Foliar application of biostimulants (including resistance inducers or elicitors) in the vineyard has become an interesting strategy to prevent plant diseases and improve grape quality on the grapevine. This also represents a partial alternative to soil fertilisation, avoiding some of the negative effects to the environment from leaching of nutrients into the groundwater. The foliar applications that most promote the synthesis of secondary metabolites in grape berries are treatments with nitrogen, elicitors, other biostimulants, and waste from the agricultural industry. However, the impact of their use in the vineyard depends on a number of conditions, including mainly the type of compound, application rate, timing and number of applications, and cultivar. This review thus summarises the influence of biostimulants as foliar applications to grapevines on grape amino acids and their phenolic and volatile concentrations, to define the most important factors in their effectiveness. © 2018 Society of Chemical Industry.

A review of the use of biostimulants in the vineyard for improved grape and wine quality: effects on prevention of grapevine diseases.

This review addresses the role of nitrogen (N) in vine balance and grape composition. It offers an integrative approach to managing grapevine N nutrition. Keeping in mind that N excess is just as detrimental to wine quality as N depletion, the control of grapevine N status, and ultimately must N composition, is critical for high-quality grape production. N fertilisation has been intensively used in the past century, despite plants absorbing only 30 to 40 % of applied N. By adapting plant material, soil management and vine balance to environmental conditions, it would be possible for grape growers to improve plant N use efficiency and minimise N input in the vineyard. Vineyard N management is a complex exercise involving a search for a balance between controlling vigour, optimising grape composition, regulating production costs and limiting pollution. The first part of this review describes grapevine N metabolism from root N uptake to vine development and grape ripening, including the formation of grape aroma compounds. The advantages and limits of methods available for measuring plant N status are addressed. The second part focuses on the parameters that influence grapevine N metabolism, distinguishing the impacts of environmental factors from those of vineyard management practices. Areas for further research are also identified.

https://serval.unil.ch/resource/serval:BIB_2FA60400A5F6.P001/REF.pdf

Understanding and managing nitrogen nutrition in grapevine: a review

Nitrogen supply method affects growth, yield and must composition of young grape vines (Vitis vinifera L. cv Alicante Bouschet) in southern Brazil

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jib.519

Free amino acid composition of apple juices with potential for cider making as determined by UPLC‐PDA

The wine is a beverage obtained from alcoholic fermentation (AF) of the must and an important food of the Mediterranean diet due to its health properties. To carry out a correct AF, yeasts need nitrogen as a source of feed. Yeast assimilable nitrogen (YAN) is a combination of free amino nitrogen (FAN) and ammonium (NH4 +). Amino acids are the most important nutrients in musts and wines since, in addition to contributing to wine quality, they play a key role in human health. These compounds are required for the synthesis of body proteins, peptide hormones, and some neurotransmitters. Besides, they are important to the intestinal mucosal catabolism, to the enterocytes and lymphocytes, and are the precursors of nucleic acids, and nucleotides. Amino acids in these beverages do not fully satisfy the human amino acids requirements. Thus, a moderate wine consumption should form an important basis of people’s diet to contribute to an increasingly healthier life.

Amino acid composition of grape juice and wine: Principal factors that determine its content and contribution to the human diet

Vineyard applications of foliar nitrogen (N) and sulfur were evaluated in the Yadkin Valley of North Carolina in 2011 and 2012 as a means to modify grape composition of Vitis vinifera cv. petit manseng. Four treatments were applied each year in a randomized complete block design with six replicates of six vines each: untreated control, soil N at 30 kg/ha, foliar N at 15 kg/ha and foliar N at 15 kg/ha plus sulfur at 5 kg/ha. Fruit ammonia and yeast assimilable nitrogen (YAN) concentrations increased in foliar-treated vines both seasons compared to control vines. Total glycosides (TGGs) increased ∼80% in foliar N/sulfur-treated vines compared to control vines in 2011, and TGGs increased ∼157% in foliar N/sulfur-treated vines relative to glycoside level in foliar N alone in 2012. Foliar N and foliar N/sulfur applications increased the majority of amino acid concentrations analyzed in 2011. Measured concentrations of various amino acids, partly responsible for aroma and flavor of petit manseng wines, ...

Molly Kelly

Papers

Effect of foliar nitrogen and sulfur on petit manseng (Vitis vinifera L.) grape composition