Photosensitivity of cucumber (Cucumis sativus L.) seedlings exposed to ultraviolet-B radiation Fotosensibilidad de plantines de pepino de ensalada (Cucumis sativus L.) expuestos a radiación ultravioleta del tipo B

Abstract

The intensity of ultraviolet-B radiation (UV-B) has increased on the Earth́s surface due to the stratospheric ozone depletion, causing an adverse effect on a wide range of species, such as morphological, physiological, and biochemical alterations. This research studied the intraspecific photosensitivity of cucumber (Cucumis sativus L.) seedlings exposed to UV-B. Six commercial cultivars were evaluated: Laura, Sprint 440, Dasher II, Exocet, Poinsett 76, and Marketmore 76 under greenhouse-controlled environmental conditions with a hydroponic sandwich-type system with a Hoagland II nutrient solution. Seedlings were irradiated from expanded cotyledons to the third true leaf with three intensities of UV-B radiation (30, 40, and 50 μW cm-2) for 18 d between 11:40-15:40 h. Seedling growth, morphology, accumulation of photosynthetic pigments, and absorbing UV-B pigments were evaluated. 'Laura' was the least affected by chlorosis and had a total absence of leaf curl, whereas 'Poinsett 76' was t