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

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

Berry pericarp ontogenesis from fertilization to maturity of <em>Vitis vinifera</em> L. var Merlot

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 : - From fruit setting to veraison, cell number of carpellary wall located between outer epidennis and vascular bundles is multiplied by 2. - Cell size increase considerably but by different means according to tissues: hypodennis cells elongate tangentially while inner parenchyma cells round. - 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. - 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. - Amyloplasts disappear progressively. At maturity, there is scarcely no more startch in grape-berry. 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. 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. 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) : - Stage 21 : first appearance of ovary inflation. Ovary takes a round shape. The thickness of carpellary wall is about 300 μm. - Stage 22 : fruit setting. Vacuolar tannins of inner parenchym disappear. - Stage 23 : berry growth. - Stage 23A : transformation of inner parenchym into pulp. - Stage 238 : transformation of deep hypodennis into pulp - Stage 23C : pulp cell enlargement. - Stage 24 : veraison. The definitive size of the berry is about reached. - Stage 24A : beginning of veraison. The hypodermis has still some thick walls. - Stage 248 : end of veraison. The hypodennis cells near the outer pulp cells change into pulp cells - Stage 25: maturity. Pulp is became very developped

Cellular particularities of medium size shot grape berries of <em>Vitis vinifera</em> L. var. Merlot

The subject of this study is the development of medium size shot berries of Vitis vinifera. At the time of vintage, their size reaches 4-7 mm. Their cell structure development is compared stage by stage with that of normal berries. On the same cluster of grape, others are very smaller (2-3 mm in diameter at stage maturity). This smaller shot berries are already be studied and aren't the subject of this paper. The medium size shot berries have a growth delay and their histological and cellular structures are also late with regard to normal development. What is more, veraison is delayed in some berries whereas other berries stay green with their structure frozen in the growth stage. Only coloured shot berries have caught up with the development of normal berries when they arrive at the overripeness stage of the cluster of grapes : they are small (6-7mm) but have the structure of nonnal mature berries with a typical pulp and a reduced hypodennis : the cells have lost their vacuolar tannins and more their cell walls become thinner. However, shot benies recommence starch accumulation during berry maturation : this is an unexpected and unusual evolution, or, some recent papers associate the presence of polyamines and/or abscissic acid in berries to the regulation of α-amylase activity. If polyamines inhibit the α-amylase activity, the honnone unbalance « polyamines/ abscissic acid » can have an effect on the induction of this enzyme activity and therefore explain the abnormal presence of starch in shot berries on and after their veraison

Données nouvelles sur l'hypoderme et la pulpe des baies normales et des baies millerandées d'une variété de Vitis vinifera L., le Merlot noir

Dela baie juste nouée jusqu'au stade de la maturité, des changements importants interviennent au niveau des tissus de la paroi carpellaire: hypoderme et pulpe. Les cellules de l'hypoderme ont des parois épaisses et la plupart sont des cellules tanniques. Elles évoluent progressivement en cellules de pulpe, c'est-à-dire en cellules qui deviennent très grandes et non tanniques, et dont les parois s'amincissent considérablement. Les faisceaux vasculaires qui, en début d'évolution, sont situés au milieu de la paroi carpellaire deviennent par le grandissement de la baie des faisceaux periphériques. Ils finissent par ètre inclus dans la pulpe, et ne marquent donc plus lalimite interne de l'hypoderme.Les baies millerandées grandissent très peu et n'ont pas de pépins. Elles sont caractérisées aussi par l'absence d'individualisation d'une pellicule, l'absence de formation d'une pulpe typique, la répartition des tanins vacuolaires dans toute l'épaisseur de la paroi carpellaire et des faisceaux conducteurs qui ne grandissent pas.Vitis vinifera L. var. Merlot noir berries. New aspects upon hypodermis and flesh of normal and shot berriesFrom the very young berry, just after ovary fertilization until the stage of maturity, major structural changes occur in the carpellar tissues: hypodermis and flesh (or pulp). Hypodermal cells have thick cell walls and most of them are tannin cells. They evolve gradually in cells of flesh, i. e., in cells which enlarge enormously and are devoid of tannins; their walls thin down considerably. At the beginning of evolution, vascular bundles are in the middle of carpel. During grape growth, vascular bundles become localized in the periphery of the berry. They finish by being included in the flesh, and therefore, they do not mark the internal boundary of the hypodermis. Shot berries fail to grow and enlarge; they are seedless berries. They are also characterized by the absence of individualization of grape skin, the absence of formation of a typical flesh, the presence of vacuolar tannins in the carpels and no increase of vascular bundles

Relations entre le développement défectueux des ovaires et l'involution des ovules chez <em>Vitis vinifera</em> L. var. Chardonnay

Chez Vitis vinifera L. var. Chardonnay, le développement normal des ovules est de type Polygonum, 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. 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

Gynaecium ontogenesis of <em>Vitis vinifera</em> L. var. Chardonnay in closed connection with the apparition of tannic vacuoles

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 ovary, the origin of fruit septum, the pathway of pollen tubes in the style and in the septum are revealed. A close connection between the presence of vacuolar tannins in gynaecium and especially in ovule and the ovule vitality is reported. The absence of vacuolar tannins is a symptom of illness and premature breakdown of the ovules before their transformation into pips. The whole ontogenesis is summed up in a very full table

Plastids, starch and chlorophyll in <em>Vitis vinifera</em> L. berry during its ontogenesis

Structural and ultrastructural investigations on plastidial ontogenesis in the tissues of Vitis vinifera 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. 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. After that, during ripening stage, chlorophyll content strongly decreases and soluble glucides that accumulate in the berry are essentially derived from leaves

Importance des tanins vacoulaires dans le développement des ovules de la vigne

Dans les ovaires et ovules de Vitis vinifera, certaines cellules seulement, referment des vacuoles à tanins. Les tanins s'y trouvent séquestrés sous des formes allant de tres fins granules dispersés dans toute la vacuole à des amas plus ou moins agglutinés, en passant par toutes les éta pes intermédiaires. Dès les stades jeunes, tous les tissus de l'ovaire sont riches en tanins et leur teneur ne cesse de croitre pendant toute la durée de développement des ovules.Par contre, les ovules sains accumulent très précocement des tanins vacuolaires, mais seulement en des sites très précis, et il existe une concordance rigoureuse entre la répartition des tanins dans les différents tissus de l'ovule et les stades du développement ovulaire. L'appartition des tanins a lieu d'abord dans l'épiderme externe du funicule, et se poursuit dans l'épiderme du tégument externe. Plus tard, l'épiderme interne du tégument interne se charge fortement en tanins. Il en est de même de quelques cellules du parenchyme du funicule et du parenchyme du têgument externe, ainsi que des cellules situées autour du faisceau libero-ligneux chalazien. Les cellules du nucelle et celles du gamêtophyte des ovules sains ne renferment jamais de vacuoles tanniques.Certains ovules n'accumulent pas ou très peu de tanins; d'autres se chargent normalement de tanins pendant quelques étapes de leur développement, puis, les vacuoles qui les renferment sont détruites et libèrent leur contenu dans toute la cellule. Les cellules sont lysées et ces ovules avortent plus ou moins précocement.Les tanins paraissent être un marqueur de la vitalité des ovules. Leur présence en des sites bien définis de l'ovule est un signe de développement normal, tandis que leur absence ou leur rareté annonce inéluctablement leur involution.Importance of vacuolar tannins in grapevine for the development of ovaries and ovulesIn ovaries and ovules of Vitis vinifera the vacuoles of some cells contained tannins showing all forms ranging from fine granules to more or less agglutinated masses. Young ovarian tissues were rich in tannins whose amount would grow continuously during the development of the ovules. In healthy ovules vacuolar tannins occurred early but only at limited locations which were characteristic for the state of development. The tannins were oberved first in the outer epidermis of the funicle and then in the epidermis of the external integument. Later on, they accumulated also in the epidermis of the inner integument, in some parenchymatic cells of the funicle, of the outer integument and of the cells around the chalaza bundle but never in cells of the nucellus and of the gametophyte of healthy ovules. Some ovules would accumulate no tannins, others showed accumulation at early stages followed by the lysis of the vacuoles and eventually of the whole cells. Both ovule types aborted prematurely. It is concluded that the presence of tannins at certain sites of the ovule is indicator of its vitality.