Abstract: 【Objective】The dynamic changes and accumulation characteristics of quercetin and hesperetin at different nitrogen levels and different growth stages of wheat and faba bean intercropping system in order to provide a basis for further investigation of the mechanism of increasing yield and controlling diseases.【Method】 In a pot experiment, mesh barrier (MB) and, polythene barrier (PB) were used to determine the secretion amount of quercetin and hesperetin exuded by roots of wheat and faba bean at different nitrogen levels (1/2N﹕half of the normal application rate; N: conventional application rate; 3/2N: 1.5 times rate of the normal application rate) in intercropping system.【Result】N levels and root separations affected biomass and root-shoot ratio of crops in wheat and faba bean intercropping system. With the increase of nitrogen application, the biomass of wheat and faba bean increased by 45%-62.5% and 3.2%-18.9%, and the root-shoot ratio decreased by 33.8%-47.3% and 11.8%-26.9%, respectively; Compared with the plastic separation, the biomass of nylon separated wheat and faba bean increased by 4.2%-25% and 19%-38.6% at the same nitrogen levels at 60 d. With the growth stages, the differences were not significant. Root separation and nitrogen levels affected quercetin and hesperetin exuded by roots of wheat and faba bean in intercropping system. With the increase of nitrogen application, the secretion amount of quercetin and hesperetin were decreased, compared with low nitrogen conditions, under conventional nitrogen application rate and high nitrogen application rate, quercetin exuded by wheat root decreased by 23.4% and 62.3%, hesperetin decreased by 32.2% and 64.5%, quercetin exuded by faba bean root decreased by 35.4% and 44.1%, hesperetin decreased by 11.9% and 23.9%. At the same nitrogen level, quercetin and hesperetin exuded by nylon separated roots of wheat and faba bean were higher than that of plastic partition. Under the condition of low nitrogen and conventional nitrogen application rates, the secretion of quercetin in nylon-separated wheat root were higher 15.3% and 27.1% than that in plastic, the secretion of hesperetin in nylon-separated wheat root were higher 21% and13.7% than that in plastic; the quercetin secreted by nylon-separated faba bean were higher 34.6% and 56.6% than that of plastic, hesperetin was higher than plastic separated by 16.9% and 5.1%; there was no significant difference between the two root systems under high nitrogen condition.【Conclusion】Root separation affected quercetin and hesperetin secretion amount exuded by wheat and faba bean roots, but this effect was controlled by nitrogen application levels, under the conditions of low nitrogen and conventional nitrogen application rates, quercetin and hesperetin that exuded by nylon-separated root in wheat and faba bean intercropping were higher than that of plastic partition, the difference was not significant under high nitrogen condition.

Key words:  wheat, faba bean, intercropping, nitrogen application, quercetin, hesperetin