Heterophylly: Phenotypic Plasticity of Leaf Shape in Aquatic and Amphibious Plants

Abstract

Leaves show great diversity in shape, size, and color in nature. Interestingly, many plant species have the ability to alter their leaf shape in response to their surrounding environment. This phenomenon is termed heterophylly, and is thought to be an adaptive feature to environmental heterogeneity in many cases. Heterophylly is widespread among land plants, and is especially dominant in aquatic and amphibious plants. Revealing the mechanisms underlying heterophylly would provide valuable insight into the interaction between environmental conditions and plant development. Here, we review the history and recent progress of research on heterophylly in aquatic and amphibious plants.

A discordance of seasonally covarying cues uncovers misregulated phenotypes in the heterophyllous pitcher plantCephalotus follicularis

“…Heterophylly is observed in various lineages of land plants, typically in aquatic plants [ 14 ] but also in terrestrial species [ 15 ], suggesting that it plays a broad role in plant adaptation. Various environmental cues, such as submergence, temperature, photoperiod, light intensity, light quality, and humidity, trigger heterophyllous responses [ 14 , 16 ]. In contrast to textbook examples of animal plasticity, such as predator-induced morphs in water fleas and seasonal changes in butterfly wing pigmentations [ 17 ], the iterative organization of the plant body enables the plant to tailor individual developing leaves to heterogeneous environments.…”

Mechanisms of the Morphological Plasticity Induced by Phytohormones and the Environment in Plants

“…Morphological plasticity was found in many species, as shown by changing leaf size, shape and thickness, and stomatal density, which has been seen in several species under different conditions or development stages [ 50 , 112 , 113 , 160 ]. Among those, heterophyllous plants show extreme plasticity in response to environmental factors, and were regarded as an ideal system for studying environmentally induced leaf plasticity [ 3 , 11 , 86 ]. To achieve various leaf patterns with different environments, heterophyllous plants have evolved diverse mechanisms for leaf development ( Figure 4 ).…”

“…Even though heterophylly has been seen for centuries, the molecular mechanisms of these plants are still largely unknown. Recent advances in omics technologies and gene transformation have allowed genetic analyses of many heterophyllous species, which make it possible to investigate the mechanisms of plant development, morphological plasticity, and environmental adaption [ 3 , 13 ]. For example, Potamogeton octandrus is an aquatic heterophyllous plant that has ovate and flat floating leaves, but narrow and thin submerged leaves.…”

“…In a rapidly changing climate, plants are facing great challenges from the environment. Recent advances in omics technologies and gene transformation have allowed genetic analyses to investigate the molecular mechanisms of plant development, ecology, and evolution [ 3 , 170 ]. Recent works also have made great breakthroughs in the fields of environmental signals sensing [ 171 , 172 , 173 ], phytohormone interactive networks [ 29 ], and plant stress combinations [ 174 , 175 ].…”

“…Leaves are key interfaces between plants and their surrounding environment, functioning to capture sunlight, synthesize photosynthate, exchange gasses, sense ambient changes, and regulate their growth under heterogeneous conditions [ 1 , 2 , 3 ]. In part because of their sessile lifestyle, plants possess efficient systems of morphological plasticity and acclimation to environmental changes.…”