Biology · Class 11 · Chapter 13
Plant Growth and Development
13 lessons 95 min 2 simulations
A seed becomes a seedling, the seedling becomes a plant, and the plant keeps adding length and girth for as long as it lives. This chapter asks how that growth is measured and plotted, how new cells take on their final form, why the same plant can make differently shaped leaves, and how five small chemical messengers, the plant growth regulators, switch growth on and off.
What the exam asks
NEET tests the three phases of growth, the two growth equations (Lt = L0 + rt and W1 = W0 e^rt), the sigmoid curve, absolute against relative growth rate, the dedifferentiation examples, and above all the discoverers and uses of the five PGRs. Marks are lost by mixing up which regulator does what: auxin for rooting and apical dominance, gibberellin for bolting and stem length, cytokinin for overcoming apical dominance and delaying senescence, ethylene for ripening, and ABA for stomatal closure and dormancy.
Lessons
13 lessons · 95 min
1Growth and why it never stops in plantsNCERT §13 (opening text) and §13.1–§13.1.16 min2Measuring growthNCERT §13.1.26 min3Phases of growthNCERT §13.1.36 min4Arithmetic and geometric growthNCERT §13.1.410 min 1 sim5Absolute and relative growth rateNCERT §13.1.46 min6Conditions for growthNCERT §13.1.56 min7Differentiation, dedifferentiation and redifferentiationNCERT §13.26 min8Development and plasticityNCERT §13.35 min9Plant growth regulators and their discoveryNCERT §13.4.1–§13.4.28 min10AuxinsNCERT §13.4.3.110 min 1 sim11Gibberellins and cytokininsNCERT §13.4.3.2–§13.4.3.37 min12Ethylene and abscisic acidNCERT §13.4.3.4–§13.4.3.58 min13Chapter reviewMust-know facts, traps and formulas11 min