Investigations on the leaf anatomy and ultrastructure of grapevine (Vitis vinifera) under heat stress

Abstract

Leaf anatomical and ultrastructural responses of "Razegui" and "Muscat Italia" grapevine cultivars to high temperatures were studied under controlled conditions (T > 36°C), based on photonic and electron microscopy. Histological studies performed on leaves from heat-stressed and control grapevines revealed thicker leaf blades under high temperature conditions. Environmental scanning electron microscopy of leaf surfaces from both cultivars allowed observing sinuate epidermal cells on the leaves of grapevines cultivated under heat stress and irregular giant oblong pores on their adaxial surface. When observed by transmission electron microscopy, leaf cross sections in grapevines cultivated under high temperature conditions exhibited folded cuticle and cell wall on the adaxial epidermis layer. Therefore, significantly greater cell wall thicknesses were measured under heat stress than control conditions in both cultivars. Regarding chloroplasts, they were more globular in shape under heat stress compared with control conditions and had disorganized thylakoids with a reduced thickness of grana stacking. The size of starch granule decreased, while the number of plastoglobules increased with heat stress, indicating a reduced carbon metabolism and a beginning of senescence within the 3-month heat stress period. This study confirms widespread adaptive properties in two grapevine cultivars in response to high temperature stress.

Quantitative Investigation of Leaf Photosynthetic Pigments during Annual Biological Cycle of Vitis vinifera L. Table Grape Cultivars

“…In the leaves of C3-type plants, high temperatures led to a decrease in the Chl a/b and Chl/Car ratios (Aien et al, 2011). In parallel, the cultivar influences the accumulation of photosynthetic pigments through the morphological and anatomical particularities of the leaves: area, perimeter, and thickness of mesophyll (Salem-Fnayou et al, 2011). The size (area) of the leaf blade is a crucial parameter, as it determines photosynthetic activity.…”

Oenology in the Kitchen: The Sensory Experience Offered by Culinary Dishes Cooked with Alcoholic Drinks, Grapes and Grape Leaves

“…The thickness of the cuticle often corresponds with the xeromorphic degree of the leaf. Thus, cultivars grown in drier environments reveal thicker cuticles [76].…”

“…The thickness of the cuticle often corresponds with the xeromorphic degree of the leaf. Thus, cultivars grown in drier environments reveal thicker cuticles [76]. On the leaves internal anatomy, the leaf consists of a vascular system (it has several major veins, all of which depart from the same point at the base of the limbus), parenchymatous (mesophyll) and mechanical supporting tissues and also dermal tissues in the form of a persistent epidermis.…”

Water and Soil Water Availability

“…The combination of roots for the absorption of water, of vascular tissues to support the plant and convey water, of the cuticle and the epicuticular waxes that prevent evaporation, and of the stomata to allow for exchange of gasses constitute the complex of structures that gives plants the ability to live in environments with varying water availability. The epidermis of the underside of the leaf is composed of just a single layer of tubular cells that are rather small, irregular and less cutineous than those on the upper side (Salem-Fnayou et al 2011). The Vitis vinifera L. foliar epidermis displays from 100 to 400 stomata (Kriedemann 1977;Galet 2000), arranged without any apparent pattern among the parenchymatous aureoles.…”

“…Stomatic density, along with other parameters, such as the angle between the petiole and the leaf edge, the content of abscisic acid (ABA), the stomatic resistance and the water-holding potential, is one of the indicators for categorising plants' drought resistance (Li et al 2011;Gokbayrak et al 2008;Salem-Fnayou et al 2011).…”