CO2 organication in different green organs of Vitis vinifera L
2000
Palliotti, A. | Cartechini, A. (Perugia Univ. (Italy). Dipartimento di Arboricoltura e Protezione delle Piante)
One week before anthesis, in grape closed flowers, regular stomata, similar to those observed on leaves and not covered with wax, were found in the calyx (22+-3 stomata/calyx) and in the apical part of the calyptra (9+-3). The stomata size was equal to 58+-11 square micronm. Regular stomata were also found on young tendrils with density of 27+-4/square mm and dimensions of 64+-8 square micronm. On inflorescence, berry just after fruit-set and young tendrils, the CO2 exchange measurements showed: an inability in fixing the external CO2; a decline in respiration activity when these organs were transferred from the dark to the light; an absence of this decline in young berry after treatment with DCMU (herbicide that blocks the photosynthetic electron transport chain); a positive relationship between carotenoids, chlorophyll a, b and total nitrogen content and CO2-fixing ability; a rapid accumulation of epicuticular waxes just after anthesis, especially on berries. These green organs, due to their CO2-fixing capacity in the light, can recover a great amount of dry matter consumed by respiration during the daylight and therefore supply themselves, especially in the first stages of their development, favouring cellular division and the growth of inflorescence, berry and tendrils
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