Macronutrient deficiencies in tomato plants: impacts on symptomatology, growth, physiology, fruit yield, and quality

Plant growth and crop yield depend on the availability of essential nutrients in sufficient and balanced proportions. However, plants frequently encounter nutrient deficiencies throughout their life cycle. This study aimed to evaluate the effects of individual macronutrient deficiencies on visual symptoms, vegetative growth, physiological traits, fruit yield, and quality in tomato plants cultivated in a substrate medium under greenhouse conditions. The experiment, consisting of seven treatments in total, was conducted using a completely randomized design with three replications. The treatments included a complete nutrient solution (control) and six nutrient solutions, each deficient in a single macronutrient (N, P, K, Ca, Mg, or S). Deficiency treatments induced distinct visual symptoms and impaired leaf morphology and physiological processes. Vegetative growth was severely inhibited by N and P deficiencies, while Mg and S deficiencies caused moderate reductions. N deficiency led to the most significant decrease in chlorophyll and carotenoid contents. Leaf nutrient levels declined under their respective deficiency treatments. Fruit yield followed the order N > P > K > Mg > Ca > S, whereas K deficiency had the greatest adverse impact on fruit quality, reducing lycopene, titratable acidity, total soluble solids, dry matter content, and fruit size, along with pronounced color changes. Ca and N deficiencies negatively affected fruit firmness and vitamin C content, respectively. Overall, the results emphasize the importance of adequate macronutrient supply for sustaining plant performance, yield, and fruit quality in tomato cultivation.