ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Mechanical wounding by cuts or punctures caused a brief increase in ethylene production by iceberg lettuce (Lactuca sativa L.) leaf tissue. Wounding increased phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity, which was a function of the degree of injury. Wound-induced PAL activity appeared after 4 h and reached maximum activity in about 24 h before slowly declining to normal levels in about a week. A signal for PAL induction was transmitted at about 0.5 cm h−1 from the site of injury to cells up to 2.5 cm away. Treatment with 100 μ2-aminoethoxyvinylglycine prevented wound-induced ethylene production but did not affect induced PAL activity. Injury increased the concentration of several soluble phenolic compounds that were easily oxidized to brown substances by polyphenol oxidase (EC 1.10.3.2) isolated from lettuce tissue. Wounding also increased peroxidase (EC 1.11.1.7) activity and lignin content, with cell wall lignification localized in wounded and adjacent cells. Although wounding alone did not induce russet spotting, it did greatly increase susceptibility to ethylene-induced russet spot development. In the presence of 3 μ1−1 ethylene, the russet spot score increased as the degree of injury increased.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1989.tb06212.x
Permalink
