Agriculture Reference
In-Depth Information
Fig. 7.3  Opened stomata on the underside of young and expanded grapevine leaf (  Left ). An
opened stomate on a berry at fruitset (  Right )
can lead to lowered rates of photosynthesis (Candolfi-Vasconcelos and Koblet 1990 )
and under severe defoliation post-veraison berries are able to source carbohydrates
from the woody storage tissues (Kliewer and Antcliff 1970 ). The intricate balance
between photosynthetic capacity and the allocation of resources to vegetative ver-
sus reproductive components ensures that the vine maintains enough capacity for
both survival and reproduction in a resource-limited environment.
Inflorescence
The shape and size of the inflorescence is variety dependent but it is referred to as a
panicle and often includes several branches which can be further ramified. Usually
between two to five flowers are found at the terminal branch. The hypoclade is the
portion of the main stem that is located between the shoot and the first branch and
encloses the vascular bundles that carry water and nutrients from the shoot to the
flowers and berries. The main axis below this point is referred to as the rachis and
often carries a lateral wing or a tendril. The bunchstem elongates rapidly early in
the season with thickening occurring until mid-flowering. Lignification begins at
veraison and continues until berry maturity.
Reproductive Cycle and Yield Components
Reproductive development and yield formation in grapevines is a process that spans
two seasons. Inflorescence primordia are initiated in the buds that form in the axil
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