• Title/Summary/Keyword: Natural variation

Search Result 1,653, Processing Time 0.03 seconds

Variation in Demography of Taraxacum officinale Seeds Harvested from Different Seasons

  • Yang, Hyo-Sik;Oh, Man-Ho
    • The Korean Journal of Ecology
    • /
    • v.26 no.2
    • /
    • pp.82-86
    • /
    • 2003

  • We investigated the variation in adaptation to growth for four ecotypically-differentiated population of Taraxacum officinale found naturally in temporal environmental heterogeneity. Seeds collected from the four seasons were germinated in incubators and were grown for four months in greenhouse to test genetic variation among biotypes. Biotypes, segregated by seeds collected seasonally, were the part of natural population in Mokpo, South Korea. Each biotype was different in total dry weight of seeds, biomass, and leaf area, confirming previous finding. Differences between biotypes grown under a common environment indicated a genetic basis to their distinct demographic rates. Therefore, biotypes with similar annual rates of growth and contrasting seasonal rates should persist in the population. This differential response suggests that temporal variation in environment may be responsible, in part, for the maintenance of genetic variation within populations.

  • https://doi.org/10.5141/JEFB.2003.26.2.082 인용 PDF KSCI

Epifluorescence Microscopy with Image Analysis as a Promising Method for Multispecies Biofilm Quantification

  • Ji Won Lee;So-Yeon Jeong;Tae Gwan Kim
    • Journal of Microbiology and Biotechnology
    • /
    • v.33 no.3
    • /
    • pp.348-355
    • /
    • 2023

  • Epifluorescence microscopy with image analysis was evaluated as a biofilm quantification method (i.e., quantification of surface area colonized by biofilms), in comparison with crystal violet (CV) staining. We performed different experiments to generate multispecies biofilms with natural and artificial bacterial assemblages. First, four species were inoculated daily in 16 different sequences to form biofilms (surface colonization, 0.1%-56.6%). Second, a 9-species assemblage was allowed to form biofilms under 10 acylase treatment episodes (33.8%-55.6%). The two methods comparably measured the quantitative variation in biofilms, exhibiting a strong positive relationship (R2 ≥ 0.7). Moreover, the two methods exhibited similar levels of variation coefficients. Finally, six synthetic and two natural consortia were allowed to form biofilms for 14 days, and their temporal dynamics were monitored. The two methods were comparable in quantifying four biofilms colonizing ≥18.7% (R2 ≥ 0.64), but not for the other biofilms colonizing ≤ 3.7% (R2 ≤ 0.25). In addition, the two methods exhibited comparable coefficients of variation in the four biofilms. Microscopy and CV staining comparably measured the quantitative variation of biofilms, exhibiting a strongly positive relationship, although microscopy cannot appropriately quantify the biofilms below the threshold colonization. Microscopy with image analysis is a promising approach for easily and rapidly estimating absolute quantity of multispecies biofilms.

  • https://doi.org/10.4014/jmb.2209.09045 인용 PDF

On The Variation Of The Mixed Layer Depth And The Heat Flux In The Sea Of Japan

  • Shim, Taebo;Kim, Kuh
    • 한국해양학회지
    • /
    • v.16 no.2
    • /
    • pp.49-56
    • /
    • 1981

  • Annual variation of the surface mixed layer depth (MLD) in the southern part of the Sea of Japan is investigated based upon the oceanographic and meteorological data taken during 1971∼1975 by the Fisheries Research and Development Agency and the Central Meteorological Office of Korea. It is found that the variation of the MLD is strongly correlated with the heat exchange between the atmosphere and sea. The MLD and heat flux vary within ranges comparable to those in the Kuroshio region found by Bathen(1972) and Wyrtki(1965)

  • PDF