闽江河口芦苇与短叶茳芏空间扩展对湿地植物钒生物富集的影响

选择闽江河口鳝鱼滩芦苇与短叶茳芏空间扩展前的芦苇湿地、短叶茳芏湿地以及二者空间扩展过程中的交错带湿地为研究对象,探讨了空间扩展过程中不同湿地植被的钒（V）生物富集特征及其主要影响因素.结果表明,空间扩展影响下不同湿地土壤的V含量在0~40 cm土层均表现为芦苇湿地 > 交错带湿地 > 短叶茳芏湿地;芦苇湿地和交错带湿地土壤的V含量垂直变化特征较为一致,并均于40~50 cm土层出现较高值.芦苇与短叶茳芏的空间扩展整体增加了交错带湿地土壤的V含量,其均值相比短叶茳芏湿地增加了8.69%,而相比芦苇湿地仅增加0.21%.空间扩展主要通过改变湿地土壤的颗粒组成、EC以及植物的生物量、株高和密度来影响土壤的V含量分布.芦苇与短叶茳芏的V生物富集特征呈相反变化,这与二者竞争过程中植被生态特征改变以及其对V的竞争利用方式有关.此外,不同湿地植被均以根的V富集能力最强,且交错带短叶茳芏的V生物富集能力要高于交错带芦苇,这与二者在竞争生境中对V的吸收利用与转运的差异有关,交错带短叶茳芏可用于未来受V污染湿地修复的备选物种.研究发现,芦苇与短叶茳芏为应对空间扩展过程中的竞争可能采取不同的V富集策略,前者通过将富集到根中的V优先转运至光合器官（叶）的方式来保持相对竞争优势,而后者通过将富集到根中的V大量转移到地上主体（茎）的方式来抗衡来自芦苇的竞争.

Effects of spatial expansion between Phragmites australis and Cyperus malaccensis on bioaccumulation of vanadium in plants of different marshes in the min river estuary

To investigate the bioaccumulation of vanadium (V) in plants of different marshes in Shanyutan of the Min River estuary and explore its affecting factors, the Phragmites australis (PA) marsh and Cyperus malaccensis (CM) marsh before spatial expansion and the ecotonal marsh (EM, the P. australis and C. malaccensis in EM were denoted by PA'' and CM'', respectively) during spatial expansion were studied. Results showed that, as affected by spatial expansion, the V contents in marsh soils at 0~40 cm depth generally followed the sequence of PA marsh > EM marsh > CM marsh. The vertical variations of V contents in soils of PA and EM marshes were consistent and both of them achieved the higher values at 40~50 cm depth. The spatial expansion between PA and CM generally increased the V contents in soils of EM marsh, and, compared with CM and PA marshes, the levels of V in soils of EM marsh increased by 8.69% and 0.21%, respectively. The variations of V contents in soils of EM marsh might be attributed to the alterations of soil grain composition, EC, plant biomass, height and density during spatial expansion. The bioaccumulation characteristics of V in PA'' and CM'' of EM marsh were just in opposite, which was dependent on the alterations of ecological traits of plants and their competitive approaches for V utilization. Moreover, the bioaccumulation capacities of V in roots of different marsh plants were generally higher than those in other organs. In CM marsh, the V bioaccumulation capacity of CM'' was much higher than that of PA'', which mainly rested with the differences in absorption and utilization of V nutrient and the translocation mechanism of V among organs in the two plants. In future, the CM'' in EM marsh could be used as the alternative species for marsh remediation resulting from V pollution. This paper found that, during spatial expansion, the two plants might adopt different bioaccumulation strategies for V absorption and utilization to maintain their competitiveness. The PA might compete primarily by transferring the V accumulated in roots to the photosynthetic organ (leaf) preferentially, whereas the CM might resist the spatial expansion of PA by transferring large amounts of V from the roots to the key organ (stem) of aboveground parts.