No matter how many times I watch it, the magic of germination gives me awe-inspiring, like it’s the first time I’ve seen it.
How a bushel of juicy tomatoes comes from a single seed smaller than the diameter of a pencil eraser, or a spot of basil seeds can be found in a forest of woody, scented herbs that grow at least 3 feet tall I don’t know how to change.
What happens in the seeds before and after the bud is amazing, and witness such a process – what can only be experienced by growing from seeds is truly one of the wonders of life.
The anatomy of seeds and seedlings is something every gardener should know, and learning the science behind it will help you become a better gardener!
Anatomy of the species
We may simply bring in a starter factory from a nursery where we are trained and nurtured from birth and don’t understand what it takes to reach that point.
Then we’ll think about how difficult it is to keep the starter plants alive! Try growing them from seeds. You will need to try a few rounds of natural selection before you can get the perfect plant.
When you have seeds in front of you, you are looking at the seed coat, or testa. Seed coats can be soft and thin (like beans), meaty and thick (such as squash).
Think of them as armor of future plants inside. The seed coat protects from the elements until conditions present themselves in the appropriate way for germination to occur.
Seed coats are adapted to the environment and act as a barrier to damage or injury, fever or cold, bacteria or fungi, and even stomach acidity (if ingested by animals).
With all of this bomber protection in place, it’s no wonder you have a hard time budging seeds! (Soaking the seeds first can help with this. Or, for tomato seeds, it can be fermented to speed up germination.)
In some seeds, you can see the wounds, or hilms left when the seeds are removed from the mother plant (similar to the human belly button).
Hirum is the most visible bean seeds, with scars called eyes, just like the eyes have dark eyes. Others don’t stand out much and look like small nipples and dents on the seed coat.
Within the coat of seeds is the embryo (infant plants), endosperm (foliotissue), cotyledons (leaf-like structures), and the beginnings of roots and buds.
If you look closely at this wet species, you will see that the green cotyledons are actually pushed firmly inside and rounded in the fetal position. They’re just waiting to be released! (Or at least, that’s what I want every time I start some seeds.)
What happens when seeds germinate?
Germination occurs when all the appropriate variables are well suited to that particular variety (oxygen, temperature, light, or darkness), and the seed coat absorbs water, causing swelling and ruptures.
The first sign of life comes from the rad rock, a small white tail that will eventually become the main root of the plant.
The role of roots is to secure the plant to the ground and absorb water. Upon absorption of water, a rudimentary stem called hypocotyl appears, and the cotyledons begin to spread, and sometimes they ingest the coat of seeds as they rise above the soil.
(I like to call them seed hats. Sometimes they never get washed away from the cotyledons and don’t look like small berets.)
What is a cotyledon?
Cotyledons look like leaves, but in reality they are not leaves at all. They are sometimes called seed leaves, as they are part of the plant’s seeds or embryo. Their function is to absorb all endoderm and become a temporary storage of the initial supply of plant nutrients.
There are only one cotyledon (monocular, as in the case of onion and corn) or two (dicotyledons, the majority of vegetables).
Cotyledons are not the “true leaves” of plants, so most buds from the same family are similar at birth, even if they do not resemble each other when they are mature (like these tomatoes and peppers). .
(This is why it’s important to label seed trays, otherwise you’ll be waiting for the seedlings to develop more before identifying them.)
The cotyledons supply the plants until all nutrients are exhausted. When they are spent, they naturally wither and fall from the stem as the shape of new “true leaves”.
Cotyledon vs. True leaves
Generally, when cotyledons appear, it takes 1-3 weeks for the true leaves to appear. (Time frames depend on plant type and environmental factors such as sunlight, moisture, and temperature.)
So how can you tell the difference?
Cotyledons are the first leaf-like structure that forms when seeds germinate. Most cotyledons tend to be less explanatory and similar in the plant family.
For example, radish, broccoli and kale (members of the Brassicaceae) begin their lives with two stubborn, heart-shaped cotyledons. Meanwhile, tomato, pepper and eggplant seedlings (members of the Night Shade family) all start with long, narrow leaves with slightly tips.
You can see how tomatoes from these two varieties have the same cotyledon, but when the true leaves leave, one seedling has a serrated edge that is typical of a normal tomato leaf Holds, the other has smooth lines of potato leaves.
As true leaves develop, they begin to resemble the actual leaves of mature plants. True leaves grow on cotyledons and take over the task of supporting the plant for the rest of the life cycle.
After the first few sets of leaves sprout and the roots are delved deep into the soil, the seedlings draw energy from photosynthesis on the ground, drawing nutrients beneath the ground. This is when the once thin seedlings are in the process of maturation (buds, flowers, fruits, seeds).
They grow very quickly, right?
FAQ
This post was updated from an article originally published on March 19, 2014.
