Evaluation of Boron Uptake Efficiency in Lettuce, Spinach and Leaf Beet

Boron deficiency is an important disorder that can affect plant growth in calcareous soils. Various plants have different mechanisms of uptake. To investigate the different strategies of plants in increasing the efficiency of boron uptake, a factorial experiment was conducted in a completely randomized design with three replications in the greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. The experiment was conducted with three levels of boron (B0, B1.5, and B3 kg/ha) in the form of boric acid and three plant species (spinach, lettuce, and leaf beet). The results revealed that addition of boron enhanced shoot dry matter content in all plants. Lettuce shoot biomass was increased by 32% at B3, indicating that lettuce had a greater growth response to boron levels. Differences in boron concentrations in spinach (61.8 mg kg-1) and leaf beets (71.4 mg kg-1) compared to lettuce (31 mg kg-1) at the B0 level showed the importance of root characteristics and other factors affecting boron solubility and uptake efficiency such as root exudates. The concentration and uptake of boron in spinach were more affected by boron levels compared to lettuce and leaf beet. In spinach, the shoot and root boron concentration increased by 44% and 30%, respectively, and uptake in shoot and root also increased by 53% and 37%, respectively, at B3, compared to the control. Generally, different efficiencies of these plants in boron uptake were due to the high boron influx into spinach and leaf beet and low influx into lettuce.