Effectiveness of light of different wavelengths to induce chlorophyll biosynthesis in rapidly and slowly greening tissues

Abstract

Action spectra for light‐induced chlorophyll formation in etiolated leaves, potato tubers, and dark‐grown epi‐ and hypocotyls of pea and bean seedlings show a correlation between rate of greening and wavelengths with the strongest greening effect. Action spectra for the greening of leaves and the upper parts of epi‐ and hypocotyls with rapid greening and with rather high concentrations of protochlorophyll650–652 have a maximum at 650 nm. While those for slowly greening material such as potato tuber parenchyma and the lower parts of epi‐ and hypocotyls show maxima around 660‐–70 nm. This shift is discussed and it is proposed to be due to a more dominating role of light absorbed by phytochrome for the formation of chlorophyll precursors in slowly greening materials than in rapidly greening tissues. in which the protochlorophyll formation is rapid also without the influence of phytochrome. Therefore, in slowly greening material, the peak in the absorption spectrum for phytochrome in its red absorbing form will have a more dominating influence on the shape of the action spectrum, and this will be reflected in a shift of the peak from 650 nm to higher wavelengths.

Proteomic analysis of highly purified prolamellar bodies reveals their significance in chloroplast development

“…Whether these are inactive like chlorophyll synthase, as long as the PLB structure remains highly regular, remains to be shown. No doubt, presence of PLBs favours a rapid onset of chloroplast development, as compared to dark-grown tissues devoid of PLBs (Virgin 1993;Böddi et al 1996). Almost 80% of the identified proteins are coded for by nuclear genes and thus imported already at the etioplast stage.…”

High salt stress in wheat leaves causes retardation of chlorophyll accumulation due to a limited rate of protochlorophyllide formation

“…Some of the Pchlide remaining after the short flash might be phototransformed within minutes by continuous irradiation (Böddi et al 1996). The rest of the protochlorophyll and protochlorophyllide [Pchl(ide)] is slowly transformed into Chlide during a prolonged irradiation period (hours) with weak light or disappears by photobleaching (Lebedev et al 1995, Virgin 1993.…”

Formation of short‐wavelength chlorophyll(ide) after brief irradiation is correlated with the occurrence of protochlorophyll(ide)636–642 in dark‐grown epi‐ and hypocotyls of bean (Phaseolus vulgaris)

“…It is also conceivable that if the piastids do not receive light before a certain developmental stage, they will never develop into mature chloroplasts. Seedlings kept in darkness long enough for cell elongation to cease, showed no visible Chi formation irrespective of the duration of the irradiation time (Virgin 1993). Taken together these resuhs indicate that there is a developmental gradient for Chi synthesis and chloroplast development in stem tissues.…”

“…Figure 5 shows that grana were formed in plastids of cells of Hyp 6, but typical grana were scarce in plastids of the other sections. A diifference in Chi biosynthesis capacity was also seen when epicotyls of dark-grown pea was irradiated (Virgin 1993), and in light-grown stems of pine. where the Chi content decreased downwards the seedlings (Spano et al 1992).…”