TITLE	Effect of light on endogenous indole-3-acetic acid, peroxidase and indole-3-acetic acid oxidase in soybean hypocotyls
AUTHOR	Zin-Huang Liu Department of Biology, Institute of Life Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan 804, Republic of China Ho-Yih Liu Department of Biology, Institute of Life Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan 804, Republic of China Hwei-Yi Wang Department of Biology, Institute of Life Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan 804, Republic of China
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ABSTRACT	Two days of light irradiance reduced the levels of endogenous indole-3-acetic acid (IAA) in soybean (Glycine max) hypocotyls. The key enzymes for IAA metabolic degradation are peroxidases and IAA oxidases. Peroxidase activity was enhanced about twofold by light. IAA oxidase activity also increased after irradiance. The lignin content and total phenolic compounds in soybean hypocotyls were enhanced 2_2.5 fold by light treatment. Light-induced inhibition of soybean hypocotyl growth might be due to the decline of endogenous IAA, which was degraded by IAA oxidases or peroxidases. The high levels of lignin were correlated with the increased peroxidase activity in light-treated tissues. Two phenolic compounds, ferulic acid and trans-cinnamic acid, which are precursors for lignin synthesis, greatly increased in light-treated soybean hypocotyls. This suggested that lignin synthesis catalyzed by peroxidase was enhanced during irradiance.
KEYWORD	Glycine max L.; IAA; Indole-3-acetic acid; Peroxidase;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 37 Number 2 April 1996, page 113-119, 7 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China