Effect of the herbicide flumioxazin on photosynthetic performance of grapevine (Vitis vinifera L.)

International audienc

Effect of Zinc on Primary and Secondary Metabolism of Datura innoxia and Datura sanguinea.

absen

Adaptation of grapevine flowers to cold involves different mechanisms depending on stress intensity.

Grapevine flower development and fruit set are influenced by cold nights in the vineyard. To investigate the impact of cold stress on carbon metabolism in the inflorescence, we exposed the inflorescences of fruiting cuttings to chilling and freezing temperatures overnight and measured fluctuations in photosynthesis and sugar content. Whatever the temperature, after the stress treatment photosynthesis was modified in the inflorescence, but the nature of the alteration depended on the intensity of the cold stress. At 4°C, photosynthesis in the inflorescence was impaired through non-stomatal limitations, whereas at 0°C it was affected through stomatal limitations. A freezing night (-3°C) severely deregulated photosynthesis in the inflorescence, acting primarily on photosystem II. Cold nights also induced accumulation of sugars. Soluble carbohydrates increased in inflorescences exposed to -3°C, 0°C and 4°C, but starch accumulated only in inflorescences of plants treated at 0 and -3°C. These results suggest that inflorescences are able to cope with cold temperatures by adapting their carbohydrate metabolism using mechanisms that are differentially induced according to stress intensity

Desmodesmus sp. pigment and FAME profiles under different illuminations and nitrogen status

International audienc

Lumière sur nos vignes

Article dans une revue professionnell

Inflorescence photosynthate allocation of Chardonnay grapevine (Vitis vinifera L.) fruiting cuttings

National audienc

Chlorophyll Fluorescence and Colorimetric Analysis for Monitoring the Algal Development on Biocide-Treated Stone

International audienc

Modulation of the Activity of Enzymes Involved in Carbohydrate Metabolism during Flower Development of Grapevine ( Vitis Vinifera L. )

In order to further understand the relationships between flower development and sugar metabolism in grapevine, the fluctuations of both starch and sucrose contents were compared with the activity of their related enzymes, in the inflorescences, from the appearance of flower buds until the fruit set. The measurements were carried out on GW and PN cvs., differing in their sensitivity to the flower abscission. The meiosis stage, which is a crucial step for the achievement of sexual reproduction, was particularly screened. Results indicate that the main differences in carbohydrate metabolism occur during meiosis. In the inflorescences of both cvs., variations of enzyme activities can be correlated with their differences in sugar contents. Starch fluctuations were mediated by the activity of amylases (alpha- and beta-) rather than by starch synthase. Changes of sucrose were correlated with the activity of Starch Synthase degradation, both cytoplasmic and wall-bounded invertases but not with the Sucrose Phosphate Synthase activity. Finally, the significant increase of sucrose degrading enzyme activities, such as Starch Synthase degradation, cytoplasmic invertase, and wall-bound invertase, observed after the flower separating stage was interpreted as the first sign of the strong physiological modifications occurred in the ovaries between fertilization and the fruit formation.</p