Abscisic Acid and Grapevine Dormancy

It's beginning to snow along the coast in Southeastern, CT where our vineyard is located. I'm wondering how our grapevines are tolerating the onset of colder weather and found some answers in the November/December 2013 issue of Vineyard & Winery Management written by Remi Cohen called Understanding Plant Hormones.¹ Last year, after reading Marcus Keller's book on The Science of Grapevines I blogged about Grapevine Hormones. Ms. Cohen's article provided much more information about abscisic acid (ABA) and it's role in grapevine dormancy. I found the chemical structure of abscisic acid on Wikipedia² and reproduced it using the ACDLabs freeware:³

Abscisic acid:

• Initiates bud dormancy and stimulates the alteration of the last set of leaves into bud covers
• Prevents bud growth during winter dormancy

Abscisic acid also:

• Slows cellular and meristematic growth once shoots have begun to produce mature leaves
• Regulates potassium and sodium uptake in the guard cells resulting in the closure of stomates in response to water stress, thereby preventing water loss in the vine
• Regulates seed maturation and germination

In addition, ABA may be a crucial mediator of the ripening process in grapes. Okay, more reading for me to do on this snowy day.
References:
1. Cohen, Remi, Understanding Plant Hormones, Vineyard & Winery Management, November/December 2013, ppg. 33-36.
2. Wikipedia: abscisic acid.
3. All structures were drawn by the freely available drawing program from ACD Labs called ACD/ChemSketch Freeware.