Describe the modifications of the stem for food storage.

(N/A) The stem undergoes modifications to perform various functions,including the storage of food. Key examples include:
$(i)$ Rhizome: Found in plants like ginger $(Zingiber officinale)$ and turmeric $(Curcuma longa)$. These are underground stems that store food and grow horizontally. They possess nodes,internodes,scale leaves,and adventitious roots.
$(ii)$ Tuber: Seen in potato $(Solanum tuberosum)$. The tips of underground branches swell due to the accumulation of starch. The surface of the tuber has 'eyes',which are axillary buds capable of vegetative propagation.
$(iii)$ Corm: Seen in $Amorphophallus$ (Elephant foot yam) and $Colocasia$. It is a condensed,vertical form of a rhizome that stores food and helps in perennation.