Phosphatase and ATPase activities in isonuclear lines of cytoplasmic male-sterile and male-fertile petunia

✍ Scribed by M. Perl; D. Swartzberg; S. Izhar

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 414 KB
• Volume: 86
• Category: Article
• ISSN: 0040-5752
• DOI: 10.1007/bf00223807

✦ Synopsis

Soluble and membrane-bound fractions of plant leaves, cell suspension cultures and seedlings of petunia were examined for phosphohydrolase activity on p-nitrophenyl phosphate (pNPPase) and adenosine triphosphate (ATPase). One cytoplasmic male-sterile (CMS) and one fertile (F) line was examined for each tissue. Both pNPPase and ATPase exhibited a broad optimal activity between pH 5.5-7.0 for the membrane-bound fraction and between 4.5-7.0 for the soluble fractions. The activity of both were inhibited by divalent ions including Mg(2+). At pH 7.2, the activities on various triphosphonucleotides were similar and they were hydrolyzed by a rate of 20-50% of that of ATP. Significant differences between CMS and F extracts were: (a) higher activities in CMS membranes; (b) lower Ea (energy of activation) values for activities in CMS membrane functions; (c) seedling and cell-culture CMS extracts exhibited a higher sensitivity to high temperature denaturation; (d) the hydrolase activity on monoand triphospho-cytosine compounds was significantly higher in CMS than in F membranes.