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CBSE Class 11 · Biology

Plant Growth and Development

Official NCERT chapter from Biology (book code kebo1). ExamMaster notes are original teaching at CBSE Class 11 depth.

This lesson follows the official chapter “Plant Growth and Development” in Biology. The words below are ExamMaster’s teaching, not a paste from the book. Use the NCERT chapter for the classroom sequence; use these notes to hold the idea without copying exercises or figures.

  • CBSE Class 11
  • Medium level
  • 8 concepts

1Growth

Growth (school): an irreversible increase in size as taught — cell divide plus enlarge. A measure can be length, area, or dry mass as named. Growth is a measure-word, not a mood. Meristem as the divide-place if taught.

A wilt-and-recover as “growth” is a reversible look — not this heading.

Figure. A sigmoid: slow lag, steep log rise, then a plateau. Size is not a straight line.

How it works

  1. Name irreversible size-upGrowth.
  2. Pick a measure (length, dry mass, …)The look.
  3. Keep meristem as the divide-place if askedWhere.

2Differentiation, Dedifferentiation and Redifferentiation

Differentiation: a cell takes a job-look (pipe, cover) as taught. Dedifferentiation: a job-cell can restart divide (cork cambium as framed). Redifferentiation: it takes a new job again. Three words, three job-stories — not synonyms.

Calling every change “growth” hides the three words.

Figure. Differentiation is a new job. Dedifferentiation returns a cell to meristem; redifferentiation gives it a new job.

How it works

  1. Name take-a-job, restart-divide, or take-a-new-jobThe three.
  2. Keep one school case (cambium if taught)The example.
  3. Refuse one sticker for all threeDifferent words.

3Development

Development: growth plus differentiation toward a form as taught — seed to plant. Development is the whole path, not a single length-up. One path-sentence is enough.

A single day’s length as the whole development is a skip.

Figure. Development is growth plus new jobs. A bigger organ that kept the same job is growth only.

How it works

  1. Name growth + job-taking toward a formDevelopment.
  2. Keep seed-to-plant as the path-hintThe case.
  3. Refuse a one-day stretch as the whole wordA path.

4Plant Growth Regulators

Plant growth regulators: auxin, gibberellin, cytokinin, ethylene, ABA as taught — chemical signals. A regulator is a tiny-message, not a food. One job each if listed (lengthen, ripen, close-stoma as framed).

Watering as “adding auxin” is a miss.

Figure. IAA, CK and GA promote. ABA stops. Ethylene (C2H4) ripens and senesces. A regulator is a named job, not a food.

How it works

  1. Name the regulator-familyThe signal.
  2. Attach one taught jobThe use.
  3. Refuse a food-swapA message.

5Photoperiodism

Photoperiodism: day-length as a flower-cue as taught — short-day, long-day, day-neutral if split. Photoperiod is a clock-look, not “more sun = more food” (that was photosynthesis). One named plant if the lesson used one.

A shade as “short-day” without a length-of-night story may be a skip.

Figure. A short-day plant flowers when the night is the long bar. A short night leaves it vegetative. Night length is the test.

How it works

  1. Name day-length as the flower-cuePhotoperiodism.
  2. Split short / long / neutral if askedThe sort.
  3. Keep food-make as a different chapterA clock, not a meal.

6Vernalisation

Vernalisation: a cold-spell as a flower-cue as taught. Vernalisation is a winter-clock, not a freeze-damage. One cereal or a named biennial if the lesson used it.

Any chill as vernalisation without the flower-cue is a miss.

Figure. Vernalisation is a cold stretch that unlocks flowering. Skip the cold and the plant stays leafy.

How it works

  1. Name a taught cold-spell that cues flowerVernalisation.
  2. Keep damage-frost out of the testA cue, not an injury.
  3. Refuse day-length as this headingThat was photoperiod.

7A regulator is a signal, not a food

A regulator is a signal, not a food: a tiny amount turns a job on or off as taught. Sugar is a food; auxin is a message. Mixing the two words is the leftover this heading names.

A fertiliser-bag labelled “hormone food” is the mash.

Figure. Food adds mass. A regulator is a small switch. More hormone is not more dinner.

How it works

  1. Keep regulator as messageThe signal.
  2. Keep sugar/mineral as food or rawThe other word.
  3. Refuse a food-slogan as the regulatorTwo jobs.

8Keep the claim at this class

Keep the claim at this class: named regulators, day-length, a cold-cue. It is not a farm-manual and not a research paper on every mutant.

A spray-recipe is the wrong size.

Figure. Hold the school tests: sigmoid phases, PGR jobs, night length, and cold. Extra contest lists wait.

How it works

  1. Stay on the named cues and signalsThis class.
  2. Keep one plant-case if neededEnough.
  3. Refuse a how-to spray-listThe claim-size.
Auxin here is
  1. A growth-regulator — a signal, not a food
  2. A polysaccharide meal
  3. A frog organ

A message.

Notes

  • Mapped to the official NCERT chapter “Plant Growth and Development”. Original teaching only — no textbook sentences.
  • Science here is Physics, Chemistry and Biology ideas at this class, never a language or social-science chapter.

Recap

Hold these pegs from the official chapter “Plant Growth and Development”. The wording is ExamMaster’s teaching, not a textbook recap.

Growth
Growth (school): an irreversible increase in size as taught — cell divide plus enlarge.
Differentiation, Dedifferentiation and Redifferentiation
Differentiation: a cell takes a job-look (pipe, cover) as taught.
Development
Development: growth plus differentiation toward a form as taught — seed to plant.
Plant Growth Regulators
Plant growth regulators: auxin, gibberellin, cytokinin, ethylene, ABA as taught — chemical signals.
Photoperiodism
Photoperiodism: day-length as a flower-cue as taught — short-day, long-day, day-neutral if split.
Vernalisation
Vernalisation: a cold-spell as a flower-cue as taught.

Practise Plant Growth and Development

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