Partial Rootzone Drying

In the Viticulture course that I took, there was a very short discussion thread regarding partial rootzone drying (PRD). One of the things that was difficult to do was to go off topic because assignments were due on a weekly basis, so consequently the discussion on PRD languished and I was left in the dark.
Fast forward one year. In Jamie Goode's book, Science of Wine, I came across a chapter called "PRD and regulated deficit irrigation". In Goode's book, he credits the theory regarding PRD to research done in the late 1980s at the University of Lancaster, UK. Researchers there identified abscisic acid (ABA) as the plant hormone responsible for communicating the soil-water status from the roots to the shoots.
The way that ABA works is that it affects the status of the stomata, the small pores on the leaves that regulate photosynthesis as well as transpiration. During drought conditions, ABA synthesized in the roots send a signal to the shoots that causes the closing of the stomata to conserve water. They showed this by devising an experiment called the "split-pot system" where the root system of the plant was split into two pots and one side was watered and the other side experienced drought-like conditions.
Extensive practical research using the split-pot experiment was performed in Australia where water stress in the form of drought on part of the root system was found to cause the plants to switch from growing foliage to ripening fruit to ensure survival. Too much water stress leading to excessive drought-like conditions was also detrimental to the plant but just the right amount was shown to lead to the production of high quality fruit.
The split-pot experiment:

The above diagram was extracted from page 22 of 38 pages from Chapters 1-3 found on line and located here:Chapters 1-3.
The thesis project of Manfred Stoll published in October, 2000 can be found on line:Effects of partial rootzone drying on grapevine physiology and fruit quality.
This research was conducted by Brian Lovey, Jim Grant, and Manfred Stoll of CSIRO Division of Plant Industry, Peter Dry of the Department of Horticulture, Viticulture & Oenology, University of Adelaide, and Michael McCarthy of the South Australian Research and Development Institute, SA Viticulture Technical Conference, 1997.