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EFFECTS OF VISIBLE AND ULTRAVIOLET RADIATION ON THE GERMINATION OF PHACELIA TANACETIFOLIA
Author(s) -
Schulz M. Richardis,
Klein Richard M.
Publication year - 1963
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1963.tb07211.x
Subject(s) - germination , biology , phytochrome , imbibition , ultraviolet , darkness , botany , ultraviolet radiation , red light , horticulture , optics , physics , chemistry , radiochemistry
S chulz , S ister M. R ichardis , O.P., and R ichard M. K lein . (N. Y. Bot. Gard., N. Y., N. Y.) Effects of visible and ultraviolet radiation on the germination of Phacelia tanacetifolia. Amer. Jour. Bot. 50(5): 430–434. Illus. 1963.—Germination of Phacelia tanacetifolia was suppressed by exposure to white light increasing with intensity and length of illumination. The light effect decayed during 24 hr of darkness. Seeds were most sensitive to the suppressive effects of light 13–17 hr after the beginning of imbibition. Light suppression was caused by a photocatalytic reaction. Wavelengths causing the suppression lie in the far‐red, red, blue, near‐ultraviolet and far‐ultraviolet regions of the spectrum. At equal energies, blue light was less effective than far‐red, red or ultraviolet radiation. There was no evidence for the existence of the phytochrome system. Simultaneous irradiation with red and blue light or simultaneous irradiation with red and far‐red induced a synergistic repression of germination. The presentation of different wavelengths in various sequential patterns markedly altered the germination response. An interaction between elevated temperatures and visible radiation affecting germination response was also noted.