Resilience of Maize to Environmental Stress: Insights into Drought and Heat Tolerance

Abstract

Maize (Zea mays L.) is a staple cereal crop worldwide, but its productivity is significantly affected by extreme weather conditions such as drought and heat stress. Plant growth, physiological processes, and yield potential are all affected by these conditions; as such, resilient maize crops are required to tackle these abiotic challenges. With an emphasis on morphological, physiological, and biochemical reactions, this review paper investigates the processes that underlie resistance to certain environmental challenges. Features including deep root systems, osmotic adaptations, and antioxidant enzyme activity help maize withstand drought. Activation of drought- and heat-responsive genes, accumulation of osmoregulatory compounds, and changes in membrane fluidity are all components of abiotic stress tolerance. Likewise, improved transpiration efficiency, modified photosynthetic processes, and improved heat shock proteins are used to produce heat resistance. Enhancing resilience requires progress in breeding methods, genetic engineering, and agronomic techniques, such as the use of stress-tolerant cultivars, biotechnology interventions, and climate-smart agriculture tactics. A special focus was given to cutting edge technologies like CRISPER-Cas9-mediated recent advances in heat and drought resistance. This review sheds light on recent studies and potential avenues for enhancing resilience to harsh climatic conditions, guaranteeing food security in the face of climate change.

Keywords: abiotic stress; climate adaptation; drought resistance; heat stress; physiological responses.

Figure 1

Maize response to drought stress at critical growth stages. The symptoms such as stunted growth, wilting, hormonal imbalance (ABA), and reduced yield. It illustrates how drought impacts plant development from seedling emergence to grain filling, leading to issues like slower emergence and kernel abortion.

Figure 2

Root architecture parameters regulating drought tolerance in maize. The maize root system and different types of rooting in maize.

Figure 3

Illustration of the adaptive mechanisms of maize under drought stress, including osmotic adjustment, maintenance of turgor pressure, and modifications in root morphology.

Figure 4

Comprehensive overview of heat stress on maize plants. Three different plants are depicted to show different stages of growth and development. Heat stress can lead to issues such as poor seedling vigor, desiccation risk, and cellular damage during early development. As the plant matures, it may experience chlorophyll degradation, increased respiration rates, nutrient uptake impairment, and root system damage. Later stages show effects like asynchronous flowering, pollen viability issues, silk desiccation, and ultimately poor kernel formation, kernel shrinkage, and weaker stalks, which result in shortened grain filling and reduced test weight.

Figure 5

Model to illustrate the application of CRISPR-Cas9 technology in maize improvement to enhance resistance against heat and drought. The process involves targeting specific genes using guide RNA (gRNA) designed to bind to the protospacer region, enabling precise genome editing for stress tolerance enhancement.