Examination of the Vascular System in Plants
The vascular system in plants is composed of xylem, which carries water up from the roots to the leaves, and phloem, which transports nutrients down from the leaves to the roots. The arrangement of vascular bundles in dicot stems is a ring shape, while in the monocot stems the bundles are scattered. In monocot roots the vascular bundles are also scattered and have a pith, while in dicot roots the xylem resembles a star.
To describe the components of the vascular system in plants.
Water drop microscope*, plastic slides*, plastic cover slips*, 4 plastic cups, maize grains, bean seeds, water, cotton wool, GV stain*, razor blades, and 2 droppers*.
GV can stain the skin and clothes.
1. Soak maize and bean seeds in water overnight.
2. Wet cotton wool and place it into 2 plastic cups.
3. Remove the seeds from the water and put them into the two separate cups with cotton wool.
4. Cover the seeds with wet cotton wool and leave the seeds for four days.
5. Transfer the seedlings to a plastic cup that has water and a few drops of GV.
1. Cut a stem in half vertically, then cut a very thin transverse section from centre of the stem, resulting in a thin circular cross section of the stem.
2. Cut a root in half vertically, then cut a very thin transverse section from centre of the root, resulting in a thin circular cross section of the root.
3. Cut a leaf in half vertically, then cut a very thin transverse section from centre of the leaf, so that the mid rib is included. The result will be in a thin diamond-like cross section of the leaf.
4. Mount the cross sections on slides with a drop of water and cover with a cover slip.
5. Observe the specimens using the water drop microscope.
6. Draw what is seen in the microscope.
7. Classify the specimens as monocots or dicots.
The purple colour will be seen in the xylem tissue, which should be similar to the description mentioned in the introduction to this activity.
Collect all the used materials, storing items that will be used later. Waste containing GV should be disposed of in the pit latrine.
In this experiment, you will not be able to see the phloem because it is not coloured.