<p style="text-align: justify;">Chez <em>Vitis vinifera</em> L. var. Chardonnay, le développement normal des ovules est de type <em>Polygonum</em>, mais les antipodes sont éphémères. Un grand nombre d'ovules ne peuvent suivre une ontogénie normale et involuent plus ou moins précocement. Plusieurs symptômes sont indubitablement des signes annonciateurs de l'arrêt du développement et d'une involution conduisant à la dégénérescence des ovules.</p><p style="text-align: justify;">L'involution d'un ou plusieurs ovules ne retentit pas obligatoirement sur le développement de l'ovaire : ainsi, des ovaires d'aspect sain peuvent renfermer quatre ovules en cours de lyse cellulaire, et, à l'inverse, des ovaires présentant des symptômes de dégénérescence peuvent renfermer un ou deux ovules sains. Tous les cas de figure sont possibles.</p>

L'ontogenèse du gynécée de Vitis vinifera L. var. Chardonnay est suivie, étape par étape, et divisée en vingt stades, depuis le méristème initial au sommet du pédoncule floral jusqu'à la nouaison. Chaque stade est étudié du point de vue morphologique et cytologique. Les particularités du gamétophyte femelle sont analysées. Au niveau de l'ovaire, l'origine particulière de la columelle, le trajet des tubes polliniques dans le style et la columelle et leur arrivée dans les loges carpellaires sont suivis. La présence de vacuoles à tanins dans les différents tissus du gynécée et plus spécialement de l'ovule est signalée et mise en relation étroite avec la vitalité des ovules, puis avec l'évolution normale des ovules en pépins ou avec une dégénérescence plus ou moins précoce. Toute l'ontogenèse est résumée dans un tableau chronologique.Abstrac : Gynaecium ontogenesis of Vitis vinifera L. var. Chardonnay is followed up stage by stage. It is divided into twenty stages from initial meristem at the top of pedicel till just after the fruit is set. Each stage is morphologically and cytologically investigated. Special features of the female gametophyte are made conspicuous. In the

<p style="text-align: justify;">Grape-flower ovary transformations is followed from fertilized flower to berry came to maturity. Cell transformations are studied, especially vacuolar tannins, starch and cell wall thinning :</p><p style="text-align: justify;">- From fruit setting to veraison, cell number of carpellary wall located between outer epidennis and vascular bundles is multiplied by 2.</p><p style="text-align: justify;">- Cell size increase considerably but by different means according to tissues: hypodennis cells elongate tangentially while inner parenchyma cells round.</p><p style="text-align: justify;">- Vacuolar tannins content in internal parenchyma cells decrease as soon as ovary is fertilized. During growth and veraison tannic cell number decrease. At maturity, only the most external cells (superficial hypodennis) still have vacuolar tannins. All the other cells of ovary wall have no more tannins.</p><p style="text-align: justify;">- Wall thickness decrease begins as soon as growth starts and this phenomena is continuous to maturity. The wall thinning down begins near the locules of ovary and is propagated towards the ouside of pericarp.</p><p style="text-align: justify;">- Amyloplasts disappear progressively. At maturity, there is scarcely no more startch in grape-berry.</p><p style="text-align: justify;">In short, except cells of berry skin, all the cells of ovary wall enlarge, lost their vacuolar tannins and the cell walls become very thin ; they are pulp cells.</p><p style="text-align: justify;">ln the pericarp of mature berry, hypodennis is very thin (less than 50 μm in places and 2-5 layers of cells). Pulp or flesh takes up a great place.</p><p style="text-align: justify;">This work is consecutived to the one on ovary before fertilization (FOUGÈRE-RIFOT et al., 1995) that shown 20 development stages from ovary primordia to the fertilized egg. From fertilized ovary to mature berry the development of pericarp is divided into 5 stages (stages 21 to 25) :</p><p style="text-align: justify;">- Stage 21 : first appearance of ovary inflation. Ovary takes a round shape. The thickness of carpellary wall is about 300 μm.</p><p style="text-align: justify;">- Stage 22 : fruit setting. Vacuolar tannins of inner parenchym disappear.</p><p style="text-align: justify;">- Stage 23 : berry growth.</p><p style="text-align: justify;">- Stage 23A : transformation of inner parenchym into pulp.</p><p style="text-align: justify;">- Stage 238 : transformation of deep hypodennis into pulp</p><p style="text-align: justify;">- Stage 23C : pulp cell enlargement.</p><p style="text-align: justify;">- Stage 24 : veraison. The definitive size of the berry is about reached.</p><p style="text-align: justify;">- Stage 24A : beginning of veraison. The hypodermis has still some thick walls.</p><p style="text-align: justify;">- Stage 248 : end of veraison. The hypodennis cells near the outer pulp cells change into pulp cells</p><p style="text-align: justify;">- Stage 25: maturity. Pulp is became very developped.</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;">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>