Horticultural Science and Technology 원예과학기술지 ISSN:1226-8763(Print) 2465-8588(Online)

A physiological disorder, called tipburn, commonly occurs in lettuce (Lactuca sativa L.), particularly in greenhouse cultivation and in hot seasons, and reduces its marketability. Calcium (Ca) deficiency is the main cause of tipburn injury. In the present study, we investigated the effect of exogenous spermidine (Spd) on the occurrence of tipburn in hydroponically cultivated head lettuce (var. capitata L.) and elucidated the role of Ca ions (Ca²⁺) in its prevention with respect to absorption and transport. Ca deficiency in the nutrient solution resulted in reduced uptake of Ca²⁺ in lettuce roots, thereby resulting in Ca deficiency in leaves, leading to leaf senescence and tipburn. An application of exogenous Spd promoted Ca²⁺ uptake in lettuce roots under Ca deficiency and promoted Ca²⁺ transportation to leaves, especially to inner leaves, thus delaying leaf senescence and reducing the incidence of tipburn. The results indicated that application of exogenous Spd is an effective method to decrease tipburn in lettuce caused by Ca deficiency.