The effects of lead and kinetin on greening barley leaves

Abstract

The content of lead in greening etiolated barley leaves remained the same, regardless the time of incubation of excised leaves in the presence of lead ions (8-24 h). The lead deposits have not been detected within mesophyll cells, but were found in intercellular spaces of mesophyll, in guard cells and in cuticle covering stomata. This suggests that lead may be transported in the leavesvia transpiration stream. Lead reduced the content of chlorophyll, especially chlorophyllb content and the average number of grana, whereas in the presence of kinetin the content of chlorophyll increased. In the combined treatment (lead + kinetin) kinetin diminished the inhibitory effect of lead on the chlorophyll content. The number of chloroplasts in mesophyll cells remained unchanged after lead treatment, whereas kinetin alone or applied together with lead increased the average chloroplasts number. The thylakoids system in chloroplasts of kinetin and kinetin + lead treated plants was similar to that observed in control, although the grana number was smaller. Both lead and kinetin increased the content of condensed chromatin in nuclei.