Life Cycle of a Sporophyte Plant

Overview

Sporophytes encompass plants that do not flower as a means of reproduction, but develop spores or seeds. During their life cycle, these plants endure two different periods: one where they grow and produce spores (the sporophyte stage) and the fertilization of the spores (the gametophyte stage). Ferns, mosses and liverworts make good examples of sporophytes, but cycads and conifers also are sporophytes that form seeds and spend good portion of their lives in this stage.

Germination

A fertilized zygote "germinates" in hospitable soil conditions. The zygote results from either a fertilized spore or a seed. In ferns, the zygote look like a little segment of leaf that sprouts roots and then upright fronds. In cycads or conifers, the fertilized zygote is encased in a seed.

Growth

For the non-flowering plants, the general growth stage is by far the longest enduring stage in the life cycle. This is how we physically see plants in the landscape: ferns with leafy fronds, mosses in a dense carpet-like covering, and conifers like pines and spruces as needled evergreen trees. During this period of general growth, the plants are considered to be in a diploid stage--the growing and multiplying plant tissues through the mitosis process, each new cell containing the full set of chromosomes. Some plants increase their numbers asexually by producing additional roots or tiny plantlets, effectively creating new plants nearby, with the exact same genetic makeup.

Reproductive Cell Division

At appropriate times of year, usually in the warmth of spring or summer, reproduction begins. In ferns, leaves develop clusters of spores called sori on fertile frond undersides. In conifer trees, male and female cones form. At the cellular level in these reproductive locations, cells divide via the meiosis process, resulting in cells or gametes with a half of the genetic code of the parent plant. These gametes are either female (egg--megaspore) or male (sperm--microspore). In conifers or cycads, the male gametes appear in the form of shed pollen.

Fertilization

In mosses and ferns, the egg and sperm conjoin in fertilization via mobility, in rain or dew drops, on the leaves or elsewhere on the plant body. In the case of conifers and cycads, their rigid cones are pollinated by the wind. The pollen from male-gendred cones haphazardly reaches receptive female cones in huge amounts. Once the egg (megaspore) and the sperm (microspore) fuse, they create the fertilized zygote.

Death

No plant lives forever, and while the life cycle outlined repeats itself each year, there comes a time the plant succumbs to drought, extreme cold, a hungry animal or other life-ending event. The diversity of sporophyte plants and species finds some that grow perennially and repeatedly reproduce, while in some habitats the plant grows and then conducts only one reproduction before naturally dying.

Keywords: sporophytes, fern life cycle, conifer life cycle, cycad life cycle

About this Author

James Burghardt has written for "The Public Garden," "Docent Educator," nonprofit newsletters and for horticultural databases, becoming a full-time writer in 2008. He's gardened and worked professionally at public and private gardens in Colorado, Florida, Minnesota, New York, North Carolina and Pennsylvania. He has written articles for eHow and GardenGuides.