Taxonomy of Angiosperms (SAQs)

Botany-1 | 8. Taxonomy Of Angiosperms – SAQs:
Welcome to SAQs in Chapter 8: Taxonomy Of Angiosperms. This page includes the most important FAQs from previous exams. Each answer is provided in simple English, followed by a Telugu explanation, and presented in the exam format. This approach helps you prepare effectively and aim for top marks in your final exams.

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SAQ-1 : Describe the non-essential floral parts of plants belonging fabaceae.

Introduction:

The Fabaceae family, also known as the pea or legume family, includes many plants with unique flower parts. These parts, such as the calyx and corolla, help in identifying and classifying these plants.

Calyx:

The calyx is the outermost layer of the flower and consists of sepals. In the Fabaceae family, the calyx usually has five sepals that are joined together.

For example, in a pea flower, the calyx forms a cup-like shape with five sepals that protect the developing flower.

The sepals can be arranged in different ways:

• Valvate Aestivation: The sepals overlap slightly but don’t fully cover each other. You might see this in a clover flower.
• Imbricate Aestivation: The sepals overlap completely, as seen in a bean flower.

In these flowers, one sepal is often different from the others and is positioned at the front, while the rest are at the back.

Corolla:

The corolla is the second layer of the flower and consists of petals. In Fabaceae flowers, there are five separate petals.

These petals are arranged in a special way called “papilionaceous” or butterfly-like:

• Standard Petal: The large, colorful petal at the back, like in a sweet pea.
• Wings: Two smaller petals on the sides, found in flowers like lupins.
• Keels: Two petals at the front that are joined together to form a protective covering around the flower’s reproductive parts. For example, in lupin flowers, the keels help protect the stamens and pistil.

Aestivation:

In Fabaceae flowers, the petals are arranged in a specific way:

• Vexillary Aestivation: The standard petal is on the outside and partly covers the wings. You can see this in legume flowers.
• Descendingly Imbricate Aestivation: The joined petals (keels) overlap in a descending order, as seen in soybean flowers.

Summary:

Plants in the Fabaceae family have distinct floral structures. The calyx has five joined sepals, while the corolla has five separate petals arranged in a butterfly-like pattern. Understanding these features helps in identifying and classifying these plants.

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SAQ-2 : Describe the essential floral parts of plants belonging to liliaceae.

Introduction:

The Liliaceae family includes plants like lilies and tulips. To understand these plants, it’s important to know their main flower parts: the androecium (male parts) and the gynoecium (female parts).

Androecium:

The androecium is the part of the flower that makes pollen.

In Liliaceae plants:

• Stamens: There are six stamens arranged in two circles of three (3+3). These stamens are attached to the tepals (petals and sepals that are not clearly separated).
• Anthers: Each stamen has an anther with two pollen sacs. The anthers are fixed at their base and open inwards to release pollen. They split lengthwise to let the pollen out.

Gynoecium:

The gynoecium is the part of the flower that contains the ovary and is responsible for producing seeds.

In Liliaceae plants:

• Carpels: There are three fused carpels that make up a single pistil. The carpels form a single structure that holds the ovary.
• Ovary: The ovary is positioned above where other flower parts attach and has three chambers inside.
• Ovules: Many ovules are attached to the central axis of the ovary.

Style and Stigma:

• Style: The style is a tube connecting the ovary to the stigma and is located at the top of the ovary.
• Stigma: The stigma is divided into three parts and is rounded at the top.

Summary:

Liliaceae plants have unique flower structures. The androecium has six stamens with two pollen sacs each, while the gynoecium consists of three fused carpels and a three-chambered ovary. The style connects the ovary to the stigma, which is divided into three lobes. Understanding these parts helps in identifying and classifying Liliaceae plants.

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SAQ-3 : Describe the essential organs of solanaceae.

Introduction

The Solanaceae family, also known as the nightshade family, includes important plants such as tomatoes, potatoes, and bell peppers. To understand and classify these plants accurately, it is essential to know their key vegetative and reproductive organs.

Vegetative Organs

The roots of Solanaceae plants usually form a taproot system, though in some cultivated species, this system can transition to a fibrous root system. The primary function of these roots is to absorb water and nutrients from the soil.

The stems can be either herbaceous or woody. They may grow in an erect position or climb, and are often covered with hairs (trichomes), which can be glandular or non-glandular. These stems support the plant and aid in various functions such as photosynthesis and nutrient transport.

The leaves are generally simple and arranged in an alternate pattern, although some species have compound leaves. They typically lack stipules at the base, which are small, leaf-like structures found in some other plant families.

Reproductive Organs

Flowers in the Solanaceae family are usually actinomorphic, meaning they are radially symmetrical, and are bisexual, containing both male and female reproductive parts. The calyx, which is the outermost whorl of the flower, is persistent and often accrescent, meaning it continues to grow after flowering. It is made up of five sepals, which can be either free or fused.

The corolla consists of five petals that are typically fused to form a tube-like structure. This arrangement often gives the flowers a starry or bell-shaped appearance.

The androecium, or male reproductive part of the flower, includes five stamens that are adnate (attached) to the corolla. These stamens are epipetalous, meaning they are attached to the petals, and can be arranged either alternate with the petals or opposite to them.

The gynoecium, or female reproductive part, is typically bicarpellary, consisting of two fused carpels that form a bilocular (two-chambered) ovary. This ovary is superior, positioned above where other floral parts attach. Inside each locule of the ovary are numerous ovules. The style connects the ovary to the stigma, which is usually capitate (rounded) or bilobed (two-lobed).

The fruit produced by these plants is commonly a berry or a capsule, containing many seeds. These seeds have a curved embryo surrounded by a substantial amount of endosperm, which provides nourishment for the developing plant.

Summary

Understanding the vegetative and reproductive organs of the Solanaceae family is crucial for identifying and classifying these important plants. Each part, from the roots and stems to the flowers and fruit, plays a vital role in the plant’s overall function and reproduction.

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SAQ-4 : Give economic importance of plants belonging to fabaceae.

Introduction

The Fabaceae family, also known as the legume or pea family, includes a wide range of plants that are crucial for both economic and nutritional reasons. This family is known for its diverse uses and benefits.

Economic Significance of Fabaceae Plants

1. Pulses: Many plants in the Fabaceae family are grown for their edible seeds, commonly referred to as pulses. Pulses are an excellent source of protein, making them an important part of human diets. Examples include Red gram (Toor dal), Black gram, Green gram (Moong dal), and Bengal gram (Chickpeas). These pulses are widely used in various dishes and are a staple in many diets around the world.
2. Edible Oils: Some Fabaceae plants are used to produce edible oils that are used in cooking and food preparation. For instance, Soybean (Glycine max) and Groundnut (Arachis hypogea) are prominent sources of cooking oil. These oils are commonly used in kitchens for frying, baking, and salad dressings.
3. Vegetables: The Fabaceae family also provides nutritious vegetables. For example, the pods of beans (Dolichos), Soybean (Glycine max), and the leaves of Menthi (Fenugreek) are all consumed for their health benefits and flavor. These vegetables are often included in everyday meals and contribute to a balanced diet.
4. Timber: Certain Fabaceae species are valued for their wood, which is used as timber in construction and furniture making. Red Sanders and Indian Rosewood are notable examples of Fabaceae plants that provide high-quality timber used in building and crafting.
5. Fiber: Plants like Sun Hemp (Crotalaria) from the Fabaceae family are sources of fiber. This fiber is used to make various textiles such as ropes and twine. The strong and durable nature of this fiber makes it useful in many practical applications.
6. Natural Dyes: Some Fabaceae plants are used to obtain natural dyes. For example, Indigofera tinctoria is known for its blue dye, and Butea monosperma provides a yellow dye. These dyes are used in textiles and other materials to add color in a natural way.
7. Fodder: Many Fabaceae plants are used as fodder for livestock. They are rich in nutrients and help promote healthy growth in animals. Examples include Crotalaria and Phaseolus, which are commonly used as feed for various animals.
8. Green Manure: Fabaceae plants also play a crucial role in soil fertility through the practice of green manure. Plants such as Sesbania and Tephrosia are cultivated to enrich the soil with nitrogen and organic matter, which improves soil health and supports sustainable agriculture.

Summary

The Fabaceae family has great economic importance due to its diverse uses. These plants provide essential proteins, oils, and vegetables, as well as valuable timber, fibers, and natural dyes. They also contribute to sustainable agriculture by serving as fodder and green manure. Understanding their economic significance helps highlight their role in agriculture, food production, and environmental sustainability.

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SAQ-5 : Write a brief note on semi technical description of a typical flowering plant.

Introduction

A semi-technical description of a typical flowering plant involves systematically providing information about its various features, starting from its overall appearance and habitat to the detailed structure of its flowers and fruits.

Description of a Typical Flowering Plant

1. Habit and Habitat: Begin the description by stating the plant’s habit, which refers to its general growth form (e.g., herb, shrub, tree). Mention the habitat in which the plant is commonly found, such as forests, grasslands, wetlands, etc.
2. Vegetative Characters: Describe the root system, including whether it is taproot or fibrous, and its function in anchoring and absorbing nutrients. Mention details about the stem, such as its height, branching pattern, and texture (e.g., woody or herbaceous). Discuss the leaf characteristics, including their arrangement (alternate, opposite, whorled), shape, margin, and venation.
3. Floral Characters: Provide information about the type of inflorescence (arrangement of flowers on the main stem), whether it is a raceme, corymb, umbel, etc. Describe the flower’s structure, including the number of floral parts (sepals, petals, stamens, carpels), symmetry (actinomorphic or zygomorphic), and their color and size.
4. Fruits: Mention the type of fruit, whether it is a fleshy fruit like a berry or drupe, or a dry fruit like a capsule or achene. Describe the fruit’s shape, size, color, and any distinctive features.
5. Floral Diagram and Floral Formula: Include a floral diagram, a schematic representation of the flower, showing the number of each floral part and their arrangement. Provide a floral formula, a symbolic representation of the flower’s structure, using abbreviations for each floral part.

Summary

A semi-technical description of a flowering plant covers its habit, habitat, vegetative characters (root, stem, leaves), floral characters (inflorescence, flower, and parts), and fruit. It may also include a floral diagram and floral formula to offer a concise representation of the flower’s structure. This detailed description allows botanists, researchers, and students to understand the plant’s morphology and taxonomy more effectively.

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SAQ-6 : Give an account of floral diagram.

Introduction

A floral diagram is a graphical representation used to describe the structural properties of a flower. This tool is particularly useful in botany for understanding and documenting the arrangement and orientation of the various parts of a flower.

Key Elements of a Floral Diagram

1. Symmetry: Indicates the symmetry of the flower, whether it’s actinomorphic (radial symmetry) or zygomorphic (bilateral symmetry).
2. Position of Floral Organs: Depicts the spatial arrangement of the flower’s organs – the sepals, petals, stamens, and carpels.
3. Ovary Position: Shows the position of the ovary in relation to other floral parts, distinguishing between superior, inferior, and half-inferior ovaries.
4. Fusion of Floral Parts: Illustrates the fusion of different floral parts, if any, such as united petals forming a corolla tube.

Drawing a Floral Diagram

1. Start by representing the flower’s axis at the center of the diagram.
2. Add concentric circles to represent different whorls of the flower.
3. Sepals are usually depicted in the outermost circle, followed by petals, stamens, and carpels in the center.
4. Use symbols or letters to represent different parts (e.g., ‘S’ for sepals, ‘P’ for petals).
5. Indicate the ovary’s position and whether it is superior, inferior, or half-inferior.

Significance

A floral diagram provides a simplified yet comprehensive view of a flower’s structure. It’s especially helpful in comparing flowers from different species or families. The diagram aids in the identification and classification of plants.

Summary

A floral diagram is a crucial tool in botany, offering a simplified graphical representation of a flower’s structure. It outlines the symmetry, position of floral organs, ovary position, and fusion of floral parts. Drawing a floral diagram involves depicting the flower’s axis, whorls, and individual floral parts with appropriate symbols. Its significance lies in its ability to provide a clear and concise view of a flower’s architecture, aiding in the study and comparison of various plant species.

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SAQ-7 : Write a brief account on the class of dicotyledonae of Bentham and Hooker’s classification.

Introduction

The class Dicotyledonae, according to Bentham and Hooker’s classification, is a major group of plants characterized by having two cotyledons (seed leaves). This class includes a diverse range of plant species.

Key Characteristics of Dicotyledonae

Plants in the Dicotyledonae class are identified by having two cotyledons in their seeds. Their leaves generally show reticulate venation, where the veins form a network. The flowers are usually tetramerous (with four parts) or pentamerous (with five parts). These plants typically have a taproot system, and the vascular bundles in their stems are arranged in a ring.

Subdivisions in Dicotyledonae

Within the Dicotyledonae class, there are three main subclasses: Polypetalae, Gamopetalae, and Monochlamydeae. Polypetalae plants have flowers with free petals and are further divided based on the arrangement of floral parts into Thalamiflorae, Disciflorae, and Calyciflorae. Gamopetalae plants have fused petals and are categorized into Inferae, Heteromerae, and Bicarpellatae, based on the ovary position and number of carpels. Monochlamydeae consists of plants with either no petals or petals and sepals that are not distinctly separated. This group is often seen as more primitive within Dicotyledonae.

Economic Importance

Many plants in the Dicotyledonae class are economically important. They provide essential resources such as fruits, vegetables, wood, and medicinal substances.

Summary

The class Dicotyledonae is characterized by two cotyledons, reticulate leaf venation, flowers with four or five parts, a taproot system, and vascular bundles arranged in a ring. It is divided into Polypetalae, Gamopetalae, and Monochlamydeae, with further classifications based on floral characteristics. This class includes many plants of great economic and ecological significance.