Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:"Effects of light intensity on the growth and energy balance of photosystem II electron transport in Quercus alba " | Ann. For. Sci. 63 2006 111-118 INRA EDP Sciences 2006 DOI forest 2005103 111 Original article Effects of light intensity on the growth and energy balance of photosystem II electron transport in Quercus alba seedlings G. Geoff WANGa William L. BAUERLEb a Department of Forest and Natural Resources Clemson University Clemson SC 29634-0317 USA b Department of Horticulture Clemson University Clemson SC 29634-0319 USA Received 26 April 2005 accepted 24 August 2005 Abstract - Quercus alba white oak seedlings were grown at four levels of irradiance 5 15 30 and 100 of full sunlight under a rain out shelter. After one growing season the greatest diameter and height growth biomass root leaf and stem and leaf area were observed on seedlings under 100 of full sunlight. Seedlings under 15 30 and 100 of full sunlight allocated more biomass to roots 70 than seedlings under 5 of full sunlight 58 suggesting a priority in root growth unless light is severely limited. Leaf weight ratio specific leaf area and leaf area ratio increased with the degree of shading indicating acclimation of leaves to different light intensities. Acclimation to light intensity closely correlated with the fluorescence parameter 1-qp. Non-photochemical quenching was also affected as shade intensity increased. The apparent reduction in electron transport rate ETR through photosystem II PS II increased with light intensity and light saturated ETR under 5 of full sunlight was only 46 of that under full sunlight. The shift from photochemical to non-photochemical quenching occurred in response to increasing actinic light and as growth irradiance declined the quenching shift rate declined as well. Overall Quercus alba seedlings demonstrated strong growth and allometric responses to light intensity. white oak shade tolerance biomass allocation modulated chlorophyll fluorescence light acclimation Résumé - Effets de l intensite lumineuse sur la croissance et la balance énergétique du transport d electrons du .
