XI Chap 6 Plant Anatomy Flashcards
Study of internal structure of plants is called ___________
anatomy
Within angiosperms, monocots and dicots are seen to be anatomically different. T or F?
True
Define tissue
group of cells,
common origin,
performing a common function
Two main groups of plant tissues?
This difference is on the basis of ___________
Meristematic
Permanent
On the basis of whether cells are capable of dividing or not
Growth in plants is largely restricted to ___________ regions of active cell division called ___________
specialised, meristems
Meristos in ___________ (Latin/Greek) literally means ___________
Greek, divided
Meristems which occur at the tips of ___________ and ___________ and produce ___________ tissues are called apical meristems.
roots, shoots, primary
Shoot apical meristem occupies the ___________ region of the stem axis
distant most
During formation of leaves and elongation of stems, some cells ‘left behind’ from shoot apical meristem constitute the ___________
axillary bud
Axillary buds are present in the ___________ of leaves.
axils
Axillary buds are capable of forming branches or flowers. T or F?
True
What is the intercalary meristem?
meristem which occurs between mature tissues
___________ meristem occurs in grasses and regenerates parts removed by the grazing herbivores
Intercalary
Both ___________ meristems and ___________ meristems are primary meristems.
Why?
apical, intercalary
because they appear early in life of plant and contribute to formation of primary plant body
Meristem that occurs in mature regions of roots and shoots are called ___________ or ___________ meristem
secondary, lateral
Primary meristems appear later than secondary meristems. T or F?
False, other way around
Secondary and lateral meristems are cylindrical meristems. T or F?
True
Examples of lateral meristems?
Fascicular vascular cambium,
interfascicular cambium,
cork-cambium
Lateral meristems are responsible for producing ___________ tissues
secondary
Following divisions of cells in BOTH primary and secondary meristems, the newly formed cells become structurally and functionally specialised and lose the ability to divide. T or F?
True
___________ or ___________ cells lose the ability to divide and constitute permanent tissues.
Permanent, mature
During the formation of the primary plant body, specific regions of the apical meristem produce ___________, ___________ and ___________ tissues
dermal, ground, vascular
Cells of permanent tissues do not generally divide further. T or F?
True
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
Various simple tissues in plants are: (3)
parenchyma,
collenchyma,
sclerenchyma
___________ forms the major component within organs
Parenchyma
Cells of parenchyma are generally ___________
isodiametric
Parenchyma may be spherical, oval, round, polygonal or elongated in shape. T or F?
True
Parenchyma walls are ___________ (thin/thick) and made of ___________
thin, cellulose
Parenchyma may be closely packed or have small intercellular spaces. T or F?
True
Parenchyma functions: (3)
photosynthesis,
storage,
secretion
Collenchyma occurs in layers below the ___________ in most of the ___________ plants
epidermis, dicot
Collenchyma is found either as a homogeneous layer or in patches. T or F?
True
Collenchyma consists of cells which are ___________ (thin/thick)
Explain
Thick at the corners, due to deposition of cellulose, hemicellulose and pectin
Parenchymatous cells may be oval, spherical or polygonal in shape and often contain chloroplasts. T or F?
False, Collenchymatous cells
Like parenchyma, intercellular spaces may be present in collenchyma. T or F?
False, in collenchyma intercellular spaces absent
Function of collenchyma?
Mechanical support to growing parts of the plant
___________ consists of long, narrow cells with thick and lignified cell walls having few or numerous pits
Sclerenchyma
___________ cells are usually dead or without protoplasts
Sclerenchyma
Sclerenchyma may be fibres or sclereids on the basis of variation in ___________, ___________ and ___________
structure, origin and development
Fibres are ___________ (thin/thick-walled), ___________ (short/elongated) and ___________ (blunt/pointed)
thick-walled, elongated, pointed
Fibre sclerenchyma generally occur in groups in various parts of plants. T or F?
True
Sclereids are spherical, oval or cylindrical in shape, highly ___________ (thin/thickened) dead cells with ___________ (narrow/large) cavities called ___________
thickened, narrow, lumen
Sclereids are commonly found in? (4)
fruit walls of nuts,
pulp of guava, pear, sapota
legumes,
leaves of tea
___________ provides mechanical support to organs
Sclerenchyma
Complex tissues are made of multiple cells of the same type that work together as a unit. T or F?
False, multiple cells of different types, rest is correct
What are the 2 complex tissues in plants?
Xylem, phloem
Xylem functions as a ___________ tissue for water and minerals from roots to stems/leaves.
conducting
Xylem provides ___________ strength to plant parts.
mechanical
Xylem is composed of how many elements? They are?
4,
tracheids, vessels, xylem fibres and xylem parenchyma
___________ lack vessels in their xylem
angiosperms, gymnosperms
Gymnosperms
___________ are elongated / tube-like cells with thick and lignified walls and tapering ends.
Tracheids
Tracheids are ___________ (alive/dead) and ___________ (with/without) protoplasm
dead, without
Inner layers of cell walls of tracheids have ___________ which vary in form.
thickenings
In angiosperms, ___________ and ___________ are the main water transporting elements.
Tracheids, vessels
___________ is a long cylindrical tube-like structure made up of many cells, each with lignified walls and large central cavity.
Vessels
Vessel cells are called ___________
vessel members
Vessel cells are ___________ (with/without) protoplasm
without
Vessel members are interconnected through ___________
perforations in their common walls
Presence of vessels is a characteristic feature of ___________
angiosperms, gymnosperms
angiosperms
Part of xylem that ___________ have highly thickened walls and obliterated central lumens
Xylem fibres
Xylem fibres are always aseptate. T or F?
False, they may be septate or aseptate
Part of the xylem that is living and thin-walled and their cell walls are made up of cellulose
Xylem parenchyma
Xylem parenchyma store food materials in the form of ___________ or ___________ and other substances like ___________
starch, fat, tannins
Radial conduction of water takes place by the ___________ cells
ray parenchymatous
Primary xylem is of two types: ___________ and ___________
protoxylem, metaxylem
The first formed primary xylem elements are called protoxylem and later formed secondary xylem elements are called metaxylem. T or F?
False, metaxylem is later formed but also PRIMARY XYLEM element
Endarch vs. exarch?
Endarch - stems, protoxylem lies towards the centre/pith and metaxylem towards the periphery
Exarch - roots, protoxylem lies towards the periphery and metaxylem towards the centre
Phloem transports ___________ usually from ___________ to other parts of the plants
food, leaves
In angiosperms, phloem is composed of ___________, ___________, ___________ and ___________
sieve tube elements, companion cells, phloem parenchyma and phloem fibres
In gymnosperms, phloem is composed of ___________ and ___________, lacking ___________ and ___________
albuminous cells and sieve cells,
sieve tubes and companion cells
Sieve tube elements are long, tube-like structures, arranged ___________ and associated with ___________
longitudinally, companion cells
End walls of sieve tube elements are ___________ in a sieve-like manner to form the ___________
perforated, sieve plats
A mature sieve element possesses a ___________ and ___________ but lacks a ___________
peripheral cytoplasm,
large vacuole,
nucleus
Functions of sieve tubes are controlled by the ___________
nucleus of companion cells
Companion cels are ___________ cells which are closely associated with sieve tube elements
Paren / Collen / scleren?
specialised parenchymatous
Sieve tube elements and companion cells are connected by ___________ present between their common ___________ walls
pit fields, longitudinal
Companion cells help in maintaining the ___________ in the sieve tube cells
pressure gradient
Phloem parenchyma is made up of elongated, tapering cylindrical cells which have ___________ and ___________
dense cytoplasm, nucleus
Cell wall of phloem parenchyma is composed of ___________ and has pits through which ___________ connections exist between the cells
cellulose, plasmodesmatal
The phloem parenchyma stores ___________ and substances like. ___________, ___________ and ___________
food material,
resins,
latex,
mucilage
Phloem parenchyma is absent in most of the dicots. T or F?
False, absent in most of monocots
Phloem fibres aka ___________ fibres are made up of ___________ cells
bast, sclerenchymatous
Phloem fibres are generally absent in the ___________ phloem but are found in the ___________ phloem
(primary, secondary)
primary, secondary
Phloem fibres are much elongated, unbranched and pointed, needle-like ___________
apices
Cell wall of phloem fibres is ___________ (thin/thick)
thick
At maturity, phloem fibres lose their ___________ and become dead
protoplasm
Phloem fibres of ___________, ___________ and ___________ are used commercially
jute, flax, hemp
First formed primary phloem consists of ___________ and is referred to as ___________ and the later formed phloem has ___________ and is referred to as ___________
narrow sieve tubes, protophloem
bigger sieve tubes, metaphloem
What are the different types of tissues based on location?
- Epidermal tissue system
- Ground/fundamental tissue system
- Vascular/conducting tissue system
___________ tissue system forms the outer-most covering of the whole plant body
epidermal tissue system
Epidermal tissue system comprises ___________ cells, ___________ and the epidermal appendages - ___________ and ___________
epidermal, stomata, trichomes, hairs
The ___________ is the outermost layer of the plant body
epidermis
___________ is made up of elongated, compactly arranged cells which form a continuous layer
epidermis
Epidermis is usually multi-layered. T or F?
False, single-layered
Epidermal cells are ___________ cells with a small amount of ___________ lining the cell wall and a large ___________
parenchymatous, cytoplasm, vacuole
Outside of epidermis is often covered with a ___________ layer called the ___________
waxy thick layer, cuticle
Cuticle of epidermis prevents ___________
loss of water
Cuticle is present in the entire plant body, including the roots. T or F?
False, absent in roots
___________ are structures present in the epidermis of leaves
Stomata
Stomata regulate the process of ___________ and ___________
transpiration, gaseous exchange
Each stoma is composed of two bean-shaped cells known as ___________ cells which enclose stomatal pore
guard
In grasses, the guard cells are ___________ shaped
dumb-bell
The outer walls of the guard cells are ___________ (towards / away) from the stomatal pore and are ___________ (thin/thick)
away, thin
The inner walls of the guard cells are ___________ (towards / away) from the stomatal pore and are ___________ (thin/thick)
towards, highly thickened
Guard cells possess ___________ and regulate the opening and closing of ___________
chloroplasts, stomata
Sometimes a few ___________ cells in the vicinity of the guard cells become specialized in their shape and size and are known as ___________ cells
epidermal, subsidiary
___________, ___________ and ___________ together are called stomatal apparatus
Stomatal aperture, guard cells, subsidiary cells
Cell of epidermis bear a number of ___________
hairs
Root hairs are ___________ elongations of the epidermal cells
unicellular
On the stem, epidermal hairs are called ___________
trichomes
Trichomes are:
___________ (unicellular / multicellular), ___________ (branched / unbranched),
___________ (soft / stiff)
multicellular,
either branched or unbranched,
either soft or stiff
Trichomes may be secretory and help in preventing water loss due to transpiration. T or F?
True
All tissues except ___________ and ___________ constitute the ground tissue
episermis, vascular bundles
Ground Tissue system consists of simple tissues such as ___________, ___________ and___________
parenchyma, collenchyma and sclerenchyma
Paranchymatous cells are usually present in the ___________, ___________, ___________ and ___________ in primary stems and roots
cortex, pericycle, pith and medullary rays
In leaves, ground tissue consists of ___________ (thin/thick-walled) chloroplast containing cells and is called ___________
thin-walled, mesophyll
Vascular system consists of ___________ and ___________
phloem, xylem
Xylem and phloem together constitute ___________
vascular bundles
In dicot stems, ___________ is present between phloem an xylem
cambium
Dicot stem vascular bundles are also called ___________ bundles.
Why?
open vascular bundles,
because of presence of cambium => possess ability to form secondary xylem and phloem tissues
Monocot vascular bundles are referred to as ___________ (open/closed).
Why?
closed
Do not have cambium => do not form secondary tissues
Radial vs. conjoint vascular bundles? Examples?
Radial - xylem and phloem arranged in alternate manner along different radii
e.g. roots
Conjoint - xylem and phloem are jointly situated along same radius
e.g. stems, leaves
Conjoint vascular bundles can be open i.e. with ___________ or closed i.e. without ___________
cambium, cambium
Conjoint vascular bundles usually have ___________ located only on the outer side of the ___________
xylem/phloem
phloem, xylem
Sunflower root is an example of ___________ root (monocot / dicot)
dicot
Outermost layer of dicot root is ___________
epiblema
Cells of epiblema protrude in the form of ___________ (unicellular/multicellular) root hairs
unicellular
Cortex of dicot root consists of several layers of ___________ cells ___________ (with/without) intercellular spaces.
thin-walled parenchyma,
with
Innermost layer of dicot root cortex is called ___________
endodermis
Endodermis comprises a single-layer of _______-shaped cells ___________ (with/without) intercellular spaces
barrel, without
___________ as well as ___________ walls of endodermal cells of dicot root have deposits of suberin.
Tangential, radial
Suberin is:
___________ (water permeable/impermeable)
___________ (waxy / rough)
stored in the dicot root endodermal cell walls as ___________
water impermeable,
waxy,
casparian strips
Next to endodermis lies a few layers of ___________ (thin/thick-walled) parenchyomatous cells referred to as ___________
thick, pericycle
Initiation of lateral roots and vascular cambium during the secondary growth takes place in ___________
pericycle
The ___________ of dicot root is small or inconspicuous
pith
The parenchymatous cells which lie between the xylem and phloem are called ___________
conjunctive tissue
There are usually ___________ (how many?) zylem and phloem patches in dicot root?
2-4
Later in dicot root, a ___________ develops between xylem and phloem
cambium ring
All tissues on the innerside of the endodermis such as pericycle, vascular bundles, and pith constitute the ___________
stele
The anatomy of the monocot root is similar to the dicot root in many aspects. T or F?
True
Monocot root, like dicot root, has epidermis, cortex, endodermis, pericycle, vascular bundles and pith. T or F?
True
What’s unique to monocot root when compared to dicot root?
- more than 6 (polyarch) xylem bundles
- pith is large and well-developed
- no secondary growth
Transverse section of a typical young dicot stems shows that ___________ is the outermost protective layer
epidermis
Dicot stem epidermis is covered with a thin layer of cuticle, may bear trichomes and few stomata. T or F?
True
Cells in dicot stem arranged in multiple layers between ___________ and ___________ constitute the cortex
epidermis, pericycle
What are the 3 sub-zones of the dicot stem cortex?
- hypodermis
- cortical layers
- endodermis
Hypodermis is the ___________ (inner/outer) zone of the cortex and consists of a few layers of ___________ cells, which provide ___________ to the young stem
outer, collenchymatous, mechanical strength
Cortical layers below ___________ consists of rounded thin-walled ___________ cells ___________ (with/without) intercellular spaces
hypodermis, parenchymatous, with conspicuous
Innermost layer of the dicot stem cortex is called the ___________
endodermis
Cells of dicot stem endodermis are rich in ___________ and the layer is also referred to as the ___________
starch grains, starch sheath
___________ is present on the inner side of the endodermis in dicot stem
Pericycle
In dicot stem, pericycle is present above the ___________ in the form of semi-lunar patches of ___________
phloem, sclerenchyma
In between the vascular bundles of dicot stem, there are a few layers of radially placed parenchymatous cells which constitute ___________
medullary rays
A large number of vascular bundles are arranged in a ___________ - a characteristic of dicot stem
ring
Each vascular bundle in dicot stem is ___________ (radial / conjoint)
___________ (open / closed)
and with ___________ (endarch / exarch) protoxylem
conjoint, open, endarch
A large number of rounded, parenchymatous cells with large intercellular spaces which occupy the central portion of the stem constitute the ___________
pith
The monocot stem has ___________ hypodermis
sclerenchymatous
The monocot stem has a large number of ___________ vascular bundles, each surrounded by a ___________
scattered, sclerenchymatous bundle sheath
Monocot stem has a large, conspicuous parenchymatous ___________
ground tissue
Vascular bundles in monocot stem are ___________ (radial / conjoint) and ___________ (open / closed)
conjoint and closed
In monocot stems, centrally located vascular bundles are generally smaller than the peripheral ones. T or F?
False, other way around
Phloem parenchyma is ___________ (present / absent) in monocot stem
absent
______-containing cavities are present within the vascular bundles of monocot stem
water
Vertical section of dorsiventral leaf shows three parts:
epidermis
mesophyll
vascular system
Epidermis of dicot leaf covers both the upper surface aka ___________ and the lower surface aka ___________
adaxial epidermis,
abaxial epidermis
Epidermis of dicot leaf has a conspicuous cuticle. T or F?
True
___________ epidermis generally bears more stomata than ___________ epidermis
(abaxial / adaxial)
abaxial, adaxial
Adaxial epidermis may even lack stomata. T or F?
True
Tissue between the upper and lower epidermis of dicot leaf is called ___________
mesophyll
Dicot leaf is aka ___________ leaf whereas monocot leaf is aka ___________
dorsiventral, isobilateral
Mesophyll is made of up ___________ cells
parenchyma
What are the two types of cells in mesophyll?
- palisade parenchyma
2. spongy parenchyma
The ___________ (abaxially/adaxially) placed palisade parenchyma is made up of elongated cells, arranged vertically and parallel to each other
adaxially
The oval or round and loose arranged ___________ is situated below the palisade cells
spongy parenchyma
Spongy parenchyma extends to the ___________
lower epidermis
There are numerous large spaces and air cavities between the spongy mesophyll cells. T or F?
True
Vascular system can be seen in the ___________ and ___________ of the dorsiventral leaf
veins, midrib
Size of vascular bundles in dorsiventral leaf is dependent on the size of the ___________
veins
The reticulate venation of dicot leaves ensure veins of similar thickness. T or F?
False, varying thickness
Vascular bundles of dorsiventral leaf are surrounded by layer of ___________ (thin/thick-walled) ___________ cells
thick-walled, bundle sheath cells
Anatomy of isobilateral leaf is similar to that of the dorsiventral leaf in many ways. T or F?
True
In an isobilateral leaf, stomata are present on both the surfaces of the epidermis. T or F?
True
Mesophyll in monocot leaf is not differentiated into palisade and spongy. T or F?
True
In grasses (monocot) certain adaxial epidermal cells along the veins modify themselves into large, empty, colourless cells called ___________
bulliform cells
When bulliform cells have absorbed water and are ___________, the leaf surface is ___________
turgid, exposed
When bulliform cells are ___________ due to water stress, they make the leaves ___________ to minimize water loss
flaccid, curl inwards
Parallel venation in monocot leaves is reflected in the near similar sizes of vascular bundles except in ___________
main veins
Growth of roots and stems in length with the help of apical meristem is called ___________
primary growth
Apart from primary growth, most dicot plants exhibit an increase in ___________ called secondary growth
girth
Tissues involved in secondary growth are:
two lateral meristems,
vascular cambium,
cork cambium
Meristematic layer that is responsible for cutting off vascular tissues is called ___________
vascular cambium
In the young stem vascular cambium is present in ___________ as a single layer between the ___________ and ___________
patches, xylem, phloem
Intrafascicular vs. Interfascicular cambium
InTRAfascicular: in dicot stems, cambium between primary xylem and primary phloem
InTERfascicular: in dicot stems, cells of medullary rays adjoining inTRAfascicular cambium becomes meristematic and forms inTERfascicular cambium
When cambial ring becomes active, it cuts off new cells both towards inner and outer sides. T or F?
True
Cells cut off towards pith mature into ___________.
Cells cut off towards periphery mature into ___________
secondary xylem,
secondary phloem
Cambium is generally more active on the ___________ (inner / outer) side
inner
The amount of secondary xylem produced is ___________ (less / more) than the secondary phloem
more
Secondary xylem forms a ___________ mass
compact
Primary and secondary ___________ gradually get crushed due to the continued formation of the secondary ___________
phloems, xylem
Primary xylem remains more or less intact during activity of cambial ring in/around the centre. T or F?
True
At some places the cambium forms a narrow band of ___________ which passes through the secondary xylem and phloem in the ___________ directions. These are called ___________
parenchyma, radial, secondary medullary rays
In the spring season, cambium is ___________ (less active / very active) and produces a ___________ (few / large) number of xylary elements that have ___________ (narrow / wide) vessels
very active, large, wide
Wood formed during active cambium season is called ___________ or ___________
spring wood / early wood
In the winter season, cambium is ___________ (less active / very active) and produces a ___________ (few / large) number of xylary elements that have ___________ (narrow / wide) vessels
less active, few, narrow vessels
Wood formed in winter is called __________
autumn wood / late wood
Spring wood is ___________ (lighter / darker) in colour and has a ___________ (lower / higher) density
lighter, lower
Autumn wood is ___________ (lighter / darker) in colour and has a ___________ (lower / higher) density
darker, higher
Two kinds of woods appear as alternate concentric rings constituting a _________ ring
annual
Annual rings seen in a cut stem give an estimate of _________ of the tree
age
In old trees, the greater part of _________ (primary / secondary) xylem is dark brown due to the deposition of _________
secondary,
organic compounds like tannins, resins, oils, gums, aromatic substances and essential oils
Deposited substances in wood make it hard, durable and resistant to attacks of insects. T or F?
True
What is heartwood?
region comprising dead elements with highly lignified walls
Heartwood _________ (conducts / does not conduct) water and gives _________ support to the stem
doest not conduct, mechanical
What is sapwood?
Peripheral region of secondary xylem,
lighter in color,
involved in conduction of water / minerals
As the stem continues to increase in girth, the _________ and _________ layers get broken and need to be replaced to provide new protective cell layers
outer cortical, epidermis
What is cork cambium or phellogen?
another meristematic tissue,
usually in cortext region
to provide new protective cell layers for the stem
Phellogen is how many layers thick?
couple
Phellogen is made of \_\_\_\_\_\_\_\_\_ (narrow / wide) \_\_\_\_\_\_\_\_\_ (thin-walled / thick-walled) \_\_\_\_\_\_\_\_\_ (shape?) cells
narrow, thin-walled and nearly rectangular cells
Phellogen cuts off cells on both sides. T or F?
True
With phellogen, outer cells differentiate into _________ or _________ while the inner cells differentiate into _________ or _________
cork, phellem
secondary cortex, phelloderm
Cork is impervious to water due to _________ in the cell wall
suberin deposition
Cells of secondary cortex as _________ous
parenchymatous
_________, _________ and _________ are collectively known as periderm
Phellogen,
phellem,
phelloderm
Due to activity of _________, pressure builds up on remaining layers peripheral to phellogen and these layers die / slough off.
Cork cambium
Bark is a non-technical term that refers to _________
all tissues exterior to vascular cambium (including secondary phloem)
Bark refers to a number of tissue types: _________ and _________
periderm, secondary phloem
Bark that is formed early in the season is called _________. End of season is called _________
early/soft bark,
late/hard bark
At certain regions, the phellogen cuts off closely arranged _________ cells on the outer side instead of _________ cells
parenchymatous, cork
When parenchymatous cells rupture the epidermis, they form a lens-shaped opening called _________
lenticel
Lenticels permit the exchange of gases between the _________ and _________
outer atmosphere, internal tissue of stem
Lenticels occur in most _________
woody trees
In the dicot root, vascular cambium is complete _________ in origin
(primary / secondary)
secondary
In dicot root, cambium originates from the tissue located just below the _________, a portion of _________, above the _________ forming a complete and continuous wavy ring.
phloem bundles, pericycle tissue, protoxylem
Secondary growth also occurs in stems and roots of _________
gymnosperms
Secondary growth also occurs in monocotyledon roots. T or F?
False, does not occur in monocots
On the basis of presence of _________, location of _________ and _________, vascular bundles are of different types.
cambium,
xylem, phloem
Monocot and dicot plants differ in _________, _________ and _________ of vascular bundles
number, type, location
Wood is actually secondary _________
xylem
