[Diagnosis of boron deficiency and toxicity in broad bean (Vicia faba L.) and its causes]
1994
Al Mohammad, H.
One cultivar and two pure lines of broad bean were grown in a nutrient solution containing six different boron concentrations: 0, 0.05, 1, 2, 8 and 32 mg/ 1. In deficient plants plant growth was reduced; the young leaves remained small, wrinkled, thick, deformed and yellowish brown in color; irregular chlorosis appeared between the veins before leaf abscission; the deficiency progressed the terminal growing point died. Flower buds were shed without opening and black spots appeared on the rare developing pods. Symptoms of boron oxicity began with a yellowing of mature foliage, followed by a marginal necrosis and the leaves drop prematurely. The necrosis and browning of tissue caused by boron deficiency and toxicity arises from the accumulation of phenolic compounds. the boron content in the whole plant was closely related to its concentrations in the nutrient solution. The optimum boron content for mature broad bean plant was between 40 and 90 ppm
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