Explain Leaf Primordia ?
In contrast to the root, which produces branches from meristematic tissue called the pericycle, shoots have areas of meristematic tissues called nodes that give rise to leaves and branches. A node corresponds to the point of origin of a leaf, and the region of stem between two nodes is called the internode. The leaf primordium is actually an embryonic leaf that will continue to grow, develop and differentiate into a mature leaf, complete with petiole (leaf stalk). As it grows, the leaf produces another lateral shoot bud in its axil, which is protected by scales.
When the leaf eventually dies and drops off the twig, it leaves a "leaf scar" on the twig, and if you examine a leaf scar carefully, you will see the vascular bundle scars that are left on the twig, indicating where the xylem and phloem branched off the main stem to feed the leaf through the petiole. One is able to determine the leaf pattern by the arrangement of leaf scars on a twig. The lateral bud is also left behind at the node, to sprout and develop the next spring. The main stem will also have scars from the terminal bud scales that fell off when the main apical meristem started to grow, adding to the stem length.