Defining Plant Terms


Chlorosis :

Yellowing of normally green plant tissue, usually the leaves, caused by the lack of chlorophyll. This disorder can be caused by disease, lack of nutrients, shading, age, or other factors.

Fungus (fungi):

A microscopic organism lacking chlorophyll and the ability to manufacture its own food. Fungi thrive in cool, moist conditions and are usually identified by long, thread-like structures. Most plant diseases are caused by fungi. Includes molds.

Necrosis :

A dead or dying area of plant tissue.



A disease-causing agent. In the case of plants, this is usually a micro-organism such as a bacterium, fungus or virus.


The process by which plants utilize carbon dioxide (CO2), water,  and light energy, converting it to water, oxygen and carbohydrates in the form of plant biomass, including roots, stems, leaves and fruit.



Related to the function and form of a plant, including its structure, growth, and development, biochemical processes (such as photosynthesis), and environmental interactions.

Plant disease:

A condition that results in abnormal functions of a plant and is caused by pathogens or environmental conditions.


The developmental responses of plants to the relative lengths of light and dark periods.


Portion of the plant below ground that absorbs water and nutrients.


A very young plant grown from seed.



A microscopic reproductive structure released by a fungus (similar to a seed).



The main trunk of the plant. Roots are attached at the base of the stem, often below ground or in a growing medium.  Leaves, flowers, and fruits are attached to the above-ground portion of the stem.



The flow of water from the plant to the atmosphere. Water typically flows through the plant from the roots, where it is absorbed as liquid. Water flows through the plant and is evaporated through the leaves to the surrounding air.



1) A young plant after the seedling stage.  2) The process of replanting a small plant to a larger container.


Vegetative growth:

Plant growth that involves the accumulation of plant biomass, such as leaves, shoots, and stems, rather than flowers and fruit.  Vegetative growth can be controlled through climate control and irrigation supply.



Plant growth that involves the accumulation of flowers and fruit.