水培条件下铬胁迫对苗用型大白菜生长及铬积累的影响

Effects of chromium stress on the growth and chromium accumulation in Chinese cabbage seedlings under solution culture

采用实验室营养液水培法,研究了不同浓度(0,50,100μmol.L-1)Cr胁迫对4个苗用型大白菜品种生长发育和吸收、积累铬的影响。结果表明,4个苗用型大白菜品种的地上部鲜重随着Cr胁迫浓度的升高呈下降趋势,且显著低于对照,其中浙白8号在100μmol.L-1Cr胁迫下鲜重抑制率仍低于50%。浙白6号和早熟5号对Cr胁迫比较敏感,在50μmol.L-1Cr胁迫下鲜重抑制率就达到70%以上;在不同浓度Cr胁迫下,4个苗用型大白菜品种的地上部干物质含量均低于各自对照,除双耐吕种随Cr胁迫浓度的升高干物质含量下降外,其他品种均呈先降低后升高的趋势;在不同浓度Cr胁迫下,4个品种的叶片叶绿素含量和叶绿素a/b值均低于各自对照,随Cr胁迫浓度的升高,各品种叶绿素a/b值呈先降低后升高的趋势,而叶绿素含量在各品种间变化趋势不同;随Cr胁迫浓度的升高,4个品种地上部铬的含量比各自对照显著增加,双耐和浙白8号地上部铬含量较低;铬胁迫下4个品种的地上部铬耐性指数均小于1,且显著低于各自对照,随着铬胁迫浓度的升高,各品种的耐性指数呈现不同的变化趋势。

A hydroponic experiment was conducted to investigate difference in growth and chromium （Cr） accumula- tion in 4 varieties of Chinese cabbage seedlings under different concentrations of Cr （0,50,100 μmol· L-1 ）. The results showed that fresh weight of all varieties decreased with the increase of Cr concentrations, and was significantly lower than the control. Moreover, the inhibition rate of fresh weight in variety Zhebai 8 was the lowest （50%） in treatment of 100 μ mol·L-1Cr; Zhebai 6 and Zaoshu 5 were sensitive to Cr concentrations, and their inhibition rates were more than 70%. Under different concentrations of Cr, dry matter accumulations of 4 varieties in shoot were low- er than their respective controls. In addition to the variety Shuangnai, whose dry matter gradually decreased with the increase of Cr concentration, the other varieties followed the trend of first decreased and then increased. In addition, under different concentrations of Cr, chlorophyll content and chlorophyll a/b values of leaves of 4 varieties were lower than their respective controls. With the increase of Cr concentration, chlorophyll a/b value of all varieties were in the trend of first decreased and then increased, and change of chlorophyll content among the varieties was different. With the increase of Cr concentration, Cr content in 4 varieties＇ shoot was significantly higher than their respective con- trois ,＇ which of Shuangnai and Zhebai 8 was lower. The tolerance indexes of 4 varieties shoot under Cr stress were less than 1, and they were lower than their respective controls. With the increase of Cr concentration, the tolerance indexes of all varieties showed different trends.