Class 11 Biology - BIHAR
Plant Growth and Development
The chapter 'Plant Growth and Development' in Class 11 Biology explores how plants grow, differentiate, and respond to internal and external stimuli throughout their life cycle. For Bihar School Examination Board (BSEB) students, this chapter is crucial as it forms the physiological foundation of plant biology. It covers fundamental concepts like indeterminate growth, plant growth regulators (auxins, gibberellins, cytokinins, ethylene, and ABA), photoperiodism, and seed dormancy. Mastering these topics is essential for scoring high in board exams, particularly in questions related to plant hormones and physiological experiments.
Start Learning FreeKey Concepts
Plant Growth
An irreversible, permanent increase in size of an organ or its parts, accompanied by an increase in dry weight and metabolic processes.
Differentiation, Dedifferentiation, and Redifferentiation
Differentiation is when cells mature to perform specific functions; dedifferentiation is when mature cells regain capacity to divide (like interfascicular cambium); redifferentiation is when these divided cells lose division capacity again.
Plant Growth Regulators (PGRs)
Small, simple molecules of diverse chemical composition (auxins, gibberellins, cytokinins, ethylene, abscisic acid) that regulate plant growth and development.
Photoperiodism
The physiological response of plants to the relative lengths of light and dark periods (photoperiods) for flowering.
Vernalisation
Dependence of flowering either quantitatively or qualitatively on low-temperature exposure.
Important Formulas
Board Exam Info
In the Bihar (BSEB) Class 11 Biology examination, this chapter typically carries around 5 to 7 marks. Questions usually include short-answer questions defining PGRs or photoperiodism, long-answer descriptive questions on the discovery and physiological effects of plant hormones, and objective multiple-choice questions.
Frequently Asked Questions
What is the difference between short-day plants and long-day plants?
Short-day plants (SDP) require a light period below a critical length to flower, while long-day plants (LDP) require light periods above a critical threshold.
Which plant hormone is known as the stress hormone?
Abscisic Acid (ABA) is called the stress hormone because it increases plant tolerance to various kinds of stress, especially drought.
Why is plant growth said to be indeterminate?
Plant growth is indeterminate because plants retain the capacity for unlimited growth throughout their life due to the presence of meristems at certain locations.
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