Hg^(2+)、Cd^(2+)胁迫对玉米生理生态的影响

Physiological and Ecological Response of Maize to Hg^(2+) and Cd^(2+) Stress

重金属汞、镉广泛存在于自然环境中,对各种植物尤其对农作物产生重要影响。通过室内砂培实验,研究汞、镉胁迫下玉米的生理生态变化,其中包括叶绿素、根系还原酶、游离脯氨酸等的变化情况。研究发现,Hg2+、Cd2+对玉米的胁迫均是时间和质量浓度的双重因子:在低质量浓度、短时间内,叶绿素、根系还原酶及游离脯氨酸的质量分数均有上升趋势,被认为是对汞、镉离子的一种应激反应,汞、镉离子的最大应激质量浓度分别为0.5mg/L和1.0mg/L。玉米受Cd2+的毒害比Hg2+敏感,但玉米对Cd2+的忍耐性强于对Hg2+的忍耐性;其中游离脯氨酸的质量分数可以作为重金属污染的一个监测指标。

Heavy metal such as Mercury and Cadmium is widely exist in the nature, which has some outstanding influence on the plants especially on crops. Sand-culture medium is used to investigate the physiological and ecological response of maize to mercury and cadmium pollution stress, including the contents of chlorophyll,reduetase of root and free proline and so on. The results show that the toxicity of Hg^(2+) and Cd^(2+) on maize is controlled by time and mass concentration of Hg^(2+) and Cd^(2+): in the low mass concentration and short time, the mass fraction of reduetase of root and free proline increase with the increase of the mass concentration. The increase of indexes may be regarded as a respondent function of plants, and the maximum mass concentration of Hg^(2+) and Cd^(2+) are 0.5 mg/L and 1.0 mg/L,respectively. The toxicity of Cd^(2+) on maize is more sensitive than that of Hg^(2+), but its endurance to Cd^(2+) is stronger than that to Hg^(2+).The mass fraction of free proline may be regarded as the monitoring index of heavy metal pollution.