In many teaching exams including REET , KTET , KARTET, CTET , DSSSB PRT , MPTET , OSSTET etc. Science may be an interesting subject having 15 questions of Science content and 15 questions of Science Pedagogy in REET and other State TET Exams. Science comprising of various branches of studies like chemistry, physical science, and life science.
Morphology Of Flowering Plants
Morphology : The study of various external features of the organism is known as morphology.
Adaptation : Any alteration in the structure or function of an organism or any of its part that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment.
The Root :
The root is underground part of the plant and develops from elongation of radicle of the embryo.
|Various types of root|
|Tap root||Fibrous root||Adventitious root|
|Originates from radicle.||Originates from base of the stem.||Originates from parts of the plant other than radicle.|
|Dicotyledonous plants, e.g., gram, pea, mango.||Monocotyledonous plants, e.g., wheat, paddy, grasses.||Banyan tree (Prop roots) Maize (Still roots) Rhizophora (Respiratory roots)|
Root Cap : The root is covered at the apex by the thumble – like structure which protects the tender apical part.
Regions of the root :
- Region of meristematic activity : Cells of this region have the capability to divide.
- Region of elongation : Cells of this region are elongated and enlarged.
- Region of Maturation : This region has differentiated and matured cells.
Some of the epidermal cells of this region form thread – like root hairs.
Modifications of Root :
- Roots are modified for support, storage of food, respiration.
- For support : Prop roots in banyan tree, stilt roots in maize and sugarcane.
- For respiration : pneumatophores in Rhizophora (Mangrove).
- For storage of food : Fusiform (radish), Napiform (turnip), Conical (carrot).
The Stem :
Stem is the aerial part of the plant and develops from plumule of the embryo. It bears nodes and internodes.
Modifications of Stem :
In some plants the stems are modified to perform the function of storage of food, support, protection and vegetative propagation.
- For food storage : Rhizome (ginger), Tuber (potato), Bulb (onion), Corm (colocasia).
- For support : Stem tendrils of watermelon, grapvine, cucumber.
- For protection : Axillary buds of stem of citrus, Bougainvillea get modified into pointed thorns. They protect the plants from animals.
- For vegetative propagation : Underground stems of grass, strawberry, lateral branches of mint and jasmine.
- For assimilation of food : Flattened stem of opuntia contains chlorophyll and performs photosynthesis.
The Leaf :
Develops from shoot apical meristem, flattened, green structure, manufacture the food by photosynthesis. It has bud in axil. A typical leaf has leaf base, petiole and lamina.
|Types of Leaf|
|(Single leaf blade) e.g., mango, peepal||(Leaf has number of leaflets)
1. Pinnately Compound (Neem, rose)
2. Palmately Compound (Silk cotton)
The arrangement of veins and veinlets in the lamina of leaf.
Types of Venation :
- Reticulate : Veinlets form a network as in leaves of dicotyledonous plants (China rose, peepal).
- Parallel : Veins are parallel to each other as in leaves of monocotyledonous plants (grass, maize, sugarcane).
Phyllotaxy : The pattern of arrangement of leaves on the stem or branch.
|Types of phyllotaxy|
|(Single leaf at a node)
e.g., China rose, Mustard
|(Two leaves at a node)
e.g., Calotropis, guava
|(More than two leaves in a whorl at a node)
e.g., Nerium, devil tree
Modifications of Leaves :
Tendrils : (Climbing) – Sweet wild pea
Spines : (Protection) – Aloe, Opuntia, Argemone
Piture : (Nutrition) – Nepenthes
Hook : (Support) – Cat’s nail
Inflorescence : The arrangement of flowers on the floral axis.
Main types of Inflorescence :
- Racemose : Radish, Mustard, Amaranthus.
- Cymose : Cotton, Jasmine, Calotropis.
- Special type : Ficus, Salvia, Euphorbia.
The Flower :
A flower is modified shoot. It is a reproductive unit in angiosperms. Flowers may be unisexual or bisexual, bracteate or ebractiate. Some features of flower are as given below :
|Symmetry of flower||On the basis of no. of floral appendages||On the basis of position of calyx, corolla, androecium with respect of ovary|
|Actinomorphic (radial symmetry)
Zygomorphic (bilateral symmetry)
|Hypogynous (superior ovary)
Perigynous (half inferior ovary)
Epigynous (inferior ovary)
Parts of flower :
- Calyx : Sepals, green in colour, leaf like.
- Corolla : Petals, usually brightly coloured to attract insects for pollination.
- Androecium : Stamens (filament, anther), male organ and produce pollen grains. Stamens may be epipetalous (attach to petals) or epiphyloous (attach to perianth). Stamens may be monoadelphous (united into one bundle), diadelphous (two bundles) or polyadelphous (more than two bundles).
- Gynoecium : Made up of one or more carpels, female reproductive part, consists of stigma, style and ovary, ovary bears one or more ovules. Carpels may be apocarpous (free) or syncarpous (united). After fertilisation, ovules develop into seeds and ovary into fruit.
Gamosepalous – (Sepals united)
Polyseptalous – (Sepals free)
Gamopetalous – (Petals united)
Polypetalous – (Petals free)
Perianth : If calyx and corolla are not distinguishable, they are called perianth.
The mode of arrangement of sepals or petals in floral bud.
Types of aestivation :
- Valvate : Sepals or petals do not overlap the sepal or petal at margins.
- Twisted : Sepals or petals overlap the next sepal or petal.
- Imbricate : The margins of sepals or petals overlap one another but not in any definite direction.
- Vexillary : The largest petal overlaps the two lateral petals which in turn overlap two smallest anterior petals.
Placentation : The arrangement of ovules within the ovary.
Types of Placentation :
- Marginal : Placenta forms a ridge along the ventral suture of ovary.
- Axile : Margins of carpels fuse to form central axis.
- Parietal : Ovules develop on inner wall of ovary.
- Free central : Ovules borne on central axis, lacking septa.
- Basal : Placenta develop at the base of ovary.
The fruit :
After fertilisation, the mature ovary develops into fruit. The parthenocarpic fruits are formed from ovary without fertilisation.
(Plumule + Radicle)