Some Morphological and Biochemical Characteristics of C₃ and C₄ Plants Irradiated with UV‐B

Abstract

Four C3 and two C4 plants were subjected for 350 h to an enhanced UV‐B radiation (280 to 310 nm) regime simulating a 0.18 atm. cm ozone level (solar angle 55°) in growth chamber. Different degrees of response among plant species were observed. UV‐B radiation reduced plant height, fresh and dry weight, protein content, total chlorophyll, inhibited net CO2 uptake and the Hill reaction activity. Some broad‐leaved species with C3 type of carbon assimilation were more susceptible to UV‐B alterations of morphological and biochemical characteristics than the narrowleaved species with C4 type photosynthesis.

Respuestas antioxidantes en dos ecotipos de Colobanthus quitensis (Caryophyllaceae) expuestos a alta radiación UV-B y baja temperatura

“…Adicionalmente, el grosor tanto del mesófilo como del parénquima esponjoso y de empalizada fue significativamente mayor en los individuos de ambos ecotipos de C. quitensis bajo una condición de alta radiación UV-B. Este efecto ha sido demostrado con anterioridad (Newsham & Robinson 2009) y ha sido sugerido como una estrategia que presentan las plantas para aumentar la barrera mecánica a los rayos UV, evitando daños al aparato fotosintético (Basiouny et al 1978, Hideg 2002. El hecho que el ecotipo Antártico presente un grosor del parénquima esponjoso y en empalizada signifi cativamente mayor independientemente del tratamiento de UV-B (Tabla 1 y 2), sugiere que dicho ecotipo posee una protección estr uctural que podría relacionarse con la menor capacidad de respuesta bioquímica (TAS, SOD) que manifi esta el ecotipo Antártico frente a los tratamientos de UV-B.…”

Inhibition of Seagrass Photosynthesis by Ultraviolet-B Radiation

“…Ultraviolet-B radiation has also been shown to be a potent inhibitor of photosynthesis (4,5,16,26,29,30, 35) 4 To whom all correspondence should be addressed. (2,5,14), and electron transport (5,24,25).…”

“…Recently, UV-B irradiation has been shown effective in inhibiting leaf expansion (22,29,30), seedling growth (1,21), dark respiration (29), and ion transport (1), as well as altering membrane permeability (9)(10)(11). Ultraviolet-B radiation has also been shown to be a potent inhibitor of photosynthesis (4,5,16,26,29,30,35) and a number of partial reactions of phytosynthesis, including Chl synthesis (2,14), the Hill reaction 'This work was performed with the support of National Aeronautics and Space Administration contract NAS9-15516, National Science Foundation grant SER77-06567, and by a grant from the Dean 4 To whom all correspondence should be addressed. (2,5,14), and electron transport (5,24,25).…”

“…Ultraviolet-B radiation has also been shown to be a potent inhibitor of photosynthesis (4,5,16,26,29,30, 35) 4 To whom all correspondence should be addressed. (2,5,14), and electron transport (5,24,25).The objective of this study was to examine the influence of ambient and enhanced UV-B irradiation on photosynthesis in three marine angiosperms: Halodule wrightii, Syringodium fliforme, and Halophila engelmannii. The photorepair capabilities of the three seagrasses and the role of epiphytes as a shield from increased levels of UV-B irradiation were evaluated.…”

Effect of increased UV-B radiation on the anthocyanin content of maize ( Zea mays L.) leaves

“…Investigations on the effect of increased UV-B radiation were reported by Hart et al (1975) and Santos et al (1998) on the duration of maize flowering, Pfahler (1981) on the germination ability of pollen and the growth of the pollen tube, Vu et al (1982) and Santos et al (1990) on the accumulation of carbohydrates, and Basiouny et al (1978) and Santos et al (1993) on the quantities of leaf chlorophyll and total soluble protein. Walbot (2003, 2005) and Long et al (2003) emphasised the importance of the pigment and wax layers in the absorption of UV-B radiation by the maize epidermis.…”