[¹⁴C]Ethylene Metabolism during Leaf Abscission in Cotton

Ethylene-enhanced ethylene oxidation inVicia faba

“…The observations reported here suggest that the increase in AO activity during ripening (Beyer and Blomstrom 1979), abscission (Beyer 1979b), and senescence (Beyer 1977) may be due to an effect of ethylene increasing levels of AO in plant tissue. However, the fababean system with its high AO activity may be atypical, and not representative of other plant systems.…”

“…Similar enzymes occur in the actinomycete, Mycobacterium paraffinicum (De Bont 1975, De Bont and Albers 1976, De Bont et al 1979, De Bont and Harder 1978, Wiegant and De Bont 1980, animals (Ehrenberg et al. 1977, Filser andBolt 1983), and plants (Beyer 1975, Beyer 1977, Beyer 1979a, Beyer 1979b, Beyer 1980, Beyer and Blomstrom 1979, Beyer and Sundin 1978, Dodds and Hall 1982, Dodds et al 1979, Jerie and Hall 1978. In M. paraffinicum, the function of ethylene oxidation is to provide energy and carbon for the growth of this soil-inhabiting organism.…”

“…The basis for this concept stems from the observation by Beyer that both ethylene production and ethylene oxidation increase during floral senescence (Beyer 1977) and tomato ripening (Beyer and Blomstrom 1979). Beyer also demonstrated an increase in AO during abscission (Beyer 1979b). In the case of abscission, ethylene is thought to act as a result of an increase in sensitivity of the tissue to the ethylene already there, as opposed to an increase in the rate of production (Abeles 1973).…”

Role of Ethylene Metabolism in Amaranthus retroflexus

“…This suggestion was based on evidence that levels of ethylene metabolism correlated with changes in the sensitivity of pea seedlings (3), cotton leaf abscission (7), and flower senescence (4,5) to ethylene, and on the ability of Ag+ to block ethylene action and metabolism in a parallel fashion (6). However, in fava beans, a similar correlation could not be established since CS2 inhibited ethylene metabolism without a significant effect on ethylene action (1,4).…”

Mechanisms of ethylene action

“…It is appropriate at this juncture to point out that the rates of metabolism observed were very low when physiological concentrations of ethylene were supplied and would have very little impact on endogenous ethylene concentrations . Beyer and his group followed up this work with further studies on the Pisum system [6] and investigations with other species revealed that ethylene metabolism of the type demonstrated in pea was a widespread phenomenon [7,9,12] . Nevertheless, the apparent low levels of activity seemed to preclude extraction and purification of the enzyme system(s) involved and subsequent work was performed in vivo .…”