Mind the gap: Spatiotemporal patterns of airspace formation in duckweeds are regulated by hormones

The diversity of plant forms we see in nature is thanks to the adaptation of plant anatomy to many different environments and habitats.One of these adaptations is the aerenchyma, air spaces in plant leaves, shoots and roots.These air spaces help facilitate gas conductivity, which is especially needed in waterlogged situations, to facilitate oxygen transport from leaves to submerged roots.As such, aerenchyma formation can be a temporary adaptation to waterlogging in dryland species, or a constitutive part of plant anatomy in wetland species (Evans 2003).As a temporary adaptation, other than hypoxia under water submergence, it can also be activated in response to other stresses such as nutrient deficiency and drought, and is precisely regulated through mechanisms such as ethylene signalling (Evans 2003).The aerenchyma can form through two methods: lysigenous aerenchyma forms through programmed cell death (PCD), and schizogenous aerenchyma forms through differential growth of cells and cell separation (Evans 2003).Some species use only one of these, and others have both forms of aerenchyma.Aerenchyma formation in roots has been well studied, but the mechanisms behind leaf aerenchyma formation are less well understood.In leaves, aerenchyma formation occurs in three general steps: creating and expanding cavities, interconnecting those cavities, and linking with stomata for gas exchange.