Plant Reproduction (2024)

Seeds of a pomegranate fruit (megspl, Pixabay)

Biology

Plants are living organisms. That means they need to reproduce in order to pass on theirto future generations. Plants can createthrough either sexual or asexual reproduction.

Sexual reproduction requires genetic material () from two parents. The parent plants have male and female sex cells, calledgametes. The genetic material from the male and female gametes combines to produce offspring. We call this processfertilization. The product of sexual reproduction areseeds.

Seeds produced through fertilization contain genetic material from both parents. As a result, the offspring are not genetically identical to either of the parent plants. Thisgenetic diversitycan help them survive if the environment changes.

Flowering plantsreproduce sexually through a process calledpollination. Flowers contain male sex organs calledstamensand female sex organs calledpistils. Theantheris the part of the stamen that containspollen. Pollen contains the male gametes. Pollen must be moved to a part of the pistil called thestigmafor reproduction to take place.

The outermost parts of the flower are green structures calledsepals. They protect the flower before it opens. Inside the sepals are thepetals. These are usually colourful. Petals on flowers are actually modified leaves. Within the petals are thestamens.Each stamen contains afilamenttopped by pollen-producing cells. The innermost part of the flower is thecarpel.The carpel contains theovary. This is where the eggs, orovules, are located. The pollen from another flower must enter the ovary and fertilize an ovule in order for a seed to start developing.

Misconception Alert

Not all flowers are large and brightly coloured! Some flowering plants, like grasses, have flowers that aretiny and may even be green, which can make them hard to see.

Sometimes plants pollinate themselves. Other times plants pollinate other plants.

Self-pollinationhappens when a plant’s own pollen fertilizes its own ovules.Cross-pollinationhappens when the wind or animals move pollen from one plant to another. The advantage of cross-pollination is that it helps keep a species genetically diverse. Genetic diversity comes in handy when conditions change and organisms need to adapt to the change. Some plants have features that actually prevent self-pollination. This includes things such as pollen and ovules that develop at different times.

Pollinatorsare animals that carry pollen between plants. Many pollinators are insects, like bees, butterflies, moths and beetles. Some birds, including hummingbirds, also play a part. Likewise, certain mammals, like bats and rodents, move pollen between plants. The colours and smells of flowers often attract pollinators. Pollen will stick to a pollinator’s body as it feeds on the flower’s.

Fertilizationis the next step after pollination. During fertilization, the male gametes from the pollen join with the female gametes in the egg. The egg, or eggs, are found inside the stigma. The scientific word for an egg is an.

Fertilization createsfruitthat contain seeds. Some fruits are fleshy, like oranges and watermelons. Others are dry, like acorns or walnuts. Fruits are an attractive food for various animals. After eating fruit, animals expel waste that contains seeds. This way, seeds can take root and grow in places far from the plants that produced them!

Misconception Alert

Some plants have no flowers at all. Flowering plants are a group of plants calledangiosperms. There are also non-flowering plants. These include mosses, ferns and conifers.

Asexual Reproduction

Asexual reproductiononly requires DNA from one parent. It creates offspring that are genetically identical to the parent. Genetically identical offspring are calledclones. Clones lack genetic diversity. This makes them less able to fight disease. It also makes them less adaptable to changes in the environment.

There are different methods of asexual reproduction. They include vegetative propagation and fragmentation.

Vegetative propagationdoes not need seeds or spores. Instead, offspring grow from a part of the parent plant. In different plants, vegetative propagation happens in different ways. Here are a few examples.

• Garlic, onions and tulip plants all reproduce usingtrue bulbs. These short underground stems are also calledscaly bulbs. They have a base that is usually surrounded by modified leaves. These leaves form a papery covering called atunic. New bulbs grow off of the parent bulb’s base.
• Crocuses reproduce usingcorms, which are similar to true bulbs. However, a corm doesn’t have as many layers. Corms are used up during the growing season and get replaced by one or more new corms.
• Potato plants reproduce usingtubers. Tubers produce new plants from stems or growing points calledeyes.
• Ginger plants reproduce usingrhizomes. These are stems that grow sideways along the soil or just below the surface. They branch out to produce new points of growth.
• Strawberry plants reproduce usingstolons. They look like branches growing along the ground. Stolons anchor themselves to the ground and develop roots. The roots grow into new plants.

Misconception Alert

A tuber isn’t a root. It’s a modified stem that grows underground. Corms and rhizomes are other examples of specialized stems.

Did you know?

Apomixisis a form of asexual reproduction in some species of grasses. The parent plant produces seeds without fertilization.

Fragmentationis another form of asexual reproduction. It involves new plants growing from small parts of a parent plant that fall to the ground. This is one of the ways that plants likeliverworts and mossesreproduce.

Horticulturistsare people who study plants. They often use asexual reproduction through fragmentation to grow new plants. They do this by cutting a leaf or a stem off a plant and placing it in water or soil. This process is often calledpropagating from cuttings.

Did you know?

The coco de mer (sea coconut)produces the largest seed of any plant. It grows in the Seychelle Islands. On average, the seeds weigh 25 kg. They can grow to 500 cm in diameter!