In an era defined by the escalating impacts of global climate change, the frequency and severity of floods are on a sharp upward trajectory. This climate shift poses a multitude of uncontrollable risks to crop sustainability and global food security. Flood-induced waterlogging stress is a major culprit behind crop yield reduction. The primary causes include impeded gas diffusion, a rise in the concentration of toxic elements due to soil electrochemical changes, and diminished photosynthesis as a result of reduced light penetration in waterlogged conditions. Moreover, the post-flood dry environment inflicts further damage on plant tissues, leading to dehydration, photoinhibition, and accelerated senescence.
To survive in waterlogged habitats, plants have evolved a suite of adaptive phenotypes. These include the development of aerenchyma and adventitious roots, enlarged lenticels, elongation of internodes and petioles, and the suppression of high-energy metabolic processes. However, no single adaptation strategy can comprehensively account for the diverse ways plants adapt to flood stress.
Recently, the renowned journal Plant Cell & Environment published a groundbreaking review article titled “Uncovering the Secrets of How Plants Adapt to Water Stress”. This in – depth review systematically explores two major adaptive strategies employed by model plants such as rice, and watercress when facing waterlogging stress.
The first strategy is the low – oxygen quiescence strategy (LOQS). Characterized by the suppression of plant metabolism and growth during flooding, plants adopting this strategy can rapidly resume growth once the floodwaters recede. This strategy is commonly observed in species that can tolerate short – term, deep flooding.
The second strategy is the low – oxygen escape strategy (LOES). Here, plants rapidly elongate their stems or leaves to break the water surface in shallow floods, enabling gas exchange and photosynthesis.
The review also defines “heterophylly” in aquatic plants as a third adaptive strategy. Heterophylly refers to a series of phenotypic, structural, physiological, and molecular changes that aquatic plants undergo in response to fluctuating water levels. This phenomenon is of great significance in understanding plant phenotypic plasticity and environmental adaptation. Unlike LOQS, which is more of a “lying – low” approach, and LOES, which is a “rapid – escape” strategy, heterophyllous plants can “adapt to local conditions”. They produce aquatic leaves when the water level rises and terrestrial leaves when it drops, allowing them to thrive in both aquatic and terrestrial environments.
For those eager to explore the full – text of this insightful review, you can access it via the following link: http://doi.org/10.1111/pce.15571. This research not only deepens our understanding of plant – environment interactions but also offers valuable insights for sustainable agriculture in the face of an increasingly water – stressed world.