Abstract
The outcomes of Theme 3 fall within three main categories. Firstly, the project enhanced our understanding of the nutrient and carbohydrate reserve dynamics on root growth and vine perenniality in order to better target vineyard management. Secondly, the project developed methods that improved our understanding of assimilate and water movement through vines and bunches. Finally, the project determined the effects of selected climatic influences, including heat stress, on vine and berry development and growth.
Summary
Research in this theme has improved our understanding of seasonal nutrient dynamics in the perennial structure and the allocation to different organs of grapevines. This work showed the seasonal nutrient requirement by the annual growth and the importance of the perennial structure to provide nutrients to the early canopy development and, to a lesser extent to the reproductive development. The intra-seasonal changes have been assessed in two Shiraz trials, indicating the variation of the nutrient reserve pool between years. In addition, the work suggests that the nutrient reserves differ between rootstocks and can be altered by water and N supply.
The relationship between root dynamics, nutrient accumulation and vine reserves was inconclusive and this requires further research.
Furthermore, findings have identified future research directions and a proportion of the data can be utilised for further work. These existing data on nutrient acquisition and reserve mobilisation can be utilised to enhance the timing and amounts of nutrient application, with the potential of integration into a grapevine model. However, the importance of nutrient supply from uptake or storage for early canopy growth and the acquisition of nutrients during berry development on berry composition will require further experimentation.
The project has further determined the importance of the roots as a storage organ, with its accumulated nutrients showing significant seasonal changes and between seasons. These dynamics are driven by the partitioning of the grapevine and the root environment, with factors such as soil temperature, water and nutrient supply. The understanding of the response of grapevines in relation to nutrient acquisition to the range of vine root environments relevant to current and future climatic trends is crucial. The predicted climatic changes will be reflected in the above and below ground environment and is important to understand the nutrition equitation and utilisation under various conditions for sustainable grape production. The future research on nutrition needs to integrate the soil processes, since they strongly contribute to the availability of nutrients for vine development and ultimately for the characteristics of grapes produced from a particular vineyard in a wine region.