Plant Growth and Development Class 11 Biology Notes

Like animals, even plants experience growth and development. Be that as it may, not at all like animals which have a distinct lifespan, most plants can develop inconclusively. Growth is characterized as an irreversible change in physical structure. In plants, a blend of cell growth and cell division brings about a practically uncertain growth. This capacity is because of the nearness of tissues called meristems at specific pieces of the plant body. Plants total their vegetative phase to move into the conceptual phase in which flower and organic products are framed for the continuation of the life pattern of the plant. Development is the total of two procedures growth and separation. Intrinsic and extrinsic factors control the procedure of growth and development in plants. In this article, we will learn about the plant growth and development class 11 NCERT, take a look at the plant growth and development class 11 notes, and solve some MCQ on plant hormones.

Growth: Plant Growth is Generally Indeterminate 

Plants are known to hold the ability to develop inconclusively for an amazing duration, consequently, their growth is exceptional. This ability can be added to the nearness of meristems(possessing the ability to self-perpetuate and partition) at various areas in their body 

The root and shoot apical meristems are liable for the primary growth of the plants adding to the plant lengthening through the axis 

The horizontal meristems, vascular cambium, cork-cambium in gymnosperms and dicotyledonous plants show up later on. These meristems increment the bigness of dynamic structures bringing about the secondary growth of plants 

Growth: Growth is Measurable 

At the cellular level, it is the expansion in the measure of cellular material. Growth is estimated by an assortment of measurements, for example, increment in dry weight, fresh weight, area, volume, length, cell number. 

In certain plants, growth is communicated as an expansion in the cell number, increment in the cell size, while in some others, growth is estimated regarding the growth of dust tube, longwise, increment in surface area, etc. 

Growth: Phases Of Growth 

Growth period can be ordered into three phases – meristematic(root and shoot peak cells that are continually separating), prolongation (proximal cells to the meristematic region)and maturation(proximal cells to the lengthening phase cells) 

Growth Rate 

Growth rate is alluded to as the expanded growth per unit time. Elements can deliver cells from numerous points of view – number juggling, geometric. Quantitative likenesses or contrasts between the growth of living substances should be possible in two different ways – outright growth (measurement and examination of the absolute growth per unit time) and the relative growth rate which is the growth of the given system per unit time.

Differentiation, Dedifferentiation And Redifferentiation 

1. Differentiation: Cells from the root, shoot apical meristems and cambium separate and develop to complete various capacities. Here the cells experience some major basic changes both in cell dividers and cellular material 

2. Dedifferentiation: Separated cells, in the wake of losing the ability to isolate, recapture the limit of division in certain conditions. Model – cork cambium framing completely separated parenchyma cells. 

3. Redifferentiation: During dedifferentiation, meristems and tissues separate and produce cells again losing the ability to isolate, anyway develop to do explicit capacities. Model - woody tissues in dicotyledonous plants experience redifferentiation 

Plant Growth Regulators 

Plant growth regulators are basically hormones that control different capacities identified with the growth and development of the plant. They can be of two kinds, specifically

Growth Inhibitors 

1. Abscisic acid 

2. Salicylic acid 

3. Benzoic acid 

4. Coumarin 

Growth Promoters 

1. Auxins

2. Cytokinins  

3. Gibberellins 

Growth Inhibitors, as the name recommends, restrain the growth of plants and prompt lethargy. Growth Promoters advance flowering, the development of seeds, cell division and so on. 

Photoperiodism 

The reaction of plants to lengths of day/night is referred to as photoperiodism and flowering in certain plants depends on the blend of light and dark exposures and relative terms. Here, the site of the impression of light and dark lengths are leaves. 

Vernalisation 

Depending on presentation to bring down temperatures of flowering plants either subjectively or quantitatively is known as vernalisation. This procedure checks bright regenerative development at some point later in the developing season. Particularly, it very well may be alluded to the advancement of flowering by a span of low temperature.

MCQ on Plant Hormones

Plant hormones are otherwise called plant growth substances, plant growth regulators or phytohormones. Accordingly, different factors like nutrients, ecological conditions and so forth are likewise liable for growth. Auxins, cytokinin and gibberellins generally influence plant growth. Questions and replies on the plant hormones will be useful in the preparation of different tests yet additionally advise about the factors because of which plant growth is influenced.

1. Which of the Following Plant Hormone is Responsible for Saving the Crops from Falling?

A. Gibberellin

B. Cytokinin

C. Auxin

D. Ethylene

Ans. C

2. Which Amongst the Following Hormone is Found in the Gaseous Form?

A. Florigens

B. Auxin 

C. Ethylene

D. Abscisic Acid

Ans. C

3. Name the Plant Hormone That is Responsible for the Ripening of Fruits.

A. Ethylene

B. Traumatic 

C. Auxin

D. Cytokinins

Ans. A

4. Which of the Following Plant Hormone is Used in Making Rna and Protein?

A. Gibberellins

B. Ethylene

C. Cytokinins

D. Auxin

Ans. C

5. Which of the Following Given Statement is False?

A. Auxins are the most important plant hormone.

B. Auxins are generated at the region of the elongation.

C. Auxins are also important in regulating the fall of leaves and fruits.

D. Indoleacetic Acid (IAA) is a principal auxin.

Ans. B

6. Which Plant Hormone Helps to Break the Dormancy of Plants?

A. Cytokinin

B. Gibberellin

C. Auxin 

D. Ethylene

Ans. B

7. Which Hormone is Formed in the Leaves and Helps in the Blooming of Flowers?

A. Auxin

B. Traumatic 

C. Florigens

D. None of the above

Ans. C

8. Which Plant Hormone is Formed in the Injured Cells Due to Which the Injury of the Plant is Healed?

A. Abscisic Acid

B. Traumatic

C. Florigens

D. None of the above

Ans. B

9. Which of the Following Hormone Help With the Cell Division and the Development in the Presence of Auxins?

A. Auxins

B. Cytokinins

C. Ethylene

D. Florigens

Ans. B

10. Name the Plant Hormone That Increases the Activity of the Cambium in the Wooden Plants

A. Gibberellins

B. Auxins 

C .Cytokinins

D. Ethylene

Ans. A