The beauty of pistils and stigmas

Most people don’t realize what an extraordinary structure the cannabis plant is. There are so many intricate systems within the flower we don’t even realize that they have some pretty amazing functions. Pistils and stigmas are one of the most fascinating parts of the cannabis plant and are responsible for the reproductive system of the plant.

Cannabis is an annual flowering plant, meaning it completes its life cycle from germination to seed production in one year. In optimal indoor conditions, Mother plants can live many years to continue producing clones. Cannabis is also known as a dioecious plant-it can be either male or female, but hermaphrodites can pop up due to stress or unstable genetics.  Male plants don’t produce flowers, but instead, they develop pollen sacks that burst and spread when mature.

The function of pistils and stigmas

Female plants contain reproductive organs that contain three parts: the stigma, the style, and the ovary. As a unit, the entire organ is called a pistil. A collection of pistillate flowers are what make up a bud. These parts all play a vital role in the anatomy and reproductive system of the cannabis plant and act as the starting point for the reproductive process. The stigma is the part of the pistil responsible for receiving pollen. Each flower has two stigmas that stick out in the open air. It is located at the top and is sticky to allow for as much pollen as possible to stick to the plant by bending and curling toward male pollinators. Each strand is covered in small hairs known as stigmatic papillae. They are easily visible and look like vibrant hair-like strands. They play a key role in plant physiology and help growers determine the best harvest time.

The style is a long stalk that connects the stigma to the ovary. Its main function is to facilitate pollination transfer between male and female plants.

The ovary is located at the base of the pistil and contains ovules needed for pollination. It also protects ovules, which combine with male gametes to form seeds.

The bract is also a part of the reproductive system. It is small leaf tissue from which the stigma emerges and protects the ovary.

The calyx is found at the base of the cannabis flower, and it is a translucent layer that protects the ovule.

Changing colors

Pistils appear early in the flowering stage and start a whitish color. Autoflowers usually develop their first pistils around 3-4 weeks, while photos typically develop after the seasonal light decreases when growing outdoors. For indoor growing, it begins forming when light is brought down to 12/12. White pistils indicate the flowers are immature and have a low cannabinoid and terpene content. Phytochemical changes cause colors to change within the tissue. Triterpenes, known as carotenoids, are responsible for the vibrant orange color in not only pistils but also in orange peppers, carrots, oranges, and papayas. The stigmas turn orange to stand out and attract pollinating insects. This also signals to the grower that the buds are mature and cannabinoid and terpene levels are at their peak. If you see your pistils turning brown, it means 1-your plant has been pollinated by a male plant, fertilization has begun, and 2-you have missed your peak harvest window, and cannabinoid and terpene levels are starting to drop, as well as the buds and leaves are starting to die. Harvest immediately if this happens. Sometimes, you can find pink pistils. We had some on the farm last year, and they are really beautiful and vibrant. Pink pistils are also formed by triterpene, but this one is known as anthocyanins. This triterpene is also found in blueberries, red onions, cherries, and red cabbage. The pink coloration helps protect plant tissue from UV rays and attract pollinators. Only certain strains will produce pink pistils.

It’s amazing to take a deeper look inside the amazing plant we have all come to know and love. There is so much going on under the surface that we would otherwise never know about. Even the most microscopic part of the plant plays a vital role in its development and abundance. Knowing how each of these structures work is integral to being able to produce and provide some of the best cannabis in New York State.

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