Physiological response to Cd stress and Cd-accumulation of four herbaceous plants

摘要

The project evaluated the inhibitive effects of Cd on the growth of four herbaceous plants by measuring plant biomass,chlorophyll content and free proline content to examine the plants' resistance to Cd stress and the toxicity mechanism of Cd.The Cd concentrations in each part of the four kinds of plants was also analyzed to explore their Cd absorption and accumulation characteristics.The results showed that the degree of growth inhibition from Cd stress on these four kinds of plants is: Medicago sativa L.＞ Phytolacca acinosa ＞ Mirabilisjalapa ＞ Festuca arundinacea.The chlorophyll content of Phytolacca acinosa and Mirabilisjalapa decreases at high Cd treatment level,while the chlorophyll content of Festuca arundinacea and Medicago sativa L.is not affected by Cd.Proline content change vanes between plants: Festuca arundinacea shows no significant differences between each Cd treatment level; Medicago sativa L.and Phytolacca acinosa first show an increase in proline content and then a decrease as Cd concentrations increase; Mirabilisjalapa proline content increases significantly at higher Cd treatment level.Cd accumulation characteristics of the four plants are different.The amount of Cd accumulation: Festuca arundinacea ＞ Phytolacca acinosa ＞ Mirabilis jalapa ＞ Medicago sativa L.Festuca arundinacea is more resistant to Cd than the other three plants.Cd translocation factor: Phytolacca acinosa ＞ Mirabilisjalapa＞ Medicago sativa L.＞ Festuca arundinacea.While,the phytoremediation factor: Festuca arundinacea ＞Mirabilis jatapa ＞ Phytolacca acinosa ＞ Medicago sativa L.These data suggested that Festuca arundinacea and Mirabilisjalapa have strong Cd resistance,considerable biomass,and no serious poisoning symptoms and high Cd accumulating quantities,so they have the most potential to be applied to the phytoremediation of Cd polluted soil.