Charles Sturt University
Charles Sturt University

Fruit Growth & Composition

Understanding fruit development in relation to geographical and vineyard climate assists in identifying unique and important markers of wine style. NWGIC research on fruit growth and composition targets important markers and helps address the problem of unbalanced and overly alcoholic wines.

Selected Research Projects

The sugar-potassium nexus within the grape berry

Ms Zelmari Coetzee (CSU PhD student), Adjunct Associate Professor Suzy Rogiers (NSW DPI), Professor Alain Deloire (CSU), Dr Simon J. Clarke (CSU), Professor Rob Walker (CSIRO)

Funding
Australian Research Council - Industrial Transformation Research Program

Potassium is the most abundant inorganic element in the grape berry and has osmotic and biochemical functions. K is used in berries for anion neutralisation, enzyme activation, membrane transport processes and osmotic potential regulation. It is found in the skin, pulp and seeds of the berry. Within the cell it is found within the cytosol, vacuole and the apoplasm.

Sugar and K loading into the berry during ripening are closely linked but it is uncertain if this is coincidental or if one is dependent on the other. It has been hypothesised K may play a role in maintaining the osmotic gradient that facilitates phloem unloading. The aim of this project is to characterize this potential link.

Grape berries provide an excellent model on the study of sugar unloading into fleshy fruits and information gathered from this investigation will be provide potential avenues for manipulating sugar accumulation into a number of horticultural species.

This project is part of the ARC Training Centre for Innovative Wine Production administered by the University of Adelaide

Cell death in the berry and berry weight loss

Dr Simon J. Clarke (CSU Research Fellow), Adjunct Associate Professor Suzy Rogiers (NSW DPI), Professor Steve Tyerman (UA), Professor Alain Deloire (CSU)

Funding
Australian Research Council - Industrial Transformation Research Program

Mesocarp cell death in some grapevine varieties could influence flavour and aroma development, extractability of the juice, berry water relations, sugar concentration, and ultimate wine quality. Cell death is potentially important to the production of lower alcohol wines because vital grape berry cells are thought to be necessary for maintaining a high water content in the fruit. Vital berry cells promote water inflow from the parent plant, compensating for water lost to the atmosphere through the berry surface. In the absence of vascular inflows, the fruit water content will decrease and the concentration of solutes will increase. The concentrated sugars resulting from these processes are anticipated to increase the alcohol content of wine.

The general aim of this research, as well as the two projects described below, is to provide fundamental information on the processes responsible for inducing grape berry cell death. The aim of this particular research is to identify viticultural practices with the potential to delay or enhance grape berry cell death. This research will proceed by assessing whether processes extrinsic to the grape berry (such as canopy manipulations) have an effect on berry cell death. The research will then turn to assess the role of intrinsic berry characteristics (such as developmental stage) on berry cell death.

This project is part of the ARC Training Centre for Innovative Wine Production administered by the University of Adelaide

Longitudinal section of a grape berry
Longitudinal section of a grape berry stained with a cell vitality stain, fluorescein diacetate