Inhibition of high Mg concentration on seedling growth, free radical metabolism of reactive oxygen and zinc nutrition of maize in saline fluvo-aquic soils SOME PHYSIOLOGICAL CHARACTERS IN PANICLES AND ANTHERS OF PHOTOPERIOD/TEMPERATURE-SENSITIV GENIC MALE-STERILE RICE (P/TGMR) DURING TRANSFERRING FROM STERILITY TO FERTILITY Effects of simulated acid rain stress on the PSⅡ reaction center and free radical metabolism in leaves of longan