• Applied Biological Chemistry
• /
• v.25 no.4
• /
• pp.252-256
• /
• 1982

To investigate the influences of biological factors on stored rice and their interactions, the activities of red Hour beetle(Tribolium castaneum) and 2 species of Aspergillus was observed during 6 weeks at $28^{\circ}C{\pm}1^{\circ}C$. It was found that the red flour beetle could complete its life cycle on rice in six weeks. Its activity caused the increse of moisture content of rice(max. 1.3%) after 6 weeks, but the number of mold propagule on the surface of stored rice decreased. The growth of red flour beetle showed a stabilizing tendency on rice inoculated with Asp. repens while it was retarded with Asp. niger.

• The Korean Journal of Mycology
• /
• v.22 no.1
• /
• pp.50-61
• /
• 1994

From soil samples, 380 antagonistic microorgnisms were isolated. Among the isolates, 42 strains had mycelia growing inhibition ability against Fusariun solani, ginseng root rot causing pathogen. Isolates CHA 1 and S-PFHR 6 were proposed as antagonists for this study and they were identified as Promicromonospora sp. and Pseudomonas pseudoalcaligenes respectively. As an antagonism against hyphae of F. solani in dual culture test, CHA 1 and S-PFHR 6 inhibited linear growing, caused abnormal branching, and the membrane projection which formed by cell wall destruction. The secondary metabolites contained in the culture filtrates which prepared from PD broth and Nutrient broth inhibited the spore germination to 14.3%. The culture filtrate of S-PFHR 6 which prepared by a little amount of soil extract addition to nutrient rich medium had more strongly. inhibited the spore germination and spore germination decreased to less than 4.0% in it. The soil used in this study had fungistasis and the germination rate of macroconidia and chlamydospore of F.solani was 19.4% and 17.7% respectively. The steam sterilized soil lost fungistasis and germination rate of conidia increased to more than 97.9%. The soils amended with the propagule of CHA 1 and S-PFHR 6 increased fungistasis and the germination rate of macroconidia decreased to 14.7% and 11.7% respectively in each treatments. But the soil ammended with glucose and asparagine annulled fungistatic ability and the germination rate of macroconidia increased to more than 48.0%. As an antagonistic activity of the secondary metabolites of two antagonistic isolates in soil, the germination rate of macroconidia of F. solani was 9.3% in the soil amended with the culture filtrate of CHA 1 but the culture filtrate of S-PFHR 6 had no such activity. In the soil which treated with antagonist propagule or culture filtrate, the chlamydospore germination rate was lower than that in natural soil. The addition of glucose and asparagine to antagonist propagule treated soil did not enhanced the chlamydospore germination.

• Journal of Forest and Environmental Science
• /
• v.24 no.2
• /
• pp.79-88
• /
• 2008

Twenty-eight of 44 Indian Ceropegia species are endemic and their survival is threatened. As a step towards conservation, we implied in vitro methods for the sustainable propagule production in C. hirsuta, C. lawii, C. maccannii, C. oculata and C. sahyadrica. Effects of explant, growth regulators, sucrose and photoperiod were studied. High frequency microtuber production was achieved with the seedling-apical buds, grown on MS medium containing 4-6 mg $1^{-1}$ BAP, 3-8% (w/v) sucrose, under continuous illumination. Each microtuber, when subcultured proliferated to form a cluster of secondary microtubers. Every primary and secondary microtuber bore at least one shoot-bud and a root primordium. Each tuber (formed with any of the significantly effective treatments) weighed more than 500 mg, enough to plant directly in non-sterilized soils. Microtubers could be produced and proliferated round the year. Proliferation could be solely attributed to in vitro procedures as these plants bear solitary tubers in vivo. Microtubers could be sprouted in vitro to prepare ready to pot plantlets. As, this novel method succeeded for all five species, though they belong to different eco-physiological backgrounds, we recommend its implementation in the conservation programs for a broader range of Ceropegia species, supported by other integrated strategies.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.106-107
• /
• 2003

The effect of biological control agent Bacillus sp. (BAC03-3-1, BAC03-3-2, BAC02-4) on pre- and postemergence Sclerotinia rot of perilla (Perilla frutescens var. japonica) caused by Sclerotinia sclerotiorum was determined from greenhouse field trials. The ability of this antagonist to reduce germination of sclerotia of S. sclerotiorum was also evaluated. In the greenhouse, suspension of BAC03-3-1 application as root drench of perilla, which provided as little as 10$\^$7/ cells/ $m\ell$ per gram of soil, significantly increased plant stand in pathogen-infested soil over that in the untreated control. All three isolates reduced the germination of sclerotia of S. sclerotiorum in loamy sand soils in the greenhouse. In loamy sand amended with rice bran the sclerotial germination was inversely correlated (r = -0.79) with perilla stand in the greenhouse. However, a higher rate of bacterial suspension with rice bran(Ig dwt./100g soil) than that applied with bacterial suspensions only was necessary to achieve a comparable reduction in sclerotial germination. In field study, all three isolates added to soil to provide 10$\^$7/ cells/$m\ell$ per gram significantly prevented Sclerotinia rot (73-85％) after 35 days of growth. The isolate BAC02-4, BAC03-3-1 and BAC03-3-2 gave final stands of 65 to 75, 60 to 70, and 55 to 60％, respectively. The addition of rice bran(1 ％) to loamy sand in the field resulted in a 10-fold increase in propagule numbers of the three isolates within 10 days of application.

• Korean Journal of Medicinal Crop Science
• /
• v.7 no.3
• /
• pp.200-204
• /
• 1999

Ligusticum chuanxiong has been an important oriental crude drug and cultivated for a long time in Korea. Ligusticum chuanxiong has been vegetatively propagating crop without seed due to its sterility and would be an allodiploid derived from the hybridization of two allied species. Generally, vegetative propagation is more costly per unit propagule than sexual(seedling) propagation. This study was conducted to find out the techniques of mass propagation by stem cutting for reduced seedling cost. When cutted on August 30 with 1st to 2nd internode, its highest rooting percentage was 81 percent. Rhizome yield of plants cutted in 50 percent on September 1 decreased to 9 percent less than control (rhizome propagation). Rooting percentage of rooted cutting plants after field planting on October 25 was the highest being 87 percent. Rhizome yield with planting appeared 127 and 120kg/10a on September 25 and October 25, respectively.

• The Korean Journal of Mycology
• /
• v.12 no.3
• /
• pp.99-103
• /
• 1984

Hyphal growth by Fusarium moniliforme was best at -14 bars osmotic water potential. Hyphal growth was prevented at -94 bars. The production of microconidia was best at -14 bars osmotic potential and prevented at -84 bars regardless of Strain. In contrast, this fungus sporulated macroconidia best at -1.4 bars and progressively less with each increment drop in water potential below that of basal media. The rate of spore germination followed a similar pattern with all of the spores; uniformly maximal at about -1.4 bars and progressively slower as the water potential was lowered from -1.4 bars to -42 bars. Under the natural conditions, plants infected by F. moniliforme produce microconidia on the dead tissues instead of producing macroconidia. This phenomenon agrees well with the water potential experiment since the dead plant tissues have a lower water potential than the living plant.

• The Korean Journal of Mycology
• /
• v.17 no.1
• /
• pp.21-26
• /
• 1989

Saprelegnia sp. was isolated from water sample of Illgam lake in Kon-Kuk university and physiological and reproductive characteristics of this isolate were studied. The isolate grew at a broad range of temperature of $25^{\circ}C\;to\;30^{\circ}C$ and of pH 5 to 6. The maximum growth was attained at the concentrations of 5 mM to 10 mM of phosphate and of 14 g/l of vitamin-free casamino acid. Size of asexual reproductive propagule, zoospore, was $10.3{\mu}$ in diameter and cyst, $11.6{\mu}$. Diameter of oogonium was $47-85{\mu}$ and oospores, $21-31{\mu}$.

• Journal of Ecology and Environment
• /
• v.39 no.1
• /
• pp.1-10
• /
• 2016

Despite it has been mentioned that the successful restoration in landscape level was achieved in the Young-il soil erosion control project, quantitative evaluation of restored plant communities (Alnus firma as introduced species and Pinus thunbergii as native species) was hardly founded. Light availability, litter and woody debris cover, and forest structure and composition were determined for 500 m² band-quadrat in three forest types. Abiotic factors of Q. serrata stands, as reference forest, and A. firma stands were similar but not for P. thunbergii stands. There were no significant difference on mean stem density (stems ha^-1, H = 3.6, p = 0.162), and the mean basal area of each stand had marginal significance (m² ha^-1, H = 5.7, p = 0.058) among stands as total basal area was higher with the order of A. firma (21.4 m² ha^-1), P. thunbergii (19.8 m² ha^-1) and Q. serrata (16.2 m² ha^-1). Restoration of vegetation structure was more effective in fast-growing and N-fixing A. firma, as introduced species plantation. However, result of MRPP, NMS ordination and ISPAN for herbaceous layer, not for tree and shrub species composition, indicated that restoration of ground vegetation was likely influenced highly from local environment. Propagule availability from landscape context such as connectedness to natural vegetation and management practices in restored isolated stands are available explanations for restoration effects and gaps between restored plantations and secondary oak forest.

• Journal of Ecology and Environment
• /
• v.40 no.2
• /
• pp.89-106
• /
• 2016

Many plant species have two modes of reproduction: sexual and asexual. Both modes of reproduction have often been viewed as adaptations to temporally or spatially variable environments. The plant should adjust partitioning to match changes in the estimated success of the two reproductive modes. Perennial plants showed that favorable habitats in soil nutrients or water content tend to promote clonal growth over sexual reproduction. In contrast, under high light-quantity conditions, clonal plants tend to allocate more biomass to sexual reproduction and less to clonal propagation. On the other hand, plants with chasmogamous and cleistogamous flowers provides with a greater tendency of the opportunity to ensure some seed set in any stressful environmental conditions such as low light, low soil nutrients, or low soil moisture. It is considered that vegetative reproduction has high competitive ability and is the major means to expand established population of perennial plants, whereas cleistogamous reproduction is insurance to persist in stressful sites due to being strong. Chasmogamous reproduction mainly enhances established and new population. Therefore, the functions of sexual and asexual propagules of perennial or annual plants differ from each other. These traits of propagule thus determine its success at a particular region of any environmental gradients. Eventually, if environmental resources or stress levels change in either space or time, species composition will probably also change. The reason based on which the plants differ with respect to favored reproduction modes in each environmental condition, may be involved in their specific realized niche.

• The Korean Journal of Ecology
• /
• v.26 no.4
• /
• pp.209-214
• /
• 2003

In order to clarify the successional trend and its characteristics of plant community in abandoned field in Cheju Island, we investigated the seral changes of vegetation height, coverage, growth form, species richness, diversity and dominance index along with the time lapse, and then compared with those of mainland researches. And in order to seek the overall trend of vegetation changes, we used cluster, TWINSPAN and PCA ordination techniques. The succession was characterized by the lower species number, lower vegetation height, longer period of herb dominant and later invasion of tree species. These results may come from that ecological traits of Cheju Island itself, and ecosystem fragmented influences that block a seed (propagule) transport. Sere of the dominant species was shown as follows: Mazus japonicus(0.5∼1 years)→Conyza sumatrensis (2 years)→Artemisia princeps var. orientalis(4 years)→Artemisia princeps var. orientalis, indigofera pseudotinctoria(5 years)→Rosa multiflora, Miscanthus sinensis, etc.(8 years)→Miscanthus sinensis(12 years)→Boehmeria nivea, Pueraria thunbergiana etc.(15 years)→Mallotus japonicus(20 years)→Litsea japonica, Machilus thunbergii (20 years<). Abandoned fields were classified into three groups according to time lapse; earlier stage(0∼1 years), middle stage(2∼8 years) and later stage(8∼20 years).