Effect of light on endogenous levels of gibberellin and abscisic acid in seed germination of photoblastic weedy rice ( O
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J. Crop Sci. Biotech. 2009 (September) 12 (3) : 149 ~ 152 DOI No. 10.1007/s12892-009-0110-z RESEARCH ARTICLE
Effect of Light on Endogenous Levels of Gibberellin and Abscisic Acid in Seed Germination of Photoblastic Weedy Rice (Oryza sativa L.) Sang-Yeol Kim1*, Sun-Joo Hwang2, In-Jung Lee2, Dong-Hyun Shin2, Sung-Tae Park1, Un-Sang Yeo1, Hang-Won Kang1 Functional Crop Resource Development Division, Department of Functional Crop, National Institute of Crop Science, RDA, Milyang 627-803, Korea 2 Division of Plant Bioscience, College of Agriculture and Life Science, Kyungpook National University, Daegu 702-701, Korea
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Received: July 21, 2009 / Accepted: September 18, 2009 Ⓒ Korean Society of Crop Science and Springer 2009
Abstract The effect of red (R) and R/far-red (FR) lights on endogenous gibberellin (GA) and abscisic acid (ABA) content was first investigated during the germination of photoblastic black-hulled weedy rice (PBWR) seeds. The R light-treated PBWR seeds germinated after 36-48 h and germination was increased to 63% at 72 h. However, the FR light-treated seeds after R light treatment, suppressed the R light effect showing only 11% germination even at 72 h after the light treatment. The PBWR seed treated with R light rapidly increased the endogenous level of GA1 to about 200 times at 12 h before seed germination as compared with R/FR (control) which suppressed the effect of R light. The contents of other GAs like GA12, GA53, GA19, GA20, and GA8 were not affected by the R light irradiation. These results showed that the major biosynthetic pathway of GAs in PBWR seeds is the early 13-hydroxylation pathway leading to GA1, which was suggested to be physiologically active in the PBWR seed germination. The decrease in the level of ABA in the R light-treated seeds was greater than the R/FR light-treated seeds, indicating that the balance of endogenous GA1 and ABA is responsible for the induction of germination in the PBWR seed. Key words: abscisic acid, gibberellin, light, photoblastic weedy rice, seed germination
Introduction The two phytochrome-meditated straw-hulled and blackhulled weedy rice lines were found by Chung and Paek (2003) and Kim et al. (2009) with their germination characteristics well-documented. The germination of the phytochrome meditated weedy rice seeds was photoreversible by R and FR light. The R light induces seed germination and the FR light, given after R light, suppresses the effect of R light. So far, most research is focused on the effect of light on the photoreceptor phytochrome but the exact physiological mechanism regulating the events after irradiation is poorly investigated. In various reports, hormone contents, especially those of GAs and ABA have been associated with this control system. In the seed germination of phytochrome meditated lettuce (Toyomasu Sang-Yeol Kim ( ) E-mail: [email protected] Tel: +82-55-350-1174
The Korean Society of Crop Science
et al. 1993, 1994, 1998), rice (Choi et al. 1995) and Asteraceae species (Plummer et al. 1997), the early 13-hydroxylation p
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