Life Science: Session 4
Teaching Tips: Asexual Reproduction in Plants
Sexual reproduction and the unique process known as alternation of generations characterize the life cycles of plants. Other strategies for reproducing can also be observed in plants — strategies that don’t involve the union of sperm and egg. These strategies involve asexual reproduction, where one parent plant propagates offspring that are genetically identical to it. While a few animals can reproduce asexually, most do not have this ability.
Have you ever stored potatoes or onions that began to sprout new parts after a while? These are great examples of asexual reproduction in plants. Interestingly, asexual reproduction in plants is most often associated with food storage structures that the plant uses to sustain itself during times of dormancy. The new plant arises from a bud that exists on the food storage structure. The following are some examples of asexual reproduction in plants—from buds in leaves, stems, and roots.
Onions, garlic, and lilies are examples of modified leaves, called bulbs that serve as underground food storage for a dormant plant. After these plants have flowered and the above ground leaves have fallen away, buds at the base of the bulb represent next season ’s growth.
Many plants reproduce asexually from stems—either below or above ground. Corms, rhizomes, and tubers are good examples. Corms are short, rounded stems with buds located at the top. An example is a gladiola. You can tell the difference between a bulb and a corm by the presence of leaves in the storage unit of the former. Rhizomes are underground stems with buds located at the tips of the branches. Irises produce these types of rhizomes. Most people are surprised to learn that potatoes are actually enlarged parts of stems—mostly occurring underground. These types of food storage structures are called tubers. The “eyes” on a tuber consist of a tiny leaf and a bud, which can sprout into a new plant.
Sweet potatoes represent storage roots. These structures include tuberous examples, like the sweet potato, beets, and turnips as well as longer tap roots, like carrots and parsnips. On the tuberous examples, the buds occur above the root or are scattered upon it. On the taproots, tiny buds exist at the base of the shortened stem.
Consider bringing some of these examples into your classroom and starting a garden of plants that reproduce asexually!
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