Boron Toxicity on Seed Germination and Seedling Growth of Safflower (Carthamus tinctorius L.)

Abstract

To study the effect of boron on seed germination and seedling growth of safflower (Carthamus tinctorius L.), a laboratory experiment was undertaken at Department of Plant Science, Ambo University, Ethiopia. Seeds were sown in petri dishes with varying concentrations of boron (0, 0.25, 0.5, 1, 2, 4, 8, and 16 mg/l) at room temperature (24±2 0C) in completely randomized design with four replications. The result revealed that germination percentage and rate decreased beyond 2 mg/l and 1 mg/l, respectively. Shoot ( ≥ 1 mg/l) and root (>0.5 mg/l) lengths, shoot (>0.5 mg/l and >2 mg/l) and root (≥ 0.5mg/l and ≥ 1mg/l) fresh and dry weights, respectively decreased with increase in boron concentration. Root number, root - shoot ratio, and seedling vigor index were found to decrease beyond ≥ 0.25 mg/l, ≥ 2 mg/l, and ≥ 1 mg/l, respectively. In addition, phytotoxicity increased significantly (except 0.25 mg/l which promoted shoot and root) with increased in the concentration of boron. Safflower germination and seedling growth completely failed at ≥ 8mg/l of boron concentration.