Unit 2 Plant Anatomy Horticulture Roots Unit 2 Plant Anatomy Horticulture

What do roots do? absorb nutrients and moisture Purpose of roots: absorb nutrients and moisture Anchor the plant in the soil Provide physical support for the stem Serve as food storage organ

Types of Root Systems Tap Root Fibrous Roots Adventitious roots others

Taproot consist of one primary root with few branches fare well during droughts because their roots go deeper into the ground Ex. Carrots, dandelions

Advantages and Disadvantages of Taproots Penetrate deeper into the soil Obtain water from lower levels Anchor the plant Disadvantages Difficult to remove/harvest plants Do not stabilize the soil well

Fibrous Roots roots consisting of lateral roots near the surface of the soil responds quicker to fluctuations in water and nutrient levels because they tend to be shallow

Advantages and Disadvantages of Fibrous Roots Less drought resistant Tend to get exposed during cultivation Advantages Shallower, thus respond more quickly to fertilization/irrigation Stabilize the soil better

Adventitious Roots roots that appear at locations other than the normal root system develop from aerial portions of the stem ex. Prop roots on corn plants

Adventitious roots

Root Anatomy

Terminology Meristem- Apex tissue that produces new cells “Growth Tissue” Apex at the tip Meristematic Apex – at the tip of the root where new cells grow

Anatomy of the Root Root cap Zone of Cell Division (Meristematic) Root is divided into sections: (bottom up) Root cap Zone of Cell Division (Meristematic) Zone of elongation Zone of maturation/maturation

Root Cap Protects the cells of the root Tough outer covering, pushes through the soil

Meristematic Zone/ Zone of cell division located at the very tip of the root. manufactures new cells through mitosis (replication)

Zone of Elongation these cells increase in size and push the root through the soil

Zone of Maturation cells undergo changes in order to become specific tissues such as: the epidermis cortex, vascular tissue

Other parts of the root and functions. Epidermis the outermost layer of cells surrounding the root responsible for the absorption of water and minerals that are dissolved in water. root hairs develop here

Parts of the root Cortex Vascular tissue cells involved in the movement of water from the epidermis to plant tissue and in food storage Vascular tissue conduct food and water located in the center of the root in dicots and in bundles in monocots Xylem and Phloem: tube like structures that carry nutrients to the rest of the plant

External Parts of the root Root hairs found along the main root performs much of the actual water and mineral absorption. produced in the zone of maturation