A basic understanding of some major plant processes will
help growers understand why specific problems occur and what
changes should be made to prevent them from arising. Firstly however
a basic understanding of some major plant components is required.
V
ascular system
This
is the plants 'plumbing' system. It is broken into 2 distinct sections.
1)
Phloem
is responsible for:
- Carrying sugar to specific areas in the plant for respiration (i.e. to
produce energy) or for storage as starch until required.
- Carrying starches after dormancy (i.e. in spring) that were stored in
roots / stems.
- Carrying growth regulators and systemic agents.
2)
Xylem
is used to carry water, nutrients and oxygen from the roots to the rest of
the plant.
Roots
Roots
facilitate the uptake of water, oxygen and nutrients.
Root hairs are responsible for the majority of uptake. Root hairs are
alive for just a few days and cover about l cm of a roots overall length
at any given time. Root hairs are located close to the growing tip of each
root. Therefore if new root growth is limited then oxygen, water and
nutrient uptake will be restricted.
Leaves
'Parenchyma' cells are cells that photosynthesise and are concentrated on
the upper surface of the leaf.
'Stomata'
are valves concentrated on the lower side of the leaf. Through these pass
carbon dioxide (required for photosynthesis), water vapour and oxygen
(by-products of photosynthesis), water and carbon dioxide (by-products of
respiration), foliar sprays etc.
Within the leaf are vascular structures for carrying water and nutrients
to the leaf cells and for taking sugars away.
