Evolution of the hypodermal cells of grape berry during their transformation in pulp cells

Abstract

<p style="text-align: justify;">Some hypodermal cells of grape berry become pulp cells during growth stage to maturity. Their vacuolar tannins disappear and their cell walls get thinner in two times. In a first time, cell walls lose their polysaccharides (PAS negative walls), then they get thinner like pulp walls.</p>

Tartaric acid pathways in Vitis vinifera L. (cv. Ugni blanc): a comparative study of two vintages with contrasted climatic conditions

“…Indeed, at the beginning of ripening, and proportional to sugar accumulation, the GSH form of glutathione accumulates in the berry [ 54 , 55 ], potentially activating GSH-dependent DHA reductase enzymes which are present in the berry tissues [ 56 ]. An alternative process may be the recycling of ascorbate from carbons resulting from cell-wall degradation related to maturation phenomena [ 26 , 51 , 57 , 58 ] and releasing D-galacturonate, a precursor of ascorbate under the consecutive action of D-galacturonic acid reductase, aldono-lactonase, and L-galactono 1,4lactone dehydrogenase [ 59 ]. A third hypothesis might be put forward that is in relation to the climatic conditions prevalent in August 2011 in the Charente vineyard ( http://www.cognac.fr/cognac/_fr/4_pro/index.aspx?page=actualite&id=2809 and http://www.cognac.fr/cognac/_fr/4_pro/index.aspx?page=actualite&id=4018 ); following a period of severe drought, ripening took place under rainy conditions, which resulted in a phenomenon of exceptional vigor in the vines.…”