`star` Introduction
`star` The tissues
`star` Meristematic Tissues


● We can very easily see the `color{violet}("structural")` similarities and variations in the `color{brown}("external morphology")` of the larger `color{violet}("living organism,")` both `color{violet}("plants")` and `color{violet}("animals.")`

● Similarly, if we were to study the `color{violet}("internal structure,")` one also finds several similarities as well as `color{violet}("differences.")`

● Study of `color{violet}("internal structure")` of `color{violet}("plants")` is called `color{brown}("anatomy.")`

● `color{violet}("Plants")` have cells as the basic unit, `color{brown}("cells")` are `color{violet}("organised")` into tissues and in turn the `color{brown}("tissues")` are organised into organs.

● Different `color{violet}("organs")` in a `color{violet}("plant show")` differences in their internal structure.

● Within `color{violet}("angiosperms,")` the `color{brown}("monocots and dicots")` are also seen to be anatomically different.

● `color{violet}("Internal structures")` also show adaptations to `color{violet}("diverse environments")`.


● A `color{brown}("tissue")` is a `color{violet}("group of cells")` having a common `color{violet}("origin")` and usually performing a common function.

● A plant is made up of different kinds of `color{violet}("tissues.")`

● `color{violet}("Tissues")` are classified into two main groups, namely, `color{brown}("meristematic")` and `color{violet}("permanent tissues")` based on whether the `color{violet}("cells")` being formed are capable of dividing or not.


● `color{violet}("Growth in plants")` is largely restricted to specialised regions of active `color{violet}("cell division")` called `color{brown}("meristems")` ( `color{violet}("𝘎𝘬. 𝘮𝘦𝘳𝘪𝘴𝘵𝘰𝘴")`: divided).

● Plants have different `color{violet}("kinds of meristems.")`

`star` `color{green}("Primary Meristem:")`

● The `color{violet}("meristems")` which occur at the tips of `color{violet}("roots")` and `color{violet}("shoots")` and produce primary tissues are called `color{brown}("apical meristems.")`

● `color{brown}("Root apical meristem")` occupies the `color{violet}("tip of a root")` while the `color{brown}("shoot apical meristem")` occupies the distant most region of the stem axis.

● During the `color{violet}("formation of leaves")` and `color{violet}("elongation of stem")`, some cells `color{violet}("‘left behind’")` from `color{violet}("shoot apical meristem,")` constitute the `color{brown}("axillary bud.")`

● Such `color{violet}("buds")` are present in the `color{violet}("axils of leaves")` and are capable of forming a branch or a flower.

● The `color{violet}("meristem")` which occurs between `color{violet}("mature tissues")` is known as `color{brown}("intercalary meristem.")`

● They occur in grasses and `color{violet}("regenerate parts removed")` by the `color{violet}("grazing herbivores.")`

● Both `color{violet}("apical meristems")` and `color{violet}("intercalary meristems")` are `color{brown}("primary meristems")` because they appear early in life of a plant and contribute to the formation of the `color{violet}("primary plant body.")`

`star` `color{green}("Secondary Meristem:")`

● The `color{violet}("meristem")` that occurs in the `color{violet}("mature regions")` of `color{violet}("roots and shoots")` of many plants, particularly those that produce woody axis and appear later than `color{violet}("primary meristem ")` is called the `color{brown}("secondary or lateral meristem.")`

● They are `color{violet}("cylindrical meristems.")`

● `color{brown}("Fascicular vascular cambium, interfascicular cambium")` and `color{brown}("cork-cambium")` are examples of lateral

● These are responsible for `color{violet}("producing")` the `color{violet}("secondary tissues.")`

`star` `color{green}("Permanent Cells:")`

● Following `color{violet}("divisions of cells")` in both `color{violet}("primary")` and as well as `color{violet}("secondary meristems,")` the newly formed cells become structurally and functionally specialised and lose the ability to divide.

● Such cells are termed `color{brown}("permanent")` or `color{brown}("mature cells")` and `color{violet}("constitute the permanent")` tissues.

● During the formation of the `color{violet}("primary plant body")`, specific regions of the `color{violet}("apical meristem")` produce `color{brown}("dermal tissues, ground tissues")` and `color{brown}("vascular tissues.")`