Growth and physiological responses of coffee (Coffea arabica L.) seedlings irrigated with diluted deep sea water

Concentrations of 5, 10, 20, and 40% deep sea water (DSW) were tested, with irrigation water serving as the 0% control (tap water) on coffee (Coffea arabica L.) seedlings. The results showed that the growth parameters were affected significantly (α < 0.05) by the irrigation of 20 and 40% deep sea water. There were significant differences (α < 0.05) among treatments in stomata density/mm2, stomata width, and length. The highest value of stomatal measurements was obtained in the control treatment, whereas the lowest values were obtained in the 40% DSW treatments. Electrolyte leakage was enhanced in 20 and 40% DSW irrigated seedling leaves. The highest relative leaf water content (84.5%) was obtained in the control treatment and the lowest in 40% DSW (74.6%). The application of diluted deep sea water also increased the soil electrical conductivity (EC, ds/m). The overall measured parameters indicated that the control, 5, and 10% DSW treatments showed approximate results. This indicates that 5% DSW can be used as irrigation water for coffee seedlings. Also, for some period of time, the 10% DSW can be used to irrigate coffee seedlings without causing significant negative effects. Key words: Coffea arabica L., electrolyte leakage, relative water content, stomata.