Te. Kraus et al., REGULATION OF SENESCENCE BY BENZYLAMINOPURINE AND UNICONAZOLE IN INTACT AND EXCISED SOYBEAN COTYLEDONS, Plant physiology and biochemistry, 31(6), 1993, pp. 827-834
The influence of benzylaminopurine (BA) and uniconazole (UCZ) on the s
enescence of 14-day-old soybean (Glycine max) was examined by treating
cotyledons on intact plants or excised cotyledon discs. Senescence of
the cotyledons, measured as the loss of chlorophylls (Chi) a and b, c
arotenoids, protein and increased membrane leakiness, was more rapid i
n the excised system. In both systems there were high positive correla
tions among the conversion of exogenous ACC (1-aminocyclopropane-1-car
boxylic acid) to ethylene, lipoxygenase (EC 1.13.11.12) (LOX) activity
and Chl a levels which declined as the cotyledons senesced. However,
these correlations were not evident in the BA-treated cotyledons which
had relatively high Chi levels. Therefore the results of this study d
o not support the contention that LOX activity, ACC conversion and sen
escence are interrelated. In both systems BA was more effective in del
aying senescence compared to the control and UCZ-treated cotyledons. I
n the excised system UCZ tended to hasten while in the intact system U
CZ delayed senescence. This study demonstrates that UCZ acts as an ant
i-senescence agent-when applied to intact plants and the implications
of this in post-harvest physiology warrants further investigation.