Effect of Seed Size on Seedling Growth of a Shade-Tolerant Tropical Tree (Hymanea stilbocarpa Haynes)

The effect of seed size (weight and length) on seedling growth of a tropical species adapted to shaded environments was tested. Seeds of a climax tree species characteristic of the Atlantic Forest (Hymanea stilbocarpa Haynes) were sized by weight(heavy, medium, or light) and length (long, mean, or small). Seeds were scarified and sown under 3 light regimes: (1) full sun-an open forest gap (100% full solar radiation flux at noon), (2) partial shade— a closing forest gap (80% full radiation at noon), and (3) deep shade— under a forest canopy(40% full radiation at noon). Twelve weeks after the develop- ment of primary leaves, the seedlings were measured for total height and root collar diameter. Hymanea seedlings grew best under shaded conditions despite seed category. Seed weight did not significantly influence seedling height or root collar diameter under either shading treatment. Seed length influenced seedling height and root collar diameter when seedlings were grown under either shade treatment. In deep shade, seeds with longer-than-average axes yielded seedlings 24.0 mm taller and 5.5 mm thicker at the root collar than seedlings from short seeds. Tree Planters' Notes 46(4): 130-133; 1995.

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Author(s): Marlene de Matos Malavasi, Ubirajara Contro Malavasi

Publication: Tree Planters' Notes - Volume 46, Number 4 (1995)

Section: Research Reports

Volume: 46

Number: 4