Optimizing Boron Nutrition for Morphological Growth and Root Development in Acid Lime

Abstract

Boron, a critical micronutrient, plays a pivotal role in shaping the growth and development of acid lime, with its imbalance triggering profound morphological changes. This study investigates the impact of varying boron concentrations on the morphological traits of acid lime, focusing particularly on growth responses and stress symptoms associated with boron deficiency and toxicity under different boron levels (0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mM/l) under pot experiment in completely randomized deign (CRD). Plants deprived of boron (T1: no boron application) exhibited pronounced stunting, brittle stems, and impaired root development, which collectively diminished photosynthetic efficiency and nutrient transport. These deficiencies manifested as reduced plant height, fewer branches and leaves, and other morphological parameters culminating in weak canopy architecture. Root systems were also adversely affected, with shortened tap roots and diminished secondary root formation, limiting the plant’s nutrient absorption capacity. Conversely, elevated boron doses  of 2.0 mM/L of H3BO3 and 2.5 mM/L of H3BO3; (T5, T6) induced toxicity symptoms, evidenced by marked decreases in plant height, branch number, and leaf count, accompanied by significant reductions in root length, secondary root number, and root diameter. Optimal boron supplementation at concentrations between 0.5 and 1.0 mM/L (T2 and T3) was found to promote vigorous growth and root development, underscoring the crucial balance required in micronutrient management. The findings emphasize that both boron deficiency and excess detrimentally affect plant metabolism, thereby affirming the necessity for precise boron fertilization strategies to sustain healthy acid lime cultivation over successive growing seasons.