CHAPTER 7
Coordination in Plants
The control and coordination in plants takes place with the help of plant harmones
There are two type of movement in plants.
a. Independent of growth
b. Dependent of growth
Independent of growth
Example - Drooping of leaves of "Touch-me-not" plant on touching it.
-Independent growth has immediate response to the stimulus.
-Plant use electrical chemical means to convey information from cell to cell.
-For movement to happen, cells change their shape by changing the amount of water in them, resulting in swelling or shrinking of cells.
Dependent on growth
These movements are tropic movements i.e, directional movements in response to stimulus.
Tendrils- The part of tendril away from the object grows more rapidly as compared to the part near the object. This Causes circulations of tendril aroung the object.
(1) Phototropism - Movements towards light
(2) Geotropism - Movements towards gravity
(3) Chemotropism - Growth of pollen tube towards ovule
(4) Movement towards water.
Harmone- A chemical substance which help in the control and coordination in animals and plants.
Plant Harmone
1. Auxin - This hormone synthesized at shoot tiphelps the cells to grow longer and involved in phototropism
2. Gibberellin - It helps in the growth of the stem, fruit.
3. Cytokimims - It promotes cell division.
- This is present in greater concentration in fruits and seeds.
4. Abscisic acid - It inhibits growth.
- It also cause witting if leaves and known as stress harmone.
- It regulate the loss of water.
Hormones in Animals
Thyroxine
This hormone is secreated by Thyroid. The Thyroid is located in Neck/Throat region. It regulate th metabolism of carbohydrates, fats and proteins. It provide the best balance for growth.
Growth Hormone
Growth hormone is that hormone which is secreted by pituitary gland(Master gland). This gland is located in mid-brain. It regulate the growth and development The deficiency of this hjormone causes dwarfism.
Adernaline
Adrenaline is secreted by Adrenal gland, The adrenal glands is located above both kidneys. It regulate the blood pressure, heart beat, carbohydrates metabolism.
Insulin
This hormone is secreted by pancreas. The pancreas is located below stomach. It reduce and regulates blood sugar level.
Importance of Iodine
Iodised salt is necessary because iodine mineral is essential part of thyroxine hormone secreted by thyroid gland.
Thyroxine regulates metabolism of carbohydrates, fats and proteins. So, we must consume iodised salt which is necessary for proper working of thyroidgland. It's deficiency causes a disease called goitre(swollen back).
Diabetes
Diabetes is a disease in which blood sugar level increases.
Causes of Diabetes
The disease is caused due to the deficiency of insulin hormone secreted by pancreas that is responsible to control blood sugar levels.
Treatment of Diabetes
Injections of Insulin hormone can help in the treatment of diabetes.
0 Comments