II. MATERIALS AND METHODS
Testing materials: three rice restoring lines (R725, R720
and R727) and five M. oryzae physiological races (ZA5,
ZA17, ZC8, ZG1 and ZF2), were provided by rice research
Institute of Southwest University of Science and Technology.
Chemical components of soil consist of full nitrogen was
1.98 g/kg, available nitrogen was 80.3 mg/kg, available
phosphorus was 43.3 mg/kg, and available potassium was
76.2 mg/kg.
Preparation of the fungus conidia: The activated strains of
M. oryzae were inoculated in oat meal agar medium(oat
30g/L) at 28℃. Fungal conidia were harvested by scraping
the biomass grown on oat meal agar plates with a sterile
surgical blade, and resuspended in sterile water of 0.02%
Tween-20. The sample was diluted for 105 spores of M.
oryzae.
Planting the seedlings and treatment by fungus conidia:
Plants were grown in pot culture by direct seeding in
experimental station of southwest university of science and
technology. Three seedlings in 4 leaves stage were final
singled to each pot. The seedling were sprayed 20ml solution
with 105 spores of M. oryzae for one of physiological race,
respectively, with the control of sterile water of 0.02%
Tween-20 at the tillering stage. After spraying, the seedlings
would keep humidity for 24h.
Determination of indexes: Photosynthetic parameters of
upper leaves were measured by GFS-3000 photosynthesis
from 9:00-11:00 am in clear day at the tillering stage after 7d
of spraying. Meanwhile, the content of photosynthetic
pigments of the matched parts were determined referred the
methods as previous described [8].