Blowin’ in the Wind: Plants ensure their progeny travels far and wide

Plants, of course, don’t have brains. And they’re really stuck in the mud; imagine — a tree stays in the same place all its life, how boring is that? Ah, but they’ve actually done it all and much before we even came down from the trees. Also, they have a very pragmatic attitude to life, which clingy parents would do well to emulate. When their progeny reach the right age, they get rid of them, by air, sea, overland through couriers — or even with a solid kick in the pants! Go away as far as possible, find a place and settle down, that’s the lesson.

Many plants and trees despatch their seeds by air. And boy, do they know a thing or two about aerodynamics! Seeds of some tropical lianas are hitched to tissue-thin membranous wings that are so perfectly aerodynamically balanced that our wind-tunnel whiz-kids are still struggling to copy them. Freed from their moorings in breathless tropical forests, they float ethereally over immense distances, touching down lightly a long way from home. Others, like the sycamore, behave like helicopters — their seeds are attached to propellers which spin when the seed falls free and waft them away. And every child has experienced the delight of blowing a dandelion puffball apart and watching its myriad silken parachutes bear the seeds far, far away. Blow gently on them when you’re down and out and you’ll feel inexplicably lighter and happier for it.

Some seeds, like some kids, can be clingy. The Himalayan balsam has solved that problem by exploding its seed capsules (talk about kicking butt): a strategy that parents of loutish home-lounging teenagers might envy. (Parental?) pressure builds up inside the seed capsules (due to evaporation), until — boom — the inevitable explosion occurs! We’ve all delighted in popping open seed pods of plants like peas — it’s as cool and yogic as popping bubble-wrap. And then there are the seafarers. Coconut palms lean towards the sea and drop their great cannonballs on the beach in the hope the tide will bear them away to distant shores. The giant sea bean is another great seafarer and capable of ocean voyages lasting for a year.

Many plants use more direct, simple methods to send their seeds out into the world. Seed pods are equipped with hooks (sometimes fearsome grappling-iron talons), spikes, clinging hairs, or are just plain sticky. These attach easily (and sometimes, painfully) to the hairy coats or clothes of passing animals or humans and hitch a lift. And always, there’s bribery: the sweet blushing temptations of juicy, fleshy fruit — and nutritious seeds. Usually, the seeds are spat out or disgorged well away from the parent plant. Many seeds do get chewed up, but others pass through the system undigested (eaten corn lately?); not a pleasant way of being resettled, perhaps, but it works. For some African acacias, it is essential , by passing through the immense gut of an elephant, the acacia seed pods get rid of deadly beetle grubs which would otherwise have killed the seeds.

And it’s not only seeds that get to travel. Many plants jump the gun and send off gazillions of pollen grains into the air to find suitable stigmas…

And we can only…excuse me go….ATCHOO!

Ranjit Lal is an author, environmentalist and bird watcher

Email author: ranjitlal55@gmail.com