College of Forestry, Beijing Forestry University, Beijing, 100083, China.
Key Laboratory of State Forestry Administration on Tropical Forestry Research, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, 510520, China.
Photosynth Res. 2021 Aug;149(1-2):155-170. doi: 10.1007/s11120-020-00791-2. Epub 2020 Nov 1.
It is hypothesized that plant submergence tolerance could be assessed from the decline of plant biomass due to submergence, as biomass integrates all eco-physiological processes leading to fitness. An alternative hypothesis stated that the consumption rate of carbohydrate is essential in differing tolerance to submergence. In the present study, the responses of biomass, biomass allocation, and carbohydrate content to simulated long-term winter submergence were assessed in four tolerant and four sensitive perennials. The four tolerant perennials occur in a newly established riparian ecosystem created by The Three Gorges Dam, China. They had 100% survival after 120 days' simulated submergence, and had full photosynthesis recovery after 30 days' re-aeration, and the photosynthetic rate was positively related to the growth during the recovery period. Tolerant perennials were characterized by higher carbohydrate levels, compared with the four sensitive perennials (0% survival) at the end of submergence. Additionally, by using a method which simulates posterior estimates, and bootstraps the confidence interval for the difference between strata means, it was found that the biomass response to post-hypoxia, rather than that to submergence, could be a reliable indicator to assess submergence tolerance. Interestingly, the differences of changes in carbohydrate content between tolerant and sensitive perennials during submergence were significant, which were distinct from the biomass response, supporting the hypothesis that tolerant perennials could sacrifice non-vital components of biomass to prioritize the saving of carbohydrates for later recovery. Our study provides some insight into the underlying mechanism(s) of perennials' tolerance to submergence in ecosystems such as temperate wetland and reservoir riparian.
据推测，植物耐淹能力可以根据淹没导致的植物生物量下降来评估，因为生物量综合了所有导致适应性的生态生理过程。另一种假设认为，碳水化合物的消耗率对于耐淹能力的差异至关重要。本研究在四个耐淹和四个敏感的多年生植物中评估了模拟长期冬季淹没对生物量、生物量分配和碳水化合物含量的响应。四个耐淹的多年生植物生长在中国三峡大坝新建立的河岸生态系统中。它们在模拟淹没 120 天后仍有 100%的存活率，在重新充气 30 天后完全恢复光合作用，并且光合速率与恢复期间的生长呈正相关。与四个敏感的多年生植物（0%的存活率）相比，耐淹的多年生植物在淹没结束时具有更高的碳水化合物水平。此外，通过使用一种模拟后验估计并为层间平均值差异 bootstrap 置信区间的方法，发现生物量对缺氧后的响应而不是对淹没的响应，可以作为评估耐淹能力的可靠指标。有趣的是，在淹没期间，耐淹和敏感的多年生植物之间碳水化合物含量变化的差异显著，与生物量响应不同，这支持了耐淹的多年生植物可以牺牲生物量的非重要组成部分来优先保存碳水化合物以用于后期恢复的假设。我们的研究为温带湿地和水库河岸等生态系统中多年生植物耐淹的潜在机制提供了一些见解。
