【摘要】 芦苇分布广、耐性强,被广泛应用于污染修复,无性繁殖是其种群繁衍和维持的主要方式。在大气CO₂浓度升高的背景下,重金属污染将如何影响芦苇的克隆生长还不清楚。本实验以芦苇为研究对象,在人工气候室模拟大气CO₂浓度(380±20μmol·mol^-1)和倍增浓度(760±20μmol·mol^-1),设置铅处理浓度0、300、500、1500、3000 mg·kg^-1,探讨在铅污染以及CO₂倍增的双重影响下芦苇的克隆繁殖响应。随着铅处理浓度增加,根茎数和根茎长度、根茎节芽、根茎顶芽和总芽数显著减少,分蘖节芽数呈先增加后减少但均大于对照,根茎子株数显著增加,分蘖节子株数和总子株数无显著变化,芦苇各器官铅含量显著增加。CO₂浓度倍增条件下,相同浓度铅处理芦苇的根茎数、根茎长度、各类型芽数和子株数显著增加或呈增加趋势;芦苇吸收、积累的总铅含量增加,主要积累在根,但无性繁殖器官根茎和光合器官茎和叶中铅含量显著减少。以上结果表明,大气CO₂浓度升高能减缓铅污染对芦苇克隆生长的负面影响,增强芦苇的克隆生长和种群稳定,主要通过增强构件成本较低的集群生长模式、增加根茎延伸促进芦苇游击生长模式和有效的铅分配策略。更多还原

【Abstract】 Phragmites australis（ common reed）,with extensive distribution and high tolerance to stress,is widely used in pollution remediation. Vegetative propagation is the main way of population maintenance for common reed. It is unclear how Pb pollution would affect clonal growth of reeds under elevated CO₂. To explore responses of clonal reproduction to Pb pollution under elevated CO₂,we imitated the ambient CO₂ and elevated CO₂ concentrations( 380±20 and 760±20 μmol·mol^-1),and Pb pollution( 0,300,500,1500,3000 mg·kg^-1) in phytotron. The number of axillary shoot buds first increased and then decreased with increasing soil Pb concentrations. The number and length of rhizomes,the number of rhizome and apical rhizome buds and total number of buds decreased with increasing soil Pb concentrations. Soil Pb concentrations had no effect on the number of axillary daughter shoots and total number of daughter shoots,but significantly increased the number of apical rhizome daughter shoots and Pb concentrations in organs. Elevated CO₂ increased rhizome growth,the number of each type of buds and daughter shoots,and plant absorption and accumulation of Pb. The concentration of Pb in roots was significantly increased,while the Pb accumulations in rhizomes,steams,and leaves were decreased by elevated CO₂. These results indicated that elevated CO₂ alleviated the negative effects of Pb pollution on clonal growth of common reed,increased clonal propagation and population stabilization through increasing phalanx growth with low cost,guerilla growth by spreading rhizomes,and the effective Pb allocation strategy.更多还原