The effect of 2,4-dichlorophenoxyacetic acid and (2-chloroethyl)-trimethylammonium chloride on chlorophyll synthesis in barley leaves

✍ Scribed by P. R. Shewry; N. J. Pinfield; A. K. Stobart

• Publisher: Springer-Verlag
• Year: 1971
• Tongue: English
• Weight: 438 KB
• Volume: 101
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00398119

✦ Synopsis

2.4-dichlorophenoxyacetic acid (2.4-D) and (2-chloroethyl)-trimethylammonium chloride (CCC) inhibit chlorophyll synthesis and protochlorophyllide 652 regeneration in 6-8 day old barley leaves whilst having little effect on the rates of protochlorophyll 632 synthesis from exogenous δ-aminelevulinic acid (ALA) and ALA-dehydratase activity. Longer pretreatments with 2.4-D and CCC show it is only after 50 to 60 hr that the rates of P632 production from exogenous ALA and ALA-dehydratase activity are affected. Similar response times were obtained for chloramphenicol (CAP). The results indicate that 2.4-D and CCC may act by directly inhibiting specific plastid-protein synthesis similar to CAP. Hence it seems that it is only those proteins (enzymes) having a rapid turnover that are affected first i.e. the enzymes necessary for ALA synthesis in the plastid.