Many candidates confused the description for hypogeal germination with that of epigeal.
Many candidates could not state differences between epigeal and hypogeal germination, define seed dormancy or state ways by which it can be broken.
A lot of candidates could however state advantages of using contraceptives in human population.
The most common point was
- it prevents unwanted pregnancy. Other correct answers include:
Description of Epigeal Germination
- Seed absorbs/imbibes water and swells;
- testa splits and the radicle emerges;
- the hypocotyl of the germinating seed elongates;
- pushing the seed out of the soil;
- the cotyledon(s) become exposed to sunlight;
- and turn green to photosynthesize;
-
- the plumule develops into a green shoot
- and the cotyledon(s) dry up/shrink and fall off.
(ii) Differences between Epigeal and Hypogeal Germination
Epigeal Germination Hypogeal Germination
- Hypocotyl elongates; - Epicotyl elongates;
- cotyledon emerges out of the soil; - cotyledon remains in the soil;
- cotyledon(s) turn(s) green/photosynthesize - cotyledons do not photosynthesize;
- Plumule does not emerge simultaneously - Plumule emerges simultaneously with
with the radicle; the ridicle;
- Energy derived from cotyledon. - Energy derived from endosperm.
(b)(i) Seed Dormancy
- an inactive period of a seed
- during which growth slows/completely ceases;
- due to certain internal or external factors.
(ii) Ways of breaking dormancy
- removal /corrosion of testa;
- treatment of seed with acid/digestive enzymes/water;
- exposure to alternating high and low temperatures;
- addition of dormancy- breaking hormones/named hormones;
- exposure to fire;
- exposure to light.
(c) Advantages of using contraceptives in human population.
- it controls birth rate;
- reduces over population;
- promotes maternal health/reduces maternal death;
- promotes infant survival rate;
- enables parents to determine family size;
- prevents unwanted pregnancy;
- enhances good standard of living for the family;
- some prevent STIs or STDs.
