Aerenchyma formation: programmed cell death in adventitious roots of winter wheat (Triticum aestivum) under waterlogging

This study determined the characteristics of cortical cell death in wheat (Triticum aestivum L.) roots during programmed cell death (PCD) and the relationship between PCD and acid phosphatases. An examination of morphological development by light microscrope revealed that aerenchyma formed in roots waterlogged for 24 h and well developed aerenchyma formed in roots waterlogged for 120 h. The first detectable events were observed by electron microscopy and included plasma membrane invagination and the appearance of vesicles between the plasma membrane and the cell wall. Later, chromatin condensation and double-membrane-bound structures resembling autophagosomes were observed. The activity of acid phosphatases gradually increased during waterlogging and was present during the entire process of cell death. These observations suggest that cortical cell death during aerenchyma formation induced by waterlogging was a form of PCD. Acid phosphatases play an important role in PCD induced by waterlogging, being responsible for the hydrolysis of cell components at the later stages of PCD.