DETERMINING THE IMPACT OF EXCESSIVE BORON ON SOME GROWTH CHARACTERS AND SOME NUTRIENTS AT THE EARLY GROWTH STAGE OF SUNFLOWER (Helianthus annuus L.)

The effect of excess boron (B) on growth and nutrient content in sunflower (Helianthus annuus L.) were investigated due to the evaulate the capacity of cv. Sirena for phytomining. Study was carried out in a green house conditions to assess the impact of increasing levels of boron (B) on cv. Sirena. The soil was treated with 0, 4, 8, 16, 32, 64 and 128 mg kg super(-1) B as H sub(3) BO sub(3). Results indicated that plant growth was depressed with the increasing level of B. The highest B uptake was obtained from 64 mg kg super(-1) B level with 695.2 mg kg super(-1). Increasing B also enhanced calcium (Ca) and phosphorus (P) contents in sunflower shoots but led to decrease in sodium (Na) and potassium (K) uptake. Results also revealed that the sunflower cv. Sirena did not germinate at the highest boron level (128 mg kg super(-1)). The results of this study indicate that cv. Sirena could be cultivated in soils containing B up to 8 mg kg super(-1).