Anatomy Of Flowering Plants [NCERT] Flashcards
The meristems which occur at the tips of roots and shoots and
produce primary tissues are called
apical meristems
During the
formation of leaves and elongation of stem, some cells ‘left behind’ from
shoot apical meristem, constitute the
axillary bud.
Axillary Buds are present in the axils of leaves and are capable of forming
a branch or a flower.
The
meristem which occurs between mature tissues is known as
intercalary
meristem
Both apical meristems and intercalary meristems are
primary meristems because .
they appear early in life of a plant and
contribute to the formation of the primary plant body
The meristem that occurs in the mature regions of roots and shoots of
many plants, particularly those that produce woody axis and appear
later than primary meristem is called
the secondary or lateral meristem.
Lateral Meristem are..
cylindrical meristems. Fascicular vascular cambium,
interfascicular cambium and cork-cambium are examples of lateral
meristems. These are responsible for producing the secondary tissues.
the newly formed cells become structurally and functionally
specialised and lose the ability to divide. Such cells are termed
permanent
or mature cells and constitute the permanent tissues
During the
formation of the primary plant body, specific regions of the apical meristem
produce
dermal tissues, ground tissues and vascular tissues.
Permanent tissues having all cells
similar in structure and function are called
simple
tissues.
Permanent tissues having many different
types of cells are called
complex tissues
A simple tissue is made of only —— type of cells.
one
The various simple tissues in plants are
parenchyma, collenchyma and sclerenchyma
_______ forms the major
component within organs
Parenchyma
The cells of the
parenchyma are generally
isodiametric.
The walls of Parenchyma are
thin and made
up of cellulose.
Shape of Parenchyma
They
may be spherical, oval, round, polygonal or
elongated in shape
parenchyma packaging?
They may either be closely packed
or have small intercellular spaces
The
parenchyma performs various functions like
photosynthesis, storage, secretion.
The _____ occurs in layers below the
epidermis in most of the dicotyledonous plants. It is
found either as a homogeneous layer or in patches.
collenchyma
collenchyma consists of cells which are
much thickened at the
corners due to a deposition of cellulose,
hemicellulose and pectin.
Collenchymatous cells
may be
oval, spherical or polygonal and often
contain chloroplasts.
intercellular spaces in collenchyma?
absent
function of collenchymtous cells
provide mechanical support to the
growing parts of the plant such as young stem and
petiole of a leaf.
Sclerenchyma consists of
long, narrow cells
with thick and lignified cell walls having a few or
numerous pits
Sclerenchyma cells are dead/alive, w/ or w/o protoplast?
usually dead, without protoplasts
sclerenchyma may be either
fibres or sclereids
sclerenchyma fibres are
thick-walled, elongated and pointed cells,
generally occuring in groups, in various parts of
the plant.
sclerenchyma sclereids are
spherical, oval or
cylindrical, highly thickened dead cells with very narrow lumen.
Sclerenchyma provides
mechanical support
The complex tissues are made of _____ type of cells
and these work together as a unit
more than one
__________ constitute the complex tissues in plants.
Xylem & Phloem
Xylem is composed of
tracheids, vessels, xylem
fibres and xylem parenchyma.
Gymnosperms lack which Xylem component (s)
Vessels.
Function of Xylem
conducting tissue for water and
minerals from roots to the stem and leaves. It also provides
mechanical strength to the plant parts
In flowering plants, ___________ are the main water transporting elements
tracheids
and vessels
Tracheids, dead/alive, w/ or w/o protoplasm?
dead, w/o protoplasm
Basic shape/str. of Tracheids?
Tracheids are elongated or tube like cells with
thick and lignified walls and tapering ends.
The presence of vessels is a characteristic feature
of
angiosperms
__________ have highly thickened walls and
obliterated central lumens
Xylem fibres
shape/str. of xylem vessel
Vessel is
a long cylindrical tube-like structure made up of many cells
called vessel members, each with lignified walls and a large
central cavity.
do vessel cells have protoplasm?
no
Vessel members are interconnected through ______________________
perforations in their
common walls
Xylem fibres are septate or aseptate?
either
___________ (xylem) cells are living and thin-walled,
Xylem parenchyma
Xylem parenchyma cells are made up of
cellulose
xylem parenchyma store food in the form of
in the form of starch or fat, and other substances like
tannin
The radial conduction of water takes place by the
ray
parenchymatous cells.
Primary xylem is of two types –
(first formed) protoxylem and
(later formed) metaxylem
in stems, the protoxylem lies towards the
centre (pith)
in stems, the metaxylem lies towards the
periphery of the organ
in roots, the protoxylem lies towards the
periphery
in roots, the metaxylem lies towards the
centre
Protoxylem towards centre & metaxylem towards periphery, such arrangement of primary xylem is called
endarch
metaxylem towards centre & protoxylem towards periphery, such arrangement of primary xylem is called
exarch
Phloem in angiosperms is composed of
sieve tube elements, companion cells, phloem parenchyma and phloem fibres
Phloem transports
Food materials usually from leaves to other parts of the plant.
Phloem in gymnosperms have
Albuminous cells and sieve cells. [they LACK sieve tubes and companion cells.]
Basic shape/str. of Sieve tube elements-
long, tube-like structures, arranged longitudinally . Their end walls are perforated in a
sieve-like manner to form the sieve plates
Sieve tube elements are
associated with the
companion cells
A mature sieve element
possesses,
a peripheral cytoplasm and a large vacuole but lacks a nucleus.
The functions of sieve tubes are controlled by the
nucleus of companion
cells.
The sieve tube elements
and companion cells are connected by
pit fields present between their
common longitudinal walls
_________ help in maintaining the
pressure gradient in the sieve tubes
The companion cells
Phloem parenchyma is made up
of
elongated, tapering cylindrical cells which have dense cytoplasm and
nucleus.
The cell wall of Phloem Parenchyma is composed of
of cellulose and has pits through which
plasmodesmatal connections exist between the cells.
The phloem
parenchyma stores
food material and other substances like resins, latex
and mucilage.
Phloem parenchyma is absent in most of the
monocotyledons.
Phloem fibres (bast fibres) are made up of
sclerenchymatous cells.
Phloem fibres are generally absent in ______________ but are found in ______________
primary phloem; secondary phloem
Basic shape/str. of Phloem fibres -
These are much elongated,
unbranched and have pointed, needle like apices. Thick cell wall.
What happens to Phloem Fibres at maturity
these fibres lose their protoplasm and
become dead.
Phloem fibres of _________________ are used commercially
jute, flax and hemp
The first formed primary phloem consists of narrow sieve tubes and is called
protophloem
later formed phloem has bigger sieve
tubes and is called
metaphloem.
On the basis of their structure and location, there are 3 types
of tissue systems.
- Epidermal tissue system
- The ground or
fundamental tissue system - vascular or conducting tissue system.
The epidermal tissue system forms the
outer-most covering of the whole
plant body
The epidermal tissue system comprises of
epidermal cells, stomata and the epidermal
appendages – the trichomes and hairs
The outermost layer of primary plant body
The Epidermis.
Epidermis is made up of
elongated, compactly arranged cells, which form a continuous layer. Usually single-layered.
The outside of the
epidermis is often covered with a waxy thick layer called the
cuticle
cuticle prevents
loss of water
cuticle is absent in
roots
In grasses,
the guard cells are
dumb-bell shaped.
