Plant System 2nd Post

 

SHOOT SYSTEM

The areal parts of the plants such as stem, its branches, leaves, flower and fruit, etc. Specialized for different functions make the Shoot system. Here we will discuss stem and leaves:

STEM

Stem is usually the aerial part of the plants. It provides support to its branches, leaves, flower and fruit, etc. Vascular bundles (Xylem and Phloem) run through stem to leaves for transport of material with in the plant body.

A sketch of internal structure of stem is self-explanatory with in regards to the arrangement of different tissue in the plants.

LEAF

Stem and its branches bear leaves are the organs which are well exposed to light and well for preparation of food during photosynthesis. A leaf is provided with the stalk is called Petiole. Its flat green part is called Blade or Lamina, which has many veins. The middle strong vein is called Midrib.

Different shaped cells as shown in the cross section of a leaf perform different functions.

The internal structure of leaf:

CONDUCTION OF WATER AND DISSOLVED MINERALS

Movement of material   particle from the area they are more to the area where they are less is called diffusion. The diffusion through membranes (like cell membranes) is called osmosis. As the concentration of water and dissolved minerals is more in soil as  compared to the root cells they move in the root tissue (osmosis).The xylem is a tissue in p0lants which forms a system  of pipelines (xylem vessels) from roots to leaves through stem for the conduction of water, only in one direction.