STRUCTURE OF ROOTSBy Sonia, Harshita and Alex

When looking at a leaf through a microscope we’ll see chloroplasts moving around the cells. Chloroplasts are specialized cell structures that contain chlorophylls, the green pigments that absorb light energy for photosynthesis. Other pigments are also important in this light energy transfer. They include carotene and xanthophylls. Chloroplasts are made up of several layers of short membranes called grana. It is in the grana that photosynthesis takes place. The chlorophylls intercept the blue and red spectrum of light. The carotene and xanthophylls absorb the blue-green spectrum of light.

Photosynthesis

Photosynthetic energy is stored in cells in the form of carbohydrates, starch, fats, and proteins. The energy becomes available through the respiration process within the cells. The site of respiration is in the mitochondria. The released energy is used for other plant processes and the synthesis of plant compounds needed for growth

Carbohydrates Oxygen = Energy Carbon Dioxide Water

stored form of energy

taken in by the leaves = used for plant

processesgiven off by the leaves

given off by the leaves

RESPIRATION

Carrots Potatoes

Radish Celery

The root structure

Water enters the root through the epidermis. When it is inside the epidermis, water passes through the cortex, travelling through the cells. In order to enter the stele it must pass through the cytoplasm of the cells of the endodermis. Once it is inside the stele, water is free to move between cells as well as through them. In young roots water enters directly through the xylem. In older roots it has to pass through a band of phloem and cambium.

The role of roots in obtaining water and nutrients from the soil and how these are moved up to the stem and leaves.

The role of roots in obtaining water and nutrients from the soil and how these are moved up to the stem and leaves.

DIAGRAM OF ROOT SYSTEM

ROOT SYSTEMS

There are three different types of root systemsThe two basic types of root systems are the primary root systems and the adventitious root system. The primary root systems is formed of roots and their branches that arise from the primary systems. The primary root is the first-formed, main root, That originates from the radicle of a seed embryo (the portion of the embryo below the cotlyedons). Two primary root system types: Tapoot System - Single primary root dominates over branch roots ( usually found in Gymnosperms and most Dicotyledons) Fibrous Root System– A network of fine roots with no central dominant root. Fibrous root systems don't go as deep as taproots, but they spread laterally