Dispersal of fruits and seeds
Dispersal of fruits and seeds lets a species settle new places and get out of the parent’s shade. The method depends on fruit structure. Self-dispersers (autochores): balsam (xina), most legumes, vetch (burchoq), squirting cucumber (itqovun) — when the fruit ripens, internal pressure, splitting or twisting of the valves throws seeds out. Wind: fruits of poplar, willow, dandelion and cattail carry a tuft of light fluff at the tip and fly long distances; elm, ash, saksovul and maple have wings on their fruit. Water: fruits with waterproof coats (water lily, Johnson grass, plantain) float far away. Animals and birds: spiny, hooked or sticky fruits cling to wool and feathers; juicy fruits are eaten and indigestible stones and seeds are scattered with droppings. People are the most powerful disperser: in early in the 20th century camelthorn (yantoq) seed reached America mixed into lucerne seed from Central Asia. Dispersal lets plants occupy new land.
“Dispersal analysis”: sort a dried collection of fruits and seeds (dandelion, maple wing, cherry stone, legume pod, spiny fruit) into groups: wind, water, animal, self. Experiment: drop a maple wing or dandelion fruit from a height and compare the falling time with a small wingless seed. Safety: handle spiny fruits carefully; do not taste unknown fruits; do not stand on a chair to drop things (the teacher drops them).