This work reports the results of the experiment on the growth and physiology of tropical forest tree seedlings in relation to light. The experiments were carried out in a controlled environment simulating forest light conditions. The species studied were <i>Anthocephalus chinensis</i> (Lamk.) Rich. ex Walp., <i>Bischofia javanica</i> Blume, and <i>Hopea odorata</i> Roxb. from the moist forests of tropical Asia. The main aim of this study was to characterise the responses of seedlings in relation to (a) irradiance and nutrient supply, (b) shadelight quality, red to far-red (R:FR) ratio or low proportion of blue light, and (c) changing light availability. The species displayed differential growth responses when their seedlings were grown at different levels of irradiance and nutrient supply. Growth of gap species <i>Bischofia</i> was more plastic than that of the climax species <i>Hopea</i>. The growth of the former was substantially restricted when the nutrient supply was low at the higher irradiances. Pioneer species <i>Anthocephalus</i> responded to a low R:FR ratio by a large increase in stem extension growth with concomitant increase in allocation of dry matter to stem at the expense of leaf development. The effect of R:FR ratio on extension growth was independent of a low proportion of blue light. Very small amounts of blue light in the shadelight restricted leaf expansion in <i>Anthocephalus</i> and <i>Bischofia</i>, and increased specific stem length in the former. The climax species <i>Hopea</i> was relatively unresponsive to the R:FR ratios or the different proportions of blue light in the shadelight.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:657902 |
| Date | January 1991 |
| Creators | Kamaluddin, Mohammed |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/15134 |
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