Competitive Exams: Botany MCQs (Practice-Test 94 of 104)

  1. Consider the following statements about senescence and death:

    1. In the case of formation of heartwood from sapwood, the xylem parenchyma first embark on the biosynthesis of an assemblage of secondary metabolites and develop tyloses into the adjacent treachery elements; they then export most of their mineral nutrients to younger sapwood zone and finally die.

    2. In the course of differentiation of xylem elements, specific regions of the primary walls are hydrolyzed, the tonoplast then breaks down, followed by degradation of the cytoplasm membranes and the nucleus is one of the last constituents of the protoplast to die.

    3. In the senescence of leaves it is commonly found that the chloroplasts are the last organelles to show clear evidence of death.

    Of these statements

    1. 1 and 2 are correct

    2. 2 and 3 are correct

    3. 1 and 3 are correct

    4. 1, 2 and 3 are correct

  2. Ageing of leaves can be delayed by the application of

    1. Cytokinins

    2. Sugars

    3. Chlorophyll extract

    4. Abscisic acid

  3. The well-known famine in Ireland in the 40s has been attributed mainly to the failure of the potato crop which was infected by

    1. Aleraria solani

    2. Phytophthora infestans

    3. Phytophtora parasitica

    4. Pythium aphanidermatum

  4. A wheat plant is infected by the aecidiospores of black stem rust fungus produced on the alternate host. What is the correct sequence of the following stages in the disease cycle?

    1. Uredo stage

    2. Pycnidial stage

    3. Basidial stage

    4. Teleuto stage

    5. Aecidial stage

    Select the correct answer using the codes given below:

    1. 1, 4, 3, 5, 2

    2. 1, 3, 4, 5, 2

    3. 1, 2, 3, 4, 5

    4. 1, 4, 3, 2, 5

  5. Match Liar I with List II and select the correct answer:

    List-I List-II
    1. Root rot of tomato

    2. Leaf curl of tobacco

    3. Leaf blight of banana

    4. Red rust of tea

    1. Virus

    2. Bacterium

    3. Nematode

    4. Alga

    • A
    • B
    • C
    • D
      • 1
      • 3
      • 4
      • 2
      • 3
      • 1
      • 2
      • 4
      • 1
      • 3
      • 2
      • 4
      • 3
      • 1
      • 4
      • 2
  6. Which one of the following diseases is caused by mycoplasma-like organism?

    1. Sugarcane mosaic disease

    2. Wilt disease of sugarcane

    3. Ring spot of sugarcane

    4. Grassy shoot of sugarcane

  7. Bacterial blight of rice can be controlled by giving ‘Hot Water’ seed treatment at

    1. 43 degrees C for 35 mm

    2. 53 degrees C for 30 mm

    3. 59 degrees C for 25 mm

    4. 62 degrees C for 20 mm

  8. For each gene that governs resistance in the host there is a specific and related gene in the pathogen that governs its virulence. This gene-for-gene hypothesis was proposed by Flor in his studies on the inheritance of pathogen city in

    1. Flax rust

    2. Pea rust

    3. Hollyhock rust

    4. Cedar apple rust

  9. Turmeric has recently become widely popular as a

    1. Condiment

    2. Source of insecticides

    3. Source of antibiotics

    4. Source of pigments

  10. Potato is a native of

    1. Peru

    2. Mexico

    3. India

    4. China

  11. Other than sugarcane, a major source of sugar is

    1. Ipomoea batatas

    2. Beta vulgaris

    3. Acer saccharum

    4. Solanum tuberosum

  12. Which one of the following pairs represents products obtained form the same plant?

    1. Nutmeg and mace

    2. Cotton and kapok

    3. Nimbi din and nicotine

    4. Rubber and resin

  13. Match List with List II and select the correct answer

    List-I List-II
    1. Sal

    2. Shisham

    3. Chir

    4. Teak

    1. Pinus roxburghii

    2. Tectona grandis

    3. Dalbergia sissoo

    4. Shorea robusta

    • A
    • B
    • C
    • D
      • 4
      • 3
      • 1
      • 2
      • 4
      • 3
      • 2
      • 1
      • 3
      • 4
      • 1
      • 2
      • 3
      • 4
      • 2
      • 1
  14. The most important strategy for the conservation of biodiversity is the establishment of

    1. Biosphere reserves

    2. Botanical gardens

    3. National parks

    4. Wild life sanctuaries

  15. Low lying hilly vegetation with low rainfall and dominated by spinous, thorny bushes is called

    1. Dune-vegetation

    2. Taiga-Tundra

    3. Scrub jungle

    4. Xeroseral vegetation