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Effects of ethylene and some other environmental factors on different stages of germination in red root pigweed ( Amaranthus retroflexus L.) seeds *
Author(s) -
SCHONBECK M. W.,
EGLEY G. H.
Publication year - 1988
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.1365-3040.1988.tb01136.x
Subject(s) - radicle , germination , imbibition , endosperm , ethylene , embryo , biology , penetration (warfare) , horticulture , botany , agronomy , microbiology and biotechnology , mathematics , biochemistry , operations research , catalysis
. Ethylene was found to promote two distinct processes during germination of redroot pigweed ( Amarantus retroflexus L.) seeds: embryo expansion that splits the seed coat (incomplete germination), and radicle penetration through the more elastic endosperm (complete germination). The two events can be separated in time by subjecting seeds to low water potential or low CO 2 levels, which arrest germination of some seeds at the incomplete stage. Ethylene applications to incompletely germinated seeds promote complete germination, with a response threshold near 0.02 cm 3 m −3 and saturation near 0.5 cm 3 m −3 . Higher ethylene concentrations (0.5 to 50 cm 3 m −3 ) given during the first day of seed imbibition also increase the percentage of seeds which initiate embryo expansion and split the seed coat. Light and elevated CO 2 also promote radicle penetration of the endosperm in seeds incubated under water stress. The results support the view that the germination pause at the incomplete stage is an adaptation to environmental stresses that can be overcome with exogenous ethylene or certain other stimuli.