How Grapevines Respond to Water Stress
Water relations are a key factor in grapevine growth and development. Plants take up water to maintain cell turgor, to make and expand new tissues, to provide evaporative cooling, and to facilitate gas exchange for photosynthesis (C02) and respiration (O2). Vines actively regulate the flow of water in response to environmental conditions.
Water availability dramatically affects vine vegetative growth, fruit composition, and potentially winter hardiness. An overabundance of water is associated with excessive shoot vigor, canopy shading, and reduced fruit quality - and may delay the cessation of shoot growth and periderm formation, leading to poorer winter hardiness.
Moderate water stress at the right time can reduce vegetative growth and help vines achieve the appropriate balance between vegetative growth and fruit yield and quality. Severe water stress limits photosynthesis, and can delay ripening, reduce bud fruitfulness, reduce winter hardiness, and result in sudden vine collapse.
