Mechanism Of Transportation In Lower And Higher Plant
In a simple plant like alga, bryophyte and Thallophyte materials into the cell of the body by diffusion. Within the cell materials are distributed by circulating streaming movement of the cytoplasm..
In higher land plants, special conducting tissues known as vascular tissues carry out transportation. This vascular plants include all flowering plants and non-flowering plants such as ferns and gymnosperms. Many of these plant have additional system of latex tube. A vascular bundle or tissue consist of the xylem and the phloem tissue.
PROCESSES WHICH AID TRANSPORTATION IN PLANT
The major materials being transported within the plant are gases which is carbon (IV) oxide and oxygen, water, mineral salt, manufactured food, hormones and pigment.
Absorption Of Water And Mineral Salt
Absorption of soil water into plant is through the root hairs. Root hairs absorb water from the soil by osmosis. The cell sap within the root hair is a mineral solution in higher concentration than the external soil solution. Water enters the root hair cell form the soil with the cell membrane acting as a selectively permeable membrane. The extra water taken into the cell, dilute the sap, so that it becomes less concentrated than the sap of the neighboring cell in the root cortex and therefore the water passes into the neighboring cell by osmosis and again dilutes it’s sap. This process is repeated endlessly from cell to cell until the water eventually reaches the xylem vessel in the centre of the root. Some water also reaches the xylem vessel through the cell and cytoplasm by diffusion and capillarity.
ACTIVE TRANSPORT
Active transport is the transport/ transfer of heavy metallic ion, such as heavy minerals e.g. iron and copper from the soil into the plant. This process involves expenditure of energy and against osmotic gradient. It has been determined, that this energy comes from respiration. It has been experimentally supported that the uptake of mineral is greater when the root are supplied with adequate oxygen.
Water Transport In Xylem
If herbaceous plant such as sunflower is uprooted carefully and washed clean in water, then place in a beaker containing a dilute solution of EOSIN. It will be seen that the red liquid passes through the xylem tissue only. This can be seen by examining the transverse section of the root, stem and leaf. Transport of water through the xylem tissue is brought about by the combination of:
- I) Root pressure
- II) Capillarity
III) Transportation pull
TRANSPIRATION: – Is the loss of water vapour from difference part of the plant shoot into the atmosphere. These part include the stomata of leaves, the cuticles of both leaf and young stem and the lenticel of the tree truck.Water loss through the stomata is called stomata transpiration while water loss through the cuticle and lenticel are called cuticular or lenticular transpiration.
Factors Affecting The Rate of Transportation
- Plant factor
- Atmospheric factor
- Soil factor
Plant factor
- Leaf area
- Leaf structure
- Root system
Atmosphere factor
- Sunlight
- Humidity
- Temperature
- Wind
Soil Factor
- Availability of soil water
- Temperature
Importance Of Transpiration
- Cooling effect: – It brings about cooling effect
- It enhances translocation of mineral salt
- It enhances growth of plants
GUTTATION: – Is the loss of water in liquid form through the margins of the leaves of plants growing in a warm or moist soil in a humid atmosphere. Guttation is usually experienced at the early hours of the morning and is common among grasses. Such plants have specialized duct at the tip of the vein in the leaves. These special ducts are known as HYDATHODES.
TRANSLOCATION: –
Is the transport of manufactured food substances from the leaf to all other parts of the plant. The movement is usually described as downward from the leaf to the root but it is also know to occur on the reverse direction especially in the non-growing season. Translocatiosn takes place through the phloem tissues.
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