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The Self-Taught Gardener: The seed itself, or plant sex education

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By Thursday, Feb 9 Home & Garden More In Real Estate
Photo: Tim Johnson
Corn bears male and female flowers on the same plant. The male flowers of corn are what we commonly refer to as the tassels at the top of the corn and the wind carries this pollen throughout the field ensuring cross-pollination. Good fertilization of a crop depends on the production of a lot of pollen. Just growing a few plants may result in a low yield of corn for consumption, as many home gardeners have come to discover.

It seems like a fitting time of year and political moment to ruminate on the miracle of seeds. In the weeks ahead, as gardeners start seeds of their favorite tomatoes, peppers, and kale, we will gaze with a sense of awe at the glorious seedlings that come up. Some, like beans, first push up their seed leaves, or cotyledons, which, while seeming to raise their arms in joy as they reach up and begin their lives, are actually providing nourishment through these early stages. But rarely do we revel in the glory of the seeds themselves as living organisms. While we admire the miracle of germination and the maturing of young plants for the garden, we tend to take the seeds from which they sprout for granted, and we even find them boring. But their story is really rather picaresque.

Seeds, such as this for the lima bean, are living organisms and contain an embryonic plant within.

Seeds, such as this lima bean, are living organisms and contain an embryonic plant within. Photo: Tim Johnson

We rarely stop to think about the important role these seeds play in the lifecycle of members of the plant kingdom. Nor do we consider that their stories and origins are as complex and awe-inspiring as the plants that they contain in embryonic form. Their stories, which I believe Betsy DeVos may not want to include in a standard school curriculum, are complex. They often involve instances of self-fertilization, bisexuality, and the profligate spreading of pollen, which would make even the most experienced Planned Parenthood advisor blush. For many of us, the lessons of grade school botany have been forgotten and we seldom think of plants as sexual beings that reproduce through a process more diverse than that of most members of the animal kingdom. Their stories make an argument for staying out of the sex lives of others, or at least contradict the view that varied sexual approaches are unnatural.

 

The seed leaves or cotyledons of this bean seedling, were contained within the seed itself and will nourish the young plant before shriveling up and falling off. The true leaves above will gather energy from the sun so the plant can continue to grow.

The seed leaves or cotyledons of this bean seedling, were contained within the seed itself and will nourish the young plant before shriveling up and falling off. The true leaves above will gather energy from the sun so the plant can continue to grow. Photo: Tim Johnson

Some plants, such as peas and beans, have flowers that primarily pollinate themselves. Each flower contains both male and female reproductive parts that mature at the same time. This means that the flower basically mates within its own structure. The pistil receives pollen from the stamens, and the pollen is then carried into the ovary where it fertilizes the ova which, once fertilized, go on to mature and ripen into viable seeds. In the meantime, their petals enclose and shelter these parts to minimize the chance that they might be pollinated by the male parts of other flowers. These flowers which contain male and female parts are known as perfect, or bisexual flowers. Somehow human sexuality does not seem so complex, or so efficient.

 

Some plants, such as this pea, have enclosed floral structures that mean that self-pollination is almost ensured. The closed flowers are often referred to as cleistogamous.

Some plants, such as this pea, have enclosed floral structures that mean that self-pollination is almost ensured. The closed flowers are often referred to as cleistogamous. Photo: Photo: Tim Johnson

Then there are other bisexual flowers that have a more open floral structure. These flowers can either self-pollinate or can be pollinated by other flowers if pollen is brought to the flower’s pistil by insects, movement, or wind.

 

Peppers have perfect, or bisexual flowers, and can fertilize themselves or outcross if pollen from another flower comes into contact with the flower’s pistil. These flowers are known as chasmogamous for their open floral structure.

Peppers have perfect, or bisexual flowers, and can fertilize themselves or outcross if pollen from another flower comes into contact with the flower’s pistil. These flowers are known as chasmogamous for their open floral structure. Photo: Tim Johnson

Plants such as pumpkins and corn contain male and female flowers on the same plant (this is known as being monoecious), and pollen must be brought in from the outside – by bees or other insects or by the wind — for fertilization to occur. I cannot think about what some on the religious right might make of sex practices that involve another species, but it is apparent that, for some plants, reproduction may require members of the animal kingdom to take part in their sex acts. Bees are the original in-vitro fertilization experts. And even wind-pollination, which involves the pollen being carried on air currents to the awaiting female flowers, seems to have some form of political overtones. I cannot imagine the conversation that would ensue if someone’s daughter came home pregnant and claimed that it was the result of tons of pollen floating through the air in the high-school hallways. Perhaps, Secretary DeVos will determine that we need screening mechanisms to protect our daughters from pollen at school instead of guns to ward off grizzlies.

Some plants, such as Swiss chard, spread their seed as profligately as some teenage boys, and distribute their pollen on the wind.

Some plants, such as Swiss chard, spread their seed as profligately as some teenage boys, and distribute their pollen on the wind. Photo: Tim Johnson

 

Other plants, such as spinach and hollies, bear male flowers on one plant and female flowers on another (they are known as dioecious). Without a sizeable population or one very sturdy pollinator, these plants will not produce seeds. The colorful hollies that we cut down and bring indoors for their berries are dioecious, and the red fruits of the hollies are the ripened ovaries that contain the plant’s seeds. These plants are typically wind- or insect-pollinated, but other than that, seem to conform to the traditional conservative view of human sexuality — sex between a male and a female. Except, get this, sometimes if a spinach plant of the opposite sex does not exist, a plant can begin producing flowers of the opposite sex on its own so that fertilization can occur. What bathroom would this plant be allowed to use if it were in a North Carolina school? The complications of the sexuality of the plant kingdom did not come up in the confirmation process for Secretary DeVos, but I look forward to her answers about the teaching of botany in our public schools.

 

This is a female spinach plant. Spinach plants are either male or female, and both need to exist for seeds to develop. However, plants are known to be able to produce flowers of the opposite sex if a suitable partner is not available. This fact might confound some more conservative politicians today.

These are the flowers of the female spinach plant. Spinach plants are either male or female, and both need to exist for seeds to develop. However, plants are known to be able to produce flowers of the opposite sex if a suitable partner is not available. This fact might confound some more conservative politicians today. Photo: Tim Johnson

And if viable seeds are viewed as living organisms, what will pro-lifers demand that we do with the seeds left in the packet after we have sown our crops? Are all plants and seeds sacred? Not a complicated question for most gardeners, at least not when we are out in the garden weeding.

This is a male spinach plant.

These are the flowers of the male spinach plant. Photo: Tim Johnson

That is the moment when all gardeners are decidedly pro-choice. But what will our nominee for Secretary of the Department of Health and Human Services have to say about this?

__________

A gardener grows through observation, experimentation, and learning from the failures, triumphs, and hard work of oneself and others. In this sense, all gardeners are self-taught, while at the same time intrinsically connected to a tradition and a community that finds satisfaction through working the soil and sharing their experiences with one another. This column explores those relationships and how we learn about the world around us from plants and our fellow gardeners.


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