Luo Qi, Jin Wei, Li Lili, Xu Kedong, Wei Yunmin
Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China.
Henan Plant Gene and Molecular Breeding Engineering Research Center, Zhoukou Normal University, Zhoukou 466001, China.
Plants (Basel). 2025 May 26;14(11):1623. doi: 10.3390/plants14111623.
Plants are commonly exposed to fluctuating illumination under natural light conditions, causing dynamic photosynthesis and further affecting plant growth and productivity. In this context, although the vital role of potassium (K) in steady-state photosynthesis has been well-established, knowledge of the dynamic changes in photosynthesis mediated by K remains scarce. Here, the gas-exchange and chlorophyll fluorescence parameters under steady-state and dynamic photosynthetic responses were quantified in L. seedlings grown under K-deficient (-K, 0.02 mM K) and normal K (+K, 2 mM K) conditions. After a transition from low to high light, the time course-induction curves of the net photosynthetic rate (), stomatal conductance (), mesophyll conductance (), and maximum carboxylation rate () showed an obvious decline in the -K treatment. In comparison with the +K treatment, however, there were no statistical differences in the initial and values in supplied with deficient K, suggesting that the K-deficiency-induced decreases in and were light-dependent. Interestingly, the time to reach 90% of the maximum , , and significantly decreased in the -K treatment in comparison with the +K treatment by 27.2%, 45.6%, and 52.9%, respectively, whereas the time to reach 90% of the maximum was correspondingly delayed by almost two-fold. The photosynthetic limitation during the induction revealed that the biochemical limitation was the dominating factor that constrained under the -K conditions, while, under the +K conditions, the main limiting factor changed from biochemical limitation to stomatal limitation over time. Moreover, imposed the smallest limitation on during induction in both K treatments. These results indicate that a decreased K supply decreases the photosynthetic performance under fluctuating light in and that improving the induction responses of biochemical components (i.e., ) has the potential to enhance the growth and productivity of crops grown in K-poor soil.
在自然光条件下，植物通常会受到光照波动的影响，从而导致光合作用动态变化，并进一步影响植物生长和生产力。在此背景下，尽管钾（K）在稳态光合作用中的重要作用已得到充分证实，但关于钾介导的光合作用动态变化的知识仍然匮乏。在这里，对在低钾（-K，0.02 mM K）和正常钾（+K，2 mM K）条件下生长的拟南芥幼苗在稳态和动态光合响应下的气体交换和叶绿素荧光参数进行了量化。从低光过渡到高光后，净光合速率（）、气孔导度（）、叶肉导度（）和最大羧化速率（）的时间进程诱导曲线在-K处理中显示出明显下降。然而，与+K处理相比，低钾供应的拟南芥中初始和值没有统计学差异，这表明低钾诱导的和下降是光依赖性的。有趣的是，与+K处理相比，-K处理中达到最大、和的90%的时间分别显著减少了27.2%、45.6%和52.9%，而达到最大的90%的时间相应延迟了近两倍。诱导过程中的光合限制表明，生化限制是-K条件下限制的主要因素，而在+K条件下，主要限制因素随时间从生化限制转变为气孔限制。此外，在两种钾处理的诱导过程中对施加的限制最小。这些结果表明，钾供应减少会降低拟南芥在波动光下的光合性能，并且改善生化成分（即）的诱导响应有可能提高在低钾土壤中生长的作物的生长和生产力。
