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 coveting stomata. This suggests that lead may be transported in the leaves via transpiration stream. Lead reduced the content of chlorophyll, especially chlorophyll b 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.

Bioremediation of textile effluent polluted soil using kenaf (<i>Hibiscus cannabinus</i> Linn.) and composted market waste

“…Highest concentration of Pb was observed in the stem. This is not in agreement with the finding of Wozny et al (1995) who reported that Pb is more accumulated in the roots of greening barley leaves. Highest concentration of Cr was observed in the root of kenaf.…”

CONTENIDO Y TRASLOCACIÓN DE PLOMO EN AVENA (Avena sativa, L.) Y HABA (Vicia faba, L.) DE UN SUELO CONTAMINADO

“…Similarly, Hedaya (2008) found a higher concentration of Pb in the root than in the leaves of broad bean, and Wu et al (2005) report, in the same sense, that the root of Vicia cracca absorbs a greater amount of Pb in the root. Roots can accumulate from 3 to 50 times more Pb than leaves (Wozny et al, 1995). Zhang et al (2006) are toxic and 5 to 10 mg·kg -1 are normal.…”

“…De la misma manera, Hedaya (2008) determinó una mayor concentración de Pb en la raíz que en hojas de haba, y Wu et al (2005) reportan, en el mismo sentido, que la raíz de Vicia cracca absorbe una mayor cantidad de Pb en la raíz. Las raíces pueden acumular arriba de 3 a 50 veces más Pb que las hojas (Wozny et al, 1995). Zhang et al (2006) reportaron que en un suelo contaminado con Pb a una concentración de 388±23 mg·kg -1 la raíz de Vicia faba absorbe una mayor cantidad de Pb 273.1±2 y el tallo 3.3±1.1 mg·kg -1 , coincidiendo con los resultados obtenidos en este trabajo.…”

Water relations in plants subjected to heavy metal stresses

“…The number of intact stomata per unit of leaf area decreased in leaves of B. vulgaris exposed to Cd; furthermore, metal ions induced closure of intact stomata (Greger and Johansson 1992). Experiments with greening etiolated leaves of Hordeum vulgare showed that a Pb-induced decrease in stomata opening was correlated with the presence of Pb deposits in the cuticle covering guard cells and subsidiary cells (Woźny et al 1995). It has been widely documented that the quantity of anomalous (non-functional) stomata significantly increases in response to various heavy metals.…”