phototonicadj.

1875 A. W. Bennett & W. T. T. Dyer tr. J. von Sachs Text-bk. Bot. 790 Leaves which have become rigid from exposure to the dark show no irritability to variations in its intensity until they have again become phototonic [Ger. bis sie..den Phototonus wieder gewonnen haben] from long-continued exposure to light.

1897 Bot. Gaz. 23 61 It is possible for some plants to form perfect leaves in darkness.., thus showing that no invariable connection exists between the phototonic condition and leaf development.

1936 Amer. Jrnl. Bot. 23 49/2 There is required also..alternating light and dark stimuli at a given periodic frequency to obtain a more or less fixed habit of leaf movement and phototonic condition in these plants.

1989 Planta 179 123 These experiments indicate that blue light interacts with the nastic response at two levels: (i) phototonic inhibition, and (ii) addition of nastic and phototropic curvatures.