Morphology of Plants Flashcards
Root System?
The main branches and its lateral branches form the root system.
Roots are
Positively Geotropic & Negatively Phototropic.
Tap Root system is present in
Dicots.
Fibrous root system is present in,
Monocots.
Adventitious root system:
these develop from any parts of plant except radicle, e.g. Grass, Monstera, Banyan Tree.
Functions of root:
1) Absorption of water and minerals.
2) Provide anchorage to plant parts.
3) Storage of reserve food material.
4) Synthesis of plant growth regulators.
Regions of the Root?
i) Root Cap
ii) Region of meristematic activity
iii) Region of elongation
iv) Region of maturation.
Root Cap:
The apex of the root is covered by thimble like str. cld Root Cap, Multicellular. Formed of Parenchymatous Cells, Protects the tender apex.
Region of meristematic activity :?
Few mms above root cap, Cells are thin-walled, small, dense cytoplasm, Divide repeatedly to form new cells.
Region of elongation ?
proximal to meristematic region, undergo rapid elongation and enlargement & are responsible for growth of roots in length.
Region of maturation. ?
Cell Elongation zone gradually differentiates and mature. This is proximal to region of elongation.
Root Hair?
some epidermal cells from the region of maturation form very fine and delicate thread like structures called root hair.
Function of Root Hair?
Increase the surface area for absorption of water and minerals from the soil.
Storage Roots
Primary tap root is modified to store food and assumes various shapes.
Examples of Storage Roots
Tap root of Carrot, turnip, radish, beet and adventitious roots of sweet potato get swollen and store food.
Respiratory Roots
in swampy areas many roots come out of the ground vertically upwards to get oxygen for respiration. Called Pneumatophores.
Pneumatophores present in:
Rhizophora, Maangrove
Prop roots:
arise from branches of stem for providing mechanical support to heavy branches, e.g. Banyan Tree.
Banyan Tree scientific name
Ficus benghalensis
Stilt roots: ?
arise from lower nodes of stem to support main axis and enter soil obliquely, e.g. Sugarcane, Maize.
What gives rise to the stem?
The plumule of the embryo present in the germinating seed gives rise to the stem.
The region bearing leaves, present at regular intervals on the stem and its branches are called
Nodes
Part of stem present bw two nodes:
Internode.
A bud:
Young, Immature, under developed, compact shoot.
i) Terminal Bud
ii) Axillary Bud
Terminal Bud?
Present at the tip of the stem. aka apical bud.
Axillary bud?
The angle made bw the leaves and the upper part of the stem is called AXIL. The bud present at the AXIL, is called Axillary Bud.
Functions Of stem:
i) Bears and supports leaves, flowers and fruits.
ii) Conducts water and minerals salts from roots to leaves and fruits.
iii) Transport of Food.
Types of Underground stem:
i) Rhizome
ii) Tuber
iii) Corm
iv) Bulb
Modifications of stem:
- Underground Stem
i) Rhizome
ii) Tuber
iii) Corm
iv) Bulb - Stem Tendrils
- Thorn
- Sub-Aerial Weak Stem
i) Offsets
ii) Suckers
iii) Runners
iv) Stolons - Aerial Stem
- Cladode
Rhizome?
Grows parallel or horizontal to soil surface. Bears nodes, internodes, buds and scaly leaves. E.G. GINGER, BANANA, TURMERIC, FERNS.
Tuber?
Terminal portion of underground stem branch, swollen w food. e.g. Potato, Helianthus tuberosus ( jerusalem artichoke)
Corm?
grows vertically beneath the soil surface, usually unbranched, bears nodes, internodes, buds and scale leaves, e.g. Colocasia, Gladiolus, Colchicum, Crocus, Amorphophallus (Zaminkand)
Bulb? (underground stem)
stem is reduced and disc shaped, the bud is surrounded by many concentric scale leaves. leaf bases of inner ones are fleshy and edible, and of outer ones are dry. E.G. Onion, Lily, Garlic.
Stem tendrils?
Axillary buds modify to form tendrils. Long, thin, thread like spirally coiled, sensitive strcs, GRAPE VINE, GOURDS ( pumpkin, watermelon, cucumber)
THORNS?
Axillary buds lose their ability to grow and form hard, woody, and pointed structures called thorns. Protective function, e.g. Citrus & Bougainvillea
Offset? (sub aerial weak stem)
lateral branch which bear short internodes, the distance bw two nodes decreases and each node bears a rosette of leaves above and a cluster (tuft) of roots below, E.G. Pistia and Eichhornia
Suckers (sub aerial weak stem)
The lateral branches originate from the basal & underground portion of the main stem. they grow below the surface of the soil to some distance and then emerges out obliquely to form aerial root. e.g. Banana, Pineapple, Chrysanthemum
Runners (sub aerial weak stem)
elongated, prostrate branch with long internodes and roots at nodes, e.g. grasses, Oxalis etc.
Stolons (sub aerial weak stem)
slender lateral branch arises from the base of the main axis and after growing aerially for some time arch downwards to touch the ground. JASMINE & MINT.
Aerial Stem
Stem modified into flattened (Opuntia) or fleshy cylindrical structures (Euphorbia) called Phylloclade. Photosynthetic.
Cladode?
Stem modified into a leaf like str. for photosynthesis, while leaves reduced to scales or spines e.g. Asparagus, Ruscus
Most important vegetative organ for photosynthesis
Leaves
What are the part of leaves
Leaf Base
Petiole
Lamina or Leaf Blade
Leaf base may bear two lateral small leaf like structures called
Stipules
In _______ leaf base expands to form a sheath covering the stem wholly or partially.
Monocots
In some leguminous plants, the leaf base swells and is called
Pulvinus
Petiole enables leaves to flutter in the wind which allows
produces a cooling effect in the leaves by bringing fresh air to the leaf surface
The prominent vein present in the middle of the leaf blade?
Midrib
Functions of veins on the lamina?
Provide rigidity & strength to the leaf blade, act as a channel to transport water, minerals & food.
Reticulate Venation
veinlets form a network; generally in dicots, e.g. Peepal, hibiscus, Luffa etc
Parallel venation
generally in monocots, e.g. banana
Types of leaves?
Simple Leaf
Compound Leaf - Pinnately Compound leaf & Palmately compounded leaf.
What are simple leaves?
in which the leaf blade is not divided or when incised, the incision do not touch the midrib. It has bud at the axil of the petiole.
What are compound leaves?
in which the leaf blade is completely broken into different leaflets. incisions reach the midrib. contains a bud at the axil of the petiole but is absent in the axil of leaflets.
Pinnately Compound leaf?
midrib forms a common axis called rachis, a number of leaflets are present on rachis, e.g. Neem.
Palmately Compound leaf?
leaflets are attached to a common point, at the tip of the petiole, the tip of the petiole bears all the leaflets in a bunch or cluster, e.g. silk cotton.
Phyllotaxy? `
The pattern in which the leaves are arranged on the stem or its branches.
Types of Phyllotaxy?
Alternate phyllotaxy; Opposite phyllotaxy; Whorled phyllotaxy.
Alternate phyllotaxy?
single leaf is present at each node in an alternate fashion. e.g. China rose (shoe flower), mustard, sunflower
Opposite phyllotaxy?
a pair of leaves arise at each node on opposite side, leaves lie opposite each other, e.g. Guava, Calotropis
Whorled phyllotaxy. ?
more than 2 leaves arise at each node and form a whorl, e.g. Alstonia, Nerium
Leaves are modified into :
- Leaf tendrils
- Leaf spines
- Storage organ
- Phyllodes
- pitcher like
Leaf tendrils?
long, slender, thread like, sensitive structures called tendrils, sensitive to touch. coil around a support & help climbing. provide support. e.g. Pea, sweet pea
Leaf spines?
leaves modify into small, sharp pointed, structures which reduce transpiration & protect plants from animals; e.g. Aloe, Cactus
leaves as storage organ?
fleshy leaves store food, e.g. onion, garlic
leaves into phyllodes?
the petioles modify to form flat, green coloured leaf like structure which performs photosynthesis. as leaves are short lived. e.g. Australian Acacia
Leaves into pitchers?
plants obtain nutrients by digesting insects trapped in the pitcher, e.g. pitcher plant, venus-fly trap.
What is Inflorescence?
The arrangement of flowers on the floral axis of the plant.
The flower is considered to be
modified shoot
Types of Inflorescence?
Racemose & Cymose
What is Racemose Infl.?
The shoot axis grows indefinitely & the flowers are borne in an acropetal succession i.e. younger at apex, older towards base, E.G. Radish, lupin, mustard.
What is Cymose Infl.?
Main axis terminates into a flower; has limited growth. Basipetal Order. e.g. Begonia, Teak, Bougainvillea, Dianthus, Solanum.
What is Thalamus?
It is the swollen end of the pedicel or the stalk.
The 4 whorls present in a flower are?
Calyx (Sepals) , Corolla (Petals) , Androecium (Stamen) , Gynoecium (Carpel) .
Perianth?
when the calyx and corolla are not distinct. its members are called Tepals.
Bisexual Flower examples?`
Pea, Hibiscus
Unisexual flower examples?
Maize
Bracteate flower?
flowers with bracts ( reduced leaf found at base of the pedicel)
Ebracteate flower>?
flower without bracts.
Symmetry of a flower, types?`
- Actinomorphic flower - radial symmetry
- Zygomorphic flower - bilateral symmetry
- Asymmetric Flower - Irregular
Actinomorphic flower - radial symmetry
Mustard, Datura, Chilli
Zygomorphic flower - bilateral symmetry
Pea, Gulmohar, Bean, Cassia
Asymmetric Flower - Irregular
Canna
What are hypogynous flowers?
Ovary occupies the highest position, while other parts are situated below it. Superior Ovary, e.g. mustard, china rose, brinjal, Petunia.
What are perigynous flowers?
If gynoecium is situated at the centre and other parts are located at the rim almost at same level as ovary. Half-Inferior Ovary, e.g. plum, rose, peach.
What are Epigynous flowers?
Margin of thalamus grows upward, enclosing the ovary completely & getting fused with it. other parts of flower arise above ovary. Inferior Ovary. e.g. Guava, Cucumber, bittergourd, the ray floret of sunflower.
The outermost whorl of a flower?
Calyx. Members are called Sepals.
Calyx may be:
Gamosepalous (sepals united) or Polysepalous (Sepals free)
2nd whorl of the flower?
Corolla, individual leaf segment is called Petal.
Some shapes of corolla that exist in nature?
Tubular, Bell-Shaped, funnel-shaped, wheel-shaped. etc
Corolla may be;
Polypetalous (free) & gamopetalous (united)
What is Aestivation?
The mode of arrangement of sepals and petals in a floral bud with respect to the other members of the same whorl.
Types of Aestivation?
- Valvate
- Twisted
- Imbricate
- Vexillary.
what is Valvate aest.?
the margin of sepals or petals, present in a whorl just touch each other, no overlapping
what is Twisted aest?
margin of one petal or sepal overlaps the margin of the adjacent petal or sepal or so on.
what is Imbricate aest.?
margins of petals or sepals overlap each other but not in specific direction
Examples of Imbricate Aest. ?
Cassia, Gulmohar
Examples of Vexillary Aest.?
Pea, Bean flower
Androecium is composed of
Stamens. A stamen of a filament & anther.
Anthers are usually bilobed.
Each lobe of anther contains
two microsporangia or pollen sacs,
A sterile stamen is called as
Staminode
When a stamen is attached to the petal then it is called
Epipetalous
examples of Epipetalous
brinjal
when the stamen is attached to the perianth it is called
Epiphyllous, e.g. Lily
when the stamens are free they are called
Polyandrous
When the stamens are united in a single bundle, then it is called:
Monoadelphous e.g. China rose
Stamens united in 2 bundles:
Diadelphous e.g. pea
Stamens united in more than 2 bundles
Polyadelphous e.g. Citrus
Gynoecium is composed of:
one or many carpels; free or fused.
When carpels are free in gynoecium:
Apocarpous e.g. Lotus & Rose
When carpels are fused in gynoecium:
Syncarpous e.g. Mustard & Tomato
Parts of Carpel:
- Ovary
- Style
- Stigma
After fertilisation ovules develop into ______ and ovary mature to _______
seeds; fruit
Basal, swollen part of the carpel?
Ovary
Ovary bears one or more ___
ovules; ovules are attached to a flattened cushion like structure called Placenta.
The ovary has one or more chambers or ______
loculi;
1 chamber - Unilocular
2 chamber - Bilocular
3 chamber - Trilocular
The wall of the ovary after fertilisation forms the
Pericarp. (Fruit Wall)
the tube like structure which connects the stigma to the ovary is called
Style; it lies above ovary in a carpel.
generally situated at the tip of the style
stigma; acts as a receptive organ for pollen grains during pollination
An ovary may have 1 or more placenta
true
the arrangement of ovules on placenta within the ovary is k/as
Placentation
Types of Placentation:
- Marginal
- Axile
- Parietal
- Free Central
- Basal
what is Marginal placentation?
the placenta forms a ridge along the ventral suture of the ovary. the ovules are borne in 2 alternate rows along the ridge
examples of Marginal placentation?
Pea plant
what is Axile placentation?
the placenta is present in the axial position & the ovules are attached to it in a multilocular ovary.
Examples of Axile Placentaton:
China rose; Tomato; lemon
what is Parietal placentation?
unilocular ovary but becomes two chambered due to formation of false septum. the ovules develop on the inner wall of the ovary or on the peripheral part.
example of Parietal placentation?
Mustard; Argemone
what is Free Central placentation?
the ovules are borne on central axis and septa are absent in ovary.
example of Free Central placentation?
Primrose, Dianthus
what is Basal placentation?
placenta develops at base of ovary; single ovule attached to placenta.
example of Basal placentation?
Sunflower, Marigold
some fruits which are formed without fertilisation are called
Parthenocarpic fruits. e.g. Banana
Parts of a fruit:
Fruit wall/ pericarp and SEED
3 different layers of the Pericarp (if fleshy) :
Epicarp - Outer cover
Mesocarp - Middle layer
Endocarp - innermost layer
Parthenocarpic fruits are seedless
banana, grapes
The fruit which develops from ovary are called
True fruit
If any floral part takes part in fruit formation it is called
False Fruit e.g. Apple, Pear
simple fruit develops from the
syncarpous ovary of single flower w/ or w/o accessory parts.
aggregate fruits are formed from
polycarpellary, apocarpous ovary. each carpel develops into a fruitlet and all fruitlets together form aggregate fruit
the multiple fruit/composite fruit develops from
the entire inflorescence
example of simple dry dehiscent fruit
legume or pod (pea) , siliqua or silicula (Brassicaceae) ; Capsule (Datura)
example of simple dry indehiscent fruit
Cypsela (sunflower) ; Caryopsis (Wheat, Maize, Rice) ; Achene (Mirabilis) ; Nut (Litchi)
example of simple succulent or fleshy fruit
Drupe - mango, coconut Berry - Tomato, Guava, Grapes Pepo - Cucumber Pome - Apple, Pear hesperidium - orange and all citrus fruits balausta - Pomegranate
example of Aggregate fruits
strawberry, raspberry
example of composite fruits
Jackfruit, Mulberry, Pineapple, Ficus (fig)
dry dehiscent fruit
these fruit burst automatically and discharge their seeds
dry indehiscent fruit
they do not burst or split; seeds liberated only by decomposition or destruction of pericarp
what are drupes?
mostly one seeded fruits w/ pericarp differentiated into epicarp, mesocarp & hard and stony Endocarp
Mangifera indica - Mango [drupe]
Epicarp forms skin
mesocarp fleshy, juicy & edible
endocarp is hard & stony
Cocos nucifera
coconut
mesocarp is fibrous which is used in making coir so called as fibrous drupe
walnut
Juglans regia
Composition of a seed
Seed coat & an embryo. Embryo is made up of an embryonal axis & one/two cotyledons.
The outer protective covering of the seed
Seed coat - 2 layers
Outer Testa
&
Inner tegmen
What is hilum?
The hilum is a scar on the seed coat through which the developing seeds were attached to the fruit
Micropyle?
Above the helium is a small pore called micropyle.
Most important part of the seed
Embryo
The two ends of the Embryonal axis are present ——— & ———-
Radicle & Plumule
Endosperm is the result of —— — - - —— - -
Double Fertilization
Plants in which endosperm is not present in mature seed are called are
Non-Endospermous e.g. Bean, Gram, Pea.
The outer covering of endosperm separates the embryo by a proteinaceous layer called
aleurone layer
The _________ is small and situated in a groove at one end of the endosperm. (monocot seed)
Embryo
The plumule is enclosed in a sheath called (monocot seed)
coleoptile
The radicle is enclosed in a sheath called (monocot seed)
coleorrhiza
what is a perisperm seed?
mostly nucellus is consumed after fertilisation due to absorption of food by endosperm and embryo. SOMETIMES, THE NUCELLUS REMAINS PERSISTENT IN THE SEED AND IS CALLED PERISPERM.
example of perispermic seed
Piper nigrum (black pepper)
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Actinomorphic condition
