Nutrient Availability Regulates Root System Behavior

Abstract

Application of different fertilizers on agricultural crops is rising due to rapid growth of world population and high demand for food and feed. The adequate amount of nutrients is critical for avoiding yield loss and toxic effects of various nutrients in ecosystems. Root is the most important organ that absorbs nutrients from the soil. Although roots are only 20% of the total plant weight, a strong and expanded root system is vital for vigorous plant growth and development. The capability of plants to respond appropriately to nutrient availability is essential for their adaptation to different environmental conditions. In most of the crop species, addition of nutrients such as nitrogen and potassium to an infertile soil noticeably enhances, but excessive amount of the nutrients reduces root growth and development. Plants grown under suitable levels of nutrients have more root hairs than nutrient-deficient roots, which are helpful in promoting water and nutrients uptakes. These modifications in root growth and development are the result of changes in gene expression pattern and hormonal signaling under various nutritional conditions. The deficiency of some nutrients such as sulfur enhances auxin accumulation in root tissues and increases lateral root growth in plants. Based on the important roles of nutrients in regulating root growth and development, this chapter explains nutrients’ interactions with root morpho-physiological parameters in rhizosphere.