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Chilean Journal of Agricultural Research
Instituto de Investigaciones Agropecuarias, INIA
ISSN: 0718-5820
EISSN: 0718-5839
Vol. 70, No. 1, 2010, pp. 16-25
Bioline Code: cj10002
Full paper language: English
Document type: Research Article
Document available free of charge

Chilean Journal of Agricultural Research, Vol. 70, No. 1, 2010, pp. 16-25

 en Photosensitivity of cucumber ( Cucumis sativus check for this species in other resources L.) seedlings exposed to ultraviolet-B radiation
Tapia, María Luisa F.; Toro, Guillermo A.; Parra, Bélgica R. & Riquelme, Alejandro E.

Abstract

The intensity of ultraviolet-B radiation (UV-B) has increased on the Earth´s 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 check for this species in other resources 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 the most affected in the 40 and 50 μW cm-2 intensities. Both leaf area and seedling height of 'Marketmore 76' and 'Poinsett 76' had the lowest values. 'Laura' obtained the highest value in both fresh weight and dry weight. 'Poinsett 76' had the least amount of pigments absorbing UV-B and was 53% lower than that obtained by 'Laura'. 'Poinsett 76' had lower chlorophyll and carotenoids. Parameters used were indicators of the seedling response to UV-B radiation, but could not be used for cucumber seedling sensitivity to UV-B radiation.

Keywords
UV radiation, Cucumis sativus, chlorophyll, UV-B absorbing compounds, chlorosis

 
 es Fotosensibilidad de plantines de pepino de ensalada ( Cucumis sativus check for this species in other resources L.) expuestos a radiación ultravioleta del tipo B
Tapia, María Luisa F.; Toro, Guillermo A.; Parra, Bélgica R. & Riquelme, Alejandro E.

Resumen

La radiación ultravioleta tipo B (UV-B) ha ido aumentando su intensidad a nivel de la superficie terrestre producto de la disminución del ozono estratosférico, provocando efectos negativos en una amplia gama de especies, observándose alteraciones morfológicas, fisiológicas y bioquímicas. En este trabajo se estudió la fotosensibilidad intraespecífica de plantines de pepino de ensalada ( Cucumis sativus check for this species in other resources L.) expuestos a radiacion UV-B. Se evaluaron seis cultivares comerciales: Laura, Sprint 440, Dasher II, Exocet, Poinsett 76 y Marketmore 76, en condiciones ambientales controladas en invernadero con sistema hidroponico tipo sandwich en solucion nutritiva Hoagland II. Los plantines recibieron radiacion UV-B durante 18 dias desde cotiledones expandidos hasta tercera hoja verdadera. Los plantines fueron separados en tres grupos y cada uno recibio una dosis de UV-B diferente (30, 40 y 50 μW cm-2 UV-B) entre las 11:40-15:40 h. Se evaluaron variables de crecimiento, morfologicas, y de acumulacion de pigmentos fotosinteticos y pigmentos absorbedores de UV-B.  'Laura' fue el menos afectado por clorosis y tuvo ausencia total de enrollamiento foliar, en cambio, 'Poinsett 76' fue el mas afectado en las intensidades de 40 y 50 μW cm-2. En area foliar y altura de plantin, 'Marketmore 76' y 'Poinsett 76' obtuvieron los mas bajos valores. 'Laura' obtuvo el mayor valor en peso fresco y en peso seco de plantin. 'Poinsett 76' obtuvo el menor contenido de pigmentos absorbedores de UV-B, siendo un 53% inferior al obtenido por 'Laura.' 'Poinsett 76' obtuvo menor contenido de clorofila y carotenoides. Los parametros usados fueron indicadores de respuesta a la radiacion UV-B, pero no resultarian buenos indicadores de sensibilidad a la radiacion UV-B en plantines de pepino de ensalada.

Palabras-clave
radiación UV-B, Cucumis sativus, clorofila, compuestos absorbedores UV-B, clorosis

 
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