Abstract:

Objective: To provide a scientific basis for pear-jujube production with both high fruit yield and quality under watersaving irrigation. Method: The fruits of seven to eight year old dwarfing close planting pear-jujube trees receiving three drip irrigation regimes (assigned into the experimental groups), which were different in irrigation amount and frequency, or receiving no irrigation treatment (assigned into the control group) were measured for the content of total phenolics, total flavonoids and vitamin C, phenolic composition, and the antioxidant properties including the abilities to inhibit lipid peroxidation and scavenge DPPH and ABTS free radicals and reducing power. Results: Under the drip irrigation regimes designed in our study, irrigation amount and frequency had no significant effect on total phenolic content. But the contents of total flavonoids, vitamin C, and the three main compounds of flavonoids in pear-jujube fruits, catechin, epicatechin and rutin, were all significantly affected by different drip irrigation regimes. The four models of antioxidant capacity all showed significant discrepancies (P < 0.05) among different regimes, which were significantly correlated with total flavonoids content, but neither antioxidant capacity and total flavonoids content linearly increased with increasing irrigation amount and frequency. Conclusion: Irrigation with appropriate amount and frequency is an important guarantee for the high-fruit-yield and water-saving production of high-quality jujube.

Key words: pear-jujube, irrigation regime, antioxidant capacity, phenolics