What Is A Seed – A Guide To The Seed Life Cycle And Its Purpose
Most organic plant life starts out as a seed. What is a seed? It is technically described as a ripened ovule, but it is so much more than that. Seeds house an embryo, the new plant, nourish and protect it. All types of seeds fulfill this purpose, but what do seeds do for us outside of growing new plants? Seeds may be used as food for humans or animals, spices, beverages and are even used as industrial products. Not all seeds fill all of these needs and, in fact, some are poisonous.
What is a Seed?
Plant life starts with seeds unless the plant reproduces by spores or vegetatively. Where do seeds come from? They are the byproduct of a flower or flower-like structure. Sometimes seeds are encased in fruits, but not always. Seeds are the primary method of propagation in most plant families. The seed life cycle starts with the flower and ends with a seedling, but many steps in between vary from plant to plant.
Seeds vary in their size, dispersal method, germination, photo response, need for certain stimuli, and many other complicating factors. For instance, look at the seed of the coconut palm and compare it to the minute seeds of an orchid and you will get some idea of the vast variety in sizes. Each of these also has a different method of dispersal and has certain germination requirements that are only found in their natural environments.
The seed life cycle can also vary from just a few days of viability to up to 2,000 years. No matter the size or life span, a seed contains all the information necessary to produce a new plant. It is about as perfect a situation as nature has devised.
Where Do Seeds Come From?
The simple answer to this questions is from a flower or fruit, but it is more complex than that. The seeds of conifers, such as pine trees, are contained in scales inside the cone. The seeds of a maple tree are inside the little helicopters or samaras. The seed of a sunflower is contained in its large flower, familiar to most of us because they are also a popular snack food. The large pit of a peach contains a seed inside the hull or endocarp.
In angiosperms, seeds are covered while in gymnosperms, seeds are naked. Most types of seeds have a similar structure. They have an embryo, cotyledons, a hypocotyl, and a radicle. There is also an endosperm, which is the food that sustains the embryo as it begins to sprout and a seed coat of some sort.
Types of Seeds
The appearance of seeds of different varieties varies greatly. Some of the grain seeds we commonly grow are corn , wheat and rice . Each has a different appearance and the seed is the primary part of the plant we eat.
Peas , beans and other legumes grow from seeds found in their pods. Peanut seeds are another example of a seed that we eat. The huge coconut contains a seed inside the hull, much like a peach.
Some seeds are grown just for their edible seeds, like sesame seeds. Others are made into beverages as in the case of coffee . Coriander and clove are seeds used as spices. Many seeds have a powerful commercial oil value too, such as canola .
The uses of seeds are as diverse as the seeds themselves. In cultivation, there are open pollinated, hybrid, GMO and heirloom seeds just to add to the confusion. Modern cultivation has manipulated many seeds, but the basic make up is still the same – the seed houses the embryo, its initial food source and some sort of protective cover.
What is a seed? It is technically described as a ripened ovule, but it is so much more than that. Seeds house an embryo, the new plant, nourish and protect it. All types of seeds fulfill this purpose, but what do seeds do for us outside of growing new plants? Find out here.
The Gardening Cook
The vegetable and flower growing season is getting closer with each passing day. Here in NC, we have had unseasonably warm weather. It SEEMS that spring has sprung but I still don’t dare really get gardening in full steam in case we get a bit of a cold snap. Are you an avid gardener? If you are, you may have wondered about the various seed types available for planting.
You only have to walk into a gardening center or big box hardware store in spring to see rows and rows of seeds for sale. Choosing what type to purchase can seem like a daunting task, since there are so many choices. One of the choices that every gardener has to make is the choice between open-pollinated, hybrid or heirloom seed varieties. Each type offers something and often the choice depends on your own needs and interests.
Differences between the various seed types.
Open-pollination occurs in nature, naturally. It happens when a bird, insect, or even the wind pollinates plants. As long as the plants are separated from other varieties, open pollinated seeds will breed “true to type.” The advantage of open-pollinated seeds is that you can save seeds and have them to plant from one season to the next. Another big advantage of open-pollinated vegetable seeds for most people is their superior flavor.
My favorite among the seed types are the heirloom seeds. Heirloom seeds have developed outside of the commercial plant trade. I have heirloom bean seeds that originated in my great grandmother’s garden. Each generation of my family has saved seeds from the plant and grown basically an identical bean to one that my great grandmother grew. There are many smaller seed companies that have developed a niche in the market place selling heirloom seeds. Some say that heirloom seeds are identified by how long the seed has been passed down (often 50 or even 100 years is the benchmark.) Others say that the history of the seed saving is important for heirloom varieties.Heirloom seeds are always open pollinated, but not all open pollinated seeds are heirloom seeds. This sounds like a paradox but is really based on the ancestry of the seed than on the pollination.
Growing heirloom seeds
I was lucky enough to receive this kit of Heirloom vegetable seeds from Sprout Brite to try out. They no longer have this seed kit in stock but they do have other garden kits for sale.
The kit contains a wonderful selection of these heirloom seeds: Brandywine Tomato, Cherry Belle Radish, Tendersweet Carrot, Golden Beauty Corn, Great Lakes Lettuce, Red Burgundy Onion, Delikatesse Cucumber, Utah Celery, California Wonder Pepper, and Calabrese Broccoli. The kit comes in a pretty display box which makes it a great gift idea. Along with the kit, the winner will receive planting instructions and a calendar.
Hybrid seeds are those that have cross pollinated between two types of similar plants. This can result, naturally, if the plants are not separated from each other, and it can also be intentional by human intervention. Seeds of hybrid plants are unstable and cannot be saved for use in the following years. They will grow but likely will not be like the parent plants and may be less healthy. With hybrid seeds, you must purchase new seeds every year which adds to the cost of gardening.
Hybrid plants are somewhat uniform in size. If you are growing vegetables for resale purposes, this can be a big plus. Hybrid plants generally grow better and have a higher yield than open pollinated seed plants. They offer higher disease resistance. This makes them desirable for home growers as well as those in the commercial field. The main disadvantage is that flavor is not high on the list of priorities with hybrid seeds, although is not always the case.
What about GMO Seeds?
And now for the elephant in the room. If you have an interest in organic gardening, you have probably heard about the controversy concerning the use of GMO seeds.
GMO means genetically modified organism. GMO seeds are created in a lab using sophisticated techniques such as gene splicing. Instead of crossing two different but related plants (as hybrid seeds do) the cross can be much more significant (such as crossing a bacteria with a plant.) This is done to create pest resistant plants.
What are the disadvantages of GMO seeds? Sadly, that is a big fat unknown. In many other countries there is GMO labeling on products which come from GMO seeds, but here in the USA, this is not yet the case.
Many GMO seeds are those that are considered cash crops for farmers: soybean, corn, canola and cotton, but the slope is slippery and who knows what comes next?
Which of these seed types do you have experience with and which is your favorite?
Disclosure of Material Connection: Some of the links in the post above are “affiliate links.” This means if you click on the link and purchase the item, I will receive a small commission from the sale, but the price is the same for you. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: “Guides Concerning the Use of Endorsements and Testimonials in Advertising.”
There are various seed types. Hybrid, cross pollinated, heirloom and GMO all mean something different to a gardener. Do you know the differences?