Sub-Aerial Stem Modifications

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• published: 28 Nov 2011
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SUB AERIAL STEM MODIFICATIONS:Stems present partly aerial and partly underground is called SUB AERIAL STEMS.These are found in some weak stemmed plants.These are specialised for vegetative propagation.The sub aerial stem modifications are four types.They are 1 Runners, 2 Stolons, 3 Suckers and 4Offsets.RUNNERS:The sub aerial stems creep horizontally on the soil are called Runners.These are found in some weak stemmed plants.They are rooted at every node. When internodes break off, the nodes lead an independent life. It is called vegetative propagation.Examples: Hydrocotyle vulgaris, Lippia nodiflora, Some species of Oxalis.STOLONS:Sub aerial stems develop from the lower branches of the stem are called STOLONS.They grow obliquely downwards.When these branches touches the soil, produce adventitious roots into the soil.When these branches are separated from the mother plant, live as independent plant. These branches are called STOLONS.The method of raising plants vegetatively by layering depends mainly on stolon principle. Examples: Nerium, Jasminum, Rosa.SUCKERS:Sub aerial stems develop from the underground part of the stem are called SUCKERS.These are underground branches and grow obliquely upwards.These are developed from the axillary buds of the under ground part of the stem.These branches produce many adventitious roots from the lower surface.These branches separate from the mother plant, live as independent life. Examples: Chrysanthemum, Mentha.OFFSETS:Sub aerial stems which are short, slender branches of one intermodal length are called OFFSETS.These are found in free floating hydrophytes like Pistia and Eichhornia.These are rarely found in terrestrial plants like Agave americana.They grow horizontally on the surface of the water.In these plants the stem is reduced to a disc like structure.Many leaves are developed from this stem in rosette manner.The axillary buds of these leaves develop into OFFSETS.The apex of each offset bears a cluster of leaves on the upper side and adventitious roots on the lower side.When these offsets break off they develop into new plants. Stems present partly aerial and partly underground are called Sub Aerial Stems. These are found in some weak stemmed plants. These are specialised for vegetative propagation. Watch the video for full detailed lecture. Comment if u like the video.... www.7active.in