# The Early Growth of Maize Under Waterlogging Stress, as Measured by Growth, Biochemical, and Molecular Characteristics

## TL;DR

This paper studies how two types of maize respond to waterlogging stress during early growth, finding that cold-tolerant maize also handles waterlogging better.

## Contribution

The study reveals a potential link between cold and waterlogging tolerance in maize through physiological and genetic responses.

## Key findings

- The cold-tolerant maize line showed better resilience to waterlogging stress.
- Both genotypes increased their root-to-shoot ratio under stress.
- Tolerant lines managed ROS levels more effectively and showed signs of aerenchyma formation.

## Abstract

Climate change negatively affects the growth of important crops worldwide, including maize. To address this issue and reduce the harmful effects on crop yields, the agricultural sector is creating various strategies. One effective approach is early planting to reduce drought stress during critical growth phases, helping to avoid yield losses. This research evaluated how two maize inbred lines, one sensitive and one tolerant to cold respond to waterlogging stress. This is significant because early planting often occurs during cold weather and heavy rainfall. The research looked at the physiological and genetic responses during early growth stages. The results indicate that the cold-tolerant line also shows good tolerance to waterlogging, suggesting that similar mechanisms may be at play in how plants respond to both stresses, raising questions about their ability to manage both cold and excess water.

An effective strategy to address the impacts of climate change on maize involves early planting, which mitigates drought stress during critical growth phases, preventing yield reductions. The research assessed two maize inbred lines (sensitive and tolerant to low temperature) under conditions of waterlogging stress. This is crucial since early sowing often faces both low temperatures and heavy rain. Morphological, biochemical, and molecular responses were recorded after 24 h, 72 h, and 7 days of stress during the growth stage of 5-day-old seedlings. The findings indicated a more pronounced decline in all morphological characteristics in the sensitive line. Both genotypes displayed an increased root-to-shoot ratio, suggesting that the shoots deteriorate more rapidly than the roots. Physiological evaluations demonstrated that the tolerant line was more effective in managing ROS levels compared to the sensitive line. The involvement of H2O2 in aerenchyma formation implies that the decreased POD activity and elevated MDA levels observed after seven days may be associated with aerenchyma development in the tolerant line. Genes essential for PSII function revealed that waterlogging adversely affected photosynthesis in the sensitive genotype. In summary, the low-temperature tolerant genotype exhibited significant resilience to waterlogging, indicating potential interaction between the pathways governing these two abiotic stressors.