SCIENCE
BOTANY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Pinus
|
|
|
Cedrus
|
|
|
Cycas
|
|
|
Gnetum
|
Detailed explanation-1: -Cycads are like all seed-producing plants with a dominant diploid sporophyte phase in their life cycle. The male gametes are motile and ovules are orthotropous. Pollination takes place by air. The sperms cells are the largest and measure up to 300 m in size and visible to the naked eye.
Detailed explanation-2: -Updated On: 27-06-2022 (c) Cycas is a gymnospermic plant. It has the biggest sperms (antherozoids) and ovules in the plant world.
Detailed explanation-3: -Male gametes of Cycas are multiciliated, topshaped, equal and the largest in plant kingdom. It is spirally coiled in the anterior half with thousands of small cilia. Hence option C is correct.
Detailed explanation-4: -’Gargantuan gametes’ are oldest on record and have visible nuclei. A set of tiny ancient crustaceans has yielded the oldest-and some of the biggest-fossilized sperm cells ever discovered.
Detailed explanation-5: -The sperm cells are multiflagellate. These are among the biggest (300 m, or 0.01 inch) in the plant. Every dust cylinder may contain 2–22 sperm cells, contingent upon the sort. Cycad incipient organisms produce two seed leaves or cotyledons.