Chromosome doubling in a Rosa rugosa Thunb. hybrid by exposure of in vitro nodes to oryzalin: the effects of node length, oryzalin concentration and exposure time.

Abstract

Chromosome doubling was induced in vitro in a diploid hybrid of Rosa rugosa Thunb. using oryzalin as the spindle inhibitor. Nodal sections, 2 mm long, were exposed to 2.5 or 5 microM oryzalin and 10 mm nodal sections were exposed to 5 microM oryzalin for 0 (controls), 6, 12, 24 and 48 h. The ploidy of the emergent shoots was determined by flow cytometry. The frequency of tetraploid and mixoploid leaves that developed from 2 mm nodal sections exposed to 5 microM oryzalin peaked at 12 h exposure, when 35% of the leaves were tetraploid, but fell after longer exposures. Fewer tetraploid and mixoploid leaves were found when 2 mm nodes were exposed to 2.5 microM oryzalin for 6 and 12 h, indicating that it took longer for a spindle inhibiting concentration of oryzalin to build up in the meristem. However, the frequencies of tetraploid and mixoploid leaves continued to rise after 12 h and were highest at 48 h, when 44% were tetraploid. In treatments with 5 microM oryzalin, the frequencies of tetraploid and mixoploid leaves were lower, at equivalent exposure times, in 10 mm nodes than 2 mm nodes. This suggests that oryzalin diffused to the meristem mainly via the cut surfaces and that access via the epidermis and cuticle was impeded.

• Authors: J F Allum, D H Bringloe, A V Roberts
• Journal: Plant cell reports (Plant Cell Rep) Vol. 26 Issue 11 Pg. 1977-84 (Nov 2007) ISSN: 0721-7714 [Print] Germany
• PMID: 17641861 (Publication Type: Journal Article)

Chemical References

• Dinitrobenzenes
• Herbicides
• Sulfanilamides
• oryzalin

Topics

• Chromosomes, Plant (drug effects, genetics)
• Crosses, Genetic
• Dinitrobenzenes (pharmacology)
• Herbicides (pharmacology)
• Plant Leaves (drug effects, physiology)
• Plants, Genetically Modified (drug effects, physiology)
• Polyploidy
• Rosa (genetics, physiology)
• Sulfanilamides (pharmacology)