ADAPTATION IN TUNDRA PLANTS EXAMPLIFIED BY TRANSPLANTATION STUDIES AT TWO LATITUDES

ing in both ecosystems. Growth of the first two species is also studied at various temperatures and day lengths in a phytotron. At both field sites the leaves of the Spitsbergen plants started to die much earlier than those of the Dovre plants. However, the leaf bases of the two monocotyledons at both sites partly stayed green through the whole winter. Also in the phytotron, at low temperatures the monocotyledons from Spitsbergen ended their growth signifi-cantly earlier than the plants from Dovre both on short and long days, while the difference was small at somewhat higher phytotron temperatures. The plants from Spitsbergen were generally larger than the plants from Dovre during the phytotron experiment, independent of the growing temperature and the light conditions. How-ever, when grown in the field at Spitsbergen, plants from Dovre, particularly Luzula confusa, showed stronger new green growth than the native plants from Spitsbergen. At Spitsbergen, plants of Polygonum viviparum from Dovre were taller than those from Spitsbergen. The Dovre population has more vertical, but significantly narrower leaves than the arctic population. The functional adaptations to growth in low temperatures and in different light climates are discussed. 1