Morphology Of Flowering Plants

C, B, E, A, D

Explanation:

Root cap zone – The root is covered at the apex by a thimble-like structure called the root cap.

Zone of Meristem – It is a region just above the root cap. The cells of this region are very small, thin-walled and with dense protoplasm. They divide repeatedly.

Zone of elongation – The cells of this region undergo rapid elongation and enlargement and are responsible for the growth of the root in length. This region is called the region of elongation.

Zone of maturation – The cells from the zone of elongation when differentiate and mature gradually, they enter the zone of maturation.

Root hair zone – From zone of maturation, some of the epidermal cells form very fine and delicate, thread-like structures called root hairs.

Distal

Explanation:

Such type of inflorescence is called racemose type inflorescence. In such type of inflorescence, the flowers are borne laterally in acropetal succession which means the oldest flower is near the base and newest flower is present at the apex or distal. In this type of inflorescence, the growth of floral axis is unlimited.

Endosperm gets used up by the developing embryo during seed development

Explanation:

The developing embryo of the seed needs nourishment which is provided by the tissue called endosperm. In plants like grams and peas, the mature seeds don’t possess endosperm because during the development, the entire endosperm gets used up by the embryo and hence they are called non-endospermic.

Adventitious roots

Explanation:

The taproots are the roots which develop from the radicle and are found in dicotyledonous plants. Example – Mustard plant

The fibrous roots are the roots which develop from the radicle and are found in monocotyledonous plants. Example – Wheat plant

Nodular roots are also modifications of tap roots in which roots and its branches develop small or large swellings called nodules. They help in nitrogen fixation. Example - Pulses

In some plants, roots arise from parts of the plant other than the radicle and are called adventitious roots. Example - grass, Monstera and the banyan tree.

Veins and veinlets in lamina

Explanation:

Venation is the term that is used to describe the pattern of arrangement of veins and veinlets of lamina. When the veinlets form a network, the venation is termed as reticulate. When the veins run parallel to each other within a lamina, the venation is termed as parallel.

Orchids

Explanation:

The endosperm is a product of double fertilization in angiosperms and is a storing tissue which provides nourishment to the developing embryo.
The plants with seeds with no endosperm are called non-endospermic. This happens because the complete endosperm gets used up by the embryo during its development. In the above given options, only orchid is a non-endospermic plant.

Fabaceae

Explanation:

Fabaceae is the family of Trees, shrubs, herbs; root with root nodules.
Pulses have roots with root nodules. Hence they belong to the family Fabaceae. This family was earlier called Papilionoideae, a subfamily of family Leguminosae (the family of legumes or pulses).

Hilum

Explanation:

The placenta is attached to the developing seed near the Hilum. The hilum is a scar on the

seed coat through which the developing seeds were attached to the fruit.

Above the hilum is a small pore called the micropyle.

The outer layer of the seed coat is called testa.

Chalaza is a tissue where nucellus and integument are joined. Nutrients from the plant travel through vascular tissue in the funiculus and outer integuments through the chalaza into the nucellus.

Indigofera

Explanation:

The blue dye is extracted from Indigofera.

The Cassia is a shrub used as an ornamental plant.

Lupin is also an ornamental plant.

Trifolium is used as fodder.

A – ii, The outer covering of endosperm separates the embryo by a proteinous layer called aleurone layer.

B – i, Pathenocarpic fruits are the fruits which are formed without the fertilization of the ovary.

C – iv, The ovules after fertilisation, develop into seeds.

D – iii, Endosperm is formed as the result of double fertilization.

In some plants such as Rhizophora growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots, called pneumatophores, help to get oxygen for respiration.

Bisexual is represented by . Actinomorphic is represented by. Pentamerous sepals i.e. 5 sepals is represented by . 5 petals is represented by . 5 stamens is represented by . The no. of carpels is not mentioned in the question so the question is incomplete to provide a floral formula.

Opuntia is a desert plant. Its stem is modified into a flattened green structure to perform the photosynthesis.

In some plants, roots become assimilatory as in the case of Trapa and Tinospora. These roots grow outside the soil, develop chlorophyll in them and perform photosynthesis.

In Australian Acasia the petiole takes the shape of leaf and turns green to perform te function of photosynthesis.

The stem, i.e., about one internode long modifies into a leaf like structure to carry out photosynthesis, as in Asparagus.

In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called pneumatophores.

Explanation:

In some plants such as Rhizophora growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots, called pneumatophores, help to get oxygen for respiration.

In aquatic plants like Pistia and Eichhornia, leaves and roots are found near Node.

Explanation:

A lateral branch with short internodes and each node bearing a rosette of leaves and a tuft of roots is found in aquatic plants like Pistia and Eichhornia.

Reticulate and parallel venation are characteristic of dicotyledons and monocotyledons respectively.

Explanation:

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.

When the veinlets form a network, the venation is termed as reticulate. It is found in dicots.

When the veins run parallel to each other within a lamina, the venation is termed as parallel. It is found in monocots.

In ginger, edible part is rhizome which is modified shoot that stores food materials. The edible part of onion is fleshy scale leaves.

In epigynous flower, ovary is situated below the sepals, petals and androecium.

Explanation:

In epigynous flowers, the margin of thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of flower arise above the ovary. Hence, the ovary issaid to be inferior as in flowers of guava and cucumber, and the ray florets of sunflower.

The given floral formula lacks Corolla. The floral formula of the family Fabaceae is % .

The flowers of Fabaceae are bisexual, zygomorphic, have Calyx – sepals 5, gamosepalous, corolla-petals 5, consists of a posterior standard, two lateral wings, two anterior ones forming a keel, androecium – ten, diadelphous, gynoecium-superior, ovary monocarpellary.

a. Carrot – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Tap roots of carrot get swollen and store food.

b. Colocasia – Stem

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions. Underground stems of Colocasia are modified to store food in them.

c. Sweet potato – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Adventitious roots of sweet potato get swollen and store food.

d. Asparagus – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Adventitious roots of Asparagus get swollen and store food.

e. Radish – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Tap roots of radish get swollen and store food.

f. Potato – Stem

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions. Underground stems of potato are modified to store food in them.

g. Dahlia – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Adventitious roots of Dahlia get swollen and store food.

h. Turmeric – Stem

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions. Underground stems of turmeric are modified to store food in them.

i. Gladiolus – Stem

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions. Underground stems of Gladiolus are modified to store food in them.

j. Ginger – Stem

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions. Underground stems of ginger are modified to store food in them.

k. Portulaca – Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. They are modified for support, storage of food and respiration. Tap roots of Portulaca get swollen and store food.

In some plants, roots arise from parts of the plant other than the radicle. Such roots are called adventitious roots.

Banyan tree – roots develop from the lower nodes of the stem. They are prop roots which grow downwards and touch the soil. They meant for the support.

Sugarcane – roots arise from the lower nodes of stem and enter the soil. They are stilt roots which are meant to provide strength to the plant.

The terrestrial plants have roots which have mainly the function of anchorage and absorption of minerals and water. The aquatic plants don’t have to face problem in obtaining the water. Therefore the main function of the roots of the aquatic plants is anchorage.

Difference between the roots of aquatic plants and terrestrial plants –

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.

When the veinlets form a network, the venation is termed as reticulate.

When the veins run parallel to each other within a lamina, the venation is termed as parallel.

Leaves of dicotyledonous plants generally possess reticulate venation, while parallel venation is the characteristic of most monocotyledons.

In the above picture, the first leaf shows parallel venation which is shown by leaves in monocots like maize, grass etc. and the second leaf has reticulate venation which is shown by leaves in dicots like pea, gram, etc.

A typical angiosperm flower consists of 4 floral parts namely – calyx, corolla, androecium, gynoecium.

Calyx – It is the outermost whorl of the flower and the members are called sepals which are green, leaf like and protect the flower in the bud stage.

Corolla – It is composed of petals. Petals are usually brightly coloured to attract insects for pollination.

Androecium – It is composed of stamens. Each stamen which represents the male reproductive organ consists of a stalk or a filament and an anther.

Gynoecium – It is the female reproductive part of the flower and is made up of one or more carpels. A carpel consists of three parts namely stigma, style and ovary.

(i) The given floral formula shows that the flower from Solanceae family.

(ii) The given floral formula is a flower from Fabaceae family.

(iii) The given floral formula is a flower from Malvaceae family.

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.

When the veinlets form a network, the venation is termed as reticulate.

When the veins run parallel to each other within a lamina, the venation is termed as parallel.

Leaves of dicotyledonous plants generally possess reticulate venation, while parallel venation is the characteristic of most monocotyledons.

There are a few exceptions like Smilax and Discorea are monocots with reticulate venation and Calophyllum and Eryngium are dicots with parallel venation.

Leaves are often modified to perform functions other than photosynthesis. Leaves of certain insectivorous plants such as pitcher plant, venus-fly trap are also modified leaves. In pitcher plant, the leaf is modified into pitcher. The pitcher plant can’t photosynthesize like other green plants so it get its food from the insects as these insects are good source of Nitrogen for the insectivorous plants.

Generally, the fruit consists of a wall or pericarp and seeds. The pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.

The edible part of coconut is endosperm. The milk of tender coconut represents the oily endosperm in liquid form. Later it gets deposited along the walls of endocarp and forms edible flesh.

The arrangement of ovules within the ovary is known as placentation.

When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentaion is said to be axile. Examples - china rose, tomato and lemon.

When the ovules are borne on central axis and septa are absent, the placentation is called free central. Examples - Dianthus and Primrose.

a. Cucumber – Stem tendrils

Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb.

b. Peas – Leaf tendrils

Leaves are often modified to perform functions other than photosynthesis. They are converted into tendrils for climbing.

c. Pumpkins – stem tendrils

Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb.

d. Grapevines – stem tendrils

Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb.

e. Watermelons – stem tendrils

Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb.

The maize grain is usually called fruit because it is a ripened ovary which contains a ripened ovule.
This fruit is caryopsis in which the pericarp is fused with the seed coat. The maize grain occurs attached to a thick cob or peduncle.

The stem may not always be typically like what they are expected to be. They are modified to perform different functions.

Stem tendrils develop from axillary buds. They are slender and spirally coiled and help plants to climb.

Leaves are often modified to perform functions other than photosynthesis. They are converted into tendrils for climbing.

The tendrils of grapevines are homologous to the tendril of pumpkins as both are originated from the same part of the plant i.e. stem but have different functions. In grapevines, the function of tendrils is to climb while in pumpkin is creeping.

The tendrils of grapevines are analogous to the tendrils of pea because they have different origins i.e. stem and leaf respectively but they have same function i.e. climbing.

Rhizome is an underground stem which grows parallel to the soil surface. The adventitious root arises from the lower surface of nodes.

Ginger is a stem not a root because it posses nodes and internodes which are not possessed by the roots.

a.

b.

c.

d.

e.

f.

Economic Importance of Fabaceae –

Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean; edible oil (soyabean, groundnut); dye (Indigofera); fibres (sunhemp); fodder (Sesbania, rifolium), ornamentals (lupin, sweet pea); medicine (muliathi).

Economic Importance of Solanceae –

Many plants belonging to this family are source of food (tomato, brinjal,potato), spice (chilli); medicine (belladonna, ashwagandha); fumigatory(tobacco); ornamentals (petunia).

Economic importance of Liliaceae –

Many plants belonging to this family are good ornamentals (tulip, Gloriosa), source of medicine (Aloe), vegetables (Asparagus), and colchicine (Colchicum autumnale).

The stem may not always be typically like what they are expected to be.

They are modified to perform different functions like:

i) Food storage – Underground stems of potato, ginger, turmeric, zaminkand, Colocasia are modified to store food in them.

ii) Climbing – Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

iii) Protection – Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus, Bougainvillea. They protect plants from browsing animals.

The mode of arrangements of sepals or petals in a floral bud is known as aestivation.

There are 4 types of aestivations, namely –

i. Valvate –

When sepals or petals in a whorl just touch one another at the margin, without overlapping, as in Calotropis, it is said to be valvate.

ii. Twisted –

If one margin of the appendage overlaps that of the next one and so on as in china rose, lady’s finger and cotton, it is called twisted.

iii. Imbricate –

If the margins of sepals or petals overlap one another but not in any particular direction as in Cassia and gulmohur, the aestivation is called imbricate.

iv. Vexillary –

In pea and bean flowers, there are five petals, the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel); this type of aestivation is known as vexillary.

Each ovary bears one or more ovules attached to a flattened, cushion-like structure called placenta.

The arrangement of ovules within the ovary is known as placentation. There are various types of placentations, namely:

a) Marginal - In marginal placentation, the placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows. Example - pea.

b) Axile - When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentaion is said to be axile. Examples - china rose, tomato and lemon.

c) Parletal - In parietal placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but it becomes two-chambered due to the formation of the false septum, e.g., mustard and Argemone.

d) Free – Central - When the ovules are borne on central axis and septa are absent, the placentation is called free central. Examples - Dianthus and Primrose

e) Basal - In basal placentation, the placenta develops at thebase of ovary and a single ovule is attached to it. Examples - sunflower, marigold.

Sunflower is not a flower, but it is a kind of inflorescence called capitulum in which the receptacle is flattened. It bears numerous sessile and small florets. The youngest floret is in the centre and oldest lies at the periphery. Whole cluster of florets gets surrounded by bracts, known as involucre. Two kinds of florets are recognised in sunflower:

(i) Ray Florets - Arranged on the rim of receptacle having distinct yellow and strap-shaped petals. These florets are female, sterile and are always zygomorphic and may be arranged in one or more whorls.

(ii) Disc florets - Grouped in the centre, bisexual and actinomorphic.

Difference between hypogeal germination and epigeal germination:

Role of Cotyledons and Endosperm in the germination of seeds –

They contain reserved food materials. When seed imbibes water, enzymes get activated, hydrolyze reserve food material and make it available for the germinating seed.

Dormant seeds remain under non-germination conditions only for a specific period of time that may vary from days to years. This specific period is called dormancy period.

Reasons for seed dormancy –

• Impermeable and hard seed coat

• Presence of chemical inhibitors like abscisic acid

• Immature embryo

Methods to break seed dormancy are –

• Washing away of inhibitors due to rain

• Maturation of embryo

• Inactivation of growth inhibitors due to heat or cold treatment.

• Weakening and decomposition of seed coat by microorganisms.