This category explains how plants respond to environmental cues like day length (photoperiodism) and cold exposure (vernalisation) to regulate growth and flowering. It includes explanations and practice questions to help understand these developmental processes.
Heterophylly, as seen in coriander, is a form of developmental plasticity where different types of leaves are formed during different stages.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
The log (exponential) phase of the sigmoid growth curve represents rapid cell division and maximum growth rate.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Plant growth is irreversible and results from cell division and enlargement. Primary growth increases length, while secondary growth increases thickness and is common in dicots, not monocots.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Geometric growth, which includes lag, log, and stationary phases, produces an S-shaped (sigmoid) curve.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
In geometric growth, both daughter cells retain the ability to divide, leading to exponential growth.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Arithmetic growth results in a linear curve, as one daughter cell divides while the other differentiates.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Abscisic acid (ABA) inhibits seed germination by inducing dormancy. Gibberellins promote germination by breaking down starch into sugars.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Abscisic acid (ABA) is a stress hormone that induces stomatal closure to reduce water loss during drought. It promotes dormancy, not germination.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Developmental heterophylly occurs in cotton, where leaves show different shapes during juvenile and mature stages.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
Mitosis occurs in the root apical meristem, producing genetically identical daughter cells for growth.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
The stationary phase is represented by a plateau in the sigmoid growth curve, where the growth rate stabilizes.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
In geometric growth, plotting growth against time results in an exponential curve during the log phase.
Ref: NCERT Class 11 Biology Chapter 13: Plant Growth and Development Photoperiodism Vernalisation and Development
