EFFECTS OF SPRAYING ZINC FERTILIZER ON THE PHYSIOLOGICAL AND PHOTOSYNTHETIC CHARACTERISTICS OF MILLET PLANTS (SETARIA ITALICA L.) AT DIFFERENT GROWTH STAGES

Pot experiments were conducted from May 2017 to October of 2017 at the cultivation base of the Resource and Environment College of the Shanxi Agricultural University in China The physiological and photosynthetic characteristics of different cultivars treated with different Zn concentrations at different growth stages were investigated to determine the optimum spraying period and spraying concentration of Zn fertilizer (ZnSO4 center dot 7H(2)O) in Millet plants (Setaria italica L.). Results showed that spraying low Zn concentrations (20, 40, and 60 mg.L-1) solutions decreased the malondialdehyde content, Ci (intercellular CO2 concentration), and qN (non-photochemical quenching coefficient) but increased antioxidant enzymatic activities, pigment content, photosynthetic gas exchange parameters (except Ci), and chlorophyll fluorescence parameters (except qN). By contrast spraying high Zn concentration (80 and 100 mg.L-1) showed opposite effects. Moreover, 'Jingu 21' (susceptible variety, conventional cultivar) showed more remarkable variation higher than 'Zhangzagu10' (resistant variety, hybrids). Thus, low Zn concentration promoted plant growth, while high Zn concentration inhibited plant growth, which was most pronounced during the Millet booting stage. The optimal conditions were booting period and 40 mg.L-1 of Zn. Thus, a theoretical basis for the efficient use of Zinc Fertilizer in Millet is provided.