NaCl induced cross-acclimation to UV-B radiation in four Barley (Hordeum vulgare L.) cultivars

Abstract

The effect of pre-treatment with 200 mM NaCl on the response of four barley cultivars (Hordeum vulgare L. cv. to UV-B radiation was investigated. Salt stress as well as UV-B irradiation led to a decrease of the total chlorophyll (chl) content in all cultivars, except in Kalaycı-97. While carotenoids are almost not affected by NaCl treatment, UV-B irradiation caused an increase by 5-20% of carotenoid content of all cultivars. UV-B induced damages of photosynthetic apparatus were estimated by the rate of photosynthetic electron transport measured by chl fluorescence and the rate of oxygen evolution, the latter being more affected. Pre-treatment with NaCl alleviated harmful effect of UV-B irradiation on F v /F m and ETR, but not on oxygen evolution. UV-B-induced and UV-B-absorbing compounds with absorption at 300 and 438 nm increased as a result of UV-B treatment. The level of stress marker proline increased considerably as a result of NaCl treatment, while UV-B irradiation resulted in a pronounced increase of the level of H 2 O 2 . MDA enhanced in the seedlings subjected to salt and UV-B stress. Established cross-acclimation to UV-B as a result of salt treatment could be due to the increased free proline and the level of UV-B absorbing compounds in barley seedlings subjected to NaCl.

Model Examination for the Effect of Treading Stress on Young Green Barley (<i>Hordeum vulgare</i>)

“…Salt pretreatment resulted in a considerable decrease in the level of UV-induced and UV-B-absorbing compounds measured 24 h after UV-B irradiation [10]. While carotenoids are affected very little by NaCl treatment, UV-B irradiation caused a 5% -20% increased in the carotenoid content of all cultivars [11].…”

A role for Ethylene-Insensitive 2 gene in the regulation of the ultraviolet-B response in Arabidopsis

“…Pigment content was determined according to the method described by Cakırlar et al (2008). Briefly, 12-day-old seedlings (150 mg) were homogenized in 6 ml of medium containing methanol:HCl:H 2 O (79:1:20), centrifuged at 10,000g for 15 min and absorption for flavonoids and anthocyanins at 300 and 535 nm, respectively, was read using a UV-visible spectrophotometer (UV-1201 spectrophotometer).…”

“…In general, plants respond differently to irradiation with low or high doses of UV-B, either by stimulating protection mechanisms or by activating repair mechanisms to cope with the different types of stresses (Frohnmeyer and Staiger 2003). The most common protective mechanism against potentially damaging irradiation is the biosynthesis of UV-absorbing compounds (Hahlbrock and Scheel 1989;Frohnmeyer and Staiger 2003;Cakırlar et al 2008). The accumulation of certain phenylpropanoid compounds, such as flavonoids and anthocyanins, plays an important role in mitigating UV-B-induced damage (Lois and Buchanan 1994;Bharti and Khurana 1997;Cakırlar et al 2008).…”

“…The most common protective mechanism against potentially damaging irradiation is the biosynthesis of UV-absorbing compounds (Hahlbrock and Scheel 1989;Frohnmeyer and Staiger 2003;Cakırlar et al 2008). The accumulation of certain phenylpropanoid compounds, such as flavonoids and anthocyanins, plays an important role in mitigating UV-B-induced damage (Lois and Buchanan 1994;Bharti and Khurana 1997;Cakırlar et al 2008). Genetic analysis of Arabidopsis mutants with altered UV-B responses further supports the importance of chemical sunscreens; constitutive accumulation of flavonoids and other phenolics results in resistance of mutants to UV-B (Bieza and Lois 2001;Zhao et al 2007).…”

The involvement of low-molecular antioxidants in cross-adaptation of medicine plants to successive action of UV-B radiation and salinity

“…Thus, Cakirlar et al [2] showed that successive action of 200 mM NaCl and UV B radiation on four barley cultivars resulted in the accumulation of proline and carotenoids in them. Prasad et al [3] studied the com bined effect of UV B radiation and cadmium on Ric cia sp.…”