ABSTRACT
OBJECTIVE: To study the changes in physiological indices reflecting resistance to environmental stress and volatile constituents of Lysimachia nummularia Aurea. METHODS: Different concentrations (150, 200, 250 and 300 mmol · L-1) of NaCl solution was used to treat young Lysimachia nummularia Aurea to investigate the effect of saline stress on the seedling growth. The changes of physiological indices including soluble sugars, proline, SOD and so on were assayed. Volatile constituents were analyzed by head space solid-phase microextration (HS-SPME) coupled with gas chromatography-mass spectrometry (GC/MS). RESULTS: With increasing stress intensity, the contents of soluble proteins declined, those of soluble sugars increased gradually, the content of proline reached the maximum value when saline stress intensity was 250 mmol · L-1, and the contents of chlorophyll a and b decreased firstly and rose later above 250 mmol · L-1. MDA content and SOD activity rose gradually under saline stress with increasing stress intensity. POD activity was significantly lower under the saline stress than the control group. CAT activity rose firstly and rapidly declined later. The volatile constituents of L. nummularia fluctuated after saline stress. CONCLUSION: L. nummularia has relatively higher saline resistance by means of active accumulating osmoregulation substances such as soluble sugars, soluble proteins and enhancing capability of antioxidase.