The pot experiment was conducted to investigate the effects of different Cd concentrations (0, 3, 6, 10, 30, 60 mg/ kg) on the contents of pigment, malondialdehyde (MDA) , soluble sugar and free proline (PRO) , as well as Cd accumulation features in tobacco plants. The results showed that; ( 1) With the increase of Cd concentration, the pigment content at the resettling stage and bud appearance stage increased firstly and then decreased, but that at harvest stage decreased slowly. When Cd concentration in the soil was more than 10 mg/kg, the pigment contents in three growth periods were all significantly lower than those of CK (P root > stem. Under the conditions of Cd > 10 mg/kg at resettling stage and Cd stress at harvest stage, the Cd content in tobacco plants had the following order; root > leaf > stem. For Cd content in different positions of tobacco leaves, there was the sequence of lower leaf > middle leaf > upper leaf. (3 ) The order of the physiological indexes sensitivity was: total chlorophyll content ( chlorophyll a + b) > MDA > carotenoids/ soluble sugar > PRO. The total chlorophyll content in tobacco plants at three growth stages was significantly and negatively correlated with the Cd content in leaf, which was the ideal physiological index of reflecting Cd stress to flue - cured tobacco.%通过盆栽试验研究了土壤中不同Cd浓度(0、3、6、10、30、60 mg/kg)对烤烟色素、丙二醛(MDA)、可溶性糖、游离脯氨酸(PRO)含量及Cd在烟株中积累特征的影响.结果表明:(1)随Cd浓度的增大,团棵期和现蕾期色素含量呈先增后降的趋势,采收期时则逐渐降低；Cd＞10 mg/kg时,各生育时期色素含量都显著低于对照(P＜0.05).(2)随着Cd胁迫浓度的增加,烟株各部位Cd显著高于对照(P＜0.05)；团棵期Cd≤10 mg/kg和现蕾期Cd胁迫条件下的Cd含量大小是叶＞根＞茎,团棵期Cd＞ 10 mg/kg和采收期Cd胁迫条件下的Cd含量大小是根＞叶＞茎；烤烟叶片中Cd含量大小顺序为下部叶＞中部叶＞上部叶.(3)生理指标敏感性总体表现为:总叶绿素(叶绿素a+b)＞丙二醛＞类胡萝卜素/可溶性糖＞脯氨酸,其中各生育时期总叶绿素含量都与叶片镉含量显著负相关,是烤烟镉胁迫的理想生理指标.
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