Getting to know plants (Part-2)

Getting to know plants 

Q.5. What are the functions of stem?
Ans.  A stem performs following functions:

Ø  The stem holds the plant upright (or erect).

Ø  The stem and its branches hold leaves to get maximum sunlight.

Ø  It transports water and minerals from roots to different parts of the plant.

Ø  It transports food from leaves to different parts of the plant.

Ø  Stems of some plants like ginger and onion grow underground. These stems store food made by the leaves.

Q.6. Describe a simple experiment to show that the stem of a plant carries water to the leaves and flowers.
Ans. We would require a glass, water, red ink, a herb, and a blade for this activity. Pour water to fill one-third of the glass. Add a few drops of red ink to the water. Cut the base of the stem of the herb and put it in the glass as shown in Figure. Observe it the next day.
                                                           

From this activity we see that water moves up the stem. If this is kept for a longer period, the colour appears in the veins of leaves also. In other words, stem conducts water. Just like the red ink, minerals dissolved in water also move up in the stem, along with the water. The water and minerals go to leaves and other plant parts attached to the stem, through narrow tubes inside the stem.

Q.7. Stem is like a two way traffic street. Justify.

Ans. The stem of a plant has a large number of narrow tubes inside it. One type of tubes in the stem carry water and dissolved minerals from the roots to the leaves and other parts. These go up the stem.

The leaves of the plant make food by photosynthesis. Another type of tubes present in the stem carry the food from the leaves to all other parts of the plant, including roots. It comes down.

Hence, Stem is like a two way traffic street.

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