Gardening Etcetera: The fantastical chemistry transpiring within colorful autumn leaves - Arizona Daily Sun

Subscribe to our Daily Headlines newsletter.
Autumn color can be magnificent as showcased in these red maple, aspen, and cottonwood trees.
LOOK: To read more Gardening Etcetera columns, point your smartphone camera at the QR code, then tap the link.
Ahh…autumn! How I relish the season! How I revel in its gentle breezes and azure skies plush with cottony clouds! And above all, how I eagerly await northern Arizona's showcase of fall color!
For me, the harbinger of autumn is my own Virginia creeper’s leafy display of vibrant orange and burgundy in late August. Following that, the locust trees in Timberline switch from bright green to gold.
But it isn’t until September and October that autumn’s true palette shines forth in the High Country. This time of year, I oft give pause to wonder what fantastical chemistry must transpire within these leaves to give such enchanting displays of color.
If you share my curiosity, read on. Keep in mind I am discussing deciduous plants not evergreens. And my use of the word “tree” is usually interchangeable with “shrub” or “plant”.
You are already aware the chemical chlorophyll gives leaves the color green. Through a process called photosynthesis, chlorophyll helps manufacture a sugar, glucose, that feeds the entire plant or tree. It does so by capturing energy from sunlight and taking in carbon dioxide and water. All plants are genuine photosynthesis workshops throughout late spring and summer, fabricating their own food for growth, reproduction, and winter food storage.
Deciduous trees would not be able to survive winter if they retained their leaves. Liquid water is in short supply during cold months, and broad, flat leaves allow too much water to escape through their numerous pores. With the onset of fall’s shorter days and cooler nights, deciduous trees become “aware” winter is in the near future (a small miracle in itself). A tree prepares to drop its leaves by slowing chlorophyll production. The pigment is broken down into its various nutrients and transported out of the leaves to be stored in the trunk, branches, and roots. These nutrients will feed the tree throughout winter and early spring.
Once leaves lose their chlorophyll, pigments that had been in the leaves all along are now able to manifest themselves. And so, begins autumn's magnificent color showcase! Xanthophylls reflect yellow light, giving aspens, ashes, birches, locusts, and some oaks their brilliant golden hues. Carotenes (think carrots) lend sugar maples and other plants, like my sumacs, brilliant orange tones.
Anthocyanin pigments paint with the most vivid colors of all — reds, crimsons, and purples. Scarlet oaks, red sumacs, some aspen, and red maples can be truly breathtaking! Unlike other pigments, however, anthocyanins are not present throughout the life of the leaf. They are manufactured within the leaves in the fall as chlorophyll is broken down, and veins connecting leaves to branches start closing. In the process, some sugars become lodged within the leaves, triggering anthocyanin production.
Eventually, Abscisic Acid hormones stimulate trees to close all the veins connecting the leaves to branches, weakening the attachments. Hence, the leaves drop to the ground.
Now we might ask, “Does weather play a role in the tones and brightness of autumn color?” Yes, it does. Rain-free days in late summer followed by sunny days and cool nights in autumn make for ideal brilliant fall color. Here’s why:
Sunny late-summer days ramp up sugar production, and the more sugar produced, the more becomes trapped in the leaves. Cool fall nights take part by slowing the rate of sugars moving out of the leaves.
But of course, freezing temperatures cause any remaining leaves to freeze and fall off.
Plants have other amazing strategies to survive freezing temperatures. Notably, trees acclimate their cell membranes to allow water and nutrients to migrate out of cells and into intercellular spaces to be transported to branches, the trunk, or most often, the roots.
Additionally, plants may convert their starches to sugars, which we know as sap. Sap serves as an antifreeze in the plant kingdom. When this fantastical chemistry transpires in sugar maples, we humans may use a tad of chemistry of our own to convert the gooey stuff into syrup. Yum!
Cindy Murray is a biologist, co-editor of Gardening Etcetera. and a Coconino Master Gardener with Arizona Cooperative Extension.

Subscribe to our Daily Headlines newsletter.
Flagstaff will be tasked with voting in four city council members from a pool of seven candidates on Nov. 8.
Pronghorn pozole. Mule deer tacos. Frog leg gumbo. These and more were on the menu for the wild game potluck hosted by Arizona Wildlife Federa…
It takes a lot to fly pine trees off a mountain, but the cost of leaving them might be greater still.

“Across Arizona, and really the nation as a whole since 2019, we’ve seen a huge increase in opioid overdoses,” said Angeles Guzman, the manager of the Opioid Crisis Response Program at Coconino County Health and Human Services.
For police in pursuit or searching for suspects, they’re eyes in the sky. For wildland firefighters, they’re a ride out of dangerous situation…

Judge Brent Harris is used to heavy lifting -- sometimes its his case load, other times it's a 90+ pound poles thrown competitively in local Highland Games. After being appointed to the bench in June, the new judge finally had the chance to formally celebrate his new role this weekend.
National Weather Service rain gauges across northern Arizona showed significantly more rain than normal this monsoon season, which officially …
Abortion advocates in Flagstaff will be hosting several events this weekend as part of Women’s Wave Flagstaff, a week of action for abortion r…
Middle-schoolers attending the Montessori School of Flagstaff’s Cedar Campus spent a few days in nature this week as part of one of the school…
100 years ago


Autumn color can be magnificent as showcased in these red maple, aspen, and cottonwood trees.
LOOK: To read more Gardening Etcetera columns, point your smartphone camera at the QR code, then tap the link.
Get up-to-the-minute news sent straight to your device.

source https://4awesome.streamstorecloud.com/gardening-etcetera-the-fantastical-chemistry-transpiring-within-colorful-autumn-leaves-arizona-daily-sun/?feed_id=5873&_unique_id=634a727aaebcf