A split-plot experiment was conducted to study the optimum planting density of Nuomi yam in directional groove shallow cultivation. Nuomi yam was the main local cultivar of Dioscorea. The study of this paper may help to give valuable instructions of local production. Three different planting densities and shallow groove diameter were designed in the experiment. The results showed that the fresh weight of aerial part per plant, yield and planting benefit of Nuomi yam tuber were the highest when the planting density was 12 000 plants/hm~2 and the diameter of shallow growth groove was 11.0 cm, while they were the lowest when the planting density was 22 500 plants/hm~2 and the diameter of shallow growth groove was 7.5 cm. Along with the increase of planting density, the fresh weight of aerial part, tuber, fresh yield, benefit and commercial tuber rate of Nuomi yam also decreased. The commercial tuber rate of Nuomi yam of 11.0 cm diameter in shallow growing pot was the highest, while it was the lowest with no shallow growing pot. On the contrary, the content of amylopectin and mucin was the highest when there was no shallow groove, and was the lowest when the diameter of shallow groove was 7.5 cm, although there was no significant difference between the two treatments. Therefore, Nuomi yam with the directional cultivation combination of planting density of 12 000 plants/hm~2 and shallow groove diameter of 11.0 cm showed high yield, good appearance quality, high planting benefit and no obvious adverse effect on internal quality.
Dioscorea

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.
Cultural Characteristics ; Dioscorea ; Fungi ; Korea

During 2007 survey of post-harvest diseases of yam performed in May and June, severe tuber loss caused by blue mold was observed in Iksan, Cheonbuk Province. Two species of Penicillium were isolated from the infected tubers. Based on beta-tubulin gene sequence analysis, and cultural and morphological characteristics, the isolates were identified as Penicillium sclerotigenum and P. polonicum. P. sclerotigenum, which is a novel to Korea, is presently described and illustrated.
Dioscorea ; Fungi ; Korea ; Penicillium ; Sequence Analysis ; Tubulin

Animals ; Diabetic Nephropathies ; drug therapy ; Dioscorea ; chemistry ; Polysaccharides ; pharmacology ; Rats

OBJECTIVETo extract polysaccharides from Dioscorea opposita by alpha-amylase and ultrasound.

METHODThe optimum condition of enzyme-assisted extraction has been obtained through orthogonal test according to the yield of polysaccharides.

RESULTA higher yield of polysaccharides was achieved at 55 degrees C, pH 5.5 , with a load of alpha-amylase 10 mg for 1.0 hour, the extraction rate was increased by in compare of sonolysis treatment alone.

CONCLUSIONTo carry out an enzyme treatment before ultrasound--assisted extraction elevated the yield of polysaccharides.

Dioscorea ; chemistry ; Hydrogen-Ion Concentration ; Polysaccharides ; chemistry ; isolation & purification ; metabolism ; alpha-Amylases ; metabolism

OBJECTIVETo perfect the current standard of Rhizoma Diosoreae and Rhizoma Diosoreae stir-baked with bran by improving quality standards of the two processed pieces.

METHODThe quality standards were established according to 9 batches of processed pieces, separately. The standards contains items of identification, water, total ash, acid-insoluble ash, extractives, heavy metals limit, organochlorine limit, microbial limit and assay.

RESULTThe TLC of the two pieces was characteristed. The contents of acid-insoluble ash in the two pieces were increased, not more than 0.5%, 0.3%, respectively. The content limits of five kinds of heavy metals and harmful elements, two kinds of residual organochlorine pesticides and three microbial limits were increased. There were no more than 2 x 10(-7) of lead, 2 x 10(-7) of cadmium, 1 x 10(-5) of copper, 3 x 10(-7) of arsenic, 1 x 10(-7) of mercury, 1 x 10(-7) of hexachlorocyclohexane (BHC) and 1 x 10(-7) of chlorophenothane (DDT) in the two processed pieces, respectively. There were no more than 2 000 and 600 cfu x mL(-1) in the two pieces, respectively and no more than 30 MPN x 100 g(-1) and fungi can not be tested in the two pieces. The contents of allantoin in the two pieces were no more than 0.15%.

CONCLUSIONThis method is simple and suitable for the quality control of the two processed pieces.

Chemistry, Pharmaceutical ; methods ; standards ; Chromatography, Thin Layer ; Dioscorea ; chemistry ; Quality Control ; Rhizome ; chemistry

AIMTo investigate the water-soluble steroidal saponins in total saponin from Dioscorea nipponica Makino and look for new active compounds.

METHODSThe compounds were isolated with silica gel, PTLC and HPLC, and their structures were elucidated by acid hydrolysis, physical and chemical data and spectral analysis (IR, NMR, MS, HMQC, HMBC) as well as chemical correlations.

RESULTSThe two steroidal saponins (water-insoluble saponin and water-soluble saponin) were isolated from the total saponin of Dioscorea nipponica Makino. The structures were elucidated as diosgenin 3-O-[alpha-L-rhamnopy ranosyl (1-->2)-[beta-D-glucopyranosyl(1-->3)]]-beta-D-glucopyranoside (I), diosgenin 3-O-[alpha-L-rhamnopyranosyl (1-->3)-alpha-L-rhamnopyranosyl (1-->4)-alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside (II).

CONCLUSIONCompound II is a new steroidal saponin and firstly isolated from Dioscorea nipponica Makino. It was named as dioscin Dc.

Dioscorea ; chemistry ; Molecular Conformation ; Molecular Structure ; Plants, Medicinal ; chemistry ; Rhizome ; chemistry ; Saponins ; chemistry ; isolation & purification

To breed a new yam cultivar of Dioscorea alata, the different and excellent germplasm resources were investigated within artificially cultivated population and some superior individuals, with a higher yield and medicinal properties, were selected. Considering results of the yield and medicinal properties during 2006-2013 cropping season, strains and lines were established and selected. As a result, the yield of the new developed cultivar (Wenshanyao No. 1, WSY01-1) reached 2217. 0 kg per 667 m2 (fresh weight) and 348.3 kg per 667 m2 (dry weight), and increased 23.8% and 23.9% comparing with control cultivars (landraces). Comparing with control cultivars, the level of polysaccharide, allantoin, and dioscin increased 36.9%, 48.3%, 20.9%, and reached 12.2%, 1.30%, 579.7 µg · g(-1), respectively. This result showed that the systematic selection method can significantly improve yield and medicinal properties of D. alata, and the developed " Wenshanyao No. 1" exhibits wide spreading prospects.
Allantoin ; analysis ; Breeding ; Dioscorea ; chemistry ; genetics ; growth & development ; Diosgenin ; analogs & derivatives ; analysis ; Polysaccharides ; analysis

OBJECTIVEIn order to find the new varieties with different horticultural characters, and investigate the mutation effects of seeds of Dioscorea zingerbrensis.

METHODThe seeds were carried by a satellite into space and recovered. The space mutation effect on the germination, seedling growth, chromosomes and rhizome diosgenin content of SP, populations of D. zingerbrensis were investigated.

RESULTStimulated by space environment, the seed possessed the fast germinating characteristics. Germination rate showed no change. It was also found that a few plants were aneuploid or tetraploid. Fresh rhizome weight and rhizome diosgenin content in the second year plant were remarkably higher than those of the control. However, the increasing of third year plant was slow down, and rhizome diosgenin content in the third year plant declined simultaneously.

CONCLUSIONThe space environment showed stimulating effects on seed germination, fresh rhizome weight and rhizome diosgenin content.

Dioscorea ; chemistry ; genetics ; physiology ; Extraterrestrial Environment ; Germination ; Mutation ; Plant Extracts ; chemistry ; Seedlings ; chemistry ; genetics ; physiology

OBJECTIVETo study the chemical constituents in the tubers of Dioscorea bulbifera.

METHODCompounds were isolated and purified with silica gel, ODS and Sephadex LH-20 column chromatography, their structures were determined by using spectroscopic methods including MS and NMR.

RESULTFourteen compounds were isolated and identified as stigmasterol (1), mono-arachidin (2), 1,7-bis-(4-hydroxyphenyl)-1E,4E,6E-heptatrien-3-one (3), behenic acid (4), demethyl batatasin IV (5), 2,3'-di-hydroxy-4',5'-dimethoxybibenzyl (6), diosbulbin B (7), diosbulbin D (8), docosyl ferulate (9), 7-bis-(4-hydroxyphenyl) -4E, 6E-heptadien-3-one (10), 5,3,4-trihydroxy-3,7-dimethoxyflavone (11), tristin(12), protocatechuic acid (13), adenosine (14).

CONCLUSIONCompounds 24, 6, 9, 10, 12, 14 were isolated from the genus Dioscorea for the first time.

Dioscorea ; chemistry ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Plant Tubers ; chemistry