`star` Introduction
`star` Functions of Stem
`star` Modifications of Stems


● It consist of the `color{Violet}"stem"` which is the `color{Violet}"ascending part"` of the axis bearing branches, leaves, flowers and fruits.

● It develops from the `color{Violet}"plumule"` of the embryo of a germinating seed.

● `color{Brown}"General Characteristics of Stems"`
`star` The stems bear `color{Violet}"nodes and internodes"`. The region of the stem where `color{Violet}"leaves are born"` are called nodes while internodes are the `color{Violet}"portions between two nodes"`.

`star` They bears `color{Violet}"buds"`, which may be `color{Violet}"terminal or axillary"`.

`star` They are generally `color{Violet}"green"` when young and later often becomes `color{Violet}"woody and dark brown"`.


● Its main function is `color{Violet}"spreading out the branches"` bearing leaves, flowers and fruits.

● It `color{Violet}"conducts water, minerals and photosynthates"` prepared by leaves to roots and other storage organs.

● Stem becomes `color{Violet}"modified"` for storage of food, vegetative propagation, protection, support and photosynthesis.


`star` `color{Brown}"Undergound modification of Stem:"`

● `color{Violet}"Underground stems"` of potato, ginger, turmeric, zaminkand, Colocasia are `color{Violet}"modified to store food"` in them. They also act as `color{Violet}"organs of perenation"` to tide over conditions unfavourable for growth.

`star` `color{Brown}"Aerial modification of Stem:"`

● `color{Violet}"Stem tendrils"` which develop from `color{Violet}"axillary buds"`, are `color{Violet}"slender and spirally coiled"` and help plants to `color{Violet}"climb"` such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

● Axillary buds of stems may also get modified into `color{Violet}"woody, straight and pointed thorns"`. Thorns are found in many plants such as Citrus, Bougainvillea. They `color{Violet}"protect plants"` from browsing animals.

●Some plants of `color{Violet}"arid region"`s modify their stems into `color{Violet}"flattened"` (Opuntia), or fleshy `color{Violet}"cylindrical"` (Euphorbia) structures. They contain `color{Violet}"chlorophyll"` and carry out `color{Violet}"photosynthesis"`.

`star` `color{Brown}"Sub-Aerial modification of Stem:"`

● `color{Violet}"Underground stems"` of some plants such as grass and strawberry, etc., `color{Violet}"spread to new niches"` and when older parts die new plants are formed.

● In plants like mint and jasmine a `color{Violet}"slender lateral branch"` `color{Violet}"arises from the base"` of the main axis and after growing aerially for some time `color{Violet}"arch downwards"` to touch the ground.

● A `color{Violet}"lateral branch with short internodes"` and each node bearing a `color{Violet}"rosette of leaves"` and a `color{Violet}"tuft of roots"` is found in aquatic plants like Pistia and Eichhornia.

● In banana, pineapple and Chrysanthemum, the `color{Violet}"lateral branches"` originate from the `color{Violet}"basal and underground portion"` of the main stem, `color{Violet}"grow horizontally"` beneath the soil and then `color{Violet}"come out obliquely"` upward giving rise to leafy shoots.