Extraction optimization study of flavonoids from Humulus lupulus Advances in studies on flavones in Humulus lupulus Soil enzyme activity in the rhizosphere of Humulus lupulus plants of different ages Influnce of MET on vegetation and transplan-tation of Humulus lupulus Stem-segment culture and tube propagation of Humulus lupulus L. Histologial Studies on the Root-Knot Nematodes Nonresistant and Resistant Root Apex of Humulus lupulus L.