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Step-by-Step Explanation
Step 1: Understanding Generations in Plants
In flowering plants, there is an alternation of generations with a diploid sporophytic generation and a haploid gametophytic generation. The gametophytic generation develops within the tissues of the sporophyte. Hence, certain structures contain both generations simultaneously.
Step 2: Pollen Grain Inside the Anther (i)
The anther is part of the diploid sporophyte. Inside each anther, sporogenous tissue undergoes meiosis to form haploid microspores, which develop into pollen grains. Thus:
• The anther (diploid) belongs to the sporophytic generation
• The pollen grains (haploid) belong to the gametophytic generation
Therefore, pollen grains inside the diploid anther represent two generations enclosed in one structure.
Step 3: Embryo Sac Inside the Ovule (iv)
The ovule is part of the diploid sporophyte (the gynoecium in the flower). Within the ovule, a megaspore mother cell undergoes meiosis to form four haploid megaspores, one of which typically develops into the embryo sac (the female gametophyte). So:
• The ovule (diploid) belongs to the sporophytic generation
• The embryo sac (haploid) belongs to the gametophytic generation
Hence, the embryo sac inside the ovule is another clear example of two generations within one structure.
Step 4: Conclusion
From the options provided, the plant parts that consist of two generations one within the other are:
(i) Pollen grains inside the anther
(iv) Embryo sac inside the ovule
Therefore, the correct answer is (i) and (iv).
