• plant;
  • aerenchyma;
  • hypoxia;
  • Programmed Cell Death;
  • apoptosis;
  • maize (Zea mays);
  • rice (Oryza sativa)


  • Introduction 
  • II 
    Schizogenous aerenchyma formation 
  • III 
    Lysigenous aerenchyma formation 
  • IV 
    Regulators of lysigenous aerenchyma formation
  • Key questions in lysigenous aerenchyma formation 
  • VI 
    Sensing hypoxia; early events in aerenchyma formation 
  • VII 
    Ultrastructural changes associated with lysigenous aerenchyma formation 
  • VIII 
    Late events in cell death in aerenchyma formation 
  • IX 
    Comparative evidence on programmed cell death in aerenchyma formation 
  • Comparison with other abiotic initiators of cell death in plants 
  • XI 
  • XII 


Aerenchyma – tissue containing enlarged gas spaces – occurs in many plants. It is formed either as part of normal development, or in response to stress (e.g. hypoxia). Two mechanisms of aerenchyma formation have been described; schizogeny, in which development results in the cell separation and lysigeny, in which cells die to create the gas space. While schizogenous aerenchyma provides a fascinating system for study and has been described in detail at a morphological and ultrastructural level, little is known about the molecular genetics of its formation. The ultrastructure and morphology of lysigenous aerenchyma has also been researched in detail, and considerable progress has been made in describing the cell death processes involved, particularly in relation to programmed cell death. Once again, the molecular genetics of the process are not well understood. Aerenchyma is of great importance in crop survival in waterlogging. It is also important in being a major pathway for the release of the global warming gas methane to the atmosphere in flooded soils. Understanding the regulation of its development is therefore a research priority.