Objective Effects of shading on photosynthesis, growth, and aromatic composition of Pandan (Pandanus amaryllifolius) plants were studied for cultivation improvement.
Method In a pot experimentation, pandan plants were grown under either full sun exposure or 30%, 60% or 90% shading. The photosynthesis, growth, and aromatics of the plants were monitored.
Result The net photosynthetic rate, stomatal conductance, and count of the leaves on plants grown under 30% and 60% shading were significantly higher than those under either full sun exposure or 90% shading. On the other hand, the tiller number decreased significantly with increasing shading. Twenty-seven volatile aromatic compounds were identified regardless the difference in treatment. There were 10 aromatics, including 2-acetyl-1-pyrrolidine phytol, squalene, 1-propanol, acetol, 3-methyl-2-(5H)-furanone, neophytadiene, ethyl palmitate, 2,3-dihydrobenzofuran, and ethyl linoleate, commonly present, but differed significantly in relative content when the plants were under the varied shading. For instance, the contents of 2-acetyl-1-pyrroline, 3-methyl-2-(5H)-furanone, 2,3-dihydrobenzofuran, ethyl linoleate, and phytol were significantly higher under 30% and 60% shading, those of squalene and phytol significantly higher under 30% shading, and those of acetol, 2-acetyl-1-pyrroline, 3-methyl-2-(5H)-furanone, neophytadiene, ethyl palmitate, and ethyl linoleate significantly higher under 60% shading than the other treatments.
Conclusion By artificially imposing 30% or 60% shading, pandan plants grew more vigorously generating more fragrant substances in the leaves than exposing naturally to the sun.
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