CAREER POINT
PLANT MORPHOLOGY
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PLANT MORPHOLOGY
✔ INTRODUCTION
Morphology – (Morphe = form + logos = study). It deals with the study of forms and features of
different plant organs like roots, stems, leaves, flowers, seeds, fruits etc.
The body of a typical angiospermic plant is differentiated into :
✧ an underground root system
✧ an aerial shoot system.
The shoot system consists of stem (including branches), leaves, flowers and fruits.
The roots, stems and leaves are vegetative parts, while flowers constitute the reproductive part.
✔ CLASSIFICATION OF PLANTS
Depending upon their life span, plants are classified as –
Annuals – Complete their life cycle in one year or single growing season or few weeks to a few
months. They pass the unfavourable period in the form of seeds eg. Mustard, Pea.
Biennials – Complete their life cycle in two years-growing, vegetative and storing food in the first
year, flowering and fruiting in the second year. They die off after producing flowers and fruits
eg. Radish, turnip, carrot are biennial in colder areas. They become annual in warmer places.
Perennials – Survives for several years. These plants usually bears flowers and fruits every year and
do not die after producing flowers. eg. Mango, Banana, Guava
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ROOT
Radicle comes out/arise from the seed coat in the form of soft structure and move toward the soil. It
develops and forms primary root.
General Characters :
Roots are non green, underground, (+) geotropic, (–) phototropic and (+) hydrotropic.
Roots do not bear buds.
Buds present for vegetative propagation in sweet potato (Ipomea) and Indian red wood (Dalbergia)
Roots do not bear nodes and internodes.
Roots have unicellular root hairs.
✔ TYPES OF ROOTS
Roots are of two types :
✧ Tap root ✧ Adventitious root
Tap root : It develops from radicle and made up of one main branch and other sub branches. The
primary roots and its branches constitute tap root system. e.g. Dicot roots.
Adventitious roots : In some plants, after sometime of the growth of tap root which arises from radicle,
stops and then roots, develop from other part of plant, which are branched or unbranched, fibrous or
storage, are known as adventitious roots and constitute fibrous root system. e.g. Monocot roots.
✔ REGIONS OF ROOTS
Morphologically four distinct regions are present in roots.
Root cap : It is terminal structure. It protects tender apex of root.
Meristematic zone : Cells of this regions are very small and thin walled. They divide repeatedly and
increase cell number
Elongation region : The cells proximal to meristematic zone undergo rapid elongation and enlargement
and are responsible for rapid growth of roots.
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Maturation region : Cells proximal to region of elongation gradually differentiate and mature. Root
hairs are present in maturation zone.
✔ MODIFICATION OF ROOTS
1. Modified tap root for storage :
Fusiform roots : These root are thicker in the middle and tappered on both ends. In this type of roots
both hypocotyl and root help in storage of food. eg. Radish.
Conical roots : These roots are thicker at their upper side and tapering at basal end. eg. Carrot.
Napiform : These roots become swollen and spherical at upper end and tappered like a thread at their
lower end. eg. Turnip (Brassica rapa), Sugarbeet
Tuberous root : Such roots do not have regular shape and get swollen & fleshy at any portion of roots.
eg. Mirabilis.
2. Nodulated root : Nodules are formed on branches of roots by nitrogen fixing bacteria, (Rhizobium). eg.
Plants of leguminosae family (Papilionatae) – Pea.
3. Respiratory roots : Halophyte or mangrove grow in oxygen deficient marshy area. Some branches of tap
root in these plant grow vertically & comes out from soil. These roots are called pneumatophores through
which air entered inside the plant. eg. Rhizophora, Heritiera, Sonaratia and other mangrove plant.
Corporate Office: CP Tower, IPIA, Road No.1, Kota (Raj.), Ph: 0744-3040000 (6 lines) PLANT MORPHOLOGY 33
PLANT MORPHOLOGY
0 Corporate Office: CP Tower, IPIA, Road No.1, Kota (Raj.), Ph: 0744-3040000 (6 lines) PLANT MORPHOLOGY 0
, CAREER POINT
PLANT MORPHOLOGY
✔ INTRODUCTION
Morphology – (Morphe = form + logos = study). It deals with the study of forms and features of
different plant organs like roots, stems, leaves, flowers, seeds, fruits etc.
The body of a typical angiospermic plant is differentiated into :
✧ an underground root system
✧ an aerial shoot system.
The shoot system consists of stem (including branches), leaves, flowers and fruits.
The roots, stems and leaves are vegetative parts, while flowers constitute the reproductive part.
✔ CLASSIFICATION OF PLANTS
Depending upon their life span, plants are classified as –
Annuals – Complete their life cycle in one year or single growing season or few weeks to a few
months. They pass the unfavourable period in the form of seeds eg. Mustard, Pea.
Biennials – Complete their life cycle in two years-growing, vegetative and storing food in the first
year, flowering and fruiting in the second year. They die off after producing flowers and fruits
eg. Radish, turnip, carrot are biennial in colder areas. They become annual in warmer places.
Perennials – Survives for several years. These plants usually bears flowers and fruits every year and
do not die after producing flowers. eg. Mango, Banana, Guava
Corporate Office: CP Tower, IPIA, Road No.1, Kota (Raj.), Ph: 0744-3040000 (6 lines) PLANT MORPHOLOGY 11
, CAREER POINT
ROOT
Radicle comes out/arise from the seed coat in the form of soft structure and move toward the soil. It
develops and forms primary root.
General Characters :
Roots are non green, underground, (+) geotropic, (–) phototropic and (+) hydrotropic.
Roots do not bear buds.
Buds present for vegetative propagation in sweet potato (Ipomea) and Indian red wood (Dalbergia)
Roots do not bear nodes and internodes.
Roots have unicellular root hairs.
✔ TYPES OF ROOTS
Roots are of two types :
✧ Tap root ✧ Adventitious root
Tap root : It develops from radicle and made up of one main branch and other sub branches. The
primary roots and its branches constitute tap root system. e.g. Dicot roots.
Adventitious roots : In some plants, after sometime of the growth of tap root which arises from radicle,
stops and then roots, develop from other part of plant, which are branched or unbranched, fibrous or
storage, are known as adventitious roots and constitute fibrous root system. e.g. Monocot roots.
✔ REGIONS OF ROOTS
Morphologically four distinct regions are present in roots.
Root cap : It is terminal structure. It protects tender apex of root.
Meristematic zone : Cells of this regions are very small and thin walled. They divide repeatedly and
increase cell number
Elongation region : The cells proximal to meristematic zone undergo rapid elongation and enlargement
and are responsible for rapid growth of roots.
2 Corporate Office: CP Tower, IPIA, Road No.1, Kota (Raj.), Ph: 0744-3040000 (6 lines) PLANT MORPHOLOGY 2
, CAREER POINT
Maturation region : Cells proximal to region of elongation gradually differentiate and mature. Root
hairs are present in maturation zone.
✔ MODIFICATION OF ROOTS
1. Modified tap root for storage :
Fusiform roots : These root are thicker in the middle and tappered on both ends. In this type of roots
both hypocotyl and root help in storage of food. eg. Radish.
Conical roots : These roots are thicker at their upper side and tapering at basal end. eg. Carrot.
Napiform : These roots become swollen and spherical at upper end and tappered like a thread at their
lower end. eg. Turnip (Brassica rapa), Sugarbeet
Tuberous root : Such roots do not have regular shape and get swollen & fleshy at any portion of roots.
eg. Mirabilis.
2. Nodulated root : Nodules are formed on branches of roots by nitrogen fixing bacteria, (Rhizobium). eg.
Plants of leguminosae family (Papilionatae) – Pea.
3. Respiratory roots : Halophyte or mangrove grow in oxygen deficient marshy area. Some branches of tap
root in these plant grow vertically & comes out from soil. These roots are called pneumatophores through
which air entered inside the plant. eg. Rhizophora, Heritiera, Sonaratia and other mangrove plant.
Corporate Office: CP Tower, IPIA, Road No.1, Kota (Raj.), Ph: 0744-3040000 (6 lines) PLANT MORPHOLOGY 33
