Plant Tissue Culture Basics: Roles and Techniques Quiz

Explore key concepts behind plant tissue culture, including sterility, nutrients, growth regulators, and successful plantlet development. This quiz covers essential steps and knowledge for understanding how plant growth regulators function in tissue culture.

1. 1. What is plant tissue culture?

   Which of the following best describes plant tissue culture?

   1. A method of genetically modifying crops in open fields.
   2. A way of harvesting mature plant leaves for herbal medicine.
   3. A technique where small plant pieces (like leaves or stems) are grown in a sterile nutrient medium to create new plants.
   4. A process using soil to grow trees from seeds.

   Explanation: Plant tissue culture involves growing plant pieces in sterile nutrient mediums to regenerate whole plants. The other options refer to genetic modification, traditional soil cultivation, and herbal harvesting, none of which define tissue culture.

2. 2. Why is sterility important in tissue culture?

   Why must all equipment and plant materials be sterile during tissue culture?

   1. To make the culture medium change color.
   2. Because sterilizing makes the plant pieces grow bigger.
   3. Because bacteria and fungi grow faster than plants and can contaminate or kill the plant tissue.
   4. To increase the light entering the culture jars.

   Explanation: Sterility prevents contamination from bacteria and fungi that can quickly outcompete or destroy plant tissue. The other choices incorrectly relate to growth size, medium color, or light, none of which are addressed by sterility.

3. 3. What is the purpose of using agar in tissue culture?

   In tissue culture, why is agar included in the culture medium?

   1. Agar gives a sweet flavor to the growing plants.
   2. Agar attracts insects that help pollinate the tissue.
   3. Agar helps plants produce more seeds.
   4. Agar acts as a gel base that holds nutrients, vitamins, and hormones the plant needs to grow.

   Explanation: Agar provides a gel-like structure to support plant explants and evenly distribute nutrients and hormones. The other options are unrelated; agar doesn't add flavor, help seed production, or attract insects in tissue culture.

4. 4. Which part of the plant can be used as an explant?

   Which of the following parts can serve as an explant in plant tissue culture?

   1. Only roots from old plants.
   2. Only fully matured fruits.
   3. Only dry and fallen leaves.
   4. Leaves, nodes, stems, roots, buds — any healthy part suitable for regeneration.

   Explanation: Many plant parts, including leaves, stems, roots, nodes, and buds, can be used as explants if they are healthy and capable of regeneration. The distractors are too restrictive or refer to unsuitable materials for explant preparation.

5. 5. What do plant growth regulators (PGRs) do in tissue culture?

   How do plant growth regulators (PGRs) help in tissue culture?

   1. They control development — auxins help rooting, cytokinins help shoot formation.
   2. They attract bees to the culture room.
   3. They make the jars more airtight.
   4. They act as food coloring agents.

   Explanation: Plant growth regulators like auxins and cytokinins guide root and shoot development during tissue culture. The other options are unrelated; PGRs aren't coloring agents, don't affect air-tightness, and don't attract pollinators.

6. 6. Why do we surface-sterilize plant material before culturing?

   What is the main reason for surface-sterilizing explants before placing them in a culture medium?

   1. To remove dust, microbes, and spores on the outside so the plant can grow contamination-free.
   2. To increase the temperature of the medium.
   3. To add extra nutrients to the plant.
   4. To make the explant softer for cutting.

   Explanation: Surface sterilization is necessary to eliminate contaminants like microbes and spores. Making the explant softer, adding nutrients, or changing temperature are not the primary reasons for sterilization in this process.

7. 7. What is micropropagation?

   Which statement best defines micropropagation?

   1. Rapidly producing multiple identical plants from a small piece of the parent plant.
   2. Harvesting seeds from natural forests.
   3. Crossing two plants to create hybrids in soil.
   4. Cloning animal cells in a lab.

   Explanation: Micropropagation uses tissue culture to quickly multiply identical plants. Crossbreeding, animal cell cloning, and traditional seed collection do not describe micropropagation.

8. 8. What is one common reason cultures fail?

   What is a frequent cause for tissue cultures to fail during the process?

   1. Using only tap water in the medium.
   2. Contamination from dirty tools, unclean hands, or non-sterile explants.
   3. Growing cultures outdoors in sunlight.
   4. Adding too much agar.

   Explanation: Contaminants introduced by tools, hands, or explants can quickly ruin cultures. While improper agar or water and outdoor environments can cause problems, contamination remains the most common failure reason.

9. 9. Why do tissue-cultured plants grow faster in early stages?

   Why do plants in tissue culture often grow faster at the beginning compared to those in soil?

   1. Because no light is needed for growth in culture.
   2. Because they are exposed to natural wind and rain.
   3. Because they are genetically modified during culture.
   4. Because they receive perfect nutrients, hormones, and moisture in a controlled medium.

   Explanation: Optimal nutrients, hormones, and moisture under controlled conditions promote fast growth. Exposure to natural elements, genetic modification, and absence of light do not typically explain this rapid early development.

10. 10. What should you do after transferring plantlets out of the culture jar?

    After removing plantlets from the culture jar, what steps should you take for their survival?

    1. Dip them in fertilizer immediately.
    2. Leave them uncovered in dry air.
    3. Expose them to full sun and heavy watering at once.
    4. Harden them gradually — give indirect light, reduce humidity slowly, and avoid overwatering.

    Explanation: Gradual acclimatization, known as hardening, helps young plantlets adjust to external conditions and reduces shock. Sudden exposure, over-fertilization, or dry air can harm or kill delicate tissues.