The effect of magnesium levels in nutrient solution upon plant height, number of leaves and fruits, and leaf area of common bean was studied. Bean plants (3 per pot) were grown in 6 l pots containing Hoagland & Arnon n. 2 solution, modified for the magnesium concentration. The experimental design was a completely randomized factorial, replicated 3 times, with 5 magnesium levels, and 5 samplings which were done fortnightly. The number of leaves and the leaf area in the 3rd and 4th samplings were increased when the 2.4 ppm magnesium level was employed. Height and number of leaves in the 3rd sampling were increased when the plants were submitted to 24.3 ppm. On the other hand, an increased number of leaves was observed in the 3rd sampling when 72.9 ppm was used. When 97.2 ppm of magnesium was employed, there was an increase in the number of leaves at the 3rd and 5th samplings. Therefore, it can be suggested that, 2,4 ppm of magnesium is sufficient to maintain adequate development of the common bean. These results also suggest that, for the growth and development of the common bean the ideal level of magnesium is between 2.4 and 24.3 ppm.
Phaseolus vulgaris; magnesium; heigth of plants; number of leaves; number of fruits; leaf area
