Process of aerenchyma formation and reactive oxygen species induced by waterlogging in wheat seminal roots

Abstract

The development and regulation of aerenchyma in waterlogged conditions were studied in the seminal roots of wheat. Evans blue staining and the first cell death position indicated that the cortical cell death began at the root mid-cortex cells in flooding conditions. Continuous waterlogging treatment caused the spread of cell death from the mid-cortex to the neighboring cells and well-developed aerenchyma was formed after 72 h. Meanwhile, the formation of radial oxygen loss barrier was observed in the exodermis owing to the induction of Casparian bands and lignin deposition. Analysis of aerenchyma along the wheat root revealed that aerenchyma formed at 10 mm from the root tip, significantly increased toward the center of the roots, and decreased toward the basal region of the root. In situ detection of radial oxygen species (ROS) showed that ROS accumulation started in the mid-cortex cells, where cell death began indicating that cell death was probably accompanied by ROS production. Further waterlogging treatments resulted in the accumulation of ROS in the cortical cells, which were the zone for aerenchyma development. Accumulation and distribution of H₂O₂ at the subcellular level were revealed by ultracytochemical localization, which further verified the involvement of ROS in the cortical cell death process (i.e., aerenchyma formation). Furthermore, gene expression analysis indicated that ROS production might be the result of up-regulation of genes encoding for ROS-producing enzymes and the down-regulation of genes encoding for ROS-detoxifying enzymes. These results suggest that aerenchyma development in wheat roots starts in the mid-cortex cells and its formation is regulated by ROS.

Melatonin Improves Waterlogging Tolerance of Malus baccata (Linn.) Borkh. Seedlings by Maintaining Aerobic Respiration, Photosynthesis and ROS Migration

“…Under waterlogging, the seedlings changed their metabolism from aerobic to anaerobic respiration (Fukao and Bailey-Serres, 2004). During this transition, a burst of ROS was generated and this resulted in oxidative damage of the seedlings (Hossain et al, 2009; Xu et al, 2013; Takahashi et al, 2015). This was indicated by the phenotype alterations of the seedlings such as chlorosis and wilting ( Figure 1 ).…”

“…Waterlogging, is a major agricultural constraint that limits crop growth and reduces their yield (Xu et al, 2013). It is frequently encountered during the raining seasons in many areas worldwide.…”

Waterlogging and submergence stress: affects and acclimation

“…An increase in porosity enhances venting of phytotoxic compounds (ethanol, methane) formed in roots towards the shoot and finally to the atmosphere (Visser & Pierik, 2007;Yin et al, 2013). It also enhances the longitudinal diffusion of gases in roots under hypoxia (Xu et al, 2013). Aerenchyma is also observed in leaf sheaths following waterlogging favoring shoot-root ventilation (Fabbri et al, 2005).…”

Localization of BEN1-LIKE protein and nuclear degradation during development of metaphloem sieve elements inTriticum aestivumL.

“…The Zn 2+ fluorescence experiment was carried out according to Xu's methods [34]. The sections were cut on a freezing microtome (Leica CM1850, Germany) at 10 μm, stained with TSQ Zn 2+ fluorescence probe (Enzo) (10 μmol • L -1 ), kept for 5 min at 25 °C, and were washed in dd H 2 O twice for 5 min.…”