Morphology of flowering plants deals with the study of the form and structure of plants. The flowering plants are also known as angiosperms. They appear in a variety of size, shape, and forms. The morphological structures of flowering plants include the roots, the stem, leaves, flowers. The roots form the underground part of the plant and absorb water and nutrients from the soil. The stem grows above the soil. The leaves contain chlorophyll which helps in the synthesis of food. They also bear pores for transpiration.
Q.1. How do the roots of the plants growing in swamps and marshes obtain their oxygen?
A.1. The roots of the plants growing in swamps and marshes grow vertically upwards and respire. They become negatively geotropic.
Q.2. Name some modifications of plant parts for the purpose of photosynthesis.
A.2. The stem gets modified into a leaf-like structure to carry out photosynthesis. In plants like Trapa and Tinospora, the roots grow out of the soil and develop chlorophyll to perform photosynthesis.
Q.3. What are the edible parts of ginger and onion?
A.3. The modified stem is the edible part of ginger. All the food material is stored here. The fleshy leaves of onion are the edible parts.
Q.4. Differentiate between pinnately compound leaf and palmately compound leaf?
|Pinnately Compound Leaf||Palmately Compound Leaf|
|The midrib of the leaves is present on a common axis called the rachis.||Leaflets are attached at the tip of the petiole.|
Q.5. Explain different types of phyllotaxy with suitable examples.
A.5. The pattern in which the leaves are arranged on the stem is known as phyllotaxy. These are of three types:
- Alternate Phyllotaxy- The leaf arises from each node in an alternate manner. For eg., China rose, sunflower.
- Opposite Phyllotaxy- The leaves arising at each node lie opposite to each other. For eg., Calotropis
- Whorled Phyllotaxy– More than two leaves arise at each node and form a whorl. For eg., Alstonia
Q.6. Describe the modifications of the stem. Give examples for the same.
A.6. Modifications of the stem are as follows:
- Stem Tendrils- These may be branched with scaly leaves. Eg., Passiflora, Antogonon
- Stem Thorns- These are sharp needle-like structures that are formed to reduce transpiration and also act as a defence. For eg., Citrus, Pomegranate
- Phylloclades- These are green, flattened, succulent, leaf-shaped structures that perform photosynthesis. They possess indefinite growth. For eg., Opuntia, Euphorbia soyleana
- Cladodes- They are green, photosynthetic of limited growth. The leaves are either modified into spines or reduced to scales. For eg., Ruscus, Asparagus
Q.7. Which two roots develop from different parts of the angiospermic plant other than the radicle?
A.7. Prop roots of the banyan tree- Develop from lower nodes of the stem of the tree Stilt roots in sugarcane- Arise from lower nodes of the stem and penetrate the soil. Both the roots are meant to provide support.
Q.8. Differentiate between the roots of aquatic plants and terrestrial plants.
|Roots of aquatic plants||Roots of terrestrial plants|
|Roots may or may not be present.||Roots are well-developed.|
|Vascular bundles are poorly developed.||Vascular bundles are well developed.|
|They are modified to perform photosynthesis, food storage and gaseous exchange.||Anchors the plant firmly in the soil, and absorbs nutrients from the soil.|
Q.9. What role do the roots of the aquatic plants play?
A.9. The roots are green and branched in plants like Trapa and Tinospora. This provides an increased photosynthetic area for the plants. They get inflated because the air projects out of the water, which helps the plant in floating and gaseous exchange.
Q.10. Name the floral parts of an angiosperm. Also, mention their arrangements.
A.10. Following are the floral parts of a typical angiosperm:
- Calyx- Outermost whorl of the flower. It comprises of sepals. They are usually green and protective.
- Corolla- It comprises of petals. These are bright in colour.
- Androecium- It is made up of stamens which is the male reproductive organ. It consists of a filament and anther.
- Gynoecium- It is the female reproductive part of the flower and is made up of one or more carpels. Each carpel comprises of stigma, style, and ovary.
Q.11. Why is the maize grain considered as a fruit and not as a seed?
A.11. The maize grain is a ripened ovary with a ripened ovule. That is why it is considered a fruit and not as a seed. The fruit is known as a caryopsis. In this, the per carp is fused with the seed coat.
Q.12. Ginger grows underground like any other root. Then why is it considered a stem and not root?
A.12. Ginger is an underground modification of stem which bears internodes, nodes, buds and scaley leaves that give rise to aerial shoots. The lower surface of the nodes gives rise to adventitious roots. Also, it does not play any role in anchorage and absorption. It only serves as a reservoir to store food. This proves that ginger is a stem, not a root.
Q.13. Why is sunflower not a flower?
A.13. Sunflower is a kind of inflorescence called capitulum with a flat receptacle. It has sessile and small florets. The oldest floret lies in the periphery while the youngest lies in the centre. The cluster of florets is surrounded by bracts. The florets are of two types; ray florets and disc florets.
Q.14. Differentiate between the hypogeal germination and epigeal germination.
|Hypogeal Germination||Epigeal Germination|
|Rapid growth and elongation of epicotyl.||Rapid growth and elongation of the hypocotyl.|
|The seed cotyledons are inside the soil.||The seed cotyledons are above the soil.|
|Cotyledons are not green and non-photosynthetic.||Cotyledons are green and photosynthetic.|
Q.15. Mention the role of cotyledons and endosperm in seed germination.
A.15. The cotyledons and endosperm store food material. The seed imbibes water and activates the enzyme. These enzymes hydrolyze the reserve food material and provide it to the germinating seed. For more information on Morphology of Flowering Plants or any Biology article, keep visiting BYJU’S website or download BYJU’S app for further reference.
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