Corn, a globally cultivated cereal crop, produces pollen as part of its reproductive process. This plant relies on its pollen for the development of kernels, a primary food source for humans and livestock. Pollen directly influences corn’s growth and yield.
Where Corn Pollen Comes From
Corn is a monoecious plant, meaning it has both male and female flowers on the same plant. The male flower, known as the tassel, is located at the top of the corn stalk. This feathery structure produces and sheds pollen.
The tassel consists of spikelet flowers, which hold anthers. These anthers contain the pollen grains. A single corn plant can generate 2 to 5 million grains, released over 10 to 14 days. Peak pollen shed often occurs during mid-morning hours when conditions are favorable.
How Corn is Pollinated
Corn undergoes wind pollination, a process known as anemophily. Pollen grains released from the tassel are carried by air currents to the plant’s female reproductive parts. While some pollen can travel over 500 feet, most settles within 20 to 50 feet of the originating plant due to the pollen grains’ weight.
The female flowers are the developing ears, from which silks emerge. Each silk is a receptive stigma connected to an ovule on the cob. When a pollen grain lands on a silk, it germinates and grows a pollen tube down the silk, reaching and fertilizing the ovule within 24 hours. Silks remain receptive to pollen for approximately 10 days, allowing for fertilization.
Why Pollination is Essential for Corn
Successful pollination impacts the size and yield of a corn harvest. Each silk on an ear must receive a pollen grain for kernel development. If a silk is not pollinated, the ovule will not develop, resulting in barren spots or “skips” on the ear and fewer kernels.
This process, termed kernel set, is susceptible to environmental stresses like drought or high temperatures, which can interfere with pollen viability or silk emergence. The timing of pollen shed and silk emergence, referred to as “nick,” is important for optimal fertilization. Effective pollination directly impacts corn’s productivity and economic value.
Corn Pollen and Allergies
While corn produces significant pollen, it is less allergenic than pollens from other grasses or weeds. This is due to the large size of corn pollen grains, which range from 60 to 125 micrometers in diameter. Their weight limits how far they travel, meaning allergic reactions are more likely in individuals close to corn fields.
Despite lower allergenicity, some individuals experience symptoms from corn pollen exposure, especially those with sensitivities to other grass pollens. Symptoms include hay fever-like reactions such as sneezing, nasal congestion, and wheezing, and sometimes exacerbate asthma. While uncommon in the general urban population, corn pollen allergy can concern agricultural workers or those living near corn cultivation areas.