Possible participation of active oxygen species in the induction of cyanide-resistant pathway at the initial senescence of tobacco callus

Zhou, G Kong, Y Bi, Y Liang, H

G. Zhou et al., Possible participation of active oxygen species in the induction of cyanide-resistant pathway at the initial senescence of tobacco callus, RUSS J PL P, 48(5), 2001, pp. 588-594

46

INGLESE

Article

Plant Sciences

RUSSIAN JOURNAL OF PLANT PHYSIOLOGY

1021-4437 → ACNP

48

5

2001

588 - 594

ISI

1021-4437(200109/10)48:5<588:PPOAOS>2.0.ZU;2-A

Changes in active oxygen species (AOS) and respiration, with special refere nce to the alternative pathway of respiration, were followed in callus of t obacco (Nicotiana rustica L.) during its growth and senescence. Two peaks o f the total respiration rate were observed: the first one appeared on day 1 1, and the second one on day 19 (in senescing callus). H2O2 and O-2(-) cont ents increased gradually and reached the greatest values when callus senesc ence initiated (by day 11 and day 15, respectively), and then declined. The peaks of H2O2 and O-2(-) before the onset of senescence coincided with the peaks of capacity V-alt and activity rhoV(alt) of alternative pathway, res pectively. After the onset of senescence, . OH accumulated abundantly and m aintained at a relatively high level from then on, accompanied by the decre ase in both V-alt and rhoV(alt). The conclusion is that these three active oxygen species operated coordinately to regulate the alternative pathway du ring growth and senescence of tobacco callus, as confirmed by the callus tr eatments with AOS scavengers, exogenous . OH, and inhibitors of antioxidant enzymes. The possibility of AOS-induced alternative pathway respiration at the initial senescence of tobacco callus is discussed.