Effect of grapevine latent buds (<em>Vitis vinifera</em> L., cv. Merlot) chilling on their starch content: biochimical and cytological approachs

Abstract

&lt;p style="text-align: justify;"&gt;Biochimical analysis and photonic microscopy observations of starch were investigated in latent buds of &lt;em&gt;Vitis vinifera &lt;/em&gt;L. (cv. Merlot) collected during their dormancy phase and during their cold storage at 2°C. Biochimical analysis showed that starch levels of grapevine latent buds was high (70 mg/g DW). Microscopical observations confirmed this result and showed a gradient of starch content in different regions of bud in which the foliars primordiums and scales were the starch richer. Buds conservation at 2°C reduced their starch content but this decrease begun only after 9 days of chilling corresponding to the time necessary for budbreak and for the beginning of increase the bud burst ability. The hydrolysis of starch seems begun at the first in apex and then propaged to the other regions of bud. In the scales, the most exposed region to cold, storage at 2°C during 56 days induced an increase of cellular tannins content and cell walls polysaccharides. These results were discuted in relation to the increase of bud burst ability and to their cold acclimatation.&lt;/p&gt;

Sugars are under light control during bud burst in Rosa sp.

“…Thus, in several species (Quercus robur, Barnola et al 1986;Malus domestica, Ben Ismail 1989;Fagus sylvatica, Kelner, Lachaud & Bonnemain 1993;Prunus persica, Marquat et al 1999), an increase in bud sink strength takes place close to bud burst, which results in a mobilization of stem carbohydrates: starch in the oak (Quercus robur, Alaoui-Sossé et al 1994), sucrose in the walnut (Juglans regia, Decourteix et al 2008) and hexose (glucose, fructose) in the peach tree (Prunus persica, Maurel et al 2004a); the hydrolysis of bud starchy reserves (Acer pseudoplatanus, Catesson 1964;Fraxinus excelsior, Cottignies 1986; Betula pubescens, Rinne, Tuominen & Juntilla 1994; Vitis vinifera, Koussa, Cholet & Cherrad 2001); and an increase in the concentration of bud sucrose (Prunus persica, Marquat et al 1999;Aue, Lecomte & Pétel 2000;Malus domestica, Brunel 2001). In breaking down starch or sucrose in simple sugars, enzymes such as amylases, sucrose synthase (Le Hir et al 2005) and invertases (Maurel et al 2004a;Le Hir et al 2006) provide the energy and the wall material necessary for the growth that accompanies bud burst.…”

“…2008) and hexose (glucose, fructose) in the peach tree ( Prunus persica , Maurel et al. 2004a); the hydrolysis of bud starchy reserves ( Acer pseudoplatanus , Catesson 1964; Fraxinus excelsior , Cottignies 1986; Betula pubescens , Rinne, Tuominen & Juntilla 1994; Vitis vinifera , Koussa, Cholet & Cherrad 2001); and an increase in the concentration of bud sucrose ( Prunus persica , Marquat et al. 1999; Aue, Lecomte & Pétel 2000; Malus domestica , Brunel 2001).…”