Everything about a plant’s life is affected by its leaves. These powerhouses are the sugar factories of botany!

Leaves have amazing mechanisms for sustaining the plant’s life, as well as their vital role in the process of photosynthesis.

The shape of the leaf is called the blade. This flat surface is held by the petiole to have the sun cover its entire surface.

Sunlight is captured in the chloroplasts (organelles in the leaf that are stacked to work together) that convert light energy into chemical energy. The formula for photosynthesis is:

This is called a light reaction. Beyond the visible light are even longer wave lengths, infrared, microwave, and radio waves.

The movement of these waves is called photons. Leaves manufacture chlorophyll a and chlorophyll b to utilize this energy. In addition, supplementary pigments carotenoids (the yellow, orange, and red of our fall colors) assist in the reactions.

As chlorophyll A and chlorophyll B decay in the fall (less light, cooler temperature and sporadic water supply), these pigments are present to absorb the last of the sun’s energy before the leaves fall for winter.

To quickly recap the water supply system in plants: Water taken up through the roots, is carried in the xylem up the whole plant, so every plant part has access to water.

Minerals that are needed are carried along as well.

This process, called transpiration, is fueled by the leaves. Stomata are openings in the leaf that have guard cells on each side. As water is needed, the stomates open to release gas (in the form of oxygen) and water vapor. This pulls up water from the roots, as the water vapor dissipates.

Monocot leaves have veins that run parallel to each other across the whole leaf.

Dicot leaves have a large midrib that branches off into webbed or netted veins.

This way, each cell has access to water and nutrients. Species of plants give rise to unique patterns of identifiable leaves, from a simple blade to lobed, pinnate, palmate, etc.

Compound leaves have segmented leaf blades. These can be used to identify the plant.

Hughes is an Ohio State University Extension Master Gardener Volunteer in Mahoning County.