Plant Morphology MCQ Quiz - Objective Question with Answer for Plant Morphology - Download Free PDF

The correct answer is Potato.

Key Points

• Potato is a modified stem.
  • Potato, ginger, and yam are modified stems because the stems are modified to perform the function of storage of food, support and protection.

Important Points

• Root vegetables include commodities, such as carrot, radish, horseradish, sweet potato, turnip, and beetroot.

The correct answer is Cytokinin.

Key Points

• Cytokinins are a group of plant hormones that promote cell division and growth in plant roots and shoots.
• They are known to delay the aging of plant tissues by inhibiting protein degradation and promoting protein synthesis and mobilization of nutrients.
• Cytokinins are synthesized in the roots and transported to other parts of the plant, including fruits and seeds, where they are present in high concentrations.
• In fruits and seeds, cytokinins play a crucial role in cell differentiation and development, as well as in the delay of senescence.
• They work synergistically with other hormones like auxins to regulate various growth processes and morphogenesis in plants.

Additional Information

• Auxin
  • Auxins are another group of plant hormones that primarily regulate cell elongation, especially in the stem and root tips.
  • They are involved in various growth processes including phototropism, gravitropism, and the formation of lateral and adventitious roots.
• Gibberellin
  • Gibberellins are plant hormones that promote stem elongation, seed germination, and flowering.They help in breaking seed dormancy and are involved in the regulation of various developmental processes.
• Abscisic Acid (ABA)
  • Abscisic acid is a plant hormone that primarily functions in stress responses, such as closing stomata during water stress.
  • It also plays a role in seed dormancy and inhibition of growth, helping plants to survive adverse conditions.

The Correct answer is Leaf.

Key Points

• The leaf is the primary organ of the plant involved in the process of transpiration.
• Transpiration is the process by which plants release excess water vapor into the atmosphere through small openings called stomata.
• Stomata are tiny pores located on the surface of leaves, primarily on the underside, which facilitate gas exchange and water vapor release.
• This process helps maintain the plant's water balance, regulates temperature, and aids in the uptake of minerals and water from the roots.
• The leaf structure includes epidermal layers, which protect the inner tissues, and a waxy cuticle that minimizes water loss.
• Transpiration also creates a transpirational pull, which assists in the upward movement of water and nutrients through the xylem.
• Leaves are uniquely adapted for this function due to their large surface area and the presence of chlorophyll for photosynthesis, which works in conjunction with transpiration.

Additional Information

• Root
  • The root system is primarily responsible for the absorption of water and nutrients from the soil.
  • Although roots play a crucial role in the plant's water uptake, they are not directly involved in the process of transpiration.
  • Roots also anchor the plant and store food reserves in some species.
• Stem
  • The stem serves as the main support structure for the plant and facilitates the transport of water, nutrients, and food between roots and leaves through the xylem and phloem.
  • While the stem helps in water movement, it does not directly carry out transpiration.
• Flower
  • The flower is primarily involved in the process of reproduction in plants.
  • It does not play a role in water regulation or transpiration.

The Correct answer is Spines instead of leaves to reduce water loss.

Key Points

• Cacti have evolved to thrive in arid and desert environments, where water is scarce.
• The transformation of leaves into spines is a key adaptation that minimizes water loss through transpiration.
• Spines also provide protection from herbivores and reduce the surface area exposed to sunlight, further helping in reducing water evaporation.
• The absence of broad leaves allows cacti to conserve water effectively in their thick, fleshy stems, which act as water storage organs.
• The stem also carries out photosynthesis, a process usually performed by leaves in most plants, ensuring the plant's survival in extreme conditions.
• Spines also help in trapping moisture from the air, which can condense and trickle down to the plant's roots for absorption.
• This adaptation is crucial for cacti to survive in regions with extreme temperatures and minimal rainfall, such as the Sahara Desert or the Atacama Desert.

Additional Information

• Large leaves for more surface area
  • Large leaves are found in plants located in rainforests or regions with abundant water availability.
  • These leaves maximize surface area for photosynthesis but lead to significant water loss due to transpiration, making them unsuitable for arid environments.
• Small flowers to reduce water use
  • While small flowers might conserve some water, they are not a primary adaptation for survival in arid conditions.
  • Flowers in cacti are often adapted to attract specific pollinators, such as bats or insects, and their size is not directly linked to water conservation.
• Tall height to capture more sunlight
  • Tall plants are typically found in environments where competition for sunlight is high, such as dense forests.
  • Cacti, however, are generally low-growing and adapted to conserve water rather than focus on height.

The Correct answer is Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.

Key Points

• Plants, though stationary, exhibit growth and movement, showcasing their capability to adapt to environmental stimuli.
• The process of phototropism explains how plants grow towards sunlight. This is a directional movement caused by the hormone auxin, which accumulates on the shaded side of the plant, causing cells to elongate and the plant to bend towards light.
• Such movements are categorized as tropic movements, which are growth-oriented and directional, driven by stimuli such as light (phototropism) or gravity (gravitropism).
• The Assertion that "plants exhibit growth and movement despite being stationary" is correct because plants continuously grow and adjust their structure (e.g., roots growing downward or shoots growing upward).
• The Reason that "plants grow towards sunlight through phototropism" is also correct. This mechanism demonstrates movement in response to light, despite the plant's inability to relocate physically.
• Since the Reason directly explains the mechanism behind the Assertion, the correct answer is that both the Assertion and Reason are true, and the Reason provides a proper explanation.

Additional Information

• Phototropism
  • Phototropism is a type of tropic movement where plants grow towards or away from a light source.
  • This movement is controlled by the plant hormone auxin, which redistributes itself to the shaded side of a plant, causing elongation of cells on that side.
  • Examples include a sunflower bending towards sunlight and shoots of plants growing upwards towards light.
• Other Tropic Movements
  • Gravitropism: Growth in response to gravity, e.g., roots growing downward into the soil.
  • Thigmotropism: Movement or growth in response to touch, e.g., tendrils of a climber wrapping around a support.
  • Hydrotropism: Growth in response to water, e.g., roots growing towards moisture in the soil.
• Auxin
  • Auxin is a plant hormone responsible for regulating plant growth and responses to environmental stimuli.
  • It plays a key role in cell elongation, phototropism, gravitropism, and root development.
  • Auxins are primarily produced in the apical meristems of shoots and young leaves.

The correct answer is Potato.

Key Points

• Potato is a modified stem.
  • Potato, ginger, and yam are modified stems because the stems are modified to perform the function of storage of food, support and protection.

Important Points

• Root vegetables include commodities, such as carrot, radish, horseradish, sweet potato, turnip, and beetroot.

The correct answer is Papaya.

• Papaya flowers are Unisexual Flowers.

Key Points

• Flowers that contain either only pistil (Female reproductive organs) or stamen (male reproductive organ) are called Unisexual flowers.
• Corn, papaya, Cucumber are some common examples.
•  A flower which contains both pistils (Female reproductive organs) and stamen (male reproductive organs) are called bisexual flowers.
• Sunflower, Mustard, Hibiscus are some common examples.

The correct answer is Petiole.

Key Points

• Petiole is like a stem that attaches the leaf blade to the stem.
  • Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface.

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Additional Information

• Pistil: The pistil is the innermost part of the flower. It is the female part of the flower.
• Stamen: The stamen is the male part of the flower.
• Petals: The petal is the coloured part of the flower that gives it a unique shape.
• Sepals: These are leaf-like structures attached to the outside of the flower. They're very similar to petals.
• The schematic diagram of the flower is as follows:

The correct answer is a female reproductive part.

Key Points

• Pistil is the female reproductive part of a flower with a stigma at its top.
• Pistil is the ovule producing part of a flower.
• The function of a pistil is to receive pollen and produce seeds.
• The ovary often supports a long style, topped by a stigma.
• The mature ovary is a fruit, and the mature ovule is a seed. 
• Pollens are produced by the male part of a flower called the stamen.
• A flower is actually made of specialized stems and leaves.

The correct answer is Angiosperm.

Key Points

• Angiosperms are also known as Angiospermae or Magnoliophyta.
  • They are flowering and seed-producing plants.
  • It consists of 64 orders, 416 families, approximately 13,000 known genera, and 3,00,000 known species.
  • Their seeds develop in the ovaries of flowers and are surrounded by a protective fruit.
  • Examples of angiosperms are fruits, vegetables, grains, and flowers.
  • Angiosperms are classified as Monocotyledons (monocots) and Dicotyledons (dicots) where monocots are flowering plants whose seeds contain only one embryonic leaf or cotyledon and dicots are flowering plants whose seeds contain two embryonic leaves or cotyledons.

Important Points

• Naked embryos are formed after fertilization and are not formed inside the seed.
• These are also known as spores.
• These embryos are the characteristic feature of Bryophytes and Pteridophytes.
• The reproductive organs bearing spores are also called sori.
• They also occur in various species of marine organisms like algae.

Additional Information

• Thallophyta
  • The plant body is not differentiated from roots, stems, and leaves.
  • They are commonly called algae.
• Bryophyta
  • These are small terrestrial plants.
  • They show differentiation in the body design, with stem, leaf-like structures, and root-like structures.
• Pteridophyta
  • ​Plants from this group have well-developed roots, stems and leaves and separate tissues for the conduction of food and water. But, they do not bear flowers and fruits.
  • They reproduce with the help of spores formed along the back or posterior surface of their leaves.
  • Examples- ferns like Nephrolepis, Marsilea, Pteris, Adiantum, Equisetum, Selaginella, Lycopodium, etc.

The correct answer is Pitcher plant.

Key Points

Pitcher plant:

• ​Pitcher plants (or pitfall traps) are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap.
• Foraging, flying, or crawling insects such as flies are attracted to the cavity formed by the cupped leaf, often by visual lures such as anthocyanin pigments, and nectar bribes.
• The sides of the pitcher are slippery and may be grooved in such a way so as to ensure that the insects cannot climb out.
• Through a mechanism of digestion, the prey is converted into a solution of amino acids, peptides, phosphates, ammonium, and urea, from which the plant obtains its mineral nutrition (particularly nitrogen and phosphorus).
• Carnivorous plants occur in locations where the soil is too poor in minerals and/or too acidic for most plants to be able to grow.

The correct answer is roots.

Key Points

• Pneumatophores are specialized root structures that grow out from the water surface and help hydrophytic plants, such as many mangrove species, get the aeration they need for root respiration.
• Pneumatophores are specialized roots that sprout vertically out of the water or mud to reach the air and get oxygen for the root systems of marshy or tidal trees.
• Pneumatophores include mangrove knees and bald cypress. It is also known as the air root.
• These unique aerial roots allow plants to breathe air in wet environments. The roots can grow up from the stem or down from traditional roots.
• If they emerge from the earth, some botanists define them as aerating roots rather than aerial roots.

Explanation:

• Different parts of plants like roots, shoots, leaves, flowers, fruits, etc perform the function of storage of food 
• The fleshy leaves of onion are its consumable part.
• As a whole, the onion is a bulb, which is a short modified form of a stem that is surrounded by these fleshy leaves that store food for the onion shoots.

Important Points

• The stored food in onion leaves is Sugar.

Mistake Points​Food is stored in the leaves. Onion as a whole is a modified stem

Additional Information  

• In plants like carrot, reddish, beetroot, sweet potato, turnip, etc. roots perform the function of food storage.
• Some plants store their food in the form of fruit. Ex- apple, guava, grapes mango, etc.
• Plants like potato, ginger, garlic, sugarcane, etc. store their food in stems.​

The correct answer is option 4 i.e Stomata.

Key Points

• Stomata is a pore found in the epidermis of leaves, stems, and other parts of a plant.
  • Stomata help for the gas exchange.
  • The stomata is bordered by a pair of parenchyma cells called guard cells.
  • Guard cells are responsible for regulating the size of the stomatal opening.
  • Atmospheric air enters the plant through stomata by gaseous diffusion.
  • The lengths of stomata is ranging from 10 to 80 µm and width ranging from a few to 50 µm.
• Cilia are small hair-like protuberances on the outside of eukaryotic cells.

The correct answer is Root hairs.

Key Points

Fig: The regions of the root-tip