The use of saline irrigation water is an important alternative in view of the lack of good water quality throughout the world. The water requirement of jatropha (Jatropha curcas L.) is low, and the species survives and produces satisfactory yields in low-fertility soils. However, yields are higher in irrigated crops, indicating the need of studying the possibility of using saline irrigation water. This study aimed to evaluate the effect of different salinity levels of irrigation water on the morphological and physiological characteristics of jatropha seedlings. The greenhouse experiment was conducted with an interception of 50 % of solar radiation, at the State University of Goiás, Ipameri, Goiás. The experiment was conducted in 4 L pots filled with soil in a completely randomized design, with four treatments and five replications. The plants were irrigated daily with 150 mL of sweet water for the first 30 days after germination. From the 31st to the 50th day plants were subjected to four treatments: daily irrigation with water of electrical conductivity of 0.5, 8, 16, and 24 dS m-1. Fifty days after germination, the following characteristics of the jatropha seedlings were analyzed: number of leaves, plant height, branch diameter, relative water content, leaf area, total chlorophyll ratio, root mass, stem mass ratio, leaf mass ratio, shoot/root ratio, and total biomass. The results showed no reduction in vegetative growth in jatropha seedlings irrigated with water with electrical conductivity 8 dS m-1. However, irrigation water with electrical conductivity 16 dS m-1 caused a reduction in vegetative growth and increased senescence and leaf abscission. Water with electrical conductivity <img src="/img/revistas/rbcs/v37n4/12s1.jpg" align="absmiddle"> can be used to irrigate Jatropha plants in the seedling stage.
electrical conductivity; salinity tolerance; irrigation; Jatropha curcas L
