Effects of exogenous melatonin on plant growth, root hormones and photosynthetic characteristics of trifoliate orange subjected to salt stress

Soil salinity has negative effects on crop growth and production, melatonin (MT) plays an important role in regulating plant salt stress. However, it is not clear whether exogenous mitigates the effect citrus plants subjected to This study aimed explore response of (0, 50, 100, 150 µmol/L) growth, root hormone levels photosynthetic system trifoliate orange (Citrus (Poncirus) trifoliata L.) seedlings exposed 0 or mmol/L NaCl for 4 weeks. The treatment significantly increased zeatin riboside, gibberellin brassinolide levels, while dramatically reducing auxin leaf photosynthesis fluorescence indexes seedlings. partially ameliorated reductions height dry matter accumulation caused by Melatonin (100 appears interact with IAA but other hormones studied. Furthermore, stress net rate, stomatal conductance, maximum photochemical efficiency, PSII effective photon yield, quenching indicators leaves were also alleviated damage was reduced when treated melatonin. suggests that 100 µmol/L may be treatment.