Visual Symptoms of Water and Nitrogen Deficiency in Leaves of Clove Basil (Ocimum gratissimum L.)

Ocimum gratissimum L. (clove basil) is an annual herb of the Lamiaceae family, widely cultivated as a plant used in cooking and medicine worldwide. There is no information on the visual symptoms of the effects of greater or lesser water irrigation and nitrogen fertilization on the leaves of this species. There is no information on the visual symptoms of the effects of greater or lesser water irrigation and nitrogen fertilization (N) on the leaves of this species. The effects of different water application rates, 60% (I60), 70% (I70), 80% (I80), 90% (I90), 100% (I100) and 110% (I110) of field capacity (FC), and nitrogen fertilization, 0 (N0), 40 (N2), 80 (N4) and 160 (N8) kg of nitrogen/ha, on the leaves of this species were studied. The experiment was carried out for 60 days in a greenhouse in a completely randomised design with three replicates. Water stress was determinant for the appearance of leaves with wilted and stains. Symptoms of necrosis, apical necrosis, abscission and chlorosis were correlated only with N stress. This study suggests that the leaves of Ocimum gratissimum present better acclimatization with irrigation above the field capacity associated with high dose of N (I110N8) and that satisfactorily support the reduction of up to 70% FC with the use of 40 kg of N/ha in their production without presenting any visual symptoms.