铜盐毒害对紫鸭跖草养分吸收和生长的影响

Effect of Cu toxicity on nutrient uptake and growth of Setcreasea purpurea Boom

通过含有不同浓度CuSO4的Hoagland营养液培养紫鸭跖草枝条，研究了紫鸭跖草对铜的耐性和超积累以及铜胁迫下紫鸭跖草生长和营养状况。结果表明：紫鸭跖草根部铜的积累量低浓度Cu^2＋供应时增加幅度不大，高浓度Cu^2＋供应时增加幅度较大；茎部的情况与根部相似；但叶部在低浓度Cu^2＋供应时铜的积累量几乎没有变化，高浓度Cu^2＋供应时铜的积累量增幅较大。在500μmol·L^-1和1000μmol·L^-1铜处理下，紫鸭跖草整株铜积累量分别为866mg·kg^-1（DW）和1130mg·kg^-1（DW）。紫鸭跖草对铜的吸收和转运效率与铜的供给量呈正相关性。100—250μmol·L^-1铜的供应能明显促进紫鸭跖草生长。高浓度铜促进了钾、钙的吸收而阻碍了锌的吸收及镁向地上部分的运输，尽管如此，氮、磷、钾、镁、钙的浓度均在满足常规植物正常生长的浓度范围内。铜胁迫下对根部蛋白质表达活跃，氨基酸含量增加。研究结果表明紫鸭跖草对铜有很大耐性和富集能力。

The growth, nutrient uptake, copper tolerance and hyperaccumulation of Setcreasea purpurea Boom in Hoagland nutrient solution with CuSO4 were studied. Results show low Cu content in roots under low Cu dosage, while root Cu content increases greatly under high Cu dosage. Similar tendency prevails in S. purpurea stems. However, Cu content remains insensitive to low Cu dosage in S. purpurea leaves, but increases dramatically under high Cu dosage. Accumulated Cu in S. purpurea plant on the whole is 866 mg·kg^-1 （DW） and 1 130 mg·kg^-1 （DW） under 500 μmol·L^-1 and 1 000μmol·L^-1 Cu dosage. Positive correlations exist between Cu-uptake and translocation efficiencies and Cu dosage. Growth of S. purpurea improves when Cu^2＋ supply is within 100-250 μmol·L^-1. High Cu concentration accelerates uptake of K and Ca,but at the same time hinders Zn uptake and Mg translocation from roots to stems/leaves. However, N, P, K, Mg and Ca concentration in S. purpurea remains within normal range for a typical plant under natural conditions. Protein and amino acid contents in roots and leaves are influenced by solution nutrient Cu. The research demonstrates how tolerant S. purpurea is to Cu stress and its potential to serve as natural Cu hyperaccumulator.