The Circadian Rhythm of Plants

Sunset in the Garden

Sunset in the Garden

Scientists have announced a fascinating discovery about the secret life of plants.  It turns out that plants are governed by circadian rhythms, just like people.  And the circadian rhythm operates in plants even after they are harvested—even while the plants are sitting in warehouses, on grocery store shelves, or in your refrigerator.

And not only that, scientists have learned that circadian rhythms have a significant impact on the nutritional value of the plants we eat.

In plants, just as in people, circadian rhythms are endogenous, which means they originate in the cellular memory of the individual.  Our personal circadian rhythms are programmed into our DNA.  Circadian rhythms are also heavily influenced by environmental factors, such as day and night, and the rhythm can be altered with changes in the light/dark cycle.

The peak of a plant’s circadian rhythm is in the afternoon, when plants most require energy to fight heat stress and protect themselves from insect attacks.  The low ebb of the circadian rhythm for plants is the middle of the night, the same as in people.

In the recent study, scientists observed how the circadian rhythm affected the concentration of glucosinolates in plants.  Glucosinolates are compounds produced by plants to strip toxic substances from their cells.  In humans, glucosinolates are cancer-fighting agents that remove carcinogens from our bodies.  To do the most good for our health, we want to eat produce with the highest concentration of glucosinolates in every bite.

Scientists manipulated the light/dark cycle for certain plants to produce 12 hours of light and 12 hours darkness, to simulate the day and night conditions of plants in the field.  They found that plants achieved their highest concentration of glucosinolates during the afternoon, when the plants were at the peak of their circadian rhythm.

In fact, the concentration of these cancer-fighting compounds was twice as high during the afternoon compared to the middle of the night, when the plants were at the low ebb of their circadian rhythm.

It is remarkable to consider how much the nutritional density of plants can fluctuate in twelve hours simply due to changes in light.  And the circadian rhythm is only one of many factors that influence the health and taste of produce.

Scientists continue to learn new information about the nutritional density of our food.  Plants are living matter–living energy–even after the plants are harvested.  This living energy fuels our work, our growth, our wellness, our busy lives.  The quality of the plants, and the quality of the potential nutrition of the food, depends largely upon how it is grown.

To get the most nutritional density from your produce, harvest it fresh from your own garden or buy it from a source that offers locally grown and freshly picked vegetables.  Thanks to scientists, we now know that we can enjoy our produce not only at the peak of ripeness, but also at the top of the circadian rhythm, as well.

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