Effects of stolon severing on the expansion of Alternanthera philoxeroides from terrestrial to contaminated aquatic habitats |
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| Authors: | WEI GUO ZHENG‐HUA HU |
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| Institution: | 1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Beijingdonglu 71, Xuanwu District, Nanjing 210008, China;2. College of Environmental Science and Engineering, Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Ningliulu 219, Pukou District, Nanjing 210044, China;3. Shanxi Province Meteorological Institute, 030002, China |
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| Abstract: | Few studies have examined the effects of clonal integration (translocation of resources between interconnected ramets) during the expansion of amphibious clonal plants from terrestrial to aquatic habitats. We conducted a greenhouse experiment to simulate the expansion of plants from terrestrial to contaminated aquatic habitats in the amphibious stoloniferous herb Alternanthera philoxeroides (alligator weed). The proximal ramets (i.e. relatively old) of clonal fragments grown in uncontaminated soils were connected to (allowing clonal integration) or disconnected from (preventing clonal integration) distal ramets (i.e. relatively young) grown either in uncontaminated water (control, no CuSO4) or in four copper‐contaminated water treatments containing 31.25, 62.5, 125 and 250 mg/L CuSO4, respectively. When a stolon connection was severed, all distal ramets grown in the contaminated water died. When the stolon connection was intact, however, the survival rate of the distal ramets was 85–100% when they were grown at the three lower levels of contamination and 43.75% at the highest level. Moreover, the survival rate and growth of the distal ramets grown in the three lower levels of contamination treatments did not differ from those in the control (uncontaminated water). These results suggest that clonal integration could greatly improve the survival and growth of alligator weed subjected to moderate levels of copper stress. Although clonal integration could also increase the survival rate of the connected distal ramets subjected to the highest level of copper stress (250 mg/L CuSO4) compared with that of disconnected distal ramets, the survival rate and growth measures were still significantly lower than those in the control. This suggests that clonal integration plays a limited role in the survival and growth of alligator weed when it is subjected to severe stress by high levels of copper contamination. |
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| Keywords: | Alternanthera philoxeroides amphibious plants clonal integration heavy metal stress resource sharing |
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