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OBJECTIVE@#The current fertilization methods for Chinese yam are uneconomic and unfriend to environment. A rational one is very important to achieve desired balance of high yield of Chinese yam, economic and friend to environment. Here, we studied the effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizers on the yield of 'Qinfeng' Chinese yam in shallow-groove directional cultivation.@*METHODS@#The experiments were conducted in Dehua County, Fujian Province, China using a "3414" optimal design. Overall, three fertilizer factors (N, P, and K) were evaluated at the following four levels: 0, no fertilizer; 1, 0.5-fold the typical rate; 2, typical fertilization rate; and 3, 1.5-fold the typical rate. There were 14 different fertilization treatments.@*RESULTS@#Treatment 6 (N2P2K2) produced the longest (75.6 cm) and thickest tubers (4.9 cm) with the highest tuber fresh weight (1311.9 g) and yield (41 015.9 kg/hm2), whereas, treatment 1 produced the shortest (65.6 cm) and thinnest tubers (3.9 cm) with the lowest fresh weight (953.4 g) and yield (28 532.8 kg/hm2) among the 14 fertilizer combinations. The experimental data could be fitted to single-variable quadratic and binary quadratic models but not to a ternary quadratic polynomial model. Appropriate N, P, and K fertilizer application rates increased Chinese yam yield. However, excessive fertilization lowered the yield. Chinese yam yield was significantly and strongly correlated with the amounts of N, P, and K fertilizer applied.@*CONCLUSION@#Based on the single variable quadratic and binary quadratic models, we propose that the quantities of N, P, and K fertilizer used to grow 1 hm2 'Qinfeng' Chinese yam should be 360-388.3, 90-100.95, and 416.3-675 kg, respectively.
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This study was designed to study the chemical constituents from bulbil of Dioscorea opposite Thunb.. Four compounds were isolated by silica gel column chromatography. On the basis of physic-chemical characters and spectroscopic data analysis, these compounds were identified as lyzalkaloid (3,4-dihydro-6-hydroxy-4-methyl-6H-pyrido[6,5-b]indol-5(1H)-one) (1), anoectochine (2), ginsenine (3), and 2-hydroxy-3-(1H-indol-3-yl) propanoic acid methyl ester (4). Compound 1 is a new indole alkaloid, named as lyzalkaloid. Compounds 2-4 were isolated from this plant for the first time. The cytotoxic activities were assessed by MTT assay. All compounds exhibited the cytotoxic activity against HepG2 and MDA-231 with IC50 values of over 100 μmol·L-1, respectively. All compounds show no significant cytotoxic activities against HepG2, MDA-231 cancer cell.
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Objective To study the chemical constituents of Dioscorea opposita. Methods The constituents were isolated and purified by silica gel, Sephadex LH-20, and ODS column chromatography. Their structures were elucidated by NMR spectra comparison with reference data. Results Fourteen compounds were isolated from 95% ethanol extract of D. opposite. All of them included eight diarylheptanoids (1-8) and six nitrogen compounds (9-14). They were elucidated by spectroscopic data as 5-ethoxy-1,7-diphenylheptan-3-one (1), 5-hydroxy-1,7-bis(4-hydroxyphenyl)-heptan-3-one (2), 1,7-diphenyl-4-hepten-3-one (3), 1,7-bis (4-hydroxyphenyl)-4-hepten-3-one (4), hannokinol (5), 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-3,5-heptanediol (6), 1,7-bis (4-hydroxy-3-methoxyphenyl)-3,5-heptanediol (7), 1,7-bis(4-hydroxyphenyl)-1,5-epoxy-3-hydroxyheptane (8), trans-N- coumaroyltyramine (9), trans-N-feruloyltyramine (10), cis-N-coumaroyltyramine (11), trans-N-cinnamoyltyramine (12), pyrrolezanthine-6-ethyl ether (13), divaricataester A (14). Conclusion Compounds 1 is a new natural product, named as dioscoheptone A. Compounds 3, 4, 10, 12, 13, and 14 are isolated from the family of dioscoreaceae for the first time. Compounds 2, 6, and 8 are isolated from D. opposita for the first time.
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Objective: This study focused on the secondary metabolites of endophytic fungus Fusarium chlamydosporum in Dioscorea opposite. Methods: Compounds were isolated from the MeOH extract by chromatography technology and their structures were elucidated on the basis of comprehensive spectroscopic analysis. Results: Eight compounds were isolated and their structures were identified as: ergosterol-5α, 8α-peroside (1), ergosta-4, 22-dien-3-one (2), di-n-butyl phthalate (3), di-isobutyl phthalate (4), 3-pyridinecarboxylic acid (5), amber acid (6), pentanedioic acid (7), and Nb-acetyltrytamine (8). Conclusion: All these compounds are isolated from F. chlamydosporum for the first time.