Byeong-Mee Min

Effects of various pretreatments on seed germination ofCalystegia soldanella (Convolvulaceae), a coastal sand dune plant

We tested various pretreatments to enhance the germination of ‘Sea bells’ (Calystegia soldanella Roem. et Schult). One experiment, which improved the germination rate by 70%, involved first scarifying the seed coats, then immersing the seeds in 50 ppm GA3 for 24 h. A GA3-alone pretreatment did not increase germination. However, the most effective method, with a 100% success rate, included 3 h of acid pretreatment with 98% H2SO4. We also used scanning electron microscopy (SEM) to examine the seed-coat surfaces and cross-sections of dry seeds. SEM showed structural differences between seeds that were not treated and those exposed to 98% H2SO4. The latter treatment allowed the seed coats to crack and break, thereby disrupting their physical dormancy.

Flavonoid analysis ofHeloniopsis orientalis (Thunb.) by high performance liquid chromatography

We have isolated and identified seven flavonoid compounds from the foliar extracts ofHeloniopsis orientalis, a member of Liliaceae, which is habituated at Namhansanseong and Maranggol (Jinburyung). All are glycosylated derivatives of the flavonols isorhamnetin, kaempferol, and quercetin. Among them, quercetin 3-O-galactoside is the major compound, while isorhamnetin 3-O-arabinosylgalactoside, isorhamnetin 3-O-digalactoside, kaempferol 3,7-O-galactoside, kaempferol 3-O-arabinosylgalactoside, kaempferol 3-O-glycoside, and quercetin 3-O-arabinosylgalactoside are present in smaller amounts. Although the two populations do not differ significantly in their overall flavonol profiles, their relative amounts indicate that flavonoid levels, especially for isorhamnetin, are geographically controlled and specifically depend on the origin of the individual population.

Relationship between Phenological Stages and Cumulative Air Temperature in Spring Time at Namsan

To certify predictability for the times of phenological stages from cumulative air temperature in springtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants were monitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) and Nuttonson`s Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficient of variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. However, mean coefficient of variation was 0.30 in Forsythia koreana and Stephanandra incisa and 0.32 in Zanthoxylum schinifolium. Therefore, the times of each phenological stage could be predicted in the former two species but not in latter three species by two indices. Of the five phenological stages, mean coefficient of variation was the smallest at deflowering time and the largest at budding time. In five phenological stages, mean coefficient of variation of YDI was in the range of but that of Tn was in the range of . Therefore, the former was a better index than the latter. Of the species-phenological stage pair, coefficient of variation of YDI was 0.01 in Acer pseudo-sieboldianum - flower budding and below 0.05 in 11 pairs, whereas the YDIs over 0.40 were 4 pairs comprising of Prunus leveilleana - budding (0.51). Coefficient of variation of Tn was 0.01 in A. hirsuta - budding and below 0.05 in 8 pairs. The Tns over 0.40 were 5 pairs comprising of F. koreana - flower budding (0.66).

Understanding Galileo’s Inquiries About the Law of Inertia

The purpose of this research is to gain a better understanding of the role of abstraction and idealization in Galileo’s scientific inquiries about the law of inertia, which occupies an important position in the history of science. We argue that although the terms “abstraction” and “idealization” are variously described in the recent literature, the concepts must be adopted to highlight important epistemological problems. In particular, we illustrate the importance of abstraction and idealization for the formation of the law of inertia by establishing a distinction between two types of entities: quasi-ideal entities and idealized entities. These theoretical laws should therefore be justified, using deduction and induction, through quasi-idealized entities based on data from the everyday world.

Relationship between the Time and Duration of Flowering in Several Woody Plants in Springtime

To clarify the relationship between the timing and the duration of flowering among populations, plants, and individual flowers, the dates of flower budding, flowering and deflowering were monitored for ten woody species from March 1 to June 30, in 2005, 2006 and 2007, in temperate deciduous forests at three sites of Namsan, and individual plants from seven woody species were monitored from March 1 to May 31, in 2006. Total durations of flower budding, flowering, and deflowering varied among the plant species. Three durations of these phenological stages of Stephanandra incisa were the longest (74 days, 109 days, and 101 days, respectively), and those of Prunus serrulata var. spontanea were the shortest (7 days, 7 days, and 4 days, respectively). For each species, phenological durations varied among years but were similar among the study sites in the same year. There was no relationship between flowering time and flowering duration on the population level. On the plant level, the duration of flower budding was over 11 days in all specie; S. incisa had the longest duration (73.3 days), and that of Styrax japonica was long as well (29.0 days), while that of Prunus leveilleana was the shortest (11.3 days). The longer the mean flower budding duration, the greater the difference among the plants within a species. The flowering duration of for S. incisa was 92.2 days, while that of Forsythia koreana was 27.2 days. The flowering durations of all other species were 10～20 days. The deflowering duration was 92.0 days in S. incisa and <15 days in all other species. Differences among the plants in deflowering duration were smaller than those of the other phenological stages. In the species that flowered in April, the correlation coefficient between the flowering duration and the first flowering date was negative and significant. However, in the species that flowered in May, the correlation between flowering duration and the first flowering date was not significant. For individual plants of all species except for S. alnifolia, the earlier the flowering time, the longer the flowering duration. Differences between flowering time and flowering duration across years were significant in six species.

Growth Properties of Central and Peripheral Ramets in a Zoysia sinica`s Clone

A natural, tidal-flat clone of Zoysia sinica was studied to compare ramet growth properties in central area with in peripheral area. In new stolon and rhizome, internode length, weight, shoot height and weight, and spike production were monitored on July 25, 2004. The weight/height rate of shoot between stolon and rhizome, the shoot/stolon (or rhizome) rate in weight between central and peripheral area were not different. However, other properties differed in stolon from rhizome or between central and peripheral area significantly differed: 1. The rhizome in central area had a larger node number, shorter internode length, higher shoot height, larger shoot biomass, and higher rate of non-shoot nodes than that in peripheral area. 2. The stolon in central area had a smaller node number, shorter internode length, and smaller biomass than that in peripheral area. 3. In the same area, the rhizome had a larger node number (except for central area), shorter internode, higher shoot height, larger shoot biomass, higher rate of non-shoot node, and higher rate of node having over two shoots than the stolon. No relationship could be found between shoot size and spike production in shoot on vertical rhizome (lower node of old shoot).