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DEVELOPMENT OF THERMOLUMINESCENCE BANDS DURING GREENING OF WHEAT LEAVES UNDER CONTINUOUS AND INTERMITTENT ILLUMINATION
Author(s) -
Inoue Yorinao,
Ichikawa Tetsuo,
Shibata Kazuo
Publication year - 1976
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1976.tb06783.x
Subject(s) - etiolation , greening , thermoluminescence , chemistry , optics , botany , materials science , physics , biology , luminescence , biochemistry , ecology , enzyme
— Mature wheat leaves excited by 1‐min illumination at a low temperature of ‐60° C showed five thermoluminescence bands at ‐45, ‐10, +25, +40 and +55° C (denoted as Z u , A, B 1 B 2 and C bands, respectively). The development of these bands during greening of etiolated wheat leaves under continuous and intermittent illumination was investigated, and the following results were obtained. (1) Etiolated leaves showed only the C band. When these leaves were greened under continuous light, the B 1 and B 2 bands appeared at 3 h and the Z u band appeared at 10 h. The B 1 and B 2 bands were intensified during prolonged greening under continuous illumination to be the strong bands observed for mature leaves. The A band and the group of B 1 and B 2 bands were alternative: Similar experiments by excitation of thermoluminescence at ‐20° C showed the development of the A band instead of these B 1 and B 1 bands. (2) When the etiolated leaves were greened under intermittent illumination (1‐ms light + 5‐min dark), the Z u band first appeared after 5 h of illumination (60 flashes) and was gradually intensified during further illumination with 340 flashes but, interestingly, neither the B 1 nor the B 2 band appeared even after 24–28 h of illumination with 280–340 flashes. (3) On exposure of such leaves greened under intermittent illumination to continuous light, the B 1 and B 2 bands were rapidly developed. The appearance of these bands was accompanied by the generation of the Hill activity (DCIP photoreduction with water as electron donor). (4) These results were discussed in relation to the previous study on photoactivation of the latent water‐splitting system accumulated in the leaves greened under intermittent illumination. It was deduced that the structure responsible for the A band or the group of B 1 and B 2 bands is involved in the evolution of oxygen in chloroplasts, and probably involves cations of the Mn 2+ catalyst generated by the action of light.