Tomato Blossom Anatomy Part 1 of 2
Male Anatomy- Anther Cone
We are getting oh so close to the actual concepts of tomato breeding, but first let me take you through a crash course on the basic anatomy of a tomato blossom. This is where all the action happens when it comes to breeding. Tomatoes are known as “self-pollinating,” meaning a tomato blossom contains both the male and female reproductive parts inside each blossom. For self-pollination to happen, the blossom first needs to be fully mature, with all parts spread wide open, and inner parts will be bright yellow. If the blossom is closed, it is considered immature. If it is pale yellow, brown, or wilted, the blossom is considered past its prime sexual maturity. Figure 1 shows an example of a fully sexually mature blossom with a few petals removed to allow for a better view of the inner parts.
From here, we will cover some basic connecting parts as well as the male blossom parts. The pedicel (A) is a connecting part that attaches the blossom to the main body of the plant. The pedicel is important for carrying nutrition to the forming blossom and subsequent fruit. Next are the green sepals (B), which protect the maturing blossom from outside stresses while the rest of the inner parts are developing; these open wide as the blossom matures and remain with the fruit as it develops. Some breeders refer to these as “eyelashes.” At full maturity, the blossom begins to open and the yellow petals (C) spread wide open, along with the sepals, and the bright yellow anther cone (D) is exposed.
This is where the act of pollination begins. The sepals and petals are spread wide open, allowing for two things to happen. Primarily, this exposes the bright-yellow color that attracts pollinating insects; however, the insects do not physically move the pollen themselves. The pollen is formed and matures inside the anther cone, which is somewhat closed off to insects. It is actually the vibration of the insect’s wings against the petals and sepals that causes the mature pollen grains to fall down inside the anther cone and fertilize the female parts. A second way for pollen movement to happen also involves the sepals and petals: They catch a soft breeze and vibrate the blossom enough so that the pollen grains fall, sometimes without the help of an insect.