The Effect of The Biodynamic Preparations and Harvest Month of Quility Indicates in the Leaves of White Mulberry (Morus alba L.) Grown in Lithuania

Abstract

White mulberry (Morus alba L.) is not a widely grown plant in Lithuania. Our research was aimed to assess the impact of biodynamic preparations 500 and 501 on the variation of 1deoxynojirimycin (DNJ), fagomine, total phenolic compounds, total flavonoid contents and antioxidant activity in white mulberry leaves as influenced by their harvest month. Feld experiment with the white mulberry cultivars 'Plodovaja 3' and 'Turchanka' were conducted in 2017 – 2018 in Kaunas district, Lithuania. The soil and tree trunks were sprayed with preparation 500, while mulberry leaves and flowers were sprayed with preparation 501. Leaves of white mulberry were harvested once a month in June, July, August, and September. Leaves were lyophilized and finally ground to a fine powder in a laboratory mill. The amounts of DNJ and fagomine in leaves were identified using liquid chromatography-mass spectrometry. The total phenolic compounds, flavonoids were quantified by Shimadzu Prominence chromatograph (Shimadzu, Kyoto, Japan) and antioxidant activity by the DPPH radical scavenging method. The data averaged over the two experimental years suggest that the effect of the BD preparations 500 and 501 on the contents of fagomine and DNJ was negative, while leaf harvest month had a significant impact in the leaves of cultivars 'Plodovaja 3' and 'Turchanka'. However, the highest contents of total phenolic compounds, total flavonoids and antiradical activity were determined at the end of the growing season, in September. The application of biodynamic preparations 500 and 501 tended to decrease the synthesis of these compounds in the leaves of the mulberry cultivar 'Plodovaja 3' during the growing period, while in the leaves of cultivar 'Turchanka' both preparations increased these parameters.