Effect of light on endogenous levels of gibberellin and abscisic acid in seed germination of photoblastic weedy rice (Oryza sativa L.)

Journal of Crop Science and Biotechnology 09/2009; 12(3):149-152. DOI: 10.1007/s12892-009-0110-z

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.

Download full-text


Available from: Hang-Won Kang, Mar 18, 2015
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Microspore-derived embryos of Brassica napus cv Reston were used to examine the effects of exogenous (+)-abscisic acid (ABA) and related compounds on the accumulation of very-long-chain monounsaturated fatty acids (VLCMFAs), VLCMFA elongase complex activity, and induction of the 3-ketoacyl-coenzyme A synthase (KCS) gene encoding the condensing enzyme of the VLCMFA elongation system. Of the concentrations tested, (+)-ABA at 10 &mgr;M showed the strongest effect. Maximum activity of the elongase complex, observed 6 h after 10 &mgr;M (+)-ABA treatment, was 60% higher than that of the untreated embryos at 24 h. The transcript of the KCS gene was induced by 10 &mgr;M (+)-ABA within 1 h and further increased up to 6 h. The VLCMFAs eicosenoic acid (20:1) and erucoic acid (22:1) increased by 1.5- to 2-fold in embryos treated with (+)-ABA for 72 h. Also, (+)-8'-methylene ABA, which is metabolized more slowly than ABA, had a stronger ABA-like effect on the KCS gene transcription, elongase complex activity (28% higher), and level of VLCMFAs (25-30% higher) than ABA. After 24 h approximately 60% of the added (+)-[3H]ABA (10 &mgr;M) was metabolized, yielding labeled phaseic and dihydrophaseic acid. This study demonstrates that (+)-ABA promotes VLCMFA biosynthesis via increased expression of the KCS gene and that reducing ABA catabolism would increase VLCMFAs in microspore-derived embryos.
    Plant physiology 07/1998; 117(3):979-87. · 7.39 Impact Factor
  • Bioscience Biotechnology and Biochemistry 01/1995; 59(10):1969-1970. DOI:10.1271/bbb.59.1969 · 1.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: motes the germination of photoblastic seeds. The photo- reversibility of seed germination under alternating irra- The germination of rice (Oryza sativa L.) seed has been known diation of R and FR light appears to exist as a survival to be unaffected by light or darkness, but a photoblastic rice (PBR) mechanism of small-seeded plants; it induces seed ger- whose germination was favored by light was discovered in weedy rice. mination only under the optimum light condition in
    Agronomy Journal 01/2003; 95(1). DOI:10.2134/agronj2003.0184 · 1.54 Impact Factor
Show more