Page 87 - Biology Form Two

Biology for Secondary Schools

The distribution of vascular bundles 7. Compare the structure of monocot
in plants and dicot stems and roots.
The arrangement of vascular bundles in Questions
the roots, stems, and leaves of monocots 1. What differences have you
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and dicots differs in various aspects. observed in the arrangement of

Activity 4.1: Investigate the distribution vascular bundles between monocot
of vascular bundles in plants and dicot roots?

Materials 2. What differences have you
observed in the arrangement of
Microscope, microscope slides, prepared vascular bundles between monocot
slides of monocot root and stem, dicot and dicot stems?
root and stem, iodine solution, and
scalpel Monocotyledonous roots

Safety precautions Monocot plants have fibrous roots.

Observe safety precautions when This type of roots form a wide network
dealing with sharp objects of thin roots that originate from the
stem, and they do not grow deep into
Procedure the soil but remain close to the surface.
1. Cut very thin cross-sections of the The vascular structures are arranged
stems and roots of a sunflower and in a circular pattern around the central
maize to obtain a specimen. pith, as shown in Figure 4.6. The
2. Place the specimen on the pith consists of ground tissue called
microscope slide. parenchyma.
3. View the cross-section of
the sunflower stem under the
microscope. What do you observe?
4. Stain it with a drop of iodine Endodermis
solution. Then, observe it again Pericycle Pith
Cortex
under the microscope. Phloem
5. Describe what you have observed. Xylem

6. Repeat steps 2 to 5 using the Epidermis
Root hair
sunflower root, maize stem, and
maize root and compare your
observation with the prepared
slides. Figure 4.6: Cross-section of a monocot root

Student’s Book - Form Two 81

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