Estimation of stomatal conductance and chlorophyll fluorescence in Croatian grapevine germplasm under water deficit    

The effects of climate change in viticulture are currently a major concern, with heat waves and drought affecting yield, wine quality, and in extreme cases, even plant survival. Ancient grapevine varieties have high intravarietal genetic variability that so far has been explored successfully to improve yield and must quality. Currently, there is little information available on intravarietal variability regarding responses to stress. In the current work, the intravarietal genetic variability of several Portuguese varieties was studied for yield, must quality, and tolerance to abiotic stress, through indirect, rapid, and nondestructive measurements carried out in the field.

Pre-fermentative skin maceration is a technique used in white wine production to enhance varietal aroma, but it can increase protein concentration, leading to protein instability and haze formation [1]. To prevent protein instability, wine producers typically use fining agents such as bentonite, before wine bottling, which can negatively impact sensory characteristics and produce waste [2,3]. The aim of this study was to understand the impact of alternative techniques such as the application of polysaccharides (k-carrageenan and chitosan) on protein stability and on the wine macromolecular composition.

Different heat tests are used to predict the dose of bentonite necessary to prevent wine haze after bottling. The most used tests are 60-120 min. at 80°C. Nevertheless, there is a lack of information about the relationship between these tests and the turbidities observed in the bottles after the storage/transport of the wines in realistic conditions, when temperatures reach 35-42°C during 3-12 days.

In mid to late ripening, sugar and potassium (K+) accumulation into the berry slows and is eventually completed1. K+ is the most abundant cation in the berry, undertaking important physiological roles.

Context and purpose of the study. The vine is generally a very fertile plant when compared to other tree species.