No abstract

Plant species distribution was studied on five reclaimed lands and one intertidal fiat (control) on the western coast of Korea. Nineteen soil properties were analyzed. Of these, soil moisture, el@ condu~, and levels of Na and CI had the 8reatest effect on plant distribution. The plant species were divided into four Moulps, accordin 8 to the amount of soil moisture found at their habitats. ~hin maritlmum and Typha angustah were found on the wettest sites; PhrAgmiles cornmunis, Carex scabrifolia, Suaeda japon/ca, Zoys/a s/n/ca, and 5a#com/a herbacea in places with relatively high moisture; Aster tripolium and Phacelurus latifofius in areas with medium levels of moisture; and Atriplex subco~ata, Chenopodium virgatum, and Trifolium repens in the driest areas. The species also were divided into four groups, according to the degree of soil electrical conductivity: H~hest, $. herbacea, Limonium tetragonum, Suaeda asparagoides, and $. japonica; Relatively high, A. tripolium, C. scabrifolia, R communis, Artemisia scoparia, and 7_. sinica; Relatively low, Setaria viridis, C. virgatum, Sonchus brachyotus, ,4. subcordata, Calamagrostis epigeios, and T. angustata; and Lowest, Imperata cylindrica var. koenigii, Aeschynomene indica, Lotus corniculatus var. japonicus, and T. repens. On reclaimed land, plant species were found in zones, accordin 8 to the degree of desalinization (i.e., levels of Na and CI).

Phenologicai properties of woody species were compared between two urban climates during 1997 and 1998. The study areas were Chungdam Park, Chungdam-dong, Kangnam.gu, Seoul (the urban center, 43 species) and Namhansansung Area, Sansung-ri, Joongbu-myon, Kwan~u Gun, Kyonggl Province (the urban periphery, 16 species). Distance between these sites was 13.5 km. The differences of budding, foliation, and flowering times (1997 versus 1998) were 10.9, 3.2, and 7.4 days, respectively. Species that budded and flowered earlier were strongly influenced by Nuttonson's Index (Tn) of February and March, but those with later dates were only weakly influenced. Unlike for budding and flowering times, foliation time was determined by air temperature or other factors in the leaf-growing season rather than by Tn. The Tn influence over phenology was stronger in shrubs and lianas than in trees. Phenophases in Chungdam Park appeared earlier than those in the Namhansansung area. The phenological differences between the two areas were 7.3 days in budding time, 8.3 days in foliation time, and 10.2 days in flowering time in mean values, with variations among species. Based on flowering-time data, the phenological variation between the two areas was equivalent to a 2.5 ~ latitude difference. Budding time varied the most (20 days) in Zelkova serrata, compared with only 3 days for Prunus padus. Differences in foliation time ranged from 15 days (in Alnus hirsuta and Styrax obassia) to 0 days (P. padus). Flowering time differences were largest (24 days) in Rhododendron mucronulatum and smallest (2 days) in P. padus. One can conclude that heat pollution in the urban center in Seoul severely changed phenology, and that sensitivity to that pollution differed among plant species.

To clarify the vesetation muctu~e o~ salty areas, species distribution was surva~ed accordi~ ~o t~aphy, species association, community ordination, and community dasl~icullkm. We studied one natural ticld Pat and ~te redaimed lands on the western coast of Korea. Species composition and ve~lalJem proliles changed cemspicnoudy over lime and by toflo~aphical regiom. Re~udleu ot the lime that ~ after reclamation, ~ and gb/cophytes coexisted on the sites where the leaching o~ soil salts was dow. Species a~mciation was weak amon 8 plants in the early stages on reclaimed lands. With time, however, the strenBth of species aMoci~ increased amon 8 haiophytes and glycophytes, and the two groups were linked by salt.tolerant gl,/cophytes. This resulted in a series of species associations on old reclaimed lands. In the study of plant community ordination, halophytJc communities were located on one side of axis I, glycophytic communities on the other. Several communities of salt-tolerant ~)hytes were located between the two groups. When key species were used to classify communities, we found that halophytlc and glycophytlc communities were intermixed.

Annual changes in the leaves and reproductive organs of Heloniopsis orientalis C. Tanaka (Liliaceae), a perennial evergreen herb, were studied from 1991 to 1997 in two areas of South Korea, Namhansanseong and Maranggol. The period for active growth in the leaves was from mid-March to early June. Average leaf angle was 70 ~ in early June, decreasing to 50 ~ in late October. From December until June of each following year, leaf angle was maintained a 0 ~ to horizontal. The specific leaf area (SLA) value was 185 cm2.g -1 early in the growing season, increasing to 332 cm2.g -1 in early June. By the end of October, SLA had decreased to 159 cm2.g -1, after which it increased again from March to June. Because the SLA curve had two peaks, it was inferred that H. orientalis possesses two means for survival: 1) an anti-freezing mechanism by which its leaves thicken during the winter, and 2) a reallocation of energy from old leaves to new leaves or to reproductive organs. H. orientalis flowered in a semi-enclosed state in late March. Blooming out of the bract, the front of the flower faced the ground. Growth of the peduncle ended in early June, at which point it was 60 cm long, At that time, the fruit was oriented so that the seeds were dispersed upward. Therefore one can see that H. orientalis has two physiological features that enhance long-distance seed dispersal -a rather long peduncle relative to overall plant size and an upward seed-dispersal mechanism. In the Namhansanseong area, energy from the roots and old leaves was translocated to new leaves early in the growing season (from late March to early May). However, after mid-May, energy was re-translocated from new leaves to the roots. Moreover, the leaves on flowering plants grew more slowly than on non-flowering plants because energy was translocation to the reproductive organs. Therefore, new leaf growth depended on energy stores of the roots and the hiomass of old leaves early in the growing season.