In this study wheat seedlings cv Ningchun 4 is used to evaluate the changes of chlorophyll and osmotic regulator contents as well as the activities of proline metabolic enzymes in response to different CuCl2 and FeCl3 concentrations. The results show that chlorophyll a', chlorophyll b and total chlorophyll contents significantly increas in wheat treated with 100 μmol·L-1 copper, while these three parameters due to 300 μmol'L-1 and 500 μmol·L-1 Cu are obviously lower than those in untreated seedlings. By contrast, the 100 μmol · L-1 concentration of iron do not affect the amount of chlorophyll a, total chlorophyll, soluble sugar and soluble protein, but these parameters significantly elevate in the leaves of wheat under 300 μmol·LT-1 and 500 μmol·L-1 Fe3+ treatments. In addition, Cu2+ and Fe3+ treatments induce an increase in proline content in wheat seedlings, but the enhanced degree under FeCl3 treatment is markedly higher than that in response to CuCl2. Further studies show that both copper and iron treatments result in the decrease of PDH activity, but a notable elevation in the activity of OAT is caused by 500 μmol'L-1 Cu2+ and different Fe3+ concentrations. In conclusion, these results suggest that 300 L-1 and 500 μmol·L-1 CuCl2 treatments lead to damage to chlorophyll in wheat seedlings, while 100 L-1 CuCl2, 300 μmol·L-1 and 500 μmol·L-1 FeCl3 treatments have benefit to the synthesis of chlorophyll; both copper and iron induce the enhancements of soluble sugar, soluble protein and proline content, resulting in strong osmotic adjustment ability, which may improve wheat tolerance to Cu2+ and Fe3+ treatments. Additionally, proline accumulation may be associated with decreased PDH activity and elevated OAT activity in wheat seedlings under copper and iron stresses.%以小麦“宁春四号”为供试材料,研究其在不同浓度的CuCl2和FeCl3处理下叶绿素、渗透性调节物含量及脯氨酸代谢酶活性的变化.小麦在低浓度(100 μmol·L-1)铜处理下叶片叶绿素a、叶绿素b和总叶绿素含量显著升高,中高浓度(300 μmol·L-1和500 μmol·L-1)铜胁迫下这3个参数均低于对照；不同浓度的Cu2+胁迫诱导小麦幼苗可溶性糖和可溶性蛋白含量明显增加.与铜处理相比,低浓度的铁不影响叶绿素a、总叶绿素、可溶性糖和可溶性蛋白含量,却使叶绿素b含量增加,但中、高浓度Fe3+胁迫下这些参数均明显高于对照.此外,Cu2+和Fe3+处理下小麦幼苗叶片脯氨酸含量增多,且FeCl3处理下的增高幅度明显大于CuCl2处理.进一步研究发现,铜和铁胁迫诱导叶片脯氨酸脱氢酶(PDH)活性降低,而高浓度Cu2+和3种浓度的铁处理诱导鸟氨酸转氨酶(OAT)活性升高.结果表明,300 μmol·L-1和500 μmol· L-1的CuCl2胁迫对小麦幼苗叶绿素造成了破坏,而100 μmol·L-1的铜、300 μmol·L- 1和500 μmol·L-1的FeCl3处理则刺激叶绿素的合成；铜和铁均不同程度诱导可溶性糖、可溶性蛋白和脯氨酸含量升高,使小麦幼苗表现出较强的渗透调节能力.此外,小麦幼苗在铜和铁胁迫下脯氨酸的积累与PDH活性降低和OAT活性升高有关.
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