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Physiological and biochemical events leading to vitrification of plants cultured in vitro
Author(s) -
Kevers C.,
Coumans M.,
CoumansGillès M.F.,
Caspar Th.
Publication year - 1984
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1984.tb06102.x
Subject(s) - peroxidase , ethylene , vitrification , chemistry , biochemistry , phenylalanine , cellulose , lignin , biosynthesis , in vitro , enzyme , botany , amino acid , organic chemistry , biology , medicine , andrology , catalysis
Water content, peroxidase activity and isoperoxidases, phenylalanine ammonia‐lyase activity and phenolic content were comparatively analyzed in tissues of normal and vitreous plants cultured in vitro. The release of ethylene in flask atmospheres by normal and vitrifying plants was also measured. On the basis of the results, it is hypothesized that vitrification results from a burst of ethylene controlled by the peroxidase‐IAA‐oxidase system. An initiating stress (e.g. excess of cytokinins or of NH 4 + ions) would mediate the enhancement of the activity of soluble and membrane‐bound peroxidases through a rapid modification of the phenolic level. The excess of ethylene in the atmosphere of stressed plants would retroinhibit its own biosynthesis and as a consequence decrease the activities of PAL and acidic peroxidases, thus hindering lignification processes. A parallel decrease in cellulose synthesis due to a diverted conversion of sugars to amino acids is expected (from data in the literature). Deficiency of both cellulose and lignin would allow more water uptake due to reduced wall pressure and bring about the hyperhydric malformations.