Question

In autumn, leaf fall occurs because

• A. Formation of abscission layer at bases
• B. Leaf becomes heavy
• C. Leaf does not remain green
• D. Of low temperature

Answer 1

The correct option is A Formation of abscission layer at bases

By the end of summer, the leaves may be damaged by insects, disease or general wear and tear and ready for renewal. They are equipped to self-destruct. At the point where the leaf stem meets twig or branch is an array of cells called the abscission layer. As autumn days shorten, this layer begins to choke off the veins that move water into the leaf and food into the tree. Once the leaf is completely choked off, the layer becomes dry and flakey and, through decomposition, detaches the leaf from the tree.

So, the correct option is 'Formation of an abscission layer at bases'.