蚯蚓对污染土壤中黑麦草和印度芥菜吸收累积锌的影响

以长江冲积物形成的高沙土为供试土壤，分别加入4个浓度的Zn（100、200、300、400mg／kg）以模拟Zn污染土壤，设置了接种蚯蚓（Pheretima sp．）处理与不加蚯蚓的对照处理，并种植黑麦草和印度芥菜，以研究蚯蚓活动对不同植物吸收、累积Zn的影响。结果表明：除低浓度Zn处理外（Zn≤100mg／kg），蚯蚓活动明显增加了污染土壤的DTPA提取态Zn含量，进而促进植物对Zn的吸收。蚯蚓活动同时提高了印度芥菜和黑麦草地上部和地下部生物量及植株体Zn浓度，促进了植物对土壤Zn的吸收。加入蚯蚓后印度芥菜和黑麦草中Zn总累积量较无蚯蚓对照分别提高了57．8％～131．6％、51．4％～150．5％。两种植物相比，印度芥菜植株Zn浓度明显高于黑麦草，但由于印度芥菜生物量低，不论是否接种蚯蚓，其Zn累积量均低于黑麦草（未加Zn处理除外）。黑麦草生长条件要求不高、可多次刈割，因而具有很大的修复中、轻度Zn污染土壤的潜力。

In <i>Vitro</i>Anthelmintic Activity of Leaf Extracts of <i>Celosia</i>laxa Schum. &Thonn

Background: Celosia laxa (Amaranthaceae) is mainly a west African plant species used in Traditional Medicine as an anthelmintic, anticancer, antibacterial and analgesic agent. The seeming prevalence of worm infection in Gwandu community of Gwandu Local Government Area of Kebbi State-Nigeria prompted this study. Methods: Whole plant of C. laxa extracts obtained through maceration in aqueous (AE), methanol (ME) and hexane (HE) solvents were investigated for their anthelmintic activity against Indian earthworms (Pheretima posthuman) at four different (gradient) concentrations of 10, 20, 40 and 80 (mg/ml) for each extract. The study involved the determination of time of paralysis (P) and time of death (D) of the worms. Results: Both the aqueous and ethanolic extracts exhibited significant anthelmintic activity at the highest concentration of 80 mg/ml as compared to the standard drug, praziquantel (10 mg/ml). Consequently, the aqueous extract showed a higher activity at 80 mg/ml compared to standard praziquantel at 10 mg/ml (with no significant value of p < 0.05). The time of paralysis and death observed for AE was 13.0 ± 1.8 and 16.8 ± 1.5 while the ME was less bioactive with 15.7 ± 0.5 and 23.0 ± 0.0 respectively. However, on the other hand, the hexane extract recorded no-activity on all the test sample concentrations, compared to the standard drug (with a significant difference of p-value, p > 0.05). Conclusion: It was concluded that the leaves of C. laxa are likely to yield a potent anthelminthic drug owing to soluble phytoconstituent which are largely hydrophilicity extracted by the polar solvents. Also, considering that the plants’ mode of preparation for use by the locals was aqueous decoction before administration, the folkloric therapeutic claims can be said to have been justified.

蚯蚓对印度芥菜修复Zn、Pb污染土壤的影响

以褐土为供试土壤,分别加入不同浓度梯度Zn2+(0,100,200,400 mg kg^(-1))或Pb2+(0,200,400,800 mg kg^(-1))模拟土壤污染,设置添加蚯蚓与不添加蚯蚓处理,通过盆栽实验,研究蚯蚓对印度芥菜生长量和重金属吸收量的影响,旨在探讨蚯蚓在植物-土壤系统中影响重金属迁移转化的作用机理,为蚯蚓在植物修复技术的实践与完善提供理论参考。结果表明:(1)在Zn、Pb污染土壤中,蚯蚓生长率分别降低3%～24%、6%～29%;(2)蚯蚓活动可以降低土壤的pH,显著增加土壤中Zn的有效态含量;(3)蚯蚓活动显著增加了印度芥菜地上部生物量(22.6%～88.6%鲜重,31.3%～122%干重)和印度芥菜地上部Zn的浓度及Zn和Pb的吸收量。印度芥菜地上部重金属浓度和吸收量与土壤中DTPA提取态含量呈极显著正相关(P <0.01),与土壤pH呈负相关。(4)蚯蚓对重金属的活化和对植物生长的促进是解决植物修复瓶颈问题的有效手段。