection analysis suggests that interspecific divergence in the traits related to reproduction and habitat preference is adaptive and most likely driven by natural selection. Together, our case study on the Sri Lankan O. rufipogon and O. nivara enhances the understanding of the roles of phenotypic plasticity and environmental factors in the processes of adaptation and speciation.
物候和形态变异被广泛视为生态适应和物种形成的关键驱动力。在此，我们通过结合自然栖息地的原位观察和共同花园中的操纵实验，研究了斯里兰卡野生稻和尼瓦拉野生稻种群内部及之间开花物候和形态特征的变异模式。首先，我们观察到在不同的时间和空间条件下存在不同程度的物候变异，这表明两种稻属物种的开花物候因环境和管理方式而异。特别是，斯里兰卡的尼瓦拉野生稻在开花物候上表现出高度可塑性，这意味着尼瓦拉野生稻可能并非严格意义上的一年生植物。其次，两种物种开花时间重叠的观察结果表明，在斯里兰卡维持物种分化的主要因素可能不是开花时间，而是环境。第三，我们的选择分析表明，与繁殖和栖息地偏好相关的性状的种间分化具有适应性，很可能是由自然选择驱动的。总之，我们对斯里兰卡野生稻和尼瓦拉野生稻的案例研究增进了对表型可塑性和环境因素在适应和物种形成过程中所起作用的理解。
