锰渣-土壤混合基质上黑麦草和紫花苜蓿生长状况及其对锰的累积特征

以紫花苜蓿(Medicago sativa)和黑麦草(Lolium perenne)为材料,在盆栽条件下探讨紫花苜蓿和黑麦草在电解锰渣-土壤混合基质中的生长状况及其对锰(Mn)的吸收特点.结果表明:土壤添加7％、14％、21％、28％、35％的电解锰渣后,紫花苜蓿、黑麦草的发芽率明显下降,而总生物量随着电解锰渣添加量的增加先增加后降低;但两种植物的株高均出现不同程度的增加,特别是黑麦草.随着电解锰渣添加量的增加,黑麦草中光合色素含量增加,在锰渣添加为14％时叶绿素含量最大,显著高出无锰渣对照34.7％(P<0.05);紫花苜蓿中叶绿素和类胡萝卜素含量随着锰渣添加先增加后下降,在锰渣添加量为14％时达到最大,分别高出对照59.7％、28.0％.在土壤中添加锰渣后,紫花苜蓿中丙二醛(MDA)含量、抗氧化酶包括超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性明显提高,而黑麦草中MDA含量、SOD、CAT和POD活性没有明显变化,说明黑麦草的耐受性大于紫花苜蓿.同时,在锰渣-土壤混合基质上紫花苜蓿、黑麦草的地上部分和根系中的锰含量均随着电解锰渣的添加量增加而提高,总体上黑麦草的富集系数大于紫花苜蓿,而对Mn的转移能力是紫花苜蓿大于黑麦草.研究结果显示,两种植物都可作为锰渣堆场生态修复的备选植物,但锰渣对紫花苜蓿的抑制作用大于黑麦草,因此,黑麦草更适合作为锰渣堆场生态修复的先锋植物.

Growth status of Lolium perenne and Medicago sativa and their manganese absorption in manganese residue-soil mixed matrixes

Using Medicago sativa and Lolium perenne as the experimental materials, the growth status of M. sativa and L. perenne and their absorption characteristics of manganese in electrolytic manganese residue-soil mixed matrixes were examined in this study. The germination rate of M. sativa and L. perenne decreased after mixing variable proportions (7%, 14%, 21%, 28%, and 35%) of electrolytic manganese residue (EMR) in the soil, whereas the biomass first increased and then decreased with an increase in the amount of EMR. The height of the two plants increased to different degrees, especially for L. perenne. With an increase in EMR, the photosynthetic pigment content in L. perenne was increased. In the 14% EMR treatment, the chlorophyll content was the highest, significantly higher than the control by 34.7% (P < 0.05). The chlorophyll and carotenoid content in M. sativa first increased and then decreased with the addition of EMR. In the 14% EMR treatment, the chlorophyll and carotenoid content increased significantly, 59.7% and 28.0% higher than the control, respectively. After adding EMR to the soil, the malonaldehyde (MDA) content and activity of the antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in M. sativa increased significantly, whereas the MDA content and activity of SOD, CAT, and POD in L. perenne did not change, indicating that the tolerance of ryegrass > alfalfa. The manganese content in the aerial parts and roots of M. sativa and L. perenne increased with an increase in EMR. The enrichment coefficient of manganese was L. perenne > M. sativa, and the transfer ability of manganese was M. sativa > L. perenne. Both plants could be used as candidate plants for the ecological restoration of manganese residue; however, the inhibitory effect of manganese residue on M. sativa was greater than that of L. perenne. Therefore, L. perenne was more suitable as a pioneer plant for the ecological restoration of manganese residue.