The challenges of size in plants - OCR GatewayPlant organisation
During transpiration plants move water from the roots to their leaves for photosynthesis in xylem vessels. Glucose made in photosynthesis is then moved to all cells in phloem vessels for respiration.
The main roles of plant stems and roots are to transport substances around the plant. They have two types of transport systems – xylem vesselsNarrow, hollow, dead tubes with lignin, responsible for the transport of water and minerals in plants. and phloemThe tissue in plants that transports the products of photosynthesis, including sugars and amino acids.. Xylem transports water and minerals. Phloem transports sugars and amino acidThe building blocks that make up a protein molecule. dissolved in water.
These are distributed differently in roots and stems. In the root, the xylem forms a central column. It forms a solid support. The phloem is towards the centre, outside the xylem.
In the stem, the transport tissueTypes of tissue that transport water and nutrients. of the xylem and phloem are grouped into vascular bundlesGroups of xylem and phloem tissue in a plant..
Any green part of a plant above ground, where it is exposed to light, can photosynthesise. But a plant’s leaves are the main organ of photosynthesis.
Plant leaves are adapted for gas exchange and photosynthesis.
Feature
Function
Large surface area
For maximum absorption of light. For optimum absorption of carbon dioxide.
A thin, flattened blade - though there are exceptions
So that water and gases have a limited distance to diffuse.
Vascular tissue in the midrib and veins
Branches of the xylem, to transport water and minerals to the leaf. Branches of the phloem. To transport glucose and other products of photosynthesis to other parts of the plant.
Air spaces between cells within the leaf
For the diffusion of gases.
Feature
Large surface area
Function
For maximum absorption of light. For optimum absorption of carbon dioxide.
Feature
A thin, flattened blade - though there are exceptions
Function
So that water and gases have a limited distance to diffuse.
Feature
Vascular tissue in the midrib and veins
Function
Branches of the xylem, to transport water and minerals to the leaf. Branches of the phloem. To transport glucose and other products of photosynthesis to other parts of the plant.
Feature
Air spaces between cells within the leaf
Function
For the diffusion of gases.
Learn more about plant organisation with Dr Alex Lathbridge.