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

Abstract

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.

Mechanisms of waterlogging tolerance in wheat – a review of root and shoot physiology

“…) via programmed cell death (PCD) as described for wheat (Jiang et al . ) and more generally (Evans ; Shiono et al . ; Takahashi et al .…”

“…Aerenchyma formation in roots of wheat, like lysigenous aerenchyma in other species, results from the degradation of cortical cells Huang et al 1994b;Malik et al 2001) via programmed cell death (PCD) as described for wheat (Jiang et al 2010) and more generally (Evans 2004;Shiono et al 2008;Takahashi et al 2014). Interestingly, exposure to O 2 deficiency of only the apical portion of adventitious roots is enough to trigger the development of aerenchyma along the entire main axis (Malik et al 2003).…”

Metabolic control and regulation of the tricarboxylic acid cycle in photosynthetic and heterotrophic plant tissues

“…It is well known that both metabolic and anatomical adjustments are important strategies in order to allow plants to cope with spatial and temporal variations of the oxygen availability. The major structural change is an increased formation of aerenchyma to lower the resistance to oxygen diffusion into the respiring tissue (Drew, He & Morgan 2000;Jiang et al 2010). From a metabolic perspective, the hypoxic responses includes the down-regulation of a suite of energy-, and therefore, oxygen-consuming, metabolic pathways (Geigenberger 2003).…”

Comparative spatiotemporal analysis of root aerenchyma formation processes in maize due to sulphate, nitrate or phosphate deprivation

“…Aerenchyma is a parenchyma tissue that contains lacunae, created by lysigeny or schizogeny, and is formed during different environmental conditions such as oxygen shortage or deprivation of some nutrients (Drew et al 2000;Visser and Voesenek 2004;Haque et al 2010;Jiang et al 2010;Fagerstedt 2010). It aims to facilitate effective translocation of oxygen, carbon dioxide and ethylene or other gases, to redirect scarce resources or to provide a rapid diffusion path for solutes within the root cortex.…”