Allometric and biochemical responses of grapevines subjected to drought and enhanced ultraviolet-B radiation

Abstract

Background and Aims:The aim of this study was to evaluate differences in adaptive responses in grapevines (Vitis vinifera L. cv Soultanina) exposed to either drought, enhanced ultraviolet-B (UV-B) radiation or the combination of the two environmental stresses. Methods and Results: Results indicated pronounced effects on allometric parameters in plants exposed to the enhanced UV-B radiation. The combined application of drought and enhanced UV-B radiation considerably affected shoot growth rate and leaf dry weight. Guaiacol peroxidase (GPX, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), superoxide dismutase (SOD, 1.15.1.1) and catalase (CAT, 1.11.1.6) activities increased significantly in the enhanced UV-B radiation treatment. Drought resulted in a significant increase in proline concentration, while the exposure of plants to enhanced UV-B radiation resulted in the production of UV-B absorbing compounds (UVabs). Conclusions: Under drought conditions proline accumulation seemed to be the main mechanism of adaptation contributing to plant's antioxidant defence. On the other hand, under enhanced UV-B radiation, the accumulation of the UV-B absorbing compounds and the increase in antioxidant enzymes activities constitute the main mechanisms of grapevine adaptation. Significance of the Study: The data obtained indicate the occurrence of two different mechanisms of adaptation in response to the stressor applied. Furthermore, the patterns of proline and UVabs concentration changes under stress conditions suggest that the biosynthesis of these two compounds might follow competing metabolic pathways.

UV Light Acclimation Capacity of Leaf Photosynthetic and Photochemical Behaviour in Near-isohydric and Anisohydric Grapevines in Hot and Dry Environments

“…caused by high UV-B radiation levels (Berli et al, 2010;Doupis et al, 2011). In our study, light treatment did not induce significant differences in the development of total leaf area, and mild to moderate water stress imposed by deficit irrigation allowed the leaf area to keep growing, also in the −UV plants, although subjected to higher heat stress.…”

Acclimation mechanisms elicited by sprayed abscisic acid, solar UV-B and water deficit in leaf tissues of field-grown grapevines

“…In grapevine leaves UVAC are mainly phenols, such as flavonols (quercetin and kaempferol) and hydroxycinnamic acids (caffeic acid, p-coumaric acid and ferulic acid; Berli et al, 2010). Doupis et al (2011) and Martínez-Lüscher et al (2015) working with cv. Soultanina and cv.…”

“…While the effects of water deficit in grapevines have Abbreviations: ABA, abscisic acid; þABA, plus ABA treatment; ÀABA, minus ABA treatment; DAF, days after flowering; þD, moderate water deficit treatment; ÀD, well watered treatment; g s , stomatal conductance; MDA, malondialdehyde; PAR, photosynthetic active radiation; P n , net photosynthesis; UVAC, UV-A; ultraviolet-A radiation, UV-absorbing compounds; UV-B, ultraviolet-B radiation; þUV-B, solar UV-B treatment; ÀUV-B, minus UV-B treatment; J s , stem water potential. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 been widely studied (Chaves et al, 2010 and literature cited therein), there are only limited reports in relation to water deficit and UV-B interactions (Doupis et al, 2011;Martínez-Lüscher et al, 2015). The phytohormone abscisic acid (ABA) regulates many physiological and biochemical acclimation processes, and some of them are common for different stress conditions (Creelman, 1989;Seki et al, 2002).…”

Abiotic Stress-Induced Morphological and Anatomical Changes in Plants

“…However, most data suggest ethylene minor contribution in the SIMRs process under abiotic stress conditions mainly indirectly through alteration in the auxin sensitivity of plants (Takahashi et al 2003 ). Enhanced ROS production is associated with a broad range of abiotic stresses including drought (Beis and Patakas 2010 ) , heat stress, enhanced UV-B radiation stress (Doupis et al 2011 ), heavy metal stress and anoxia. This increase in ROS production induce an upregulation of ROS scavenging systems, involving enzymatic components such as superoxide dismutase, catalase, and ascorbate peroxidase, as well as antioxidants such as ascorbate and glutathione (Noctor and Foyer 1998 ) .…”

“…It is well known that abiotic stresses such as extremes in temperature, drought, salinity, heavy metals, and radiation represent the most limiting factors for agricultural productivity worldwide (Doupis et al 2011 ) . Plant responses to abiotic stresses comprises morphological, physiological, and biochemical changes that either decrease plant's stress exposure and/or limit damage and facilitate recovery of impaired systems (Potters et al 2007 ) .…”