Effects of water levels and soil nutrients on the growth of Iris laevigata seedlings

Iris laevigata is geographically restricted and legally protected in Korea. In this study, a mesocosm study was conducted to examine the effects of environmental conditions such as water levels and soil nutrient conditions on the growth and survival of I. laevigata seedlings. Complete submergence lowered the total number of leaves, biomass, and survival rates. A rise in soil nutrients increased overall seedling growth and increased tiller numbers via the promotion of asexual reproduction. Also, we found that the lowest measured values of seedlings are associated with the most stressful condition due to the interaction of low soil nutrients and high water levels. I. laevigata seedlings, however, are distributed in low-nutrient habitats such as floating mat, even though they do not grow well under these conditions. This study suggests that I. laevigata does not prefer low-nutrient condition but choose another benefit such as low competition. Also, the water level must be lower than the seedling height for effective growth and management of I. laevigata.This study was funded by the Korea Ministry of Environment (MOE) as public technology program based on Environmental Policy (2016000210003)

The effect of water turnover time on decomposition of wild rice (Zizania latifolia) and nutrient dynamics in an artificial wetland system

The effect of different turnover time of water on the decomposition of emergent macrophyte litter (Zizania latifolia Griseb.) was investigated using a microcosm experiment. Microcosm treatment represented different turnover time of water; 1, 2, 4 and 8 weeks. The litterbags from each treatment were retrieved every 2 weeks until the 8th week and the water simultaneously sampled with the litterbag. The dry weight and the content of major cations in the litter, and the content of available N, P, and major cations in the water were analyzed. Dry weight loss after 8 weeks indicated the lower decay rates under the condition of short turnover time of water. Major cations from the litter and the water showed that the leached amounts of K and Mg from the litter were highest in the 2nd week and dramatically decreased from the 4th week. The dynamics of available nitrogen and phosphorus in the water showed that as the water turnover time was getting longer, the amounts of available nitrogen and phosphorus remained higher. These results suggest that wetlands with longer turnover time of water could maintain the increased nitrogen and hosphorus and no outflow of the nutrients could cause eutrophication problem.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2012R1A1A2001007 and No. 2011-0028564) and by the Center for Aquatic Ecosystem Restoration (CAER) of the Eco-STAR project from the Ministry of Environment (MOE), Republic of Korea (EW33-08-12).OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000026049/2SEQ:2PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000026049ADJUST_YN:NEMP_ID:A075900DEPT_CD:719FILENAME:2014jecoenv37(1).pdfDEPT_NM:생물교육과EMAIL:[email protected]:

Antioxidant compounds from marine seaweeds and their mechanism of action

Investigation of natural products has moved toward marine environments as they are a source of many biologically active agents. The natural antioxidant compounds isolated from seaweeds provide a valuable contribution to the innovation of new drugs for chronic diseases associated with oxidative stress. While the antioxidant activity and nutritional benefits of various seaweed products are well recognized, their proper utilization as antioxidants remains at initial stages that require further investigative studies. This review provides a detailed study of isolated antioxidant compounds from seaweeds and their major mechanism of action by focusing on the reports from 2015 to 2019. The report discusses various active antioxidant compounds, including phenolics (e.g., phlorotannins), polysaccharides, and pigments with proven benefits against oxidative stress-related diseases, especially carotenoids, from the aspect of benefits to human health

Experience of an Abdominal Aortic Aneurysm in a Patient Having Crossed Ectopia with Fusion Anomaly of the Kidney

We report a case of surgically treated abdominal aortic aneurysm (AAA) in a patient having crossed ectopia with fusion anomaly of the kidney. One artery from the abdominal aorta above the aneurysm supplies the right kidney while three renal arteries (two from the aneurysm itself and one from the left common iliac artery) supply the crossed ectopic kidney. Preoperative imaging to define the arterial and collecting systems along with a detailed planning of the operation is essential to prevent ischemic renal injury as well as ureteral injury during AAA repair

Changes in vegetation and flora of abandoned paddy terraces in responses to drawdown

In order to assess the impacts of drawdown for land-use change on a Sphagnum-marsh, we compared the vegetation and flora of the wetland before and after the drawdown with focusing on the population of Sphagnum palustre L. Remarkable changes in the coverage of S. palustre and the major vegetational components of the wetland were observed. The coverage of S. palustre markedly decreased by about 75% (from approx. 247 m2 in 2011 to approx. 62 m2 in 2015) after the drawdown. Tree species such as Salix spp. extended (from about 70% to about 83% in the total coverage of the wetland), whereas herbaceous species shrunk after the drawdown. Upland-inhabiting species such as obligate plants for uplands (OBU) increased, whereas wetland-inhabiting species such as facultative plants for wetlands (FACW) and OBW decreased in terms of vegetational coverage. The total number of plant species decreased from 70 species to 62 species after the drawdown, including the disappearance of some wetland-inhabiting species from the wetland. We suggest that the attention for further studies on the abandoned paddy terraces (APTs) and effort for the management and conservation of APTs and APT-inhabiting species that are vulnerable to human-induced disturbances have to be paid more.This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the Korea government (MSIT) (NRF-2018R1A2B2002267)

Carotid Endarterectomy for Symptomatic Complete Occlusion of the Internal Carotid Artery

We described 9 consecutive patients who underwent operative carotid artery exploration with attempted carotid endarterectomy (CEA) for symptomatic internal carotid artery (ICA) occlusion. Indications for this surgery based on vascular imaging included segmental occlusion of the proximal ICA and also extensive occlusion of the distal ICA in selected patients in whom color-flow duplex ultrasound showed a poorly echogenic or anechoic thrombus with a flow void, suggestive of an acute thrombus. CEA was performed successfully to restore blood flow in all 9 patients:CEA in 5 and CEA with Fogarty thrombectomy in 4. Postoperative magnetic resonance (MR) angiography confirmed that revascularization had been successful in all 9 patients, and MR imaging displayed improved perfusion in 4 patients. Despite the lack of a generalized efficacy of surgical revascularization for symptomatic ICA occlusion, our study demonstrated that preoperative vascular imaging allows the selection of patients who may benefit from CEA

Differences in functional traits of leaf blade and culm of common reed in four habitat types

We compared the functional traits of leaf blades and culms of common reed (Phragmites australis) in four habitat types of distinguished environments such as temperature, precipitation, water characteristics, and indices related to biomass production (montane fen, MF; riparian marsh, RM; lagoon, LG; and salt marsh, SM). We also examined the relationships between the functional traits within and among populations. Four populations showed remarkable differences in the functional traits of leaf blades and culms. MF and RM had relatively tall (> 300 cm) and thick (> 8 mm) culms bearing long leaf blades (> 40 cm), whereas LG and SM had relatively shorter and thinner culms bearing shorter leaf blades than MF and RM. Some relationships between the functional traits of leaf blades and culms showed negative or not significant correlations within the population, whereas most of the relationships between the functional traits showed positive correlations particularly when all the data from four populations was included into the correlation analysis.This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the Korea government (MSIT) (NRF-2018R1A2B2002267)

Effects of different day length and wind conditions to the seedling growth performance of Phragmites australis

Background To understand shade and wind effects on seedling traits of common reed (Phragmites australis), we conducted a mesocosm experiment manipulating day length (10 h daytime a day as open canopy conditions or 6 h daytime a day as partially closed canopy conditions) and wind speed (0 m/s as windless conditions or 4 m/s as windy conditions). Results Most values of functional traits of leaf blades, culms, and biomass production of P. australis were higher under long day length. In particular, we found sole positive effects of long day length in several functional traits such as internode and leaf blade lengths and the values of above-ground dry weight (DW), rhizome DW, and total DW. Wind-induced effects on functional traits were different depending on functional traits. Wind contributed to relatively low values of chlorophyll contents, angles between leaf blades, mean culm height, and maximum culm height. In contrast, wind contributed to relatively high values of culm density and below-ground DW. Conclusions Although wind appeared to inhibit the vertical growth of P. australis through physiological and morphological changes in leaf blades, it seemed that P. australis might compensate the inhibited vertical growth with increased horizontal growth such as more numerous culms, indicating a highly adaptive characteristic of P. australis in terms of phenotypic plasticity under windy environments.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01057373) and by the National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science and ICT) (NRF-2018R1A2B2002267)