What Plant Hormone is Produced Due to Water Deficiency

Plants, like other living organisms, need water to survive. Without adequate water supply, they wilt, show signs of stress and may eventually die. When water is scarce, plants resort to different mechanisms to conserve moisture and adapt to their environment. One of the plant's responses to water deficiency is the production of a hormone called abscisic acid (ABA).

What is Abscisic Acid (ABA)?

Abscisic acid is a type of plant hormone that regulates plant growth and development in response to various environmental stresses. It was first discovered in the 1960s, and since then, scientists have unraveled its many functions in plant physiology. ABA is synthesized in different plant tissues but is mostly produced in the roots and then transported to other plant parts. This hormone plays a vital role in various physiological processes in plants, including seed germination, dormancy, stomatal closure, and stress adaptation, among others.

How Does Water Deficiency Trigger ABA Production?

Plants detect water deficiency by sensing changes in soil water potential or the water content in their tissues. The detection of low water availability triggers a physiological response that leads to ABA production. ABA biosynthesis occurs in the roots under drought stress, where enzymes convert carotenoids into ABA. Once produced, ABA is transported to different parts of the plant, where it affects various physiological processes that help the plant cope with water scarcity.

What Are The Functions of ABA in Response To Water Deficiency?

The primary role of ABA in response to water deficiency is to promote stomatal closure, decrease transpiration, and conserve water. Stomata are the small pores on leaves that allow gases to exchange between the plant and the atmosphere. When water is scarce, plants close their stomata to reduce water loss through transpiration. ABA promotes stomatal closure by stimulating the efflux of potassium ions from guard cells, leading to water efflux and subsequent closure of stomata. This mechanism ensures that the plant conserves as much water as possible during water deficiency.

ABA also regulates gene expression during stress, leading to the synthesis of stress-responsive proteins that protect the plant from damage. ABA stimulates the expression of genes that encode enzymes that synthesize osmoprotectants, such as proline, trehalose, and glycine betaine. These osmoprotectants help stabilize plant proteins and membranes, prevent water loss and maintain essential physiological processes during water deficiency.

Another function of ABA during water deficiency is to inhibit cell growth and promote dormancy. Under drought stress, ABA inhibits cell growth and division, leading to reduced plant growth. This mechanism helps the plant conserve energy and resources during the drought period. ABA also promotes dormancy by inhibiting seed germination and promoting the synthesis of proteins that protect the plant from desiccation damage during prolonged drought periods.

In Conclusion

Water deficiency is a significant problem that affects plant growth and productivity. However, plants have evolved various mechanisms that help them cope with water scarcity, including the production of abscisic acid. ABA promotes stomatal closure, regulates gene expression, promotes dormancy, and inhibits cell growth in response to water deficiency. Understanding the functions of ABA in plant physiology is essential for developing strategies to improve crop yield and reduce the impact of drought on agriculture.