How Do Plants Spread Their Seeds? An Analysis of Common Dispersal Methods

In life, many plants grow through artificial cultivation, but some rely on wind, animals, and other means to spread their seeds. So what relies on what to spread seeds?

1. Animal dispersal

Plants that rely on animals to spread their seeds include cocklebur, puncture vine, beggarticks, wild grape, pine, cherry, pine nut, and chestnut. The seeds of plants such as beggarticks and cocklebur have bristles and barbs on their outer surface, and they stick to animal fur at the slightest touch. Most plants such as cherry and wild grape have fleshy fruits. After the fruits of these plants are eaten by birds, the seeds pass through the digestive tract and are excreted at random in various places. Chestnuts, pine nuts, and the like are carried home and stored by squirrels; some are eaten, and the rest take root and sprout the following year.

2. Wind dispersal

Plants that rely on wind to spread their seeds include dandelion, willow, poplar, and maple. The seeds of these plants are usually light in weight and can float in the air; a gentle breeze can carry them to the ends of the earth. Some plant seeds also grow special structures suited to flying with the help of wind, such as the fine hairs on cotton and willow seeds, the umbrella-like pappus on dandelion fruits, and the wing-like structures on the seeds of pine, maple, and elm.

3. Water dispersal

Plants growing in water or by the water usually spread their seeds with the help of water, such as coconut palm and water lily. When the fruit of the coconut palm ripens, its shell is hard, and like a small boat it drifts far away with the seawater; after being washed ashore by the waves, a new coconut palm grows. When the fruit of the water lily ripens, it falls into the water and slowly rots, and the seeds wrapped in a spongy outer seed coat float up, drift with the current on the water surface, and finally sink to the bottom to take root and sprout.

4. Ballistic dispersal

Ballistic dispersal means shooting seeds out like cannonballs. Common examples include rapeseed, mustard, pea, soybean, mung bean, wood sorrel, and garden balsam. When the seeds of these plants ripen, the dry and hard fruit walls often burst with a “pop” under the baking of the blazing sun, and the seeds are shot into the distance like bullets flying out of a gun barrel. The most interesting among them is a plant called the “squirting cucumber.” When the fruit ripens, it falls off at the slightest touch and in an instant squirts the seeds inside the fruit out from the top.