Students can go through AP Inter 2nd Year Botany Notes 6th Lesson Plant Growth and Development will help students in revising the entire concepts quickly.
AP Inter 2nd Year Botany Notes 6th Lesson Plant Growth and Development
→ Growth is one of the most conspicuous events in any living organism. It is an irreversible increase in size, area, length height, volume etc.,
→ Meristems are the sites of Growth.
→ Root, Shoot apical meristems, Intercalary Meristems contribute to the longitudinal growth of plant axis.
→ Growth can be arithmetic or geometrical.
→ Growth Involves three phases, the lag, the log and the senescent phase.
→ When a cell looses capacity to divide leads to differentiation.
→ The development is the Sun of Growth differentiation.
→ Plants exhibit plasticity in development.
→ Plant Growth and development are under the control of both Intrinsic and extrinsic factors.
→ Intrinsic factors are called Plant Growth Regulators.
→ They are Auxins, Gibberellins, Cytokinins, Absicic acid and Ethylene.
→ Plant growth and development is also affected by light, temperature, nutrition, oxygen status, gravity etc.,
→ Auxin was Isolated by F.W. Went from the tips of colebptiles of oat seedlings.
→ The bakane. disease of rice seedlings is caused by a fungus, Gibberella fujikuroi.
→ Skoog and Miller later Identified and crystallised the cytokinesis promoting active substance that they termed kinetin.
→ A B A is a natural anti transplant.
→ Ethylene is a gaseous PGR.
→ IAA, IBA are natural auxins.
→ NAA, 2, 4-D are synthetic auxins.
→ The seed when it is unable to Germinate because favourable external conditions normally required for growth is called quiescence.
→ The seed when it fails to germinate because of internal conditions even though the external conditions are suitable is called dormancy.
→ The flowering response of plants to periods of day/night is termed as photoperiodism.
→ Some plants require the exposure to light for a period exceeding a well defined critical duration are called long day plants.
→ Some plants must be exposed to light for a period less than critical duration before flowering are called short day plants.
→ Some plants do not require exposure to light duration and induction of flowering are called day neutral plants.
→ Method of inducing flowering in plants by pre-chilling treatment is called vernalisation.