Morphology of Flowering Plants

Sol. From the region of maturation, some epidermal cells form very fine and delicate, thread like structures called root hairs.

Is the floral formula for Solanaceae.

It shows actinomorphic, bisexual, pentamerous flower with epipetalous condition

Generally in Solanaceae, calyx (K) and Corolla (C) shows fusion in sepals and petals respectively.

Hence the floral formula must exhibit gamosepalous and gamopetalous condition.

In racemose type of inflorescence, the main axis continues to grow and the flowers are borne laterally in an acropetal succession. On the contrary, in cymose type of inflorescence, the main axis terminates into a flower and hence, is limited in growth.

Marginal placentation is found in pea, axile placentation is found in lemon, parietal placentation is found in mustard and basal placentation is found in marigold.

Phyllotaxy is the pattern of arrangement of leaves on the stem.

Marginal placentation - Pea

Axile placentation - Tomato

Parietal placentation - Argemone

Free central placentation - Primrose

In Solanaceae family, flowers are bisexual and actinomorphic. Calyx include five sepals that are united. Androecium include five stamens and it is epipetalous. Ovary is superior.

Zygomorphic flowers can be divided into two equal halves by only a single vertical plane and shows bilateral symmetry.

Pea possess zygomorphic flowers.

Chilli, Petunia and Datura possess actinomorphic flowers.

The floral formula symbol $\oplus$ is used for actinomorphic flower, while $\%$ is used for zygomorphic flower.

The symbol G represents gynoecium and $\underline{\mathrm{G}}$ symbol represent superior ovary, while inferior ovary is represented by $\bar{G}$.

Thus, statement I is incorrect and Statement II is correct.

In pea, vexillary aestivation is found.

Perigynous flowers are observed in peach.

Epiphyllous stamens are found in lily.

Epipetalous stamens are found in brinjal.

China rose exhibits axile placentation.

Mustard exhibits parietal placentation.

Primrose exhibits free central placentation.

Marigold exhibits basal placentation.

To determine the correct answer, let's first understand the terms monocarpellary, unilocular, and the presence of many ovules.

A monocarpellary ovary is one that is formed from a single carpel. A unilocular ovary means that the ovary develops a single locule or chamber. Having many ovules indicates that numerous ovules are contained within this single locule. Now, let's examine each plant:

Sesbania: Monocarpellary and unilocular with many ovules.

Brinjal (Eggplant): Typically, this has a bicarpellary (two carpels) and bilocular (two chambers) ovary, not fitting the criteria.

Indigofera: Monocarpellary and unilocular with many ovules.

Tobacco: Usually has a bicarpellary and bilocular ovary, so it does not meet the criteria.

Asparagus: It usually has a tricarpellary and trilocular ovary, so it does not fit the criteria.

Based on the above information, the plants that have monocarpellary, unilocular ovaries with many ovules are Sesbania and Indigofera.

Therefore, the correct answer is:

Option D: A and C only

The correct answer is:

An actinomorphic flower is one that can be divided into two equal halves along any plane passing through its center. This is also known as radial symmetry.

• Datura flowers exhibit radial symmetry, as their petals are arranged in a circular pattern around the center.

The other options are incorrect:

• Cassia: Zygomorphic (bilateral symmetry)


• Pisum: Zygomorphic (bilateral symmetry)


• Sesbania: Zygomorphic (bilateral symmetry)

The radicle is the part of the seed that will develop into the root when the seed germinates.

In the provided diagram, 'C' represents the radicle.

If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called perigynous.

Both diagram shows perigynous condition.

Bulliform cells, which are specialized cells found in the leaves of many monocot plants such as grasses, play a crucial role in responding to environmental stress conditions like water scarcity. Their primary function is associated with the mechanism of leaf folding or rolling during drought or high temperature conditions. This adaptive feature helps in reducing the leaf surface exposed to the air, thereby minimizing water loss through transpiration.

Now, let’s evaluate each option in relation to the role of bulliform cells:

Option A: Inward curling of leaves in monocots.

This option is correct. Bulliform cells are large, thin-walled, and filled with water. When these cells lose water under dry conditions, they collapse, causing the leaf to fold or roll inward. This curling mechanism helps to reduce the exposure of the surface area of the leaf to the harsh environment, thus reducing water loss and protecting the plant during drought.

Option B: Protecting the plant from salt stress.

This option is not correct. While bulliform cells are involved in protecting the plant by reducing transpiration, their role specifically in protecting from salt stress isn't well-documented. Salt stress protection involves other physiological and biochemical responses in plants.

Option C: Increased photosynthesis in monocots.

This is also incorrect. Bulliform cells do not directly influence photosynthesis rates. Their function is mainly related to the mechanical folding of the leaf, which indirectly may influence photosynthetic efficiency under stress conditions but is not their primary role.

Option D: Providing large spaces for storage of sugars.

This option is incorrect. Bulliform cells are not involved in the storage of sugars. Their structure and function are geared towards managing water content for leaf folding mechanisms, rather than nutrient storage.

Therefore, the correct answer is Option A: Inward curling of leaves in monocots.

Rose have half-inferior ovary, thus it is known as Perigynous flower.

In Pea, the placenta form a ridge along the ventral suture of the ovary and ovules are borne on this ridge forming two rows.

In Cotton, twisted aestivation is present.

In Mango, fruit is drupe.

The correct answer is: Option A: A-IV, B-II, C-I, D-III

• Monoadelphous: Stamens united into a single bundle by their filaments. Example: China rose


• Diadelphous: Stamens united into two bundles by their filaments. Example: Pea


• Polyadelphous: Stamens united into more than two bundles by their filaments. Example: Citrus


• Epiphyllous: Stamens arise from the perianth (sepals and petals) rather than from the receptacle. Example: Lily

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

Imbricate aestivation is exhibited by Cassia,

Twisted aestivation is exhibited by China rose,

Vexillary aestivation is exhibited by Pea.

The correct answer is :

Option D : Standard, Wings and Keel

In a typical pea flower, which is a type of papilionaceous flower, the petals are arranged in a specific pattern. The single large posterior petal, often larger and more visually striking than the others, is known as the 'standard' or 'banner'. The two lateral petals are referred to as 'wings'. The two anterior petals are usually fused at their edges and form a structure that looks like a boat's keel, which is why they are called the 'keel'. So, the arrangement is 'Standard, Wings and Keel'.

1. Zygomorphic : These are flowers that can only be divided into two equal halves by one particular vertical plane. An example is the flower of Cassia.




2. Hypogynous : In these types of flowers, the gynoecium occupies the highest position while the other parts are situated below it. The flower is said to have a superior ovary and is hypogynous. An example of a hypogynous flower is mustard.




3. Perigynous : In these flowers, the gynoecium is located in the center and other floral parts are located on the rim of the thalamus almost at the same level. The ovary here is said to be half inferior. Plum flowers are examples of perigynous flowers.




4. Epigynous : In these flowers, the margin of thalamus grows upward enclosing the ovary completely and gets fused with it, the ovary is said to be inferior as the other floral parts are situated above the ovary. An example of an epigynous flower is cucumber.

Fabaceae $\to$ Diadelphous and dithecous anther.

Solanaceae $\to$ Polyandrous, epipetalous and dithecous anther.

Liliaceae $\to$ Polyandrous, epiphyllous and dithecous anther.

The correct answer is :

Option D : Both A and R are true and R is the correct explanation of A

Explanation :

Statement A is true. A flower is indeed a modified shoot wherein the shoot apical meristem changes to a floral meristem.

Statement R is also true. In the process of flower formation, the internodes of the shoot get condensed, and instead of leaves, different floral appendages (such as sepals, petals, stamens, and carpels) are produced laterally at successive nodes.

Moreover, Statement R is indeed the correct explanation for Statement A. The transition from the shoot apical meristem to the floral meristem involves the condensation of internodes and the lateral production of floral appendages at nodes, which leads to the formation of a flower.

Rhizome is an underground (sub-aerial) stem. It bears distinct nodes and internodes.

The sclereids are the spherical, oval or cylindrical, highly thickened dead cells with very narrow cavities (lumen). These are found commonly in the fruit wall of nuts.

Imbricate aestivation is found in Cassia

Valvate aestivation is found in Calotropis

Vexillary aestivation is found in Bean

Twisted aestivation is found in cotton

The floral diagram given in the question represents Brassicaceae family. It can be easily identified by looking on its parietal placentation.

Axillary buds of stems get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus and Bougainvillea.

$\bullet$ Vexillary aestivation and diadelphous stamens are the characteristic features of family Fabaceae.

$\bullet$ Pisum sativum (garden pea) belongs to family Fabaceae.

$\bullet$ Allium cepa (onion) and Colchicum autumnale (colchicine) belong to family Liliaceae.

$\bullet$ Solanum nigrum belongs to Solanaceae.

When a flower can be divided into two similar halves only in one particular vertical plane, it is zygomorphic for e.g. pea, gulmohar, bean, Cassia. Mustard, Datura and Chilly show actinomorphic flowers.

The given figure is of a false unit. False fruit develops from other floral parts and thalamus alongwith the development of ovary wall.

Both options (a) and (b) are correct.

A flower is called hypogynous, when the innermost floral whorl (gynoecium) occupies the highest position (superior)-Corolla and calyx are successively arise below it (inferior), e.g. Brassica, China rose, Papaver, Citrus, Solanum, cotton, etc. In perigynous flower, all the floral whorls are occurred at the same level of height on the thalamus, so they are called half superior or half inferior, e.g. rose, peach and Prunus, plum, etc. In an epigynous flower, the innermost whorl, i.e. gynoecium is covered by the elongated margins of thalamus. Thus, their position is inferior in relation to other floral whorls, which arise above the ovary and thus superior, e.g. guava, cucumber (Cucurbita) and coriander.

Pea, bean, Cassia, gulmohar flowers show zygomorphic symmetry.

When the flower is bilaterally symmetrical, i.e. divisible into only two equal halves by a single vertical plane, it is termed as zygomorphic, e.g. pea, bean, Cassia and gulmohar.

Datura, mustard, Chilly, Canna are examples of Actinomorphic flower which show regular or radial symmetry.

The statement in option (d) is incorrect. Apple is a false fruit. Any fruit which develops from any other part of flower then ovary is called false fruit. In apple the thalamus of flower becomes juicy and edible, hence it is false fruit.

Leaf tendrils are specialised thread-like sensitive structures, which are unbranched and devoid of scales. They can coil around a support and thus, help to the plants in climbing.

The given plant belongs to the family Papilionaceae. Characters of this family include corolla papilionaceous, petals 5, posterior odd petals is called standard, two lateral ones fused to form a keel or carina.

Valvate petals are close to each other and do not overlap. In twisted, petals overlap each other regularly.

In imbricate, there are five petals, arranged in such a way that one petal is completley external and one is completely internal. In quincuncial, two out of five petals are completely external and remaining 3 are partially external and partially internal. In vexillary, the posterior petal overlaps the two smaller lateral petals and later in turn overlap the two anterior petals.

Caryopsis and achenes develop from monocarpellary unilocular, one-seeded and superior ovaries. The only difference in them is that, in caryopsis, pericarp and seed coat are fused. Caryopsis is common in Poaceae family.