17. Photosynthetic ability associated with an esterase band in rice genotypes

Jen-Hsien WENG and Ching-Yih CHEN

Department of Botany, National Chung Hsing University, Taichung, Taiwan 40227, ROC

Four Indica and six Japonica varieties of rice, their F1 plants and F2 progenies were examined with regard to photosynthetic ability and the zymograms of acid phosphatase, peroxidase and esterase. All four Indica and one Japonica variety (Tainung 67) showed an esterase band designated as E1 in this paper (Fig. 1), and also had higher photosynthetic ability than those of other five Japonica varieties which had no E1 band, when compared at the same levE1 of leaf nitrogen or soluble protein content (Table 1). The F1 plants of Tainung 67 X Mineyutaka (a Japanese variety with no E1 band and a low photosynthetic ability) showed the E1 band and a low photosynthetic ability. Of 34 F2 plants, 28 had the E1 band and 6 had no E1 band, of which 5 plants showed a low photosynthetic ability. These data suggest that there is a recessive gene for high photosynthetic ability and it is linked with an esterase gene for the E1 band. The E1 band was stable throughout the growth stages, and could be detected from the seed to the flag leaf when assayed by our method. This esterase band may be used as a marker for high photosynthetic ability in breeding programs.

For assaying esterase isozymes, we used the vertical polyacrylamide gel (7.5%, pH 7.1) and stained with fast blue RR salt and α-naphthyl acetate in phosphate buffer. We have examined the esterase zymograms of the standard strains of Dr. M. Nakagahra made available through his kindness by this method, but the zymograms observed for the strains were not comparable with those reported by him. This indicates that the esterase zymogram differs much according to the method of assay. It was not possible for us to identify the gene for band E1 in the light of genic analysis reported by Nakagahra (1977).

Fig. 1. Esterase zymograms observed in two rice varieties and growth stages. 1-Seed; 2-Four-leaf stage; 3-Flag leaf.

Table 1. Rice varieties tested, their phenol reaction, zymograms
         and photosynthetic ability
________________________________________________________________
                        Phenol Acid     Perox- Ester-  Photo
Variety           Origin reac- phospha- idase  ase     synthetic
                         tion  tase     band4C bandE1 abilitya  
________________________________________________________________
Indica,Ta-li-
ching-yu          Taiwan   +  Acp-1-4    Thick   +       High
Taichung native 1  "b      +     "         "     +         "
Taichung sen 3     "b      +     "         "     +         "
Kaohsiung-sen-yu 
213                "b      +     "         "     +         "
Japonica,
Tainung 67      Taiwanb    -  Acp-1-9    Light   +       High
Taichung 65        "b      -     "         "     -       Low
Tainan 5           "b      -     "         "     -         "
Firooz            Italy    -     "         "     -         "
Chow Sung         China    -     "         "     -         "
_______________________________________________________________
a.From Weng and Chen (1987)
b.Improved varieties.

References

Nakagahra, M., 1977. Genic analysis for esterase isoenzymes in rice cultivars. Jpn. J. Breed. 27: 141-148.

Weng, J. H. and C. Y. Chen, 1987. Differences between Indica and Japonica rice varieties in CO2 exchange rates in reponse to leaf nitrogen and temperature. Photosynthesis Research. (in press)