Some plants survive droughts by curling up tightly until they become wet. Some wait to spend out seeds until they become wet. Hydrochasy is the technical term for plants that react to water by opening to disperse seeds.
High in an alpine meadow, Gesine Pufal, from the University of Wellington, New Zealand, crouched low to the ground and splashed some water from her water bottle on a low green plant cushion, then sat back waiting to see if something would move. Sound crazy? Many hikers passing by her may have thought so, but Pufal was trying to find potential plant species that possess a type of plant movement called hygrochasy.
Although the ability to move is typically thought to be a characteristic unique to the animal kingdom, plants are also capable of movement, from the sudden quick snap of a Venus flytrap to the more subtle creeping of the growing tips of a morning glory vine.
Pufal and her colleagues were interested in another type of plant movement — one used for dispersing seeds, called hygrochasy. While most plants rely on outside sources such as animals or wind to move their seeds to new locations, some plants have specialized, self-sufficient mechanisms. Hygrochasy combines the movement of a plant organ with dispersal of seeds — in response to moisture, such as rain drops, water fills specific cells or cell walls, changing their size, which in turn pops open a capsule expelling the seeds found within. read more