Biology Booster: Plant Growth - NEET PDF Download

 Page 1


 
 
 
 
Biology Booster Dose for NEET 
 
Chapter- Plant Growth And Development  
 
 
Plant Growth  
1. Growth  An irreversible permanent increase in size of an organ or its parts 
or even of an individual cell. 
2. Plants can grow 
throughout their life  
Due to presence of Meristematic tissues (e capacity to divide and 
self-perpetuate) 
3. Open form of growth New cells always added 
4. Plant growth is 
localized 
Occur at only in the meristematic region, Apical meristem-length 
inc., intercalary meristem – Girth increase 
also called secondary growth. 
 
 
Measurement of Growth and Phases 
1. Measurement of 
Growth  
Occur by cell division and elongation which is difficult to measure 
so other method Increase in size, length(root or stem), surface 
area(leaf) weight(fruit) Auxanometer- measure length 
2. Phases of Growth Meristematic- dense cytoplasm, small size, cell wall primary 
multiple plasmodesmatal connection, vacuole absent 
Elongation phase- cell size inc, inc in protoplasm, Deposition in 
cell wall 
Maturation – size fix, vacuole maximum size, role fix, some cells 
like vessels mature by getting dead  
 
 
 
Page 2


 
 
 
 
Biology Booster Dose for NEET 
 
Chapter- Plant Growth And Development  
 
 
Plant Growth  
1. Growth  An irreversible permanent increase in size of an organ or its parts 
or even of an individual cell. 
2. Plants can grow 
throughout their life  
Due to presence of Meristematic tissues (e capacity to divide and 
self-perpetuate) 
3. Open form of growth New cells always added 
4. Plant growth is 
localized 
Occur at only in the meristematic region, Apical meristem-length 
inc., intercalary meristem – Girth increase 
also called secondary growth. 
 
 
Measurement of Growth and Phases 
1. Measurement of 
Growth  
Occur by cell division and elongation which is difficult to measure 
so other method Increase in size, length(root or stem), surface 
area(leaf) weight(fruit) Auxanometer- measure length 
2. Phases of Growth Meristematic- dense cytoplasm, small size, cell wall primary 
multiple plasmodesmatal connection, vacuole absent 
Elongation phase- cell size inc, inc in protoplasm, Deposition in 
cell wall 
Maturation – size fix, vacuole maximum size, role fix, some cells 
like vessels mature by getting dead  
 
 
 
 
 
 
Growth Rate 
Type of growth 
rate  
Arithmetic Geometric  
Out of two 
daughter cell  
One cell continue to 
divide 
Both cell continue to divide 
Equation  LT = L0 + rt (r- Arithmetic 
growth rate) 
Wt = Wo e 
rt (r- Geometric growth rate or efficiency index 
Curve shape Straight line Sigmoid- lag phase-initial part, than log phase 
rapid growth and stationary phase- resources 
limited 
Example  Length of stem Most plant tissue or organ  
 
Initial area leaf Final area Absolute growth Relative growth 
Leaf A=5cm² 10 cm² Final -initial = 10-5 = 5 cm² Final-initial/initial = 10-5/5 = 100 % 
Leaf B= 50 cm² 55 cm² 55-50= 5 cm² 55-50/50 = 10 %  
 
Observation -Two leaf -different initial area can have same absolute growth and different 
relative growth 
Conditions for growth- (A) Water -for enzyme activity and cell turgidity (B) Oxygen- energy 
produced for aerobic respiration (C) Nutrients (D) light and gravity act as signal  
 
Types of Tissues 
Tissue or Cell  Undergo process To Form 
Primary meristem 
Apical meristem 
Intercalary meristem 
Differentiation (meristem to 
permanent) 
Primary tissue Epidermis, cortex, 
pith, primary xylem, primary 
phloem 
Permanent tissue 
Medullary rays 
Cortex 
Dedifferentiation(permanent 
cell again become dividing) 
Medullary rays give intrafascicular 
cambium and cortex give cork 
cambium 
both secondary meristem  
Page 3


 
 
 
 
Biology Booster Dose for NEET 
 
Chapter- Plant Growth And Development  
 
 
Plant Growth  
1. Growth  An irreversible permanent increase in size of an organ or its parts 
or even of an individual cell. 
2. Plants can grow 
throughout their life  
Due to presence of Meristematic tissues (e capacity to divide and 
self-perpetuate) 
3. Open form of growth New cells always added 
4. Plant growth is 
localized 
Occur at only in the meristematic region, Apical meristem-length 
inc., intercalary meristem – Girth increase 
also called secondary growth. 
 
 
Measurement of Growth and Phases 
1. Measurement of 
Growth  
Occur by cell division and elongation which is difficult to measure 
so other method Increase in size, length(root or stem), surface 
area(leaf) weight(fruit) Auxanometer- measure length 
2. Phases of Growth Meristematic- dense cytoplasm, small size, cell wall primary 
multiple plasmodesmatal connection, vacuole absent 
Elongation phase- cell size inc, inc in protoplasm, Deposition in 
cell wall 
Maturation – size fix, vacuole maximum size, role fix, some cells 
like vessels mature by getting dead  
 
 
 
 
 
 
Growth Rate 
Type of growth 
rate  
Arithmetic Geometric  
Out of two 
daughter cell  
One cell continue to 
divide 
Both cell continue to divide 
Equation  LT = L0 + rt (r- Arithmetic 
growth rate) 
Wt = Wo e 
rt (r- Geometric growth rate or efficiency index 
Curve shape Straight line Sigmoid- lag phase-initial part, than log phase 
rapid growth and stationary phase- resources 
limited 
Example  Length of stem Most plant tissue or organ  
 
Initial area leaf Final area Absolute growth Relative growth 
Leaf A=5cm² 10 cm² Final -initial = 10-5 = 5 cm² Final-initial/initial = 10-5/5 = 100 % 
Leaf B= 50 cm² 55 cm² 55-50= 5 cm² 55-50/50 = 10 %  
 
Observation -Two leaf -different initial area can have same absolute growth and different 
relative growth 
Conditions for growth- (A) Water -for enzyme activity and cell turgidity (B) Oxygen- energy 
produced for aerobic respiration (C) Nutrients (D) light and gravity act as signal  
 
Types of Tissues 
Tissue or Cell  Undergo process To Form 
Primary meristem 
Apical meristem 
Intercalary meristem 
Differentiation (meristem to 
permanent) 
Primary tissue Epidermis, cortex, 
pith, primary xylem, primary 
phloem 
Permanent tissue 
Medullary rays 
Cortex 
Dedifferentiation(permanent 
cell again become dividing) 
Medullary rays give intrafascicular 
cambium and cortex give cork 
cambium 
both secondary meristem  
 
 
 
Vascular cambium 
Cork cambium  
Redifferentiation (secondary 
meristem to secondary 
tissue) 
Secondary xylem + secondary 
phloem Phelloderm-Sec cortex+ 
phellem- cork  
 
Overall Developmental process for: 
a) Cell  
 Cell division + plasmatic growth + maturation + death 
 
b) Seed 
Seed- seed germination + Growth + Flowering + fruit and seed + senescence  
 
Plasticity  
plant follow different pathway in response of environment known as Plasticity example is -
Heterophylly (Developmental- cotton, coriander and larkspur and Environmental – Buttercup  
 
Factors control plant Growth and development  
External (oxygen, water, nutrients, light) 
Internal – Intercellular factor -Hormones, Intracellular (Genes)  
 
Plant Hormones   
phytohormones,plant growth regulator -PGRs (PGP-plant growth promoter) 
1. Auxin 
2. Cytokinin 
3. Gibberellin  
4. PGI (plant growth inhibitor- Abscisic acid)  
5. Ethylene is both PGP and PGI but more PGI. 
 
 
 
 
Page 4


 
 
 
 
Biology Booster Dose for NEET 
 
Chapter- Plant Growth And Development  
 
 
Plant Growth  
1. Growth  An irreversible permanent increase in size of an organ or its parts 
or even of an individual cell. 
2. Plants can grow 
throughout their life  
Due to presence of Meristematic tissues (e capacity to divide and 
self-perpetuate) 
3. Open form of growth New cells always added 
4. Plant growth is 
localized 
Occur at only in the meristematic region, Apical meristem-length 
inc., intercalary meristem – Girth increase 
also called secondary growth. 
 
 
Measurement of Growth and Phases 
1. Measurement of 
Growth  
Occur by cell division and elongation which is difficult to measure 
so other method Increase in size, length(root or stem), surface 
area(leaf) weight(fruit) Auxanometer- measure length 
2. Phases of Growth Meristematic- dense cytoplasm, small size, cell wall primary 
multiple plasmodesmatal connection, vacuole absent 
Elongation phase- cell size inc, inc in protoplasm, Deposition in 
cell wall 
Maturation – size fix, vacuole maximum size, role fix, some cells 
like vessels mature by getting dead  
 
 
 
 
 
 
Growth Rate 
Type of growth 
rate  
Arithmetic Geometric  
Out of two 
daughter cell  
One cell continue to 
divide 
Both cell continue to divide 
Equation  LT = L0 + rt (r- Arithmetic 
growth rate) 
Wt = Wo e 
rt (r- Geometric growth rate or efficiency index 
Curve shape Straight line Sigmoid- lag phase-initial part, than log phase 
rapid growth and stationary phase- resources 
limited 
Example  Length of stem Most plant tissue or organ  
 
Initial area leaf Final area Absolute growth Relative growth 
Leaf A=5cm² 10 cm² Final -initial = 10-5 = 5 cm² Final-initial/initial = 10-5/5 = 100 % 
Leaf B= 50 cm² 55 cm² 55-50= 5 cm² 55-50/50 = 10 %  
 
Observation -Two leaf -different initial area can have same absolute growth and different 
relative growth 
Conditions for growth- (A) Water -for enzyme activity and cell turgidity (B) Oxygen- energy 
produced for aerobic respiration (C) Nutrients (D) light and gravity act as signal  
 
Types of Tissues 
Tissue or Cell  Undergo process To Form 
Primary meristem 
Apical meristem 
Intercalary meristem 
Differentiation (meristem to 
permanent) 
Primary tissue Epidermis, cortex, 
pith, primary xylem, primary 
phloem 
Permanent tissue 
Medullary rays 
Cortex 
Dedifferentiation(permanent 
cell again become dividing) 
Medullary rays give intrafascicular 
cambium and cortex give cork 
cambium 
both secondary meristem  
 
 
 
Vascular cambium 
Cork cambium  
Redifferentiation (secondary 
meristem to secondary 
tissue) 
Secondary xylem + secondary 
phloem Phelloderm-Sec cortex+ 
phellem- cork  
 
Overall Developmental process for: 
a) Cell  
 Cell division + plasmatic growth + maturation + death 
 
b) Seed 
Seed- seed germination + Growth + Flowering + fruit and seed + senescence  
 
Plasticity  
plant follow different pathway in response of environment known as Plasticity example is -
Heterophylly (Developmental- cotton, coriander and larkspur and Environmental – Buttercup  
 
Factors control plant Growth and development  
External (oxygen, water, nutrients, light) 
Internal – Intercellular factor -Hormones, Intracellular (Genes)  
 
Plant Hormones   
phytohormones,plant growth regulator -PGRs (PGP-plant growth promoter) 
1. Auxin 
2. Cytokinin 
3. Gibberellin  
4. PGI (plant growth inhibitor- Abscisic acid)  
5. Ethylene is both PGP and PGI but more PGI. 
 
 
 
 
 
 
 
PGPs 
Hormone Auxin Gibberellic acid Cytokinin 
Discovery  Francis Darwin and Charles  
Darwin - canary grass- tip 
produce auxin 
F.W went – Auxin isolated 
From tip of avena coleoptile on 
Agar 
Kogl and smith – isolated 
from Human urine  
E.Kurosawa- 1926- 
Bakane (foolish 
seedling) disease on 
rice – due to fungus 
GIbberella fujikuroi 
Sterile filtrate give 
symptom-increase 
length of stem 
F. Skoog and his 
coworkers - 
yeast extract, 
coconut water and 
Vascular tissue 
promote callus 
formation  
 
Bioassay Avena coleoptile curvature test Barley endosperm 
Genetic dwarfism 
overcome bioassay 
Delay in leaf 
(Richmond lang effect) 
Site of 
Synthesis  
Stem and branch tip, root tip in 
area which is not in light  
Nodes and seed Area with Cell division 
cambium, apical 
meristem, young fruit  
Example  Natural- IAA-indole acetic acid 
IBA- indole butyric acid 
Synthetic- 2,4-D -2,4 
dichloroacetic acid, 
Naphthalene acetic acid 
GA1, GA2 ……….. 
GA100 
From -fungi and higher 
plants 
GA3 – First discovered 
GA 
First discovered 
Kinetin-from herring 
fish Zeatin- from plant 
maize and coconut  
Precursor Tryptophan amino acid Diterpenoids Amino purine 
Role  1. rooting in Stem cutting 
2. Parthenocarpy 
3. Promote abscission in old 
leaf and fruit and prevent 
abscission in young leaf and 
fruit 
4. Apical dominance (tip 
removal promote branching -
tea plantation and hedge 
making 
5. Flowering in Pineapple 
6. Xylem differentiation 
7. Act as weedicide against 
dicot Ex.2,4-D  
 
1. Increase axis of 
grapes 
2. Improve shape and 
size of apple 
3. Hastens or fastens 
juvenile phase in 
conifers 
4. Promote malting- 
barley seed-help in 
brewing 
5. Increase ripening 
period of fruit on tree 
6. Increase internode 
length in sugarcane 
7. Promote bolting 
internodal elongation 
prior to flowering 
1. cell division 
2. chloroplasts division 
3. New leaves 
formation 
4. Adventitious bud 
5. lateral shoot 
6. Overcome apical 
dominance 
7. Nutrient 
mobilization to 
overcome seed 
dormancy  
 
Page 5


 
 
 
 
Biology Booster Dose for NEET 
 
Chapter- Plant Growth And Development  
 
 
Plant Growth  
1. Growth  An irreversible permanent increase in size of an organ or its parts 
or even of an individual cell. 
2. Plants can grow 
throughout their life  
Due to presence of Meristematic tissues (e capacity to divide and 
self-perpetuate) 
3. Open form of growth New cells always added 
4. Plant growth is 
localized 
Occur at only in the meristematic region, Apical meristem-length 
inc., intercalary meristem – Girth increase 
also called secondary growth. 
 
 
Measurement of Growth and Phases 
1. Measurement of 
Growth  
Occur by cell division and elongation which is difficult to measure 
so other method Increase in size, length(root or stem), surface 
area(leaf) weight(fruit) Auxanometer- measure length 
2. Phases of Growth Meristematic- dense cytoplasm, small size, cell wall primary 
multiple plasmodesmatal connection, vacuole absent 
Elongation phase- cell size inc, inc in protoplasm, Deposition in 
cell wall 
Maturation – size fix, vacuole maximum size, role fix, some cells 
like vessels mature by getting dead  
 
 
 
 
 
 
Growth Rate 
Type of growth 
rate  
Arithmetic Geometric  
Out of two 
daughter cell  
One cell continue to 
divide 
Both cell continue to divide 
Equation  LT = L0 + rt (r- Arithmetic 
growth rate) 
Wt = Wo e 
rt (r- Geometric growth rate or efficiency index 
Curve shape Straight line Sigmoid- lag phase-initial part, than log phase 
rapid growth and stationary phase- resources 
limited 
Example  Length of stem Most plant tissue or organ  
 
Initial area leaf Final area Absolute growth Relative growth 
Leaf A=5cm² 10 cm² Final -initial = 10-5 = 5 cm² Final-initial/initial = 10-5/5 = 100 % 
Leaf B= 50 cm² 55 cm² 55-50= 5 cm² 55-50/50 = 10 %  
 
Observation -Two leaf -different initial area can have same absolute growth and different 
relative growth 
Conditions for growth- (A) Water -for enzyme activity and cell turgidity (B) Oxygen- energy 
produced for aerobic respiration (C) Nutrients (D) light and gravity act as signal  
 
Types of Tissues 
Tissue or Cell  Undergo process To Form 
Primary meristem 
Apical meristem 
Intercalary meristem 
Differentiation (meristem to 
permanent) 
Primary tissue Epidermis, cortex, 
pith, primary xylem, primary 
phloem 
Permanent tissue 
Medullary rays 
Cortex 
Dedifferentiation(permanent 
cell again become dividing) 
Medullary rays give intrafascicular 
cambium and cortex give cork 
cambium 
both secondary meristem  
 
 
 
Vascular cambium 
Cork cambium  
Redifferentiation (secondary 
meristem to secondary 
tissue) 
Secondary xylem + secondary 
phloem Phelloderm-Sec cortex+ 
phellem- cork  
 
Overall Developmental process for: 
a) Cell  
 Cell division + plasmatic growth + maturation + death 
 
b) Seed 
Seed- seed germination + Growth + Flowering + fruit and seed + senescence  
 
Plasticity  
plant follow different pathway in response of environment known as Plasticity example is -
Heterophylly (Developmental- cotton, coriander and larkspur and Environmental – Buttercup  
 
Factors control plant Growth and development  
External (oxygen, water, nutrients, light) 
Internal – Intercellular factor -Hormones, Intracellular (Genes)  
 
Plant Hormones   
phytohormones,plant growth regulator -PGRs (PGP-plant growth promoter) 
1. Auxin 
2. Cytokinin 
3. Gibberellin  
4. PGI (plant growth inhibitor- Abscisic acid)  
5. Ethylene is both PGP and PGI but more PGI. 
 
 
 
 
 
 
 
PGPs 
Hormone Auxin Gibberellic acid Cytokinin 
Discovery  Francis Darwin and Charles  
Darwin - canary grass- tip 
produce auxin 
F.W went – Auxin isolated 
From tip of avena coleoptile on 
Agar 
Kogl and smith – isolated 
from Human urine  
E.Kurosawa- 1926- 
Bakane (foolish 
seedling) disease on 
rice – due to fungus 
GIbberella fujikuroi 
Sterile filtrate give 
symptom-increase 
length of stem 
F. Skoog and his 
coworkers - 
yeast extract, 
coconut water and 
Vascular tissue 
promote callus 
formation  
 
Bioassay Avena coleoptile curvature test Barley endosperm 
Genetic dwarfism 
overcome bioassay 
Delay in leaf 
(Richmond lang effect) 
Site of 
Synthesis  
Stem and branch tip, root tip in 
area which is not in light  
Nodes and seed Area with Cell division 
cambium, apical 
meristem, young fruit  
Example  Natural- IAA-indole acetic acid 
IBA- indole butyric acid 
Synthetic- 2,4-D -2,4 
dichloroacetic acid, 
Naphthalene acetic acid 
GA1, GA2 ……….. 
GA100 
From -fungi and higher 
plants 
GA3 – First discovered 
GA 
First discovered 
Kinetin-from herring 
fish Zeatin- from plant 
maize and coconut  
Precursor Tryptophan amino acid Diterpenoids Amino purine 
Role  1. rooting in Stem cutting 
2. Parthenocarpy 
3. Promote abscission in old 
leaf and fruit and prevent 
abscission in young leaf and 
fruit 
4. Apical dominance (tip 
removal promote branching -
tea plantation and hedge 
making 
5. Flowering in Pineapple 
6. Xylem differentiation 
7. Act as weedicide against 
dicot Ex.2,4-D  
 
1. Increase axis of 
grapes 
2. Improve shape and 
size of apple 
3. Hastens or fastens 
juvenile phase in 
conifers 
4. Promote malting- 
barley seed-help in 
brewing 
5. Increase ripening 
period of fruit on tree 
6. Increase internode 
length in sugarcane 
7. Promote bolting 
internodal elongation 
prior to flowering 
1. cell division 
2. chloroplasts division 
3. New leaves 
formation 
4. Adventitious bud 
5. lateral shoot 
6. Overcome apical 
dominance 
7. Nutrient 
mobilization to 
overcome seed 
dormancy  
 
 
 
 
PGIs 
Hormone Ethylene Abscisic acid 
Discovery  Cousins -ripened oranges promote ripening of 
banana  
mid-1960s, inhibitor-B, 
abscission II and dormin 
discovered  
Bioassay Triple response bioassay- horizontal growth of 
shoot tip, broadening of axis, apical hook 
formation 
 
Site of 
synthesis 
Plant part leaf, fruit and stem undergoing 
abscission  
 
Precursor Methionine Carotenoid 
Role  1.Climacteric ripening (CO 2 release increase) 
2.Petiole and underwater stem elongate in rice 
stem 
3. Break seed dormancy(peanuts) and bud 
dormancy 
in potato tuber 
4. increase surface area by increasing root hair 
5. Flowering and fruiting in pineapple 
6.Flowering in Mango 
1. General plant growth 
inhibitor and inhibitor of plant 
growth 
2.inhibit seed germination 
3. closure of stomata 
4. Promote leaf abscission 
5. Control seed germination 
dormancy, development  
 
 
Ethephon- Aqueous form, slowly diffuse readily 
absorb Role-female flower in cucumber, ripening 
in 
tomato and apple and abscission in cherry 
walnut, cotton  
Antagonist to ABA in seed 
germination  
 
 
 
Association  Hormone pair  
Agonist or 
synergistic  
 
Auxin-Ethylene -flowering in pineapple, abscission of leaf and fruit 
Auxin-Cytokinin – tissue culture  
Antagonist GA(break) ABA (promote) – seed dormancy Auxin-cytokinin- Apical 
dominance