<p style="text-align: justify;">Biochimical analysis and photonic microscopy observations of starch were investigated in latent buds of <em>Vitis vinifera </em>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.</p>

<p style="text-align: justify;">On Cabernet sauvignon, eutypiosis sensible variety, we have compared fatty acids content in healthy Jeaves (S: leaves beared by healthy vine stock), in leaves seeming healthy (Ap.S: leaves beared by arm without symptoms, the other arm is diseased) and in diseased leaves (M: leaves beared by diseased arm). The results show that disease does not alter the fatty acids order. Linolenic acid (CI 8:3) content is always the most important, followed by palmitic (CI6:0) and Iinoleic acids, then by stearic (CI8:0) and oleic acids and at last by arachidic acid (C20:0). During the three stages studied (flowers buds: H, flowering: I and closed cluster: L), only the development of CI 8:3 content was modified by disease. It increases in healthy leaves at stage I, while in Ap.S and M leaves there is a decrease from H to L stages. Otherwise, development of fatty acids proportions does not seem to be changed by eutypiosis.</p><p style="text-align: justify;">Proportions and content comparison in S, Ap.S and M leaves show a decrease of C 18:3 synthesis benefit of C 18:2.</p><p style="text-align: justify;">This increases is important as well as the symptoms are evident. These results seem to be in relationship with decrease of leaves size caused by eutypiosis. At the end, the disease induces a desaturation decrease of C18:0 and C18:2 as well as an aliphatic chain lengthening of C16:0. These inhibitions are showed by more increase of CI 6:0 and CI 8:2 in diseased leaves than in healthy leaves. No action is observed in CI 8: 1 desaturation.</p>

<p style="text-align: justify;">Structural and ultrastructural investigations on plastidial ontogenesis in the tissues of <em>Vitis vinifera</em> berry arc realised in narrow association with starch and chlorophyll dosages from the stage of fruit setting till berry ripeness. During the whole of that period, some chloroplasts, starch and chlorophyll arc noted in grape berry.</p><p style="text-align: justify;">Well developed starch chloroplasts and a great deal of chlorophyll are present in herbaceous stage of berry development. A large starch content perhaps seems to show that berries arc involved in their own glucides synthesis during this stage.</p><p style="text-align: justify;">After that, during ripening stage, chlorophyll content strongly decreases and soluble glucides that accumulate in the berry are essentially derived from leaves.</p>

<p style="text-align: justify;">Cinq catégories de pépins de Cabernet Sauvignon ont été séparées à la véraison. Plus de 95 p. 100 des acides gras sont contenus dans les lipides neutres. La différence de composition en acides gras des lipides polaires montre que la localisation des pépins dans une seule loge ou dans deux loges séparées a pour conséquence une modification du fonctionnement des désaturases.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">Five categories of Cabernet Sauvignon seeds were separated at the beginning of ripening. The neutral lipids contain more than 95 per cent of the fatty acids. The difference in the fatty acid content of polar lipids shows that seeds localized in just one section or in two separate sections results in a modification of the « desaturase » functioning.</p>

Dans un travail précédent (ATALAY et al., 1973), nous avons signalé l'existence de plusieurs acides gras dans les sarments aoûtés de l'Ugni blanc. A la suite de ces premières recherches sur les lipides de la Vigne, nous nous sommes demandés si les divers organes portés par les sarments renfermaient tous les mêmes acides gras. La présente étude se rapporte aux feuilles et nous avons analysé à part les limbes et les pétioles. Nous avons recherché également si l'existence des phénomènes rythmiques de croissance, bien connus maintenant en ce qui concerne les sarments (BOUARD, 1966), se traduisait dans les feuilles, en ce qui concerne les acides gras, par des différences qualitatives ou quantitatives.