Abstract: Acidification of the root environment to pH 2, 3, 4, 5 and 6.5 (control) with sulfuric acid decreased transpiration rate, stomata! opening, soluble sugars, soluble proteins and total free amino acids content and increased leaf osmotic potential in Sorghum bicolor plants. Leaf area was markedly reduced at lower soil reaction (pH 3 and 2). However, leaf relative water content (RWC) was higher at pH 5 and pH 4 than at pH 6.5 and was lower at pH 3 and pH 2. Hydrolysable carbohydrates (KC.) were markedly reduced at pH 2. Application of kinetin enhanced transpiration rate, stomata! opening and improved leaf water content especially at higher soil acidity. Kinetin-treated plants had higer soluble sugars, hydrolysable carbohydrates, soluble proteins and total free amino acids content than in untreated plants. Leaf osmotic potential was lower (more negative value) in plants receiving kinetin solutions at all acidity levels (pH 6.5 receiving 5 mg dm–3) kinetin was an exception). Leaf growth was positively affected by the three kinetin concentrations at pH 2. The effects of soil acidity (A), kinetin (K) and their interaction (A×K) on the parameters tested were statistically significant. Applied kinetin had a dominant role (contributes to largest share in total treatment effect) in affecting plant water relations. The share of interaction (A×K) was dominant in affecting soluble sugars, hydrolysable carbohydrates, soluble proteins and total free amino acids (coefficient of determination (η2) = 0.47, 0.53, 0.80 and 0.81 respectively). The role of soil acidity was dominant for leaf area (η2 = 0.62). The results show that the application of kinetin can alleviate the deleterious effects of acidity on the parameters tested.