Effect of Shading on Vine Morphology and Productivity and Leaf Gas Exchange Characteristics in Grapevines in the Field

Delayed grape ripening by intermittent shading to counter global warming depends on carry-over effects and water deficit conditions

“…Intriguingly, the influence of heavy whole-plant shading on reproductive development has been reported to be far less in previous studies (Cartechini and Palliotti, 1995) than in the present one. Here, the daily alternation of shade and sun conditions produced by fixed panels over the plants resulted in an averaged shading ratio of 55 %.…”

“…Delayed veraison and a slower rate of berry colouring caused by shading have been reported in other studies that used nets to permanently shade the whole plant (Bureau et al, 2000;Cartechini and Palliotti, 1995). However, shading did not delay veraison by more than 10 days in all previous studies (Abeysinghe et al, 2019;Guan et al, 2015;Lu et al, 2021), which is much lower than in the present study.…”

“…Most studies on the impact of shade on grapevine has focused on permanent shading nets, which consistently reduce light intensity. Such shading typically alters carbon assimilation at leaf level (Cartechini and Palliotti, 1995;Greer et al, 2011). A series of physiological acclimations, called the shade avoidance syndrome, may partly compensate for this reduced assimilation due to low radiation (Ballaré and Pierik, 2017;Niinemets, 2010).…”

“…In spite of the various and sometimes opposing influences of shading on plant physiology, delayed veraison has been consistently reported in response to permanent shading on parts or the totality of the vine during long periods of the plant cycle (Cartechini and Palliotti, 1995;Lu et al, 2021). However, panels produce intra-day alternations of shaded and unshaded periods that may alter phenology and ripening in a different way to permanent shading.…”

Analyzing anatomy over three dimensions unpacks the differences in mesophyll diffusive area between sun and shadeVitis viniferaleaves

“…We set out to describe the relationship between 3D anatomy and the potential for carbon assimilation in sun and shade leaves of two grapevine ( Vitis vinifera L.) cultivars. Light levels within dense grapevine canopies can drop below 1 % at some locations in the inner canopy ( Smart, 1985 ), but even a moderate reduction (50–60 %) in the light availability results in marked differences in stomatal conductance, photosynthetic rates and leaf anatomy ( Schultz et al , 1996 ; Vanden Heuvel et al , 2004 ), and has led to managing the access of leaves to light in vineyards ( Smart et al , 1982 ; Cartechini and Palliotti, 1995 ; Dokoozlian and Kliewer, 1995 ; Palliotti et al , 2000 ; Chavarria et al , 2012 ; González et al , 2021 ). Instead of focusing on how individual traits, such as thickness or porosity, vary depending on the light environment, we analyzed their contribution to a functional trait: the surface area available for diffusion.…”