Leaf anatomy and light acclimation in woody seedlings after gap formation in a cool-temperate deciduous forest
The photosynthetic light acclimation of fully expanded leaves of tree seedlings in response to gap formation was studied with respect to anatomical and photosynthetic characteristics in a natural cool-temperate deciduous forest. Eight woody species of different functional groups were used; two species each from mid-successional canopy species (Kalopanax pictus and Magnolia obovata), from late-successional canopy species (Quercus crispula and Acer mono), from sub-canopy species (Acer japonicum and Fraxinus lanuginosa) and from vine species (Schizophragma hydrangeoides and Hydrangea petiolaris). The light-saturated rate of photosynthesis (P max) increased significantly after gap formation in six species other than vine species. Shade leaves of K. pictus, M. obovata and Q. crispula had vacant spaces along cell walls in mesophyll cells, where chloroplasts were absent. The vacant space was filled after the gap formation by increased chloroplast volume, which in turn increased P max. In two Acer species, an increase in the area of mesophyll cells facing the intercellular space enabled the leaves to increase P max after maturation. The two vine species did not significantly change their anatomical traits. Although the response and the mechanism of acclimation to light improvement varied from species to species, the increase in the area of chloroplast surface facing the intercellular space per unit leaf area accounted for most of the increase in P max, demonstrating the importance of leaf anatomy in increasing P max.
KeywordsAcclimation potential Chloroplasts Photosynthetic capacity Sun/shade acclimation Mature leaves
We thank the staff at Tomakomai Experimental Forest for their technical support and the experimental set-up, T. Koike, T. Kohyama and S. Tsuyuzaki for the generous offer of instruments, and S. Kitaoka, T. Aikawa, S. Kosuge, S. Takahashi, O. Muller, E. Nabeshima and Y. Miyazaki for support for the experiments, advice and discussion. This work was financially supported in part by Grants-in-Aid of the Japan Ministry of Education, Culture, Sports, Science and Technology and by a JSPS Research Fellowship for Young Scientists.
- Distefano JF, Gholz HL (1986) A proposed use of ion-exchange resins to measure nitrogen mineralization and nitrification in intact soil cores. Commun Soil Sci Plant Anal 17:989–998Google Scholar
- Fujimoto S, Motai T (1981) An analysis of growth and form for tree seedlings in a natural forest. In: Igarashi T (ed) Some analyses of community structure and regeneration for natural forests in Hokkaido. Hokkaido Forestry Service, Sapporo, pp 123–141Google Scholar
- JSSSPN (Japanese Society of Soil Science and Plant Nutrition) (1990) Analysis methods of nitrogen compounds. In: Editors commission of experimental methods of plant nutrition (eds) Experimental methods of plant nutrition. Hakuyu-sya, Tokyo, pp 174–203Google Scholar
- Keeney DR, Nelson DW (1982) Nitrogen-inorganic forms. In: Page AL, Miller RH, Keeney DR (eds) Chemical and microbiological properties, 2nd edn. American Society of Agronomy, Soil Science Society of America, Madison, Wis., pp 643–698Google Scholar
- Kikuzawa K (1983) Leaf survival of woody-plants in deciduous broadleaved forests. 1. Tall trees. Can J Bot 61:2133–2139Google Scholar
- Naidu SL, Delucia EH (1997b) Acclimation of shade-developed leaves on saplings exposed to late-season canopy gaps. Tree Physiol 17:367–376Google Scholar
- Pearcy RW, Sims DA (1994) Photosynthetic acclimation to changing light environments: scaling from the leaf to the whole plant. In: Caldwell MM, Pearcy RW (eds) Exploitation of environmental heterogeneity by plants: ecophysiological processes above and below ground. Academic Press, San Diego, Calif., pp 145–174Google Scholar
- Porra RJ, Thompson WA, Kriedemann PE (1989) Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: verification of the concentration of chlorophyll standards by atomic absorption spectroscopy. Biochim Biophys Acta 975:384–394CrossRefGoogle Scholar
- Romme WH, Martin WH (1982) Natural disturbance by tree falls in old-growth mixed mesophytic forest: Lilley Cornett woods, Kentucky. In: Proceedings from the Fourth Central Hardwood Forest Conference. University of Kentucky, Lexington, Ky., pp 367–383 Google Scholar
- Ryel RJ, Beyschlag W (2000) Gap dynamics. In: Marshall B, Roberts JA (eds) Leaf development and canopy growth. Sheffield Academic Press, Sheffield, pp 250–279Google Scholar
- Schmidt MG, Ogden AE, Lertzman KP (1998) Seasonal comparison of soil temperature and moisture in pits and mounds under vine maple gaps and conifer canopy in a coastal western hemlock forest. Can J Soil Sci 78:291–300Google Scholar
- Whitmore TC (1996) A review of some aspects of tropical rain forest seedling ecology with suggestions for further enquiry. In: Swaine MD (ed) The ecology of tropical forest tree seedlings (Man and the biosphere series vol. 17). UNESCO, Paris, pp 3–39Google Scholar