Corn’s reproduction relies on a process called pollination, the transfer of pollen from the male part of a plant to the female part. This process is necessary for fertilization and the subsequent production of seeds. Corn has a unique method for achieving this, relying entirely on natural forces rather than animal helpers.
Key Structures of the Corn Plant
A corn plant possesses distinct male and female reproductive structures. The male part, the tassel, is at the top of the plant and produces and releases the pollen grains. The female reproductive structure is the ear, found lower on the corn stalk and encased in protective husks, developing into the cob that holds the kernels. From the ear, numerous strands emerge, known as silks; each silk is connected to a single potential kernel, or ovule, and captures pollen.
The Role of Wind in Pollination
Corn is a wind-pollinated plant. The tassel, located at the plant’s apex, matures and begins to release vast quantities of pollen grains; a single tassel can produce anywhere from 2 to 25 million. This pollen is typically shed in the mid-morning, particularly when conditions are dry, and wind plays the primary role in dispersing it, carrying the grains through the air. While pollen can travel considerable distances, most of it settles within 20 to 50 feet of the plant, where silks emerging from the ear are covered with fine, sticky hairs that catch airborne pollen. Each silk must receive at least one pollen grain for its corresponding kernel to develop, and pollen release and silk emergence are generally synchronized, ensuring that receptive silks are available.
From Pollen to Kernel
Once a pollen grain lands on a receptive silk, it germinates, involving the growth of a pollen tube, an extension that travels down the length of the silk strand. The pollen tube acts as a conduit, delivering male genetic material to the ovule located at the base of the silk. Fertilization, the fusion of the male gametes from the pollen with the female gametes in the ovule, occurs after the pollen lands on the silk; although multiple pollen grains may land on a single silk, usually only one fertilizes the ovule. Following fertilization, the ovule develops into a single corn kernel. A developed ear of corn, with its rows of plump kernels, signifies that most or all of its silks were pollinated and fertilized.