Test: General Science (Plant World) - Software Development MCQ

The correct answer is Potato.

Modifications of Root

1. For storage of food
   • Roots are modified in some plants for storing reserve food materials.
   • These modified roots usually are swollen and assume different forms such as spindle-shaped, e.g., radish; top-shaped, e.g., beet, turnip; cone-like, e.g., carrot; indefinite shape, e.g., sweet potatoes.
   • Dahlia, Asparagus, Portulaca are some other examples of plants with modified roots for food storage.
2. Nodulated roots
   • The roots of pea and other leguminous plants have numerous swollen nodules on fine branches of roots.
   • These nodules are formed due to the symbiotic association of Rhizobium (bacterium) that live inside the root cortical cells of the roots.
   • They fix nitrogen and an active nodule is pink in colour.
3. For mechanical support
   • Roots are modified to provide mechanical support as seen in a banyan tree which has roots growing vertically/obliquely downwards (prop roots); sugarcane/maize in which roots arise from the nodes in the cluster at the base of the stem (stilt roots) and betel/black pepper in which nodes and internodes bear roots which help in climbing.
4. For gaseous exchange
   • Pneumatophores or breathing roots are found in plants growing in mangroves or swamps with saline water for exchange of gases.
   • They are erect peg-like structures with numerous pores through which air circulates e.g., Rhizophora mangle.

• Modifications of Stem

1. For storage of food
   • Stems get modified into underground structures for storage of food as seen in potato (tuber), ginger (rhizome), garlic (bulb), yam (corm).
   • Presence of an eye (node) in potato, distinct nodes with internodes and scaly leaves in ginger/yam, a cluster of roots at the base of the reduced stem in garlic/ onion, all indicate that these underground plant parts are modified stem.
2. For vegetative propagation
   • Plants besides reproducing sexually also propagate through vegetative parts.
   • For this purpose, stems may be modified into a runner (Cyanodon dactylon, Oxalis). Runners are slender prostrate branches arising from axillary buds;
   • stolon (e.g., mint, strawberry) which is a slender lateral branch arising from the base of the stem grows upward and then down to develop new daughter plants;
   • offset having a single long horizontal internode growing up to some distance and producing a tuft of leaves above and a cluster of roots below at the apex (Eichornia, Pistia) and
   • sucker, which arises from the underground part of the stem, grow obliquely and gives rise to a new shoot. (Chrysanthemum, Banana, Pineapple).
3. For protection
   • Some modified stem provides protection as thorns which are hard, pointed structures each representing a branch that arises from the axil of a leaf.
   • Thorns are found in plants like Duranta, Pomegranate, Acacia, Ber, Prosopis, Bougainvillea, Citrus, etc.
4. For support
   • Tendrils are modifications of the stem to provide support to plants, e.g., Vitis, passionflower, Bignonia etc.
5. For photosynthesis
   • Stems are also modified into Phylloclade, to facilitate photosynthesis.
   • Phylloclades are flattened/cylindrical stem or branches of unlimited growth (Cactus).

The correct answer is Mode of Nutrition.

• In 1969, R.H. Whittaker introduced the five-kingdom system of classification.
• In the five-kingdom system, the basis of classification is the complexity of cell structure, physical organization, nutrition method, and life cycle.
• Aristotle firstly divided the living world into two groups, namely, flora and fauna.
• After that, in his book 'Systema Naturae', Linnaeus classified all animals into plants and animals.
• Linnaeus is called the 'father of modern classification system'.

Additional Information

• Whittaker classified all creatures in the following five kingdoms -

1. Kingdom Monera-
   • ​​This world consists of prokaryotic organisms ie Bacteria, Cyanobacteria, and Archaebacteria.
2. Kingdom Protista-

• This world consists of unicellular eukaryotic organisms. Yuglina, which is situated between plants and animals, is included in this world.

3. Kingdom Fungi-

• This includes organisms dependent on parasites and dead food for food. Their cell wall is made of chitin.

4. Plant World (Kingdom Plantae)-

• This world consists of algae and multicellular green plants.

5. Kingdom Animal-

• This includes all multicellular animals. It is also called 'Metazoa'.

• Parenchyma, Sclerenchyma, and Collenchyma are the Simple Permanent Plant tissues.
• Xylem and Phloem are the Complex Permanent Plant tissue.
• Sclerenchyma: supporting tissue in higher plants.
• Parenchyma: makes up most of the cells within leaves, flowers, and fruits.
• Collenchyma: provides support, structure, tensile strength, and flexibility which helps the plant to bend.
• Xylem:
  • It is plant tissue that transports food water and other dissolved minerals from roots to other parts of the plant.
• Phloem:
  • The main function of the phloem is to transport food materials from the leaf to other parts of the plant.

Concept:

• Plants have different types of roots.
• Some store food, some breathe some hang from the branches.

Explanation:

• Roots are the underground structures that help in the absorption of water and minerals provide a proper anchorage to the plant parts, storage of reserve food material (Carrot, Radish), and synthesis of PGR (plant growth regulators).
• Sometimes roots get modified to perform different functions like storage of food, respiration, climbing, etc.
• These types of roots are called modified roots.
• Examples - prop root of the Banyan tree for providing support, Pneumatophores of Rhizophora, and Mangrove plants for respiration.

So, these statements are correct.

• To give support to the plant.
• To store food.
• To absorb water and minerals.

Thus, roots do not function to provide humus.

Concept:

• Plant growth hormones or phytohormones are simple molecules with complex chemical composition, that regulates the growth and physiology of plants.
• Based on their functions on the living plant body they can be classified into two groups:

1. Plant growth promoters - Promotes activities like cell division, cell enlargement, flowering, fruiting, etc. Eg. Auxins, Gibberellins & cytokinins.
2. Plant growth inhibitors - They are involved in various growth-inhibiting activities like dormancy, and abscission. Eg. Abscisic acid.

• Gaseous PGR like ethylene can be put into both groups, however, it is largely an inhibitor of growth activities.

Explanation:

• Ethylene is a simple gaseous PGR.
• It is synthesized in large amounts by tissues undergoing senescence and ripening fruits.
• Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis, and apical hook formation in dicot seedlings.
• Ethylene promotes senescence and abscission of plant organs, especially of leaves and flowers.
• Ethylene is highly effective in fruit ripening. It enhances the respiration rate during the ripening of the fruits. This rise in the rate of respiration is called respiratory climactic.
• Ethylene breaks seed and bud dormancy, initiates germination in peanut seeds, sprouting of potato tubers.
• Ethylene promotes rapid internode/petiole elongation in deepwater rice plants.
• It helps leaves/ upper parts of the shoot to remain above water.
• Ethylene also promotes root growth and root hair formation, thus helping the plants to increase their absorption surface.

Additional Information

The correct answer is Rice.

• Rice blast disease, caused by Magnaporthe oryzae (Ascomycota), occurs in about 80 countries on all continents where rice is grown, in both paddy fields and upland cultivation.
• The extent of damage caused depends on environmental factors, but worldwide it is one of the most devastating cereal diseases, resulting in losses of 10–30% of the global yield of rice.
• Other common diseases of the crop of rice are - Blight, Bacterial leaf streak, Brown spot, Sheath blight, False smut, etc.

Additional Information

• The biological agents that causing diseases to plants are known as pathogens. 
• Some of the viral diseases in plants are - bud blight (soyabeans), Curly tops (Beans, tomato, etc.), Mosaic leaf (Tomato, pea, potato,tobacco, etc.).
• Some of the bacterial diseases in plants are - Blights (vegetable crops), Bacterial wilts (Tobacco, potatoes, etc), Cankers (Woody plants), Leaf Spots, Soft Wrots, etc.
• Some of the fungal diseases in the plants are - Cankers, Ergot, Rusts, Root rots, Scabs, Smuts, etc.

Concept-

• Roots are the underground structures that help in the absorption of water and minerals, provide a proper anchorage to the plant parts, storage of reserve food material (Carrot, Radish), and synthesis of PGR (plant growth regulators).
• Sometimes roots get modified to perform different functions like Storage of food, respiration, climbing, etc.
• These types of roots are called modified roots.

Explanation-

• The Coralloid roots are the specialized roots found in cycas, these roots exhibit a symbiotic relationship between the cyanobacteria and cycas where the cyanobacteria fix the nitrogen and in return, the cycas provide a stable environment to live.
• Cycas, a genus of 105 species of palmlike tropical and subtropical ornamental cycads (family Cycadaceae), among them trees 12 meters (40 feet) or more in height. 
• Their leaves are dark green and circinate (uncoiling as fern leaves do), differing from those of other members of the family in having a midrib but no lateral veins. 
• The seeds are borne along the margins of modified leaves, which are arranged in a whorl at the top of the trunk, rather than in compact cones. 

Thereby coralloid roots are found in cycas.

Additional Information

• Lycopodiopsida
  • It is a class of herbaceous vascular plants known as lycopods, lycophytes.
  • Members of the class are called clubmosses, firmosses, and quillworts.
• Pine
  • A pine is any conifer in the genus Pinus of the family Pinaceae. Pinus is the sole genus in the subfamily Pinoideae.
• Dryopteris
  • It is commonly called the wood ferns, male ferns, or buckler ferns is a fern genus in the family Dryopteridaceae.​

Concept:

• Nutrition is a process by which an organism consumes and uses food materials.
• According to WHO, Nutrition is the intake of food, considered in relation to the body's dietary needs.
• There are various modes of nutrition mainly Autotrophic, Heterotrophic, Chemoautotrophic, Saprophytic,  etc.

Explanation:

• Holophytic or autotrophic nutrition: In this type of nutrition the organisms prepare their food by themselves. Eg - green plants.
• Plants prepare their food by the process called photosynthesis. 
• During photosynthesis, plants trap solar energy or light energy with the help of chloroplast present in the green leaves and convert it into Chemical energy
• A pigment called chlorophyll is present in the chloroplasts which are required in trapping sunlight
• Plants utilize Carbon dioxide and Water for the synthesis of carbohydrates during photosynthesis, oxygen is liberated as a side product
• This gaseous exchange occurs through the stomata present on the leaf surface

• These events can be demonstrated by the following equation:

  

Therefore, Plants require CO₂, Chlorophyll, Sunlight and water for autotrophic nutrition and hence the correct option will be ''All of these''.

The correct answer is Flower.

• Flower is known as the reproductive part of a plant.
  • Plant reproduction is accomplished by sexual or asexual reproduction.
  • The male part of a flower is known as androecium.
  • The stamens in the flower of a seed plant collectively called the androecium.
  • The female part of a flower is known as gynoecium.
  • The process of transfer of pollen grains from the anther to stigma is called pollination.
  • Pollination is possible only with the help of pollen agents such as insects, birds, bats; water; and wind.
  • In sunflowers, pollination is occurred by honeybee.
  • In pepper, pollination is occurred by rain.
• ​Root is part of a vascular plant that normally lies below the surface of the soil.
  • Roots help for the absorption of water and dissolved minerals from the soil.
• The stem helps to conduct water, minerals, and food to different parts of the plant.

Concept-

• We know that all living organisms need food.
• Food supplies proteins, carbohydrates, fats, vitamins, and minerals, all of which we require for body development, growth, and health.
• Both plants and animals are major sources of food for us.
• We obtain most of this food from agriculture and animal husbandry.
• Cereals such as wheat, rice, maize, millets, and sorghum provide us carbohydrates for energy requirements.

Explanation-

The principal food crop of the world is wheat.

• Wheat is a Rabi crop that belongs to the Gramineae family.
• The scientific name of rice is Triticum aestivum.
• Wheat is the principal crop for millions of people in the world.
• Wheat grain is used for cooking.
• So, it is the principal cereal crop compared to rice, maize, and barley. 

Additional Information

• The major food crop of the world that belongs to the family is Gramineae. 
• Gramineae is also known as the Poaceae is the family that contains all the major crops that belong to the grass family.
• Poaceae or Gramineae is the most economically important plant family, providing staple foods from domesticated cereal crops as well as feed for meat-producing animals. 
• Examples such as maize, wheat, rice, barley, and millets, etc.