Effect of Water Stress on the Growth and Physiology of Coffee Plants

Water stress effects on the growth and physiology of three coffee species, arabica, robusta, and liberica, were investigated. Unlike in plants that had water supply, plant height, leaf length, and leaf width values decreased significantly in arabica and liberica in a water deficit condition but did not statistically differ in robusta coffee plants. The highest values of reduction in growth characteristics of coffee plants under water deficit condition were observed in arabica, but they did not significantly differ from those in robusta or liberica. The highest value of relative water content in a water deficit condition was observed in liberica, but it was similar to that of robusta. The SPAD value and Fv/Fm of all coffee species decreased significantly during the period without irrigation but increased significantly after re-watering. SPAD values of robusta and liberica in a water deficit condition were higher than those of arabica. The highest value of relative ion leakage during drought was observed in arabica. On the other hand, robusta generally appeared to be more vigorous than arabica and liberica, as shown by its relatively lower percentage of wilting plants and higher percentage of recovering plants.