Morphogenic Light Reflected to Developing Cotton Leaves Affects Insect-Attracting Terpene Concentrations
- Michael J. Kasperbauer * and
- John H. Loughrin
Cotton (Gossypium hirsutum L.) leaves accumulate volatile terpenes that have been implicated in the attraction of both insect pests and the arthropods which prey on them. Our objective was to determine if altering the light environment of developing cotton leaves could affect the accumulation of these attractants. Plants were grown in drip-irrigated plots over colored polyethylene soil covers that reflected various combinations and intensities of red (R), far-red (FR), blue (BL), and photosynthetic photon flux (PPF). Individual terpenes were quantified by gas chromatography and identified by mass spectroscopy. Leaves exposed to a low amount of reflected BL and a FR/R ratio higher than that of incoming sunlight were thinner than leaves exposed to high amounts of reflected BL and PPF during development. Increasing the FR/R ratio while decreasing the amount of BL reflected to developing cotton leaves increased the leaf content of insect-attracting terpenes such as α-pinene and β-pinene on both leaf area and fresh weight bases. We conclude that altering the color of light reflected to developing cotton leaves can affect leaf content of insect attractants.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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