ALUMINUM EFFECTS ON PLANT AND NUTRIENT-UPTAKE PARAMETERS OF SOIL AND SOLUTION-GROWN SORGHUM GENOTYPES

Recently, controlled environmental screening techniques have been pref erred to field trials to identify sorghum genotypes that can tolerate aluminum (Al) stress. Soil and solution culture experiments were under taken under greenhouse conditions to evaluate the effect of Al on plan t growth and nutrient uptake parameters of three sorghum genotypes: 1) SC283, 2) BR003R, and 3) BR007B. Earlier field studies indicated that the order of tolerance to Al decreased from genotype 1 to 3. A dark r ed latosol was used with seven levels of dolomitic lime (0, 0.50, 0.75 , 1.0, 2.0, 4.0, and 8.0 t/ha) and solution culture with seven levels of Al (0, 0.15, 0.20, 0.25, 0.30, 0.60, and 1.20 mmol/L). Plant growth (shoot and root weight; root length; specific root length, SRL; and r elative shoot and root growth reduction, RGR) and nutrient uptake (tot al uptake; influx; nutrient efficiency ratio, ER; and percent of nutri ent inhibition, PI) parameters were influenced similarly by Al in solu tion culture and soil experiment. Significant differences were observe d for genotype-Al interactions and there was a stimulating effect, amo ng genotypes, by low Al concentrations (up to 0.15 mmol/L). However, t he plant growth and nutrient uptake parameters were negatively affecte d by Al stress. The performance of the genotypes in relation to Al tol erance in both solution and soil experiments was the same as observed in the field: SC283 > BR003R > BR007B.