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Growth and photosynthetic responses of Canarium pimelaand Nephelium topengii seedlings to a light gradientWenjie Yang • Fude Liu • Lingyan Zhou •Shiting Zhang • Shuqing AnReceived: 20 September 2011/Accepted: 11 September 2012/Published online: 25 September 2012? Springer Science+Business Media B.V. 2012Abstract We analyzed the growth and photosyn-thetic responses of Canarium pimela K. D. Koenig(Chinese black olive) and Nephelium topengii (Merr.)H. S. Lo. (Hainan shaozi) to a light gradient torecommend better procedures for optimizing seedlingestablishment and growth of both species in restora-tion and agroforestry practices. One-month-old seed-lings were exposed to four irradiance levels (46, 13, 2and 0.2 % full sunlight) inside shade cloth coveredshadehouses for 1 year. With decreased sunlight bothspecies displayed trends of decreased relative growthrate (RGR) and leaf area (LA), and increased specif i cleafareaandleafarearatio(LAR).Themeanvaluesoflight-saturated net photosynthetic rate (Pmax) in 46and 0.2 % full sunlight were 10.11 and 3.44 lmolCO 2 m -2 s -1 for C. pimela and 6.26 and 3.47 lmolCO 2 m -2 s -1 for N. topengii, respectively. C. pimelahad higher RGR in 46 and 13 % full sunlight than in 2and 0.2 % full sunlight. Differences in growth ratescan be explained by the different values of LA, LARandleafmassratio,aswellasbythedifferentvaluesofphotosynthetic saturation irradiance and net photo-synthetic rate (Pmax) between the two species. Bothmorphological and physiological responses to shadingindicate N. topengii could be rated as ‘‘very shade-tolerant,’’ while C. pimela could be rated as ‘‘inter-mediately shade-tolerant’’.Keywords Chinese black olive ? Ecophysiology ?Hainan shaozi ? Light environment ? Photosynthesis ?Seedling establishment ? Shade toleranceAbbreviationAQE Apparent quantum eff i ciencyIc Photosynthetic compensation irradianceIs Photosynthetic saturation irradianceLA Leaf areaLAR Leaf area ratioLMR Leaf mass ratioPAR Photosynthetic available radiationPmax Light-saturated rate of CO 2 assimilationPn Net photosynthetic ratePPFD Photosynthetic photon f l ux densityRd Dark respiration rateRGRd Relative growth rate in root collar diameterRGRh Relative growth rate in heightRGRm Relative growth rate in massWenjie Yang and Fude Liu contributed equally to this study.W. Yang ? F. Liu ? L. Zhou ? S. Zhang ? S. An (&)Laboratory of Forest Ecology and Global Changes, Schoolof Life Science, Nanjing University, 22 Hankou Road,Nanjing 210093, Chinae-mail: anshq@nju.edu.cnW. YangCollege of Horticulture and Forestry Science, HuazhongAgricultural University, Wuhan 430070, ChinaF. LiuKey Laboratory of Water Resources and Environmentof Shandong Province, Water Resources ResearchInstitute of Shandong Province, Jinan 250013, China123Agroforest Syst (2013) 87:507–516DOI 10.1007/s10457-012-9570-0