Fig. 6 shows the production of
H2O2-derived radicals during the development of barley secondary
leaves between 18 and 35 DAS with (+) and without (−) NaN3.
It is apparent that the production of H2O2 increases during the
development of barley reaching the highest value 25 DAS. Thereafter,
production of H2O2 was temporally decreased and increased again in the late stages of senescence when chl levels had already
diminished substantially. Comparison of H2O2 production in samples
illuminated with and without NaN3 showed a strong increase
in hydrogen peroxide production when NaN3 was present in the
reaction medium. The effect of uncoupling was more pronounced
in younger thylakoids. Expressed in numbers, production of H2O2
was 2.48 times higher for day 18; 2.46 for day 21; 2.14 for day 25;
1.81 for day 29; 1.78 for day 32 and 1.78 for day 35. In parallel, the
production of H2O2 was determined by using Amplex Red which
reacts with H2O2 creating a product that can be detected with a
fluorimeter. The determination of H2O2 with Amplex Red showed
similar results