Vine growth and physiological performance of two red grape cultivars under natural and reduced UV solar radiation

Abstract

Background and Aims Under natural conditions the grapevine has shown different growth and physiological responses to high UV radiation. We evaluate the effect of natural and reduced UV‐B, UV‐A and photosynthetically active radiation (PAR) on vine growth, physiological status and berry composition in Bovale Grande (syn. Carignan) and Cannonau (syn. Grenache) field‐grown grapes. Methods and Results During the two seasons of the trial, UV‐screening treatments Visible + UV‐A and Visible, imposed with plastic tunnels from pea size onward, promoted a significant difference in UV and PAR transmission as compared with that of plants exposed to natural sunlight, but did not reduce canopy growth and yield. Plants adjusted leaf gas exchange and water status to both high and reduced UV and PAR radiation. The concentration of phenolic substances of berries was significantly higher under natural UV, whereas accumulation of anthocyanins responded differently in the two cultivars according to the duration of high temperature. Conclusions The results indicate that red grapes of Mediterranean origin are able to adapt growth and physiological responses to high natural UV and temperature, but accumulation of berry anthocyanins and phenolic substances can vary considerably according to sensitivity of cultivars to these abiotic factors. Significance of the Study Increasing knowledge on the acclimation responses to high UV and solar irradiance environments by grape cultivars may help to improve management practices towards greater adaption to global warming conditions and projected climate change.

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

“…Nevertheless, the differences in stomatal regulation under drought conditions among the varieties studied to date make it possible to classify them as near-isohydric (pessimistic) or near-anisohydric (optimistic) (Schultz, 2003;Dal Santo et al, 2016;Zarrouk et al, 2016). Optimistic performance has been reported in Carignan under Mediterranean climate conditions, in comparison with the pessimistic response of varieties from the Grenache family (Chaves et al, 2010;Lovisolo et al, 2010;Keller, 2016;Fernandes de Oliveira & Nieddu 2016b).…”

“…Grapevine varieties are considered drought-tolerant plants (Chaves et al, 2010) and are able to develop different strategies to respond to environmental constraints (Poni et al, 2018). The stomatal control over transpiration is particularly sensitive to abiotic stresses (Düring, 1998;Soar, 2006;Fernandes de Oliveira & Nieddu, 2016b). Due to the combination of varietal differences in hydraulic properties and cellwall elasticity with hormonal signals, leaf gas exchange performance may vary greatly among cultivars, depending upon the growing conditions of the site (Hugalde & Vila, 2018;Lovisolo et al, 2016).…”

“…We hypothesise that varietal differences in grapevine acclimation responses to UV radiation and heat stresses, so far as leaf photosynthesis and photochemistry performance are concerned, also depend on differences in leaf pigment-accumulation dynamics according to genetic differences in phenolic profiles (Xu et al, 2014;Fernandes de Oliveira et al, 2015). To investigate these relationships, two grapevine varieties that are widespread in Mediterranean viticultural areas (Anderson & Aryal, 2013) were chosen for their different leaf gas exchange performance under water stress and high temperatures (Fernandes de Oliveira & Nieddu, 2016b). During vegetative growth, the effects of UV radiation on grape leaf gas exchange, primary photochemistry and the non-invasive rapid evaluation of leaf pigment balance (Goulas et al, 2004) were analysed to detect alterations in assimilation capacity, photoinhibition and recovery capacity, and to investigate correlations with the accumulation of leaf pigment photoprotection mechanisms.…”

Accumulation and partitioning of anthocyanins in two red grape cultivars under natural and reduced UV solar radiation

“…The experiment was undertaken in the 2009 and 2010 growing seasons at the grapevine clonal collection fields of the University of Sassari in Oristano, Sardinia, Italy (39° 54'N, 8° 37'E) in 3‐year‐old Bovale Grande and Cannonau plants, grafted on 779 rootstock, with 2.5 m × 1.0 m and north–south row orientation. The vines were trained to a vertical trellis and cane pruned to a single Guyot; deficit irrigation was applied before ripening (Fernandes de Oliveira and Nieddu ). In three randomised blocks, the entire canopy of 24 plants per treatment (of two contiguous rows, one for each cultivar) was covered with two polyester films (Ginegar Plastic Products, Kibbutz Ginegar, Israel), with different sunlight transmittance [visible (VIS), visible + UV‐A (VIS + UV‐A)] and compared with a control directly exposed to sunlight (Control), from fruitset until harvest.…”

“…To allow complete air circulation inside the structure, plastic tunnels (5 m width, 9 m length, 2.5 m height) were designed and used, and kept open laterally at the base of the east and west sides; both north and south sides of the structure were open. Further details regarding the trial are described in Fernandes de Oliveira and Nieddu ().…”