0000000000083014
AUTHOR
Caroline S. James
A comparison of the effects of ?-ketotriazole, MCPA and carbaryl on the plasma membrane Mg2+-ATPase activity and lipid composition of rice shoots (Oryza sativa)
The effect of γ-ketotriazole, MCPA and carbaryl on the lipid composition and ATPase activity associated with plasma membrane fractions from rice (Oryza sativa cv Bahia) shoots was investigated. With γ-ketotriazole and MCPA treatments the relative amount of δ5-avenasterol (%) was reduced in the plasma membrane, whereas with γ-ketotriazole a reduction was also found in the sitosterol content, expressed as a percentage of the total free sterol composition. The fatty acyl chain length of phosphatidylcholine fractions from MCPA-treated plants was also reduced. The plasma membrane Mg2+-ATPase activity was only stimulated in MCPA-treated plants. No changes were observed in lipid composition or ATP…
The lipid composition, fluidity, and Mg2+-ATPase activity of rice (Oryza sativa L. cv. Bahia) shoot plasma membranes: effects of ABA and GA3
Six-day-old rice plants (Oryza sativa L., cv Bahia) were grown for 5 days more in nutrient solution culture containing 10−5 M abscisic acid (ABA) or gibberellic acid (GA3) (treated plants). Plasma membrane (PM) vesicles were isolated from the shoots of treated or control plants, and ATPase hydrolytic and proton-pumping activity, fluidity, and free sterol and phospholipid composition were determined. Both treatments resulted in modified plant growth and increases in PM fluidity. The ATPase hydrolytic activity was decreased by 25% of control values with ABA treatment and by 35% with GA3. Both treatments reduced proton-pumping by 23%. GA3 treatment reduced the relative amount (%) of stigmaster…