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为进一步探究放射性重金属铀污染环境对植物种子萌芽及生长所产生的迫害,根据我国铀矿冶废水中铀的质量浓度(5 mg/L)选择不同质量浓度(0、1 mg/L、5 mg/L、10 mg/L、15 mg/L、20 mg/L)的铀溶液进行试验,用以胁迫5种1年生牧草(三叶草、苜蓿草、黑麦草、高丹草和苏丹草)种子,同时观察记录各自的萌发状况(发芽数和第7 d幼苗生长长度),计算其发芽率、发芽势、发芽指数(GI)、活力指数(VI)及耐性指数,并与对照组进行量化指标比较。最后比较各牧草种子所受到的危害并做出评价。结果表明:对于不同程度的铀污染,多数植物表现为低质量浓度促进其种子萌发,高质量浓度则严重抑制甚至致死。对于三叶草、苜蓿草和黑麦草种子,低质量浓度(1 mg/L)铀溶液促进种子的萌发,质量浓度升高则为抑制,其中黑麦草表现稍异常,质量浓度为5 mg/L时对种子萌发有促进作用,使最终发芽率较对照提升14%;对于高丹草,低质量浓度(5 mg/L)时促进种子萌发,而在质量浓度稍低于或超过5 mg/L时表现出明显的抑制现象,各指标低于对照13%左右;苏丹草则仅呈现抑制现象,铀质量浓度为5mg/L时抑制现象稍轻,最终发芽率较对照组仅降4%,小于或大于5mg/L时均受抑制,且质量浓度越高抑制现象越明显,最终发芽率最高仅28%。
In order to further investigate the persecution caused by germination and growth of plant seeds caused by radioactive heavy metal uranium pollution, different concentrations (0, 1 mg / L, 5 mg / L) were selected according to the concentration of uranium in uranium mine wastewater / L, 10 mg / L, 15 mg / L, 20 mg / L) were used to inoculate seeds of five perennial grasses (clover, alfalfa, ryegrass, sudangrass and sudangrass) At the same time, the germination status (germination number and seedling growth length on the 7th day) were observed and recorded. The germination rate, germination potential, germination index (GI), vitality index (VI) and tolerance index were calculated and compared with those of the control group . Finally, we compared the hazards of forage seeds and made the evaluation. The results showed that for different degrees of uranium pollution, most plants showed low concentration to promote the germination of their seeds while high concentration could seriously inhibit or even cause death. For the clover, alfalfa and ryegrass seeds, low concentration (1 mg / L) uranium solution promoted the seed germination and the increase of the concentration was inhibited, of which the ryegrass was a little abnormal and the concentration of 5 mg / L Seed germination was promoted by increasing the final germination rate by 14% compared with the control; for Sorghumgrass, seed germination was promoted at a low concentration (5 mg / L) and slightly below or above 5 mg / L The inhibition rate was lower than that of the control group. Sudan grass showed inhibition only. When the concentration of uranium was 5 mg / L, the inhibition phenomenon was slightly lighter, and the final germination rate was only 4% lower than that of the control group, less than or greater than 5mg / L were inhibited, and the higher the concentration of the more obvious inhibition, the ultimate germination rate of only 28%.