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蚯蚓-菌根相互作用对土壤-植物系统中Cd迁移转化的影响 总被引:9,自引:0,他引:9
以灰化土(Aquods soil)为供试土壤,分别加入4种含量的Cd2 (0、5、10、20 mg·kg-1)模拟土壤污染,设置单独加8条蚯蚓(Pheretima sp.)、单独接种菌根(Inoculum Endorize-Mix2)、同时接种蚯蚓和菌根的3种处理,以不加蚯蚓和菌根为对照,各处理均种植黑麦草(Lolium multiflorum),研究蚯蚓、菌根相互作用对土壤-植物系统中Cd迁移转化的影响.结果表明:(1)菌根对土壤pH无明显影响,加蚯蚓可使土壤pH比对照约降低0.2,蚯蚓和菌根同时作用对土壤pH降低没有协同作用.(2)蚯蚓或菌根的加入均能显著增加土壤中可溶性有机碳(DOC)含量,蚯蚓的影响大于菌根,同时加入蚯蚓和接种菌根对土壤中DOC的增加有一定的拮抗作用.(3)蚯蚓活动增加了黑麦草根部Cd的积累,菌根则能促进Cd从黑麦草根部向地上部转移,二者具有促进Cd向地上部分转移的协同作用.(4)蚓粪和土壤中DTPA提取态Cd含量与黑麦草吸收Cd量呈显著相关(p<0.01),而蚓粪中DTPA提取态Cd含量均显著高于土壤中的含量(p<0.05).因此,蚓粪中有效态Cd是植物吸收Cd的重要供源. 相似文献
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The nitrogen (N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009.
Results showed that soil N had significant seasonal fluctuations and vertical distribution. The N/P ratio (15.73±1.77) of S. salsa was
less than 16, indicating that plant growth was limited by both N and P. The N absorption coefficient of S. salsa was very low (0.007),
while the N utilization and cycle coefficients were high (0.824 and 0.331, respectively). The N turnover among compartments of S.
salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2, respectively. The N translocation
from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2, respectively. The N translocation from aboveground
living bodies to litter was 0.497 g/m2, the annual N return from litter to soil was far less than 0.368 g/m2, and the net N mineralization
in topsoil during the growing season was 0.033 g/m2. N was an important limiting factor in S. salsa marsh, and the ecosystem was
classified as unstable and vulnerable. S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the
nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S. salsa marsh. Excessive nutrient
loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were
not taken. The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective
measures. 相似文献
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以内蒙古短花针茅荒漠草地生物量为研究对象,比较分析个体、种群、功能群、群落尺度地上生物量的关联与变异.结果显示:(1)个体尺度上,高产草地的兴安胡枝子生物量最大,为(22.96±7.31)g/株,羊草生物量最小,为(0.16±0.69)g/株;种群尺度上,兴安胡枝子生物量较小,羊草的生物量较大;在功能群尺度上,兴安胡枝子生物量在灌木、半灌木该功能群的权重值为0.144,羊草的生物量在多年生禾草的权重值为0.303.(2)种群尺度上短花针茅在低产草地生物量最高(80.33 g/m2±5.15 g/m2),在个体尺度生物量同样最高(6.99 g/株±0.68 g/株);蒙古葱在种群尺度下生物量最低(0.12 g/m2±0.10 g/m2),在个体尺度下也最低(0.01 g/株±0.05 g/株).(3)高产草地的变异系数均值几乎都大于低产草地的变异系数均值,且随个体、种群、功能群、群落尺度的递进呈现下降趋势.本研究表明,从植物不同组织尺度研究短花针茅荒漠草原地上生物量,能够更好地揭示群落生物量置配过程和资源利用,这对于不同地区物种潜在规律的比较以及科学地实施区域生态系统保护具有重要意义. 相似文献
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盐池封育草场土壤种子库特征及其与植被的关系 总被引:1,自引:0,他引:1
封育是退化草场恢复的重要措施之一,封育的效果在一定程度上取决于土壤中种子库的状况。以毛乌素沙地西南缘宁夏盐池县的退化草场为研究对象,采用相似性分析和排序方法对封育和未封育草场土壤种子库的特征及其与地上植被间关系进行了研究,结果表明无论封育区还是未封育区,土壤种子库中的种子主要分布于0~5cm的土层,6~15cm土层的种子数很少;封育区土壤种子库的物种丰富度大于未封育区,物种多样性则表现为H值较大,而D值较小,总体上看封育措施可以提高地上植被和土壤中种子的种类和数量,一些一年生植物、中生植物和盐生植物开始出现在地面或土壤种子库中。地上植被和土壤种子库间的相似性分析结果则表明相同措施同一土层间种子库中等相似,而不同土层间还是存在着一些差异。由于封育措施导致了植被样方的相似性较低,然而土壤种子库间的相似性仍然较高,两者间是否存在着一定程度的滞后效应有待于进一步研究。 相似文献
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