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Anatomy of Flowering Plants — BIOLOGY STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceBIOLOGYAnatomy of Flowering Plants3 Marks
Question
Deciduous plants shed their leaves during hot summer or autumn. This process of shedding of leaves is called abscission. Apart from physiological changes, what anatomical mechanism is involved in the abscission of leaves?
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Answer

The hormones secreted by plant body influence anatomical changes in it. In the future area of abscission, a special narrow abscission zone develops. It consists of a upper lignified and suberised protective layer. The separation layer consists of unthickened cells where the hydrolysing enzymes develop. Pectinases are secreted out to dissolve middle lamellae. Cellulases bring about hydrolysis of cell walls. Due to this, the separation layer becomes soft and weak. This leads to shedding of leaves from plants.

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