식물정화를 위한 중금속 내성 작물의 선발과 수수-수단그라스 교잡종의 구리와 아연 흡수능력

Abstract

As essential trace elements, copper and zinc play important roles in many physiological events in plants. In excess, however, these elements can limit plant growth. This study selected a heavy metal-tolerant plant by analyzing seed germination and biomass of alfalfa (Medicago sativa), canola (Brassica campestris subsp. napus var. nippo-oleifera), Chinese corn (Setaria italica), and a sorghum-sudangrass hybrid (Sorghum bicolor S. sudanense), and determined heavy metal uptake capacity by analyzing biomass, chlorophyll a fluorescence, and heavy metal contents under high external copper or zinc levels. The seed germination rate and biomass of the sorghum-sudangrass hybrid were higher under copper or zinc stress compared to the other three plants. The plant biomass and photosynthetic pigment contents of the sorghum-sudangrass hybrid seedlings were less vulnerable under low levels of heavy metals ( copper or zinc). The maximum quantum yield of PSII () and the maximum primary yield of PSII () decreased with increasing copper or zinc levels. Under high copper levels, the decline in was caused only by the decline in , and was accompanied by an increase in non-photochemical quenching (NPQ). The declined under high levels of zinc due to both a decrease in the maximum fluorescence () and an increase in the initial fluorescence (), and this was accompanied by a marked decrease in photochemical quenching (qP), but not by an increase in NPQ. Accumulations of copper and zinc were found in both aboveand below-ground parts of plants, but were greater in the below-ground parts. The uptake capacity of the sorghum-sudangrass hybrid for copper and zinc reached 4459.1 mg/kg under 400 ppm copper and 9028.5 mg/kg under 1600 ppm zinc. Our results indicate that the sorghum-sudangrass hybrid contributes to the in situ phytoremediation of copper or zinc polluted soils due to its high biomass yield.