Deficiency, Stimulating and Toxic Effects of Boron and Manganese on Tobacco

Tobacco plants in water culture exhibited the deficiency symptoms of both boron and manganese 15 and 20 days respectively after the commencement of the experiment. The symptoms became more pronounced with age and in the final stages, resulted in the premature death of plants. Optimum doses of 0.5 ppm of boron and 30 ppm of manganese, when supplied to the plants in sand culture, induced them to grow tall and produce large number of leaves of larger and broader size as compared to the control. Boron also prolonged the duration of flowering. By the application of both the elements in toxic doses in sand cultures, toxic symptoms appeared within 6 and 3 days respectively. Plants did not survive in extreme cases of toxicity.