Evaluation of a High Throughput Starch Analysis Optimised for Wood

Starch is the most important long-term reserve in trees, and the analysis of starch is therefore useful source of physiological information. Currently published protocols for wood starch analysis impose several limitations, such as long procedures and a neutralization step. The high-throughput standard protocols for starch analysis in food and feed represent a valuable alternative. However, they have not been optimised or tested with woody samples. These have particular chemical and structural characteristics, including the presence of interfering secondary metabolites, low reactivity of starch, and low starch content. In this study, a standard method for starch analysis used for food and feed (AOAC standard method 996.11) was optimised to improve precision and accuracy for the analysis of starch in wood. Key modifications were introduced in the digestion conditions and in the glucose assay. The optimised protocol was then evaluated through 430 starch analyses of standards at known starch content, matrix polysaccharides, and wood collected from three organs (roots, twigs, mature wood) of four species (coniferous and flowering plants). The optimised protocol proved to be remarkably precise and accurate (3%), suitable for a high throughput routine analysis (35 samples a day) of specimens with a starch content between 40 mg and 21 µg. Samples may include lignified organs of coniferous and flowering plants and non-lignified organs, such as leaves, fruits and rhizomes

Responses of "Chardonnay" to deficit irrigation applied at different phenological stages: vine growth, must composition, and wine quality

Adoption of water-saving irrigation strategies is necessary especially for grapevine that has the highest acreage of any fruit crop in the world. We applied deficit irrigation to Chardonnay wine grape at the following phenological stages: anthesis to fruit set, fruit set to veraison, and veraison to harvest. Four irrigation levels (0, 25, 50, and 100 % of crop evapotranspiration, ETc) were applied in 2009. Vines grown in large containers were used to enable imposition of water stress early in the growing season. The following parameters were measured: midday leaf water potential, vine growth, yield, and quality of must and wine. The same parameters were measured in 2010 although all vines were fully irrigated. The 0 and 25 % treatments caused defoliation and had negative impacts on yield and wine quality in both 2009 and 2010. Chardonnay was most sensitive to water stress in post-veraison in terms of productivity and wine quality

Low source-sink ratio reduces reserve starch in grapevine woody canes and modulates sugar transport and metabolism at transcriptional and enzyme activity levels

Severe leaf removal decreases storage starch and sucrose in grapevine cv. Cabernet Sauvignon fruiting cuttings and modulates the activity of key enzymes and the expression of sugar transporter genes.The work was supported by European Union Funds (INTERACT-NORTE-01-0145-FEDER-000017-Linha VitalityWineON 0013), Portuguese national funds (FCT-Portuguese Foundation for Science and Technology) under the Project UID/AGR/04033/2013 and the Conseil Interprofessionnel du Vin de Bordeaux (CIVB, France) under the Project CANOGRAPE N 44233. HN (SFRH/BPD/ 115518/2016) was supported by postdoctoral grant from FCT.info:eu-repo/semantics/publishedVersio