### Theory:

Onion root-meristematic tissue experiment:

*Onion bulb experiment - presence of apical meristem*- Take
**two**jars (jar \(1\) & jar \(2\)) and**two**onion bulbs with**roots**protruding from them. Pour water into the jars until the jars are nearly full. - Place the two onions with their roots immersed in the water into each of the jars as shown in the picture.
- Measure the length of the roots on day \(1\), \(2\) and \(3\).
- After a few days we observe that
**both the roots**have grown to a**certain length**. - Take onion bulb out of the jar \(2\) and cut the tip of the root by about \(1\) cm. Place it again in the jar and observe the growth of roots in both jar \(1\) and jar \(2\) for another \(5\) days. Mark the jar of the root-trimmed
**onion bulb**.

**Note the measurement of the length of the roots in the below table before cutting the tip of the root:**

Day \(1\) | Day \(2\) | Day \(3\) | |

Jar \(1\) | |||

Jar \(2\) |

**Note the measurement of the length of the roots in the below table after cutting the tip of the root:**

Day \(1\) | Day \(2\) | Day \(3\) | Day \(4\) | Day \(5\) | |

Jar\(1\) | |||||

Jar \(2\) |

Questions:

- Is there a difference in
**length of roots**between the(in jar \(2\)) and the un-trimmed one (in jar \(1\))? Give reasons.**root-trimmed onion** - Do the roots continue growing even after we have removed their tip?

Answers:

- Yes, there will be a
**difference**in the length of the roots. The**root-trimmed**onion's root (in jar \(2\)) is shorter in**length**than the**un-trimmed**one (in jar \(1\)). Tips of the plant roots contain apical meristematic tissue, and is responsible for the elongation or length of the roots. As the tip of the onion roots in jar \(2\) is cut, apical meristematic tissue is removed from it. There will not be any observable growth in the roots of the onion in jar \(2\) . So the length of the roots of the onion in jar \(2\) is**lesser**than the length of the roots of the onion in jar\(1\). - No, the roots won't grow after their tips are removed. Tips of the plant roots contain apical meristematic tissue, and is responsible for the elongation or length of the roots. As the tip of the onion roots in jar \(2\) is cut, apical meristematic tissue is removed from it. So there will not be any growth in the roots of the onion in jar \(2\) after the tips are cut.