Phosphorus-induced Leaf Abscission in Olive and Citrus Explants

Abscission of citrus leaf explants: no correlation with naphthaleneacetic Acid conjugation in the abscission zone.

The role of alpha-naphthaleneacetic acid (NAA) in the control of abscission in Citrus (Citrus sinensis L. Osbeck) leaf explants and its conjugation were studied in non-aged and 24-hour-aged explants. Dipping non-aged explants in 1.5 micromolar NAA for 15 minutes immediately after excision did not delay abscission whereas 150 micromolar NAA effectively delayed it. As incubation time was prolonge...

Activity of pectin esterase and cellulase in the abscission zone of citrus leaf explants.

The activity of pectin esterase and cellulase in abscission of citrus explants was studied. No relation was established between pectin esterase and abscission, while cellulase activity was markedly increased before abscission and for a certain period after excision. IAA and cycloheximide delay abscission and cellulase activity, while ethylene and, to a lesser extent, GA(3) accelerate them. Appl...

Effects of some salts and acids on citrus leaf abscission

Mercury-induced Ethylene Formation and Abscission in Citrus and Coleus Explants.

Mercury vapor induces ethylene formation and abscission in Citrus and Coleus explants. Both responses are markedly greater in the absence of CO(2). The stimulation of these metabolically complex processes indicates that the action of mercury vapor is not consistent with the more popular conception of mercury toxicity. This was manifested in its complete failure to disturb respiratory gas exchan...

Synthesis of Cellulase during Abscission of Phaseolus vulgaris Leaf Explants.

When abscission in leaf explants from Phaseolus vulgaris, cultivar Red Kidney, was allowed to proceed while the explants were in (2)H(2)O, a 1.25% increase in the buoyant density of cellulase in a cesium chloride gradient was observed. These data indicate that the increase in cellulase activity during abscission is a result of the synthesis of new protein. Two differentially soluble forms of ce...