MAGNESIUM LEVELS IN NUTRIENT SOLUTION AND COMMON BEAN (PHASEOLUS-VULGARIS L CV CARIOCA) DEVELOPMENT - EVALUATION OF THE GROWTH RELATIONS AND ASSIMILATE PARTITIONING

The effect of magnesium levels in nutrient solution upon relation betw een shoot and root, leaf weight ratio and assimilate partitioning of c ommon bean (Phaseolus vulgaris L. cv Carioca) was studied. Bean plants (3 per pot) were grown in 6 l pots containing Hoagland & Arnon n. 2 s olution modified to obtain 2.4, 24.3, 48.6, 72.9 and 97.2 ppm of magne sium. The experimental design was a completely randomized factorial re plicated 3 times with 5 levels of magnesium and 5 samplings wich were done forthnightly. Therefore, it may be suggested that the 48.6 ppm of magnesium level proposed by Hoagland & Amen (1950) is the best choice for the common bean, according to the conditions of this experiment. Magnesium concentrations over 48.6 ppm didn't show significant alterat ions of the evaluated parameters. Nutrient solution with 2.4 ppm of ma gnesium content provides higher efficiency to the common bean plants d uring almost all its cycle, except the final of the reproductive phase . These results suggest that magnesium concentration increased to 48.6 ppm, in the cycle final perhaps could increase the productivity.