Growth of Alaskan tundra plants in relation to water potential

The relationship of growth to plant water potential was studied in several arctic tundra species by experimentally altering the water regimes on excised tussocks, by clipping leaf area, and by clipping roots. Most species, including evergreen shrubs, showed greater growth under waterlogged conditions. The reduction of leaf area did not affect plant water potentials or growth. Root pruning decreased both plant water potentials and growth. Growth was suppressed when plant water potentials were −12 to −15 bars.