Most of the cannabis plants we know produce green buds. However, the strains from The Red Family come out of the pattern and adopt reddish, purple or bluish tones. The adjectives red, purple and blue stimulate the curiosity of the growers but, in cannabis, the color is not only a matter of aesthetic beauty. They are the expression of a whole range of very special molecules. We are talking about the anthocyanins, which are also responsible for the coloration of many dark fruits and for most of the autumnal tones.
The purple color shown during flowering by the plants from The Red Family genetic collection is the result of its richness in anthocyanins (from the Greek anthos, flower + kyáneos, blue) These are water-soluble pigments that are present in plant cells and contribute to the production of red, purple or blue colors in leaves, flowers and stems of the cannabis plant.
Several hundred different anthocyanins are known and they produce a wide range of colors: malvidin gives purple; the flavones, yellow; the delphinidin, blue; the cyanidin, violet; pelargonidin, red and orange. The combination of several of these anthocyanins in the same tissue in different patterns of concentrations generates a wide variety of intensities, tones and colors.
Anthocyanins have been found in all tissues of plants, including leaves, stems, roots, flowers and fruits. In cannabis they are not present in the roots and very few can be found in the seeds, but in the leaves, stems and flowers the anthocyanin contents can reach up to 2.5% of the total dry weight.
It is possible to extract purple and pink resins from the buds of red-flowered plants. The anthocyanins that give the red color to the bud are also present inside the resin glands (trichomes), producing extractions of beauty like no other.
Dark fruits and vegetables such as plums, blackberries, grapes, cranberries, cherries, aubergines, or red cabbages, are rich in anthocyanins.
Anthocyanins belong to the group of flavonoids (from Latin flavus, yellow), which are a series of secondary metabolites of plants. There are four classes of flavonoids: flavonoids, isoflavonoids, neoflavonoids and anthocyanins.
Flavonoids have different functions in plants, which vary according to the species:
- Protecting tissues from damage caused by ultraviolet radiation.
- Generating bitter flavors to dissuade herbivores from using the plant as food.
- Releasing pleasant aromas to attract herbivorous seed dispersers and make them eat the fruits.
- Attracting insect pollinators.
- Regulating the transport of the auxin hormone.
- Fighting against the attack of some fungi.
Not all colors seen in cannabis that are not green are due to anthocyanins. In varieties that do not produce purple, blue or red colors, often appear golden, orange or yellowish tones at the end of flowering due to carotenoids. Carotenoids are pigments naturally present in the tissues, but they are not usually seen, because they are camouflaged by the intense green of chlorophyll. When a leaf loses chlorophyll it becomes yellow because the carotenoids, which were already there, become visible.
With anthocyanins seems like it does not happen in the same way, because the plants produce them especially at the end of their life cycle, when flowering is about to finish and the days get shorter. In this stage of the life cycle of the cannabis plant the production of chlorophyll decreases and all energy is concentrated in the production of flowers and seeds, but the production of anthocyanins increases at this stage. As the chlorophyll disappears from the tissues of the plant, anthocyanins and other pigments become more visible. It is possible that the anthocyanins help the plants to cope better with the maturity stage, to resist the damage produced by ultraviolet radiation, keeping the herbivores at a safe distance while the seeds complete the maturation process.