Developmental Physiology and Climate part 2 Flashcards
In hot regions, temperature often exceeds the photosynthetic optimum during a large part of the day. Moreover, high T increases
night time respiration.
The surface of green berries exposed to full sunlight can be 12 °C warmer than the surrounding air, and that of dark-colored berries can be as much as 17 °C, whereas shaded berries are close to air (ambient) temperature. What can we say about wind and cluster compactness in terms of T?
Wind also reduces the difference between cluster and air T, while loose clusters heat less than thick counterparts. This is because berries touching each other conduct more heat and lose less for convection.
How does temperature affect sugar and acids?
Low temperatures can often limit photosynthesis and sugar production in the leaves.
Earlier veraison (e.g.due to climate chage) implies that…
The critical ripening period shifts towards the hotter part of the growing season
Hot conditions favor the formation of
Malvadin (at the expense of anthrocyanins, which are less tolerant to heat)
The degradation of anthrocyanins can lead to…
berry burning
Which row orientation can get the worst sunburn?
NS
4 different ripening disorders
- Sour shrivel (berry shrivel)
- Bunch stem Necrosis (BSN)
- Sunburn
- Dehydration
What are some symptoms of sunburn?
The wax on the berry skin is no longer present and the grapes look glossy.
What is the physical appearance of a dehydrated grape? What is the pedicel color and brix?
It looks like a golf ball. The pedicel color is green and brix are 32
What do berries with sour shrivel look like? What is the pedicel color and brix?
a deflated ball. The pedicel is green and brix are the lowest at 15
What do berries with BSN look like? What is the pedicel color and brix?
a raisin. The pedicel is brown and brix are around 18
Air temperature above _______ is optimal for ripening and at _________ we can see either increase (dehydration) or decrease in brix (no dehydration)
- 20 degrees C
- 35 degrees C
Cold and heat do what?
They delay ripening
How does Temperature affect Anthocyanins?
It increase until about 22 then plateaus until 31 and then steadily decreases
