Photomorphogenic Responses of Dodder Seedlings

Abstract

At least 2 photoreactions are involved in the control of hook opening and twining of seedlings of Cuscuta indecora. One has peak action in the blue and far-red spectral regions and requires high irradi-ances. The other is reversibly controlled by low red and far-red irradi-ances. The 2 photoreactions act in sequence, the high-energy reaction being first in the sequence. Their action is synergistic in hook opening and antagonistic in twining. Application of 3(3,-4 dichloropheny 1-1, 1 dimethy 1) urea did not affect the action of the high-energy photoreaction.