What is Meristem?
[[Image:Méristème couches.png|thumb|240px|Apical meristem or growing tip. <br/>The epidermal (L1) and subepidermal (L2) layers form the outer layers called the [[tunica]]. The inner L3 layer is called the corpus. Cells in the L1 and L2 layers divide in a sideways fashion, which keeps these layers distinct, whereas the L3 layer divides in a more random fashion.|right]] A '''meristem''' is a [[biological tissue|tissue]] in [[plant]]s made of [[cell division|dividing cells]]. They are in parts of the plant where growth can take place. Plant cells which are [[Cell differentiation|differentiated]] generally cannot divide or produce cells of a different type. Therefore, [[mitosis|cell division]] in the meristem is necessary to get new cells. This allows for the growth of tissues and new organs needed by the plant. Meristematic cells have the same function for plants as [[stem cell]]s have for [[animal]]s. They are incompletely or not at all differentiated, and are capable of continued cell division. The cells are small and [[protoplasm]] fills the cell completely. The [[vacuole]]s are extremely small. The cytoplasm does not contain plastids (such as [[chloroplasts]], but they are there in rudimentary form ('proplastids'). Meristematic cells are packed closely together without intercellular cavities. The [[cell wall]] is a very thin primary cell wall. == Apical meristem == [[Image:Root-tip-tag.png|thumb|right|10x microscope image of root tip with meristem<br /> 1 – quiescent center <br /> 2 – calyptrogen (live rootcap cells) <br /> 3 – rootcap <br /> 4 – sloughed off dead rootcap cells<br /> 5 – procambium]] The apical meristem, or growing tip, is found in the buds and growing tips of roots in plants. It begins growth of new cells in young seedlings at the tips of roots and shoots (forming buds, among other things). Specifically, an active apical meristem lays down a growing root or shoot behind itself, pushing itself forward. Apical meristems are very small, compared to the cylinder-shaped lateral meristems.<re