Wilt disease is a major disease of cultivated Salvia miltiorrhiza, which is caused by Fusarium oxysporum. Since the infection process of F. oxysporum in plants is affected by environment factors, this study was conducted to reveal the relationship between disease severity and concentration of the pathogen in plants in the infection process of F. oxysporum in seedlings of S. miltiorrhiza by pot experiments and to reveal the effects of temperature and humidity on the infection process. The results showed that, after inoculation of S. miltiorrhiza seedlings with F. oxysporum, the pathogen in different parts was detected at different time, and it was first detected in substrates. With the continuous propagation of the pathogen(4-5 d), it gradually infected the roots and stems of the seedlings, and the plants had yellowing leaves and withering. The number of the pathogen reached the maximum in each part after 7-8 d, and then gradually decreased in the later stage of the disease. The concentration of the pathogen in substrates, roots and stems of S. miltiorrhiza showed a trend of decreasing after increasing with the aggravation of the disease and reached the maximum in the samples of moderate morbidity, while the concentration in the samples of severe morbidity decreased. In addition, the infection of F. oxysporum in seedlings of S. miltiorrhiza was affected by temperature and humidity. The suitable temperature was 25-30 ℃ and the suitable humidity was 80%-90%. This study could provide guidance for the experiments on pathogenicity of F. oxysporum, screening of biocontrol bacteria and controlling of wilt.
Seedlings/microbiology* ; Salvia miltiorrhiza ; Temperature ; Humidity ; Fusarium

OBJECTIVETo explore effects on allelopathic autotoxicity of Rehmannia glutinosa of different abatement measures.

METHODThe experiments for abating allelopathic effects of R. glutinosa were designed with the reducing rate as a indication, three measures of the treating soil with lime nitrogen, and water washing were employed, R. glutinosa- Achyranthes bidentata rotation system and using Achyranthes bidentata as green manure, and seedling transplant were also studied for the abatement effect.

RESULTEffect of seedling transplant was the best, reducing rate of transplant and bare root transplant on the 20th day after emergence was 76.80%, 71.70%, respectively. The reducing rate of the treating soil with microorganism reached 54.25%. The effects of water washing and R. glutinosa-A. bidentata rotation system and using A. bidentata as green manure were not satisfied. Especially only using A. bidentata as green manure without rotation system worsened the allelopathic effects of R. glutinosa.

CONCLUSIONAll measures can abate allelopathic effects of R. glutinosa to some extent except only using A. bidentata as green manure.

Crops, Agricultural ; Rehmannia ; growth & development ; toxicity ; Seedlings ; physiology ; Soil Microbiology

OBJECTIVETo isolate and identify pathogen of the seedling blight occurred in Platycodon grandiflorum.

METHODThe morphological observation, rDNA ITS sequence analysis, and Koch's postulates were used to identify the isolates of the causal agent.

RESULTThe isolates of the causal agent was Rhizoctonia solani.

CONCLUSIONThe result confirmed that R. solani is the pathogen of seedling blight of P. grandiflorum.

Molecular Sequence Data ; Phylogeny ; Plant Diseases ; microbiology ; Platycodon ; microbiology ; Rhizoctonia ; classification ; genetics ; isolation & purification ; Seedlings ; microbiology

Salinity is the most important factor for the growth of crops. It is an effective method to alleviate the toxic effect caused by salt stress using saline-alkali-tolerant and growth-promoting bacteria in agriculture. Seven salt-tolerant bacteria were screened from saline-alkali soil, and the abilities of EPS production, alkalinity reduction and IAA production of the selected strains were investigated. A dominant strain DB01 was evaluated. The abilities of EPS production, alkalinity reduction and IAA production of strain DB01 were 0.21 g/g, 8.7% and 8.97 mg/L, respectively. The isolate was identified as Halomonas aquamarina by partial sequencing analysis of its 16S rRNA genes, and had the ability to inhibit the growth of Fusarium oxysporum f. sp., Alternaria solani, Phytophthora sojae and Rhizoctonia cerealis. It also could promote root length and germination rate of wheat seedlings under salt stress. Halomonas aquamarina can provide theoretical basis for the development of soil microbial resources and the application in saline-alkali soil improvement.
Alkalies ; metabolism ; Bacteria ; drug effects ; genetics ; Halomonas ; genetics ; Plant Roots ; microbiology ; RNA, Ribosomal, 16S ; genetics ; Salt Tolerance ; genetics ; Seedlings ; growth & development ; microbiology ; Soil ; chemistry ; Soil Microbiology ; Triticum ; microbiology

The epiphytic orchid, Dendrobium aphyllum and D. devonianum are used as traditional Chinese medicine, and became locally endangered in recent years because of over-collection. We test the effect of inoculations of endophytic fungi FDaI7 (Tulasnella sp.), FDd1 (Epulorhiza sp. ) and FCb4 (Epulorhiza sp.), which isolated from D. aphyllum, D. denonianum and Cymbidium mannii, respectively, on artificial substrate in these two Dendrobium species. In the symbiotic germination experiment, FDaI7 and FDd1 were effective for protocorm formation and seedling development of D. aphyllum and D. denonianum separately. After 60 days, 14.46% of the D. aphyllum seeds grown to protocorms and 12.07% developed to seedlings inoculated only with FDaI7, while contrasted with 0 when inoculated the other two isolates and non-inoculation treatment. However, in D. denonianum, seeds only grown to protocorms and developed to seedlings when inoculated with FDd1, the percentages were 44.36% and 42.91% distinguishingly. High specificity was shown in symbiotic germination on artificial substrate of Dendrobium. Protocorms could further develop to seedlings within or without light when inoculated the compatible fungi. However, light condition (12/12 h Light/Dark) produced the normal seedlings, while dark condition (0/24 h L/D) produced the abnormal seedlings. These may suggest that the development of young seedlings require light based on the effective symbiotic fungi. These findings will aid in seedling production of simulation-forestry ecology cultivation, conservation and reintroduction of Dendrobium.
Basidiomycota ; classification ; physiology ; Darkness ; Dendrobium ; classification ; growth & development ; microbiology ; Germination ; Host-Pathogen Interactions ; Light ; Plants, Medicinal ; classification ; growth & development ; microbiology ; Seedlings ; growth & development ; microbiology ; radiation effects ; Seeds ; growth & development ; microbiology ; Species Specificity ; Symbiosis

OBJECTIVEDetect the pathogenicity of fungi isolated from American ginseng seeds and select new fungicides against the pathogenic seed-born fungi.

METHODinoculate the isolates to American ginseng seedlings to detect the pathogenicity, and seeded the hyphae disk at the center of agar plate containing chemicals to do fungicide bioassay.

RESULTFusarium sp. isolate 5 and Alternara sp. isolate 13 had pathogenicity to American ginseng seedling. Sportak had the strongest inhibition to the two isolates, Carbendazim had better inhibition and Celest had weak inhibition.

CONCLUSIONSportak and Celest could be used as efficacious candidate chemicals to treat or coat the American ginseng seeds, and substitute Carbendazim, which has been used for many years, to control the diseases occurring in seedling stage of American ginseng.

Alternaria ; drug effects ; isolation & purification ; Benzimidazoles ; pharmacology ; Carbamates ; pharmacology ; Fungicides, Industrial ; pharmacology ; Fusarium ; drug effects ; isolation & purification ; Panax ; growth & development ; microbiology ; Plants, Medicinal ; growth & development ; microbiology ; Seedlings ; growth & development ; microbiology ; Seeds ; growth & development ; microbiology

Based on previous results of 16S rDNA sequence homologuous and results of physic-biochemical indexes and morphological characteristics in the present work, bacterial strain ge15 isolated from roots of ginseng plants was identified as Stenotrophomonas rhizophila. Confronting incubation results showed that, strain ge15 inhibited the growth of Alternaria panax, Phytophthora cactorum, and Cylindrocapon destructans significantly, and the width of inhibition zone was 13.3, 24.0, 12.0 mm, respectively. Further results showed that the emergence rate and seedling survive rate of ge15 treatment was significantly higher than those of the control, and which was similar to pesticide carbendazol treatment. The ge15 strain has good application potential in ginseng diseases control without contamination.
Alternaria ; growth & development ; physiology ; Antibiosis ; Biological Control Agents ; Hypocreales ; growth & development ; physiology ; Panax ; growth & development ; microbiology ; Phytophthora ; growth & development ; physiology ; Plant Diseases ; microbiology ; Plant Roots ; growth & development ; microbiology ; Seedlings ; growth & development ; microbiology ; Stenotrophomonas ; classification ; cytology ; isolation & purification ; physiology

OBJECTIVEIn order to provide a scientific water management for the standardized cultivation, the effects of soil water content on the seedlings growth and active ingredients of S. miltiorrhiza were studied.

METHODA water stress experiment with pot culture was applied to study the effects of different soil water content on the seedlings growth, biomass and the accumulation of tanshinone, salvianolic acid B and mineral nutrition of S. miltiorrhiza.

RESULTSoil water content had serious influence on the growth, yield, outer appearance and inner quality of S. miltiorrhiza when the soil was under severe drought or with too much water. But the shoot and root biomass of S. miltiorrhiza was increased significantly under mild drought. As well as the content and cumulant of dihydrotanshinone I , cryptotanshinone, tanshinone I , tanshinone IIA and salvianolic acid B in root of mild drought were increased. It also enhanced the P, K, Ca, Mg, Mn, Zn, Cu and Fe contents of S. miltiorrhiza under mild drought.

CONCLUSIONThe overall results from the experiment suggest that the appropriate soil water content is 55% to 60% in seedling stage of S. miltiorrhiza. And it will be strongly recommended that the ridge culture and suitable soil moisture management must be carry out in production of S. miltiorrhiza in order to improve the yield and quality of medicinal materials.

Benzofurans ; analysis ; Biomass ; Diterpenes, Abietane ; analysis ; Minerals ; analysis ; Plant Roots ; growth & development ; microbiology ; Salvia miltiorrhiza ; chemistry ; growth & development ; Seedlings ; growth & development ; Soil ; chemistry ; Stress, Physiological ; Water

The endophytic fungi with plant growth promoting effects were screened by co-culture of each endophytic fungus and seedlings of Dendrobium officinale. Anatomical features of the inoculated roots were studied by paraffin sectioning. Morphological characteristics and rDNA ITS1-5. 8S-ITS2 sequences were applied for the taxonomy of endophytic fungi. The results showed that 8 strains inoculated to D. officinale seedlings greatly enhanced plant height, stem diameter, new roots number and biomass. According to the anatomical features of the inoculated roots, each fungus could infect the velamina of seedlings. The hyphae or pelotons were existed in the exodermis passage cells and cortex cells. The effective fungi could not infect the endodermis and vascular bundle sheath, but which was exception for other fungi with harmful to seedlings. Combined with classic morphologic classification, 2 effective strains were identified which were subjected to Pestalotiopsis and Eurotium. Six species of fungi without conidiophore belonged to Pyrenochaeta, Coprinellus, Pholiota, Alternaria, Helotiales, which were identified by sequencing the PCR-amplified rDNA ITS1-5. 8S-ITS2 regions. The co-culture technology of effective endophytic fungi and plant can apply to cultivate the seedlings of D. officinale. It is feasible to shorten growth cycle of D. officinale and increase the resource of Chinese herbs.
Biomass ; DNA, Fungal ; genetics ; DNA, Ribosomal ; genetics ; DNA, Ribosomal Spacer ; genetics ; Dendrobium ; cytology ; growth & development ; microbiology ; Endophytes ; classification ; genetics ; physiology ; Fungi ; classification ; genetics ; physiology ; Host-Pathogen Interactions ; Hyphae ; physiology ; Plant Roots ; cytology ; growth & development ; microbiology ; Plants, Medicinal ; growth & development ; microbiology ; RNA, Ribosomal, 5.8S ; genetics ; Seedlings ; cytology ; growth & development ; microbiology ; Species Specificity