Why do the leaves produce more anthocyanins in the fall?

Although scientists offer several different reasons for why some trees produce anthocyanins and autumn leaves change color, the prevailing theory is that anthocyanins protect the leaves from excess sunlight and enable the trees to recover any last remaining nutrients.

What do anthocyanins do to a leaves color?

Anthocyanins. A third pigment, or class of pigments, that occur in leaves are the anthocyanins. Anthocyanins absorb blue, blue-green, and green light. Therefore, the light reflected by leaves containing anthocyanins appears red.

How do anthocyanins protect leaves?

Anthocyanins protect leaves from the stress of photoinhibitory light fluxes by absorbing the excess photons that would otherwise be intercepted by chlorophyll b.

What are the benefits of plants producing anthocyanin pigments in autumn?

Unlike carotenoids, anthocyanins are generated for the sole purpose of shading the chlorophyll, preventing it from producing excess light energy. That’s why trees with anthocyanins are so much more vibrant: because that red pigment is being actively and intentionally produced to block sunlight.

What causes the red pigment seen in autumn leaves?

The yellow colour seen in some autumn trees results from the loss of chlorophyll simply unmasking the yellow carotinoids that were there all along. But red coloration comes from a pigment called anthocyanin, which has to be made afresh as autumn takes hold.

Why do plants produce more anthocyanins?

So plants produce anthocyanins specifically when light intensity is high, but temperatures are low enough to slow photosynthesis. They produce anthocyanins to protect themselves against the damaging effects of collecting more energy than they can use.

What is the function of anthocyanin in leaf?

Anthocyanins are a group of polyphenolic pigments that are ubiquitously found in the plant kingdom. In plants, anthocyanins play a role not only in reproduction, by attracting pollinators and seed dispersers, but also in protection against various abiotic and biotic stresses.

What makes leaves turn red vs yellow?

When the green chlorophyll in leaves diminishes, the yellow pigments that already exist become dominant and give their color to the leaves. Red autumn leaves result from a different process: As the chlorophyll diminishes, a red pigment, anthocyanin, which was not previously present, is produced in the leaf.

What triggers anthocyanin production?

Reactive oxygen species (ROS) are common by-products produced under different biotic and abiotic conditions and cause oxidative stress when accumulated at a high level in plant cells. This in turn leads to the production of anthocyanins.

What is the role of anthocyanins in plant abiotic stress?

Given that anthocyanins possess antioxidant properties, they protect plants from growth inhibition and cell death by reducing oxidative stress through scavenging abiotic stress-induced ROS, thereby enabling plant adaption to abiotic stress (Figure 3) (Ai et al., 2018; Chalker-Scott, 1999; Naing et al., 2017; Petrussa …

Are anthocyanins useful for intercepting light during autumn senescence?

Anthocyanins appear to be particularly appropriate during autumn senescence for intercepting light that would otherwise be captured by chloroplasts undergoing massive chlorophyll turnover.

Why is autumn senescence bad for plants?

Because autumn senescence involves the rapid liberation of the entire pool of chlorophyll (Sanger, 1971; Matile, 2000), it presents a substantial opportunity for oxidative damage that may reduce the efficiency of nutrient recovery from senescing leaves.

Do anthocyanins protect leaf chloroplasts from excess sunlight during senescence?

We suggest that the buildup of anthocyanins in autumn leaves contributes to the shielding of leaf chloroplasts from excess sunlight during senescence.

Is red coloration a reliable indicator of anthocyanin presence in leaves?

Thus, red coloration was a reliable indicator of anthocyanin presence. For up to 3 weeks after the beginning of autumn senescence, the lower surfaces of red- and yellow-senescing leaves of similar age appeared equally green in color.