-1 ) provided the highest average efficiency of water use and resulted in an increase of 180.6 kg ha -1 of watermelon for each kg ha -1 of K 2 O applied.

The objective of this study was to evaluate the influence of irrigation with brackish water on the production of bamboo seedlings (Bambusa vulgaris). The experiment was carried out at the Fazenda Experimental Piroás, in the municipality of Redenção, CE, Brazil (4° 14’ 53” S, 38° 45’ 10” W, and altitude of 230 m), in a completely randomized design with five treatments and six repetitions. The treatments consisted of five irrigation water electrical conductivity (ECw): 0.5 (control); 1.5; 2.5; 3.5 and 4.5 dS m-1. At 120 days after the beginning of the application of the treatments the leaf gas exchange, relative chlorophyll index (RCI), plant height (H), shoot dry matter (SDM), H/SDM ratio, and the concentrations of Na+ and K+ in stems and leaves were evaluated. Salt tolerance indexes were calculated based on SDM, H, photosynthesis rate and RCI. The increase in the ECw reduced leaf gas exchange, and the reduction in the photosynthesis rate was caused by stomatal and non-stomatal effects. The salinity affected negatively the growth and quality of bamboo seedlings, with the greatest effects being with ECw equal to or greater than 2.5 dS m-1. Bamboo seedlings present Na+ retention in the stems and low Na+/K+ ratio in the leaves. Bamboo seedlings are tolerant to salinity up to 1.5 dS m-1, indicating that waters with this salinity can be used for seedling production of this species, without loss of growth and quality.

A relação Na/K apresentou menor valor nas folhas. O bambu mostrou-se tolerante ou moderadamente tolerante para água com salinidade até 2,5 dS m -1 , sendo um indicativo que essas águas podem ser utilizadas na fase inicial de crescimento da cultura. PALAVRAS-CHAVE: Água de irrigação, bambu, tolerância à salinidade GROWTH AND PHYSIOLOGICAL RESPONSES OF Bambusa vulgaris SEEDLINGSIRRIGATED WITH SALINA WATERABSTRACT: The objective of this study was to evaluate the influence of irrigation with saline water on growth and physiological responses of bamboo (Bambusa vulgaris) seedlings. The experiment was carried out at Experimental Farm Piroás, municipality of Redenção, Ceará, from July to December 2015. A completely randomized design (DIC) was used, with five