NCERT Class 11 Biology Chapter 5 Notes Morphology Of Flowering Plants- Download PDF Notes

Class 11 Biology chapter 5 notes on the morphology of flowering plants will teach you about the different parts of plants. Morphology Of Flowering Plants Class 11 notes explore the complete characteristics of flowering plants, including their structure, functions, classifications, and other morphological characteristics of roots, stems, leaves, flowers, fruits, and seeds. Flowering plants, according to notes for Class 11 Biology chapter 5, vary greatly in shape, size, structure, mode of nourishment, life span, habit, and environment. Download the CBSE Notes for Class 11 Biology, Chapter 5, PDF to use offline anywhere. Students must go through each topic from morphology of flowering plants in Class 11 Notes Biology in the easiest and most effective way possible with the help of NCERT Notes for Class 11.

Morphology of flowering plants NCERT Notes for Class 11 Biology help you revise these major concepts given in the NCERT Book in a short period of time during CBSE Board exam preparation. Plant physiology is not included in the CBSE Notes of Ch 5 Morphology of Flowering Plants, Class 11th Biology. These Morphology of Flowering Plants Class 11 notes will supply you with further information on the subject, which will help you pass your tests. Students can also get the Morphology of Flowering Plants PDF download. Having revision notes and NCERT Solutions for Class 11 Biology Chapter 5 handy is beneficial to save you time.

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NCERT Class 11 Chapter 5 Class Notes

Morphology of Flowering Plants

With 300,000 known species, flowering plants are the most diverse group of land plants. These plants, also known as angiosperms, have seed-bearing fruits. Flowering plants are thought to have evolved from gymnosperms during the Triassic period, with the first flowering plant appearing 140 million years ago. Standard technical terms and definitions are required for any successful attempt at classification and understanding of any higher plant (or, for that matter, any living organism). We also need to know about the possible differences in various parts identified as adaptations of the plants to their environment such as adaptations to varied habitats, for protection, climbing, storage, and so on.

Parts of Flowering Plants:

The Root

• In most of the dicotyledonous plants, direct radicle elongation results in the formation of a primary root that develops inside the soil. It has lateral roots of various orders, which are referred to as secondary, tertiary, and so on.
• The tap root system, as seen in the mustard plant, is made up of the primary roots and their branches.

• The primary root in monocotyledonous plants is short-lived and is replaced by a large number of roots. These roots grow from the base of the stem and form the fibrous root system which is seen in wheat plants.
• Adventitious roots are roots that are formed from parts of the plant other than the radicle. Grass, Monstera, and the banyan tree are some examples.
• The root system's primary roles are to absorb water and nutrients from the soil, to provide correct anchoring for plant components, to store reserve food material, and synthesize plant growth regulators.

Regions of The Root:

• The root cap is a thimble-like structure that covers the root at its apex. It shields the root's tender apex as it travels through the soil.
• Meristematic activity occurs a few millimetres above the root cap. This region's cells are very small, thin-walled, and have dense protoplasm. They divide repeatedly.
• The cells close to this region undergo rapid elongation and expansion and are responsible for the root's length growth. This region is called the region of elongation.
• The cells of the elongation zone gradually mature and differentiate. As a result, this zone, which is close to the region of elongation, is known as the region of maturation. Some epidermal cells from this region form very fine and delicate thread-like structures known as root hairs. These root hairs are responsible for absorbing water and minerals from the soil.

Modifications of Root:

• Roots are transformed to aid in storage, nitrogen fixation, aeration, and support.
• Carrot tap root, turnip tap root, and sweet potato's adventitious root swell to store food.
• Banyan's prop root and maize and sugarcane stilt root have supporting roots that emerge from the lower node of the stem.
• Pneumatophores help Rhizophora get oxygen for respiration because it grows in swampy areas.

The Shoot System: The Stem

• The ascending portion of the axis that bears branches, leaves, flowers, and fruits is known as the stem. It grows from the plumule of a germinating seed's embryo.
• Nodes and internodes are found on the stem. Nodes are the areas of the stem where leaves develop, whereas internodes are the areas between two nodes. The stem has buds that can be terminal or axillary.
• When young, the stem is generally green, but it quickly turns woody and dark brown.
• The stem's primary function is to spread out branches that bear leaves, flowers, and fruits. Water, minerals, and photosynthates are all carried by it.
• Some stems serve as food storage, support, protection, and vegetative propagation.

Modifications of Stem:

• Stems can be modified to perform a variety of functions. Stems that are underground like Potato, ginger, turmeric, zaminkand, and Colocasia have been modified to store food.
• They also serve as organs of perennation, allowing them to survive in unfavorable growth conditions.
• Stem tendrils, which emerge from axillary buds and are slender and spirally coiled, aid in the climbing of plants such as gourds (cucumber, pumpkins, and watermelon) and grapevines.
• Stem’s axillary buds can also be transformed into woody, straight, and pointed thorns.
• Thorns can be found in a variety of plants, including citrus and bougainvillaea. They shield plants from grazing animals. Some arid-zone plants sculpt their stems into flattened (Opuntia) or fleshy cylindrical (Euphorbia) structures. They have chlorophyll and perform photosynthesis.
• Grass and strawberries, for example, spread their underground stems to new niches and when older parts die, new plants emerge. A slender lateral branch emerges from the base of the main axis in plants such as mint and jasmine and after growing aerially for a time arch downwards to touch the ground.
• Aquatic plants such as Pistia and Eichhornia have lateral branches with short internodes and each node contains a rosette of leaves and a tuft of roots.
• The lateral branches of bananas, pineapples, and Chrysanthemums emerge from the main stem's basal and underground portion, grow horizontally beneath the soil, and then emerge obliquely upward giving rise to leafy shoots.

THE LEAF

• The leaf is a flattened, lateral structure that grows on the stem. It grows from the node and possesses a bud in the axil. The axillary bud develops into a branch over time.
• Leaves grow from shoot apical meristems and are arranged acropetally. They are the most significant photosynthetic vegetative organs.
• A typical leaf is made up of three major parts: the leaf base, the petiole, and the lamina. The leaf base connects the leaf to the stem, and it may have two lateral small leaf-like structures called stipules.
• The leaf base expands into a sheath that partially or completely covers the stem in monocotyledons. The leaf base of some leguminous plants may become swollen, a condition known as pulvinus.
• Thin, long, and malleable Petioles allow leaf blades to flutter in the wind, resulting in cooling the leaf and bringing fresh air to the surface of the leaf.
• The lamina, also known as the leaf blade, is the green expanded part of the leaf that contains veins and veinlets.
• Veins give the leaf blade rigidity and serve as channels for water, minerals, and food materials. The midrib is a prominent vein located in the middle of the body.
• The shape, margin, apex, surface, and extent of lamina incision vary among leaves.

Venation:

• In the leaf lamina, venation refers to the arrangement of veins and veinlets. The venation is referred to as reticulate when the veinlets form a network. Parallel venation occurs when veins run parallel to each other within a lamina.
• The leaves of dicotyledonous plants have reticulate venation, whereas most monocotyledons have parallel venation.

Types of Leaves:

• A simple leaf is a single leaf that cannot be divided into smaller units or leaflets. This type of leaf connects to the stem via the petiole, with no further subdivision.
• When the lamina incisions go up to the midrib, breaking the leaf into a number of leaflets, the leaf is called a compound.
• Both simple and complex leaves have a bud in the axil of the petiole, but not in the axil of the compound leaflet.
• There are two kinds of compound leaves. A pinnately compound leaf, such as a neem, has a number of leaflets on a common axis called the rachis, which symbolizes the leaf's midrib.
• As in silk cotton, the leaflets of palmately compound leaves are linked at a common point, such as the apex of the petiole.

Phyllotaxy

• The pattern of leaf arrangement on a stem or branch is known as phyllotaxy. This is usually divided into three types: alternate, opposite, and whorled (Figure 5.9). As in China rose, mustard and sunflower plants, an alternate type of phyllotaxy occurs in which a single leaf emerges at each node in an alternate manner.
• In the opposite type, as in Calotropis and guava plants, a pair of leaves emerges at each node and lie opposite each other. It is called whorled when more than two leaves emerge from a node and form a whorl, as in Alstonia.

Modifications of Leaves:

• Other than photosynthesis, leaves are frequently modified to perform other functions. In peas, they are converted into tendrils for climbing, and in cacti, they are converted into spines for defence.
• Onion and garlic leaves have fleshy leaves that store food. The leaves of some plants, such as Australian acacia, are small and short-lived. Petioles turn green, synthesize food and expand in these plants.

The Inflorescence

• A flower is a modified shoot in which the apical meristem of the shoot transforms into the floral meristem.
• The axis becomes condensed as the internodes do not stretch. Instead of leaves, the apex generates several types of floral appendages at consecutive nodes.
• The transformation of a shoot tip into bloom is always solitary. Inflorescence refers to the arrangement of flowers along the loral axis.
• The primary axis of racemose inflorescences continues to develop, while the flowers are borne laterally in acropetal succession.
• A cymose inflorescence's principal axis comes to a halt in a flower, limiting its growth. In a basipetal design, the blooms open.

The Flower

• In angiosperms, the flower is the reproductive unit. It's designed to be used for sexual reproduction.
• On the swollen end of the stalk or pedicel, called the thalamus or receptacle, a typical flower has four different kinds of whorls grouped sequentially.
• Calyx, corolla, androecium, and gynoecium are the four parts of the flower. Androecium and gynoecium are reproductive organs, whereas calyx and corolla are accessory parts.
• If a flower possesses both androecium and gynoecium, it is bisexual. Unisexual flowers are those that have just stamens or carpels.
• The flower can be actinomorphic (radial symmetry) or zygomorphic (bilateral symmetry) in terms of symmetry.
• Actinomorphic flowers, such as mustard, datura, and chilli, may be split into two equal radial halves in any radial plane running through the Centre.
• It is zygomorphic when it can be separated into two comparable halves only in one vertical plane, as in pea, Gul mohur, bean, and Cassia. A flower, such as a canna, is asymmetric if it cannot be divided into two equivalent halves by any vertical line passing through the centre(irregular).
• When the floral appendages are in multiples of 3, 4, or 5, a flower is said to be trimerous, tetramerous, or pentamerous. Bracteate flowers have a shortened leaf at the base of the pedicel, whereas ebracteate flowers do not have bracts.
• The gynoecium is at the top of the hypogynous flower, while the rest of the components are below it. Such flowers, such as mustard, china rose, and brinjal, is considered to have superior ovaries.
• It's called perigynous when the gynoecium is in the centre and the other components of the flower are virtually at the same level on the thalamus's rim. Plum, rose, and peach, for example, have a half inferior ovary.
• The thalamus margin develops upward in epigynous flowers, entirely enclosing and fusing with the ovary; the other components of the flower ascend above the ovary.

Parts of a Flower:

Calyx:

Sepals are the members of the calyx, which is the flower's outermost whorl. Sepals are green, leaf-like structures that protect the flower when it is in the bud stage. The calyx can be either gamosepalous (all sepals are together) or polysepalous (all sepals are apart).

Corolla:

Petals make up the corolla. Petals are often vividly coloured to attract pollinating insects. The corolla, like the calyx, can be gamopetalous (petals joined) or polypetalous (petals separated).

Aestivation:

Aestivation refers to the way sepals or petals of a floral bud are arranged in relation to the other members of the same whorl. Valvate, twisted, imbricate, and vexillary aestivation are the most common kinds.

• It is described to be valvate when the sepals or petals of a whorl only touch at the margin, without overlapping, as in Calotropis.
• When one appendage's edge overlaps that of the next, and so on, as in the china rose, lady's finger, and cotton, the aestivation is said to be twisted.
• Imbricate aestivation occurs when the borders of sepals or petals overlap but not in any specific orientation, as in Cassia and Gul mohur.
• The biggest petal overlaps the two lateral petals, which overlap the two smallest anterior petals in pea and bean flowers; this kind of aestivation is known as vexillary.

Androecium:

Stamens make up the androecium. A stalk or filament and an anther make up each stamen, which represents the male reproductive organ. Each anther is normally bilobed, with two pollen-sac chambers in each lobe. Pollen-sacs are used to manufacture pollen grains. The staminode is the name for a sterile stamen.

• Flower stamens can be joined to other components of the flower, such as petals, or to each other. When stamens are connected to the perianth, they are epiphyllous, like in lily flowers, and are epipetalous when stamens are connected to the petals.
• A flower's stamens can either remain free (polyandrous) or be joined to varying degrees. The stamens can be grouped into a single bunch or bundle (monadelphous) as in the china rose, or two bundles (diadelphous) such as in pea, or more than two bundles (polyadelphous) as in citrus.

Gynoecium:

The female reproductive organ of the flower, made up of one or more carpels, is known as the gynoecium. The stigma, style, and ovary are the three sections of a carpel. The expanded basal portion of the ovary is where the elongated tube, the style, is located.

The ovary is linked to the stigma by the style. The stigma is the receptive surface for pollen grains and is generally found near the tip of the style. One or more ovules are linked to a flattened, cushion-like placenta in each ovary.

• When there are several carpels present, they might be free (as in the lotus and rose) and are referred to as apocarpous.
• When carpels fuse, as in mustard and tomato, they are called syncarpous. The ovules develop into seeds after fertilization and the ovary matures into a fruit.

Placentation

The arrangement of ovules within the ovary is referred to as placentation. There are several varieties of placentation which are marginal, axile, parietal, basal, central, and free central.

• The placenta forms a ridge along the ventral suture of the ovary in marginal placentation, and the ovules are carried in two rows on this ridge, as in pea.
• The placentation is considered to be axile when the placenta is axial and the ovules are linked to it in a multilocular ovary, as in the china rose, tomato, and lemon.
• Ovules form on the inner wall of the ovary or on the peripheral region in the parietal placentation.
• The placentation is called free central when the ovules are carried on the central axis with no septa, as in Dianthus and Primrose.
• As in sunflower and marigold, the placenta forms at the base of the ovary and is connected to a single ovule in basal placentation.

THE FRUIT

• Flowering plants are known for their fruit. After fertilization, it is a mature or ripened ovary. A parthenocarpic fruit is one that is produced without the need for fertilization for the ovary.
• A wall or pericarp and seeds make up the majority of the fruit. The pericarp can be dry or meaty depending on the fruit.
• The outside epicarp, the middle mesocarp, and the inner endocarp are formed when the pericarp is thick and meaty.
• An exterior thin epicarp, a middle mushy edible mesocarp, and an interior stony hard endocarp are distinguished in the mango pericarp. The mesocarp of coconut, which is a drupe, is also fibrous.

The Seed

After fertilization, the ovules mature into seeds. There are two components to a seed: the seed coat and the embryo. A radicle, an embryonal axis, and one or two cotyledons make up the embryo.

Structure of a Dicotyledonous Seed:

• The seed coat is the seed's outermost coating. The outer testa and the inner tegmen make up the seed coat.
• The hilum is a scar on the seed coat that connects the growing seeds to the fruit. The micropyle is a tiny pore located above the hilum.
• The embryo, which consists of an embryonal axis and two cotyledons, is contained within the seed coat. The cotyledons are usually plump and rich with food reserves. The radicle and the plumule are located at the two extremities of the embryonal axis.
• The endosperm developed as a result of multiple fertilization in some seeds, such as castor, is a food-storing tissue and is referred to as endospermic seeds. The endosperm is absent in mature seeds and such seeds are called non-endospermous.

Structure of Monocotyledonous Seed:

• Some monocotyledonous seeds are endospermic, whereas others, such as those found in orchids, are non-endospermic. The seed coat of cereal seeds, such as maize, is membranous and usually united with the fruit wall.
• The endosperm is a large, thick organ that stores food. The embryo is separated from the outer coating of the endosperm by a proteinous layer known as the aleurone layer.
• The embryo is tiny and sits in a groove at one end of the endosperm. It consists of a scutellum, a huge shield-shaped cotyledon, and a short axis with a plumule and radicle. Coleoptile and coleorhiza are sheaths that surround the plumule and radicle respectively.

Semi-Technical Description of a Typical Flowering Plant

A blooming plant is described by a variety of morphological traits. The description must be succinct, written in plain and scientific language, and given in the correct order. The plant's habit, vegetative properties such as roots, stems, and leaves, and floral characteristics such as inflorescence and flower components should be discussed first.

• A floral diagram and a floral formula are offered after discussing various components of the plant. Symbols are used to represent the flower formula.
• Br stands for bracteate, K for calyx, C for corolla, P for perianth, A for androecium, G stands for Gynoecium, G stands for superior ovary and Ḡ for inferior ovary; ♂ for male, ♀ for female, ⚥ for bisexual plants, ⊕ for actinomorphic and % for zygomorphic flower. Fusion is represented by enclosing the figure within a bracket, and adhesion is represented by a line drawn above the floral part symbols.
• A floral diagram shows how many pieces make up a flower, how they're arranged, and how they are related. A dot on the top of the floral diagram indicates the position of the mother axis in relation to the flower.
• The calyx, corolla, androecium, and gynoecium are drawn in whorls, with the calyx on the outside and the gynoecium in the centre.

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Morphology of Flowering Plants Class 11th Notes will assist you in revising the chapter and gaining an understanding of the main subjects addressed. These Notes for Class 11 Biology Chapter 5 are also beneficial for covering the main themes of the CBSE Biology Syllabus in Class 11 as well as for competitive exams such as AIPMT, AIIMS, NEET, and others. The Class 11 Biology chapter 5 notes pdf download can be utilized for offline preparation.

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