Question : What are sub aerial stem modifications? Explain the types of sub aerial stem modifications?

Question : What are sub aerial stem modifications? Explain the types o

1.	Question : What are sub aerial stem modifications? Explain the types of sub aerial stem modifications?
Answer» Solution :Sub aerial stem FOUND in plants with weak stem in which branches lie HORIZONTALLY on the ground. These are meant for vegetative PROPAGATION. Types of sub aerial stem modifications: 1. Runner: Slender, prostrate branch creeping on the ground and rooting at the nodes. Eg: Centella, Oxalis. 2. Stolon : Slender, lateral branch originating from the base of the stem. But it first grows obliquely above the ground, produces a loop and bends down towards the ground. When touches the ground it produces roots and becomes an independent plantlet. Eg: Mentha piperita, Fragaria. 3. Sucker: Sucker develops from a UNDERGROUND stem and grows obliquely upwards and gives rise to a separate plantlet or new plant. Eg: Chrysanthemum. 4. Offset: Offset is similar to runner but found in aquatic plants ESPECIALLY in rosette leaved forms. A short thick lateral branch arises from the lower axil and grows horizontally leafless for a short 1 distance, then it produces a bunch of rosette leaves and root at nodes. Eg: Eichhornia.