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B. Rajendra
Subject Expert,
Hyderabad
First Year
(UNIT-VI)
The Unit VI is of only one chapter i.e chapter 12- Histology and Anatomy of Flowering Plants. The internal structure and organization is described in this chapter very briefly. Most
of the students feel this topic as a dry
one and understanding is not easy.
The reason is without diagrams this
topic cannot be explained easily and
efficiently. All anatomical features in
plants are microscopic. The diagrams
in the text book are insufficiently less.
Student needs a three dimensional
visual ability to understand anatomy.
In the beginning of the chapter different tissues are described. The structural aspects of the meristematic cells are not clearly given. To understand this student should read this slowly
and many times. He should compare
his understanding with the diagrams
given there. With his three dimensional visual abilities he should compare
with other types of tissues. Without
proper understanding the complex tissues it will be difficult to understand
the later part of the chapter.
Internal structure of dicot stem,
dicot root, monocot stem and monocot roots are described very briefly.
All these four descriptions are very
important for IP examinations. One
of the three LAQ in I.P.E will be from this chapter. For IP examinations
the chapter is having 14 marks weightage. But the description given in
the text book is insufficient to write a
Long Answer Question. Student is
advised to write separately with subheadings after going through the description given in the text book and
practice it.
In writing an essay the descripti-
TS EAMCET
1. Which of the characters are found
in cells producing primary tissues
I) Rich in protoplasm, conspicuous nucleus
II) Thick cell wall, few plasmodesmatal connections.
III) Thin cell wall, many plasmodesmatal connection
IV) Lignin in cell wall, inconspicuous nucleus
1) III & IV
2) I & II
3) I & IV
4) I & III
2. Identify the correct pair from
the following
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Intercalary meristems are primary..
on must include structural features
and functional aspects of every layer
and every part of the organ.
The student can practice with
the following sub-headings:
a) Epidermis b) Cortex c) Stele
For example, the description of
the epidermis of the root:It is a multicellular single layered
living cells arranged without intercellular spaces. Cuticle is absent. Root
hairs are unicellular and projections
of the epidermal cells. Function of
the epidermis in root is protection
and absorption of water, minerals.
For a long answer question such
a description is necessary.
Well labeled diagrams are the part
of the answer. Student has to learn from their lecturers the method of drawing the diagrams and practice twice
before the exams. The description and
diagram should correlate each other.
Student with good skills in drawing diagrams only should attempt this question. Comparing to other LAQs
from other chapters, answering this
question will take longer time.
Studying Secondary growth is
important for SAQs
Preparing for SAQs from this
chapter is very easy. But every question needs a diagram in their answers.
For EAMCET point of view this
chapter is very important.
At least 2-3 questions can be expected from this chapter. Questions will be in the form of multiple answers
or multiple choice type. Students should read this chapter several times to
become perfect. All anatomical characters of Gymnosperms and Pteridophytes are given in the chapter 4. After
reading this chapter they can understand the details of the chapter 4.
I) Primary phloem is commercially important in flax
II) The food material in water
conducting tissue are stored
in thin walled cells.
III) The water movement in
vessels is bidirectional
IV) Mature cells where hydrostatic pressure increases during
sugar transportation show the
presence of peripheral cytoplasm and absence of nucleus
1) II & IV
2) II & III
3) I & II
4) III & IV
Answers: 1) 4; 2) 1.
Important points to
remember for EAMCET.
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Intermediate
Botany
Botany
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Important LAQs for I.P.E
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1. Describe the T.S of dicot stem.
2. Describe the T.S of monocot stem.
3. Describe the internal structure of
a dicot root.
4. Describe the internal structure of
a monocot root.
There is little difference between
T. S of dicot root and T.S of monocot
root. Monocot roots show polyarch
condition and medulla is present.
While in Dicot roots number of vascular bundles are limited and medulla
may be present or may not be present. With this small difference preparation of these questions is very easy.
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Important SAQs for I.P.E
1. State the location and function of
different types of meristems.
2. What is periderm? How does periderm formation takes place in
the dicot stems.
3. A transverse section of the trunk
of a tree shows concentric rings
which are known as annular
rings. How are these rings
formed? What is the significance
of these rings?
4. Name the three basic tissue systems in the flowering plants. Give the tissue names under each
system.
AP EAMCET
1. These cells are absent in phloem
of Gymnosperms
1) Albuminous cells
2) Companion cells
3) Phloem parenchyma
4) Phloem fibre
2. Periderm of stem includes
1) Phelloderm, hypodermis and
pericycle
2) Phellogen, Phellum, phelloderm
3) Phellum, phelloderm and lenticels
4) Phellum, phelloderm and pericycle
Answers: 1) 2; 2) 2.
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All apical meristems are primary
but all primary meristems are not
apical.
All secondary meristems are lateral but all lateral meristems are
not secondary.
Intercalary meristems are primary.
Lateral meristems increases the
girth of the plant.
Secondary meristems produce
secondary tissues.
All living cells can divide in the
plants but meristematic cells continuously divide.
Intercellular spaces are absent in
the meristems.
Nucleus is centrally located. Vacuoles are absent are minute.
Root apex show four layers of
meristematic layers.
Location of collenchyma is always peripheral. They can provide
mechanical support.
Collenchyma is absent in underground parts and monocots.
All living cells can divide, store
food and secrete.
Dead cells provide mechanical
support.
Cambium is always single layered. It cuts off cells towards inside
and outside. Inside it forms primary xylem outside it forms into
primary phloem.
First cell of primary xylem is always away from the phloem and
is called protoxylem. This xylem
is called as endarch xylem.
Endarch xylem is present in stems. And exarch xylem is present
in roots
If xylem and phloem is attached
this condition is called as conjoint.
Conjoint vascular bundles are present in stems. Separate in roots.
If phloem is outside and present on
the same radius they are collateral.
Collateral bundles are present in
stems. Radial bundles are in roots.
If cambium is still present between
xylem and phloem they are open
(open for secondary growth).
In dicot stems vascular bundles
are open. In monocot stems and
roots they are closed.
In leaves vascular bundles are
endarch. Protoxylem always towards upper epidermis.
Epidermal tissue system protects
plant, helps in secretion, transpiration, gaseous exchange and
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rarely helps in assimilation.
Monocot roots differ from dicots
in having polyarch (many vascular bundles) condition.
In mature roots root surface is
covered by exodermis. Exodermis is suberised and protect plants from loosing water besides
protecting from pathogens.
Cortex in roots always shows intercellular spaces. Casparian bands
in the endodermis of roots block
the movement water to get inside.
Monocot stems are hard due to sclerenchyma below the epidermis.
Phloem parenchyma is absent in
monocot stems.
Stele and cortex is reduced. Stele
is atactostele. Protoxylem lacuna
is present in the vascular bundles.
They are closed. Secondary growth in monocots is not normal.
In leaves upper side is adaxial
side or ventral side. Lower surface is dorsal or abaxial.
Bulliform cells are present in Graminaceae and Cyperaceae. They
are present only on upper surface.
They help in the rolling of the
leaves during dry conditions.
Isobilateral leaves need not be
monocot always.
Epidermis does not show chloroplasts generally except in completely submerged water plants.
Leaves also show collenchyma.
Normal secondary growth takes
place in dicot stems.
In Gymnosperms and monocots
secondary growth is not normal.
In dicot roots vascular bundles
are closed but secondary growth
is present.
Annular rings appear where seasons are clearly demarcated. Every plant undergoing secondary
growth shows the rings.
Growth depends on the activity
of the vascular cambium.
Vascular cambium is ring shaped
and lateral. Part of it (fascicular
part) is primary.
Sap wood can conduct water. Heart wood is mechanical in function. Oils tannins resins may be
stored in the heart wood.
Cork is part of bark. Cork is impervious to water.
Lenticels help in gaseous exchange and little transpiration.
Secondary cortex may be secretory or photosynthetic or store food.
Lenticels can be seen on the
roots, fruit walls or petioles.