Fast growing aspens in the development of a plant micropropagation system based on plant-produced ethylene action

► Aspen in vitro cultures were grown in different vessels. ► Small-volume vessels were used for restriction of gas exchange. ► Aspen explants produced most shoots in small-volume vessels. ► Shoot proliferation was increased due to explant response to ethylene. ► Explants from small-volume vessels formed more roots during subsequent culture.