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(Botany) botany a nastic movement in response to a temperature change, as occurs in the opening of certain flowers
the tendency in certain plant species to respond to temperature changes by developing a sufficient cellular force or growth on one side of an axis to change the form or position of the axis, as in the closing or folding of rhododendron leaves in cold air. Cf. photonasty. — thermonastic, adj.See also: Plants