Liu Xinyue, Li Mingyan, Zhang Haijie, Jiao Jibo, Guo Xianhu, Yang Jikai, Liu Cuiju, Guo Shaoxia, Sun Yingkun, Guo Weihua, Guo Xiao
Qingdao Key Laboratory of Ecological Protection and Restoration, School of Life Sciences, Shandong University, 72 Binhai Road, Qingdao, 266237, China.
College of Landscape Architecture and Forestry, Qingdao Agricultural University, No. 700 Changcheng Road, Qingdao, 266109, P.R. China.
BMC Plant Biol. 2025 Sep 2;25(1):1179. doi: 10.1186/s12870-025-07070-z.
Phenotypic plasticity is recognized as the important driver of adapting to the heterogeneous habitats and environment changes. The climate variability hypothesis suggests that plant populations in high latitudes experience greater environmental fluctuations and may exhibit higher phenotypic plasticity. Wild Camellia japonica is an important but small number of species, which is mainly distributed in warm-temperature and subtropical zones of China, yet it is not clear how its different populations have adapted to environmental changes.
In our study, wild C. japonica from both zones were subjected to three soil moisture levels and two light intensity levels in the common garden experiments. We focused on examining the morphological and physiological responses to determine how wild C. japonica populations adapt to heterogeneous habitats and environmental changes through phenotypic plasticity.
The experimental results showed that severe drought stress reduced the activity of antioxidant enzymes and damaged the antioxidant enzyme system of subtropical wild C. japonica. In contrast, warm-temperate wild C. japonica performed better under variable soil moisture conditions and had higher phenotypic plasticity to soil moisture, which confirmed the climate variability hypothesis. Meanwhile, the warm-temperate and subtropical wild C. japonica showed similar phenotypic plasticity in response to light intensity, and both could reduce the effects of light deficit by improving its ability to capture sunlight energy. The similar phenotypic plasticity to light intensity might be due to the conservative strategy of subtropical wild C. japonica to avoid resource wastage.
Our study suggests that conservation efforts for wild C. japonica should account for the response mechanisms of their different populations to environmental changes, providing differentiated conservation strategies tailored to each population.
表型可塑性被认为是适应异质生境和环境变化的重要驱动力。气候变异性假说表明，高纬度地区的植物种群经历更大的环境波动，可能表现出更高的表型可塑性。野生山茶是一种重要但数量稀少的物种，主要分布在中国的暖温带和亚热带地区，但其不同种群如何适应环境变化尚不清楚。
在我们的研究中，来自这两个地区的野生山茶在共同花园实验中接受了三种土壤湿度水平和两种光照强度水平的处理。我们着重研究形态和生理反应，以确定野生山茶种群如何通过表型可塑性适应异质生境和环境变化。
实验结果表明，严重干旱胁迫降低了亚热带野生山茶抗氧化酶的活性，破坏了其抗氧化酶系统。相比之下，暖温带野生山茶在可变土壤湿度条件下表现更好，对土壤湿度具有更高的表型可塑性，这证实了气候变异性假说。同时，暖温带和亚热带野生山茶对光照强度表现出相似的表型可塑性，两者都可以通过提高捕获光能的能力来降低光照不足的影响。对光照强度相似的表型可塑性可能是由于亚热带野生山茶避免资源浪费的保守策略。
我们的研究表明，对野生山茶的保护工作应考虑其不同种群对环境变化的响应机制，为每个种群提供量身定制的差异化保护策略。
