Shoot Growth Flashcards
What is Shoot Growth?
The elongation and expansion of a vines shoots during the growing season.
Why is shoot growth important in vines?
Shoot growth determines how much photosynthesis can occur and therefore how much canopy is produced and therefore fruit quality and yield.
Name 2 physiological mechanisms that affect shoot growth
Vascular system - The quality of a vines vascular system will affect shoot growth, as it will effect how much water, nutrients and signals can be carried around the vine.
Hormonal regulation - Auxins promote elongation, Cytokinins promote cell division and Gibberellins regulate growth rate.
What are the 2 growth phases of shoot growth
Initially carbohydrate reserves are used for shoot growth but as leaves develop and mature, they provide energy for further growth via photosynthesis.
What 4 factors might contribute to low carbohydrate reserve levels?
In the previous season:
- Water stress
- Disease and Mildew infections
Name 2 environmental factors that effect shoot growth?
Light intensity - More light = More photosynthesis, increased rates of transpiration and activates enzymes that break down auxins, preventing excessive growth
Air temperature - the minimum temp for shoot growth is 10 degrees and optimum temperature is around 25 degrees.
What 2 cultural factors affect shoot growth?
Vine density - Competition decreases shoot growth and so higher denity planted vines reduce growth.
Shoot thinning - Early in the season will promote growth of any remaining shoots.
