Page 19 - Ranger SPM 2022 Biology

Biology SPM Chapter 2 Leaf Structure and Function

Aim: To compare the distributions of stomata on upper epidermis and lower epidermis
of monocot leaf and eudicot leaf.
Hypothesis: Distributions of stomata on the lower epidermis of monocot leaf and
eudicot leaf are denser than the distributions of stomata on their respective upper
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epidermis.
Procedure:
Leaf surface of hibiscus is
observed under a low power
light microscope
Forceps Cover slips
A transparent nail varnish The dried nail
is applied on about
5 mm × 5 mm of varnish is
epidermis of peeled off
hibiscus leaf Leaf peel Glass slide
The experiment using maize
plant leaf is repeated
Figure 2.5 Experimental procedure

Type of plant Name of plant Part of plant Number of stomata
Form 5
Upper epidermis 2
Eudicot Hibiscus
Lower epidermis 10

Upper epidermis 4
Monocot Maize
Lower epidermis 5

Discussions:
1. The lower epidermis of hibiscus leaf has more stomata than its upper epidermis.
This is to reduce excessive loss of water through the stomata during transpiration.
2. The hibiscus leaves are positioned perpendicular to sunlight. If more stomata
were to be found on the upper epidermis, the direct sunlight will cause excessive
evaporation of water from the leaves. Hence, photosynthesis cannot take place
at the maximum level.
3. The distributions of stomata in maize leaf on both the upper and lower epidermis
are almost even.
4. The position of maize leaves are parallel to sunlight. Maize leaves roll up during
hot weather to prevent excessive loss of water.
Conclusion: The lower epidermis of eudicot leaf has more stomata than its upper
epidermis. The stomata distribution of monocot leaf are almost the same on both
the upper and the lower epidermis.

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F5 Chapter 2.indd 214 3/29/22 4:35 PM