Question
(a) Study the diagram (Diagram 1.1) given below showing the modes of pollination. Answer the questions that follow.i) The given diagram shows three methods of pollen transfer in plants. What are the technical terms used for pollen transfer methods '1', '2' and '3' ?ii) How do the following plants achieve pollination successfully ?1. Water lily2.Vallisneriaiii) Flowering plants have developed many devices to avoid inbreeding depression. Explain one hereditary and one physiological device which helps plants to achieve this target.
or
(b) Observe the diagram (Diagram 1.2) given below showing the menstrual cycle of a normal human female and answer the questions that follow :i) What are the suitable technical terms used for the following ?1. Days 1-72. Days 8-123. Days 16-284. Days 13-15ii) Explain the role of ovarian and pituitary hormones during the following time periods :1. Days 8-122. Days 13-153. Days 16-28
Answer :
(a)
i)
1. Autogamy
2. Geitonogamy
3. Xenogamy
ii)
1. Water lily: pollinated by insects/wind.
2. Vallisneria : Female flowers on long stalks reach water surface male flowers or pollen released on water and carried by water current to female flowers to achievepollination.
iii) Genetic : Self-incompatibility / prevents self-pollen (same flower or other flowers of same plant) from fertilizing the ovules by inhibiting pollen germination, pollen tube growth in pistil.Physiological : Pollen release and stigma receptivity are not synchronized, either pollen matures earlier and stigma later or pollen matures later than stigma.
or
(b)
i)
1. Menstrual period
2. Follicular phase/proliferative phase
3. Luteal phase/secretory phase
4. Ovulatory phase
ii)
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