Manganese toxicity and UV-B radiation differentially influence the physiology and biochemistry of highbush blueberry (Vaccinium corymbosum) cultivars

Abstract

Manganese (Mn 2+ ) toxicity or UV-B radiation and their individual effects on plants have been documented previously. However, no study about the combined effect of these stresses is available. We evaluated the individual and combined effects of excess Mn 2+ and UV-B radiation on physiological and biochemical parameters in two highbush blueberry (Vaccinium corymbosum L.) cultivars differing in resistance to Mn toxicity (Brigitta (resistant) and Bluegold (sensitive)). Plants grown in Hoagland nutrient solution were subjected to the following treatments: 2 mM MnCl 2 (control), 500 mM MnCl 2 (toxic Mn 2+ ), UV-B radiation (a daily dose of 94.4 kJ m -2 ), and the combined treatment (toxic Mn 2+ + UV-B) for 30 days. In both cultivars, the Mn 2+ + UV-B treatment caused a more negative effect on net photosynthesis (P n ), stomatal conductance (g s ), the photochemical parameters of PSII and the chl a/b ratio than the treatments with toxic Mn 2+ or UV-B alone. However, Brigitta showed also a better acclimation response in P n and g s than Bluegold at the end of the experiment. The Mn 2+ + UV-B treatment inhibited growth, enhanced radical scavenging activity and superoxide dismutase activity, and increased the concentration of total UV-absorbing compounds, phenols and anthocyanins, mainly in Bluegold. In conclusion, Mn-resistant Brigitta showed a better acclimation response and greater resistance to the combined stress of Mn 2+ toxicity and UV-B exposure than the Mn-sensitive Bluegold. An increased concentration of photoprotective compounds and enhanced resistance to oxidative stress in Brigitta could underpin increased resistance to the combined stress.(pH water between 4.5 to 5.5); however, there is a serious risk of Mn 2+ and aluminum (Al 3+ ) toxicity affecting plant metabolic processes and productivity (Horst 1988;Mora et al. 2004;Ducic and Polle 2005;Reyes-Díaz et al. 2010). In addition, an expansion of the hole in the ozone layer over Antarctica results in higher UV-B radiation doses in southern Chile, particularly in spring and

Boron accumulation and tolerance in sweet basil (Ocimum basilicum L.) with green or purple leaves

“…Rojas-Lillo et al 2014). Contrasting results are reported on the effect of excess B on leaf total phenolic concentration, which remained either unchanged (e.g.…”

Distinct physiological and metabolic reprogramming by highbush blueberry (Vaccinium corymbosum) cultivars revealed during long‐term UV‐B radiation

“…We observed that although both cultivars were affected by UV‐B radiation in terms of shoot growth, their plant performance was completely different. Previous studies have suggested that UV‐B radiation alone and combined with manganese toxicity affects stem elongation in highbush blueberry (Rojas‐Lillo et al ). It has also been demonstrated that plant growth is strongly affected by UV‐B radiation (Teramura and Sullivan , Krizek et al , Conner and Neumeier, , Kumari et al , Zhu and Yang ).…”

“…Anthocyanins have been previously reported as being induced by stress factors in V . corymbosum (Inostroza‐Blancheteau et al , Rojas‐Lillo et al , Yañez‐Mansilla et al , Reyes‐Díaz et al 2016). In our case, these cultivars did not show a clear induction of anthocyanins under UV‐B radiation.…”

“…The high antioxidant attributes of its fruits, as well as its high economic returns, have positioned the blueberry as an important crop in this region (Ribera et al 2010). Our previous studies have shown different capacities of cultivars to respond to the abiotic stresses such as aluminum and manganese toxicities frequently found in south-central Chile (Reyes-Díaz et al 2009, Rojas-Lillo et al 2014. In these studies, we demonstrated that some V. corymbosum cultivars showed contrasting behavior under these abiotic constrains, with Legacy being considered a resistant and Bluegold a sensitive cultivar.…”

Criopreservación de Espermatozoides de Canino con Extracto de Hojas de Arándano (Vaccinium corymbosum L.)

“…Este arbusto, originario de Norteamérica, se ha adaptado muy bien a las condiciones edáficas y climáticas de la región centro sur de Chile, donde se ha establecido como un cultivo muy importante, debido a su alta riqueza en antioxidantes. Estudios de la actividad antioxidante (AA) en cultivares de esta especie han demostrado que esta actividad es mayor en hojas (InostrozaBlancheteau et al, 2014) que en frutos (Ribera et al, 2010), la cual está dada tanto por antioxidantes enzimáticos (principalmente SOD) como no enzimáticos (ácidos fenólicos, flavonoides y antocianinas) (Reyes Díaz et al, 2011;Inostroza-Blacheteau et al, 2014;Rojas-Lillo et al, 2014). En la actualidad no existen estudios que hayan evaluado el efecto de extracto de hojas de arándano (EHA) en semen de canino criopreservado o en otras especies.…”