Understanding the spatial regulation mechanism of ROS distributions in the root developmental zone under abiotic stress

High-temperature stress is an agricultural problem in various places in the world. High temperature leads to an array of developmental, physiological, and biochemical changes in plants, which affect plant growth and development and cause significant damage to agricultural yield. Young seedlings are very susceptible to high-temperature stress. The root growth and development of young seedlings are greatly damaged by high-temperature stress. The seedlings are unable to access the water deep in the soil.

Under ambient conditions, plants are exposed to high-temperature stress for a long time and alter their physiology and morphology to adapt to the conditions. Root development is very responsive to high temperatures. Root alters the size of the developmental zones during adaptation to high temperatures. For example, the root adapts to optimum conditions and forms a larger meristematic zone because cells actively divide and produce more cells in the meristematic zone (Fig. 3, red in the left root). In contrast, under high-temperature stress conditions, root forms a smaller meristematic zone (Fig. 3, red in the right root). Fewer cells divide in the meristematic zone. Furthermore, the cells that initiated the differentiation earlier resulted in forming a larger differentiation zone. These result in forming a shorter root with a smaller meristematic zone (Fig. 3, red in the right root) and a larger differentiation zone under high-temperature conditions (Fig. 3, blue in the right root).

High-temperature adaptation in the root developmental zone is regulated by ROS signaling. The ROS signal is altered during adaptation to high-temperature stress. With long exposure (3 days) to high-temperature stress conditions, O₂^- is reduced in the meristematic zone during high-temperature adaptation. The timing of alteration of ROS correlates with root developmental zone size change. These suggest that the ROS signals in the specific developmental zones modulated root development during high-temperature adaptation. We aim to understand the ROS regulation mechanisms under abiotic stress in the specific root developmental zone.