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Absence of phyB inhibits hypocotyl elongation in dark‐grown Ih cucumber seedlings: an active role for PrB
Author(s) -
SAEFKOW R. L.,
ALLISTON T. N.,
SHINKLE J. R.
Publication year - 1995
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1995.tb00590.x
Subject(s) - hypocotyl , cucumis , etiolation , phytochrome , elongation , darkness , mutant , biology , botany , regulator , wild type , microbiology and biotechnology , horticulture , chemistry , gene , biochemistry , red light , materials science , ultimate tensile strength , metallurgy , enzyme
Cucumber ( Cucumis sativus L.) seedlings carrying the long hypocotyl ( Ih ) mutation, which confers a lack of B‐type phytochrome (phyB), were significantly shorter than their near‐isogenic wild‐type counterparts when grown in complete darkness. Relative growth rates determined for 5 mm hypocotyl regions were lower in Ih seedlings in all growing regions, and the zone of elongation was less extensive in Ih hypocotyls. Digital imaging microscopy revealed that the pattern of epidermal cell lengths along the stem axis differed between the Ih mutant and the iso‐genic wild‐type. These findings (and the fact that experiments were conducted under conditions where phytochrome photoconversion to the far‐red‐absorbing form does not occur) suggest that the red‐absorbing form of phyB (PrB) is an active positive regulator of development in etiolated plants.