Free Kingdom Plantae MCQs with Answers

311. Endosperm is formed during the double fertilization by:

• A. Two polar nuclei and one male gamete
• B. One polar nucleus and one male gamete
• C. Ovum and male gamete
• D. Two polar nuclei and two male gametes

Explanation: Double fertilization is the simultaneous occurrence of syngamy and triple fusion. Syngamy involves fusion of one male gamete with egg cell to form zygote. The result of syngamy is zygote (2n) which ultimately develops into embryo. The second male gamete fuses with 2 polar nuclei or secondary nucleus to form triploid primary endosperm nucleus and this is called triple fusion. This primary endosperm nucleus (3n) ultimately develops into a nutritive tissue for developing embryo called endosperm

312. The embryo in sunflower has:

• A. Two cotyledons
• B. Many cotyledons
• C. No cotyledon
• D. One cotyledon

Explanation: Sunflower (Helianthus) belongs to Family Asteraceae of dicotyledons. A dicot embryo has an embryonal axis and 2 cotyledons attached to it laterally. So the number of cotyledons in sunflower will be two.

313. The role of double fertilization in angiosperms is to produce:

• A. Cotyledons
• B. Endocarp
• C. Endosperm
• D. Integuments

Explanation: Double fertilization is the simultaneous occurrence of syngamy and triple fusion. Syngamy involves fusion of one male gamete with egg cell to form zygote. The result of syngamy is zygote (2n) which ultimately develops into embryo. The second male gamete fuses with 2 polar nuclei or secondary nucleus to form triploid primary endosperm nucleus and this is called triple fusion. This primary endosperm nucleus (3n) ultimately develops into a nutritive tissue for developing embryo called endosperm.

314. If there are four cells in anthers, what will be the number of pollen grains?

• A. 16
• B. 12
• C. 8
• D. 4

Explanation: Pollen grains or microspores are formed inside anther, which is the fertile portion of stamen or microsporophyll. Inside the anther, primary sporogenous cell gives rise to microspore mother cells or pollen mother cells (MMC or PMC). Each MMC on reduction division gives rise to 4 microspores or pollens. So, these four cells will give rise to 4 × 4 = 16 pollen grains.

315. In an angiosperm, how many microspore mother cells are required to produce 100 pollen grains?

• A. 75
• B. 100
• C. 25
• D. 50

Explanation: Pollen grains or microspores are formed inside anther, which is the fertile portion of stamen or microsporophyll. The formation of microspores or pollens is called microsporogenesis. The primary sporogenous cell gives rise to microspore mother cells or pollen mother cells. Each microspore mother cell on reduction division gives rise to 4 microspores or pollens. So for the formation of 100 pollen grains, 25 MMC are required. It involves karyokinesis followed by cytokinesis.

316. The polyembryony commonly occurs in:

• A. Tomato
• B. Potato
• C. Citrus
• D. Turmeric

Explanation: Presence of more than one embryo inside the seed is called polyembryony. It is more common in gymnosperms than angiosperms. In angiosperms, it is generally present as an unusual feature in few cases like Citrus, mango etc. In Citrus many embryos are formed from the structures outside the embryo (like nucellus). This is commonly called adventive polyembryony. In Citrus upto 10 nucellar embryos are formed.

317. Double fertilization is characteristic of:

• A. Angiosperms
• B. Anatropous
• C. Gymnosperms
• D. Bryophytes

Explanation: Double fertilisation is the characteristic feature of angiosperms. This phenomenon first observed by Nawaschin, 1898 in Lilium and Fritillaria. In angiosperms one male gamete fuses with the two polar nuclei to form triploid primary endosperm nucleus. The process is called triple fusion. These two acts together are known as double fertilisation.

318. Meiosis is best observed by dividing:

• A. Cells of apical meristem
• B. Cells of lateral meristem
• C. Microspores and anther wall
• D. Microsporocytes

Explanation: Meiosis is best observed in dividing microsporocytes. Microsporocytes or microspore mother cells after meiosis give rise to microspore. Other cells do not divide by meiosis.

319. Double fertilization is fusion of:

• A. Two eggs
• B. Two eggs and polar nuclei with pollen nuclei
• C. One male gamete with egg and other with synergid
• D. One male gamete with egg and other with secondary nucleus

Explanation: Double fertilization is the simultaneous occurrence of syngamy and triple fusion. Syngamy involves fusion of one male gamete with egg cell to form zygote. The result of syngamy is zygote (2n) which ultimately develops into embryo. The second male gamete fuses with 2 polar nuclei or secondary nucleus to form triploid primary endosperm nucleus and this is called triple fusion. This primary endosperm nucleus (3n) ultimately develops into a nutritive tissue for developing embryo called endosperm

320. Plants which produce characteristic pneumat­ophores and show vivipary belong to:

• A. Halophytes
• B. Psammophytes
• C. Hydrophytes
• D. Mesophytes

Explanation: The presence of pneumatophores, i.e., small negatively geotropic vertical roots and vivipary or seed germination while attached to a plant are adaptations of halophytes, i.e., plants growing in saline habitat.