With the rapidly increasing world population and escalating food demand in the face of changing weather patterns, it is imperative to improve our understanding of how root functional traits enhance water acquisition and nutrient foraging for improved crop yields. Phosphorous (P) is poorly bioavailable element and essential for plant growth and development. Natural P reserves are very limited, and its availability is greatly influenced by several environmental factors, e.g., due to finite natural resources, soil pH, organic matter, and soluble complexes with cations (Al, Fe, and Ca); therefore, P limitation is a major factor that adversely affects crop production. To ensure an efficient and stable agricultural system, the establishment of P efficient crop production is inevitable. Plants have evolved different adaptability mechanisms to overcome these nutrient stresses. Low P adapted responses in plants are considered as an important trait for developing new lines with improved P acquisition, water uptake efficiency, and eventually protect roots from physical impedance. Previous studies showed that, modification in root architecture is potentially correlated with water, nutrient and phosphorus uptake. During P deficit condition, plant root undergoes several phenotypic (root hair density, cluster root, and lateral root) and biochemical modifications (citrate, malate, and acid phosphates secretion) leading to the solubilization and acquisition of unavailable P complexes in soil. This chapter reveals the biochemical, physiological, and molecular mechanisms of plant adaptive responses to low P availability. Moreover, this chapter proposes how plant competes with various abiotic stresses such as P deficiency, drought, and salinity. Screening of plants with superior root hair traits would be an important approach toward the development of P efficient crop varieties.