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Acta Prataculturae Sinica ›› 2014, Vol. 23 ›› Issue (6): 217-224.DOI: 10.11686/cyxb20140626

• Orginal Article • Previous Articles     Next Articles

Effects of water extracts from Solidago canadensis on the growth of maize seedlings and the underlying photosynthetic mechanisms

YE Xiao-qi,WU Ming,SHAO Xue-xin,LIANG Lei   

  1. Research Station of Hangzhou Bay Wetlands Ecosystem, National Forestry Bureau, Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang 311400, China
  • Received:2014-04-10 Online:2014-12-20 Published:2014-12-20

Abstract: Although hormesis is commonly observed with the effects of plant allelochemicals on plant growth, the mechanisms underlying this phenomenon are not clearly understood. Allelochemicals may affect plant growth via either plant resource investment in leaf tissue or photosynthesis capacity per unit leaf area. In this study, the effects of Solidago canadensis water extracts on maize seedling growth, photosynthesis capacity and biomass allocation to the total assimilation tissue were studied. The maize seedlings were cultivated in silica sand in an incubator with controlled conditions. Shoot water extracts with concentrations of 0-0.25 g/mL were applied to the maize seedlings. After 9 days treatment, plant growth (plant height, total root length, leaf length, leaf area and biomass of root, stem and leaf), photosynthesis capacity (light saturated photosynthesis rate, Pmax), apparent quantum yield (AQY), dark respiration rate (Rd) and biomass allocation (LMR, leaf mass ratio, SLA, specific leaf area and LAR, leaf area ratio) were measured. The water extracts had significant effects on growth of the maize seedlings. Compared to the control (0 g/mL), the treatments with concentrations within 0.02-0.11 g/mL promoted growth, while the treatments with 0.143-0.250 g/mL inhibited growth. The water extracts had similar hormesis effects on SLA and LAR, but no significant effects were found for LMR. The Pmax of plants treated with the concentrations of 0.02 and 0.20 g/mL, which caused the largest growth promotion and inhibition effects separately, did not differ significantly from the control treatment. The Rd of the 0.02 g/mL treatment was higher than that of the 0.20 g/mL treatment, although it was not significantly different from the control. Therefore, changes of the respiration rate could not explain the differentiated growth. Final biomass accumulation was significantly correlated with SLA and LAR, but not with LMR. These results indicate that the promotion or inhibition effects of S. canadensis water extracts on maize seedlings growth were not caused by changes in photosynthesis capacity per unit leaf area, but by changes of leaf area ratio and specific leaf area.

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