Shoot system

Shoot system

                 The stem is aerial part of the plant. This develops directly from the plumule. 

Functions of stem 

             The main function of the shoot system is transporting the absorbed water and minerals salts. It also bears leaves, branches and flowers. In some plant the aerial part of the stem is modified to perform some special functions. These are stem tendril for climbing, thorn for protection, phylloclade for food manufacture and bulbil for vegetative reproduction.

1. Stem tendril

            It is thin, wiry, leafless, spirally themselves to neighbouring objects and climb them. e.g. Passion flower, Sandwich island climber and balloon vine.

2. Thorn 

             The axillary bud is modified as a hard, straight and pointed structure. e.g. Duranta and lemon.

3. Phylloclade 

              It is a green, flattened stem, which performs the function of photosynthesis. It also stores water and mucilage. The leaves are modified into spines to reduce transpiration. e.g. Opuntia, Euphorbia.

4. Bulbil 

                        This is a special multicellular body of vegetative bud meant for reproduction of the plant, e.g. Agave, onion.