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)

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)

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)

Assessment of genetic diversity and distance of three Cicuta virosa populations in South Korea

Cicuta virosa L. (Apiaceae) is a perennial emergent plant designated as an endangered species in South Korea. Accordingto the former records, only four natural habitats remain in South Korea. A former study suggested that three of four popu-lations (Pyeongchang: PC, Hoengseong: HS, Gunsan: GS) would be classified as different ecotypes based on their differentmorphological characteristics and life cycle under different environmental conditions. To evaluate this suggestion, weestimated genetic diversity in each population and distance among three populations by random amplification of poly-morphic DNA. Seven random primers generated a total of 61 different banding positions, 36 (59%) of them were polymor-phic. Neis gene diversity and the Shannon diversity index increased in the order of PC < HS < GS, which is the same orderof population size. In the two-dimensional (2D) plot of first two principal components in principal component analysiswith the presence of 61 loci, individuals could be grouped as three populations easily (proportion of variance = 0.6125).Neis genetic distance for the three populations showed the same tendency with the geographical distance within threepopulations. And it is also similar to the result of discriminant analysis with the morphological or life-cycle factors fromthe previous study. From the results, we concluded that three different populations of C. virosa should be classified asecotypes based on not only morphology and phenology but genetic differences in terms of diversity and distance as well.This study was supported by the Korea Ministry of En-vironment as The Eco-Innovation project, 416-111-010and by the Center for Aquatic Ecosystem Restoration(CAER) of the Eco-STAR project from the Ministry of En-vironment, Republic of Korea (MOE;08-III-12).OAIID:oai:osos.snu.ac.kr:snu2013-01/102/0000026049/7SEQ:7PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:0000026049ADJUST_YN:NEMP_ID:A075900DEPT_CD:719CITE_RATE:0FILENAME:07_ecoenv_36(3)_jae geun kim_(205-210).pdfDEPT_NM:생물교육과EMAIL:[email protected]:

Arp2/3 Complex Regulates Asymmetric Division and Cytokinesis in Mouse Oocytes

Mammalian oocyte meiotic maturation involves oocyte polarization and a unique asymmetric division, but until now, the underlying mechanisms have been poorly understood. Arp2/3 complex has been shown to regulate actin nucleation and is widely involved in a diverse range of processes such as cell locomotion, phagocytosis and the establishment of cell polarity. Whether Arp2/3 complex participates in oocyte polarization and asymmetric division is unknown. The present study investigated the expression and functions of Arp2/3 complex during mouse oocyte meiotic maturation. Immunofluorescent staining showed that the Arp2/3 complex was restricted to the cortex, with a thickened cap above the meiotic apparatus, and that this localization pattern was depended on actin. Disruption of Arp2/3 complex by a newly-found specific inhibitor CK666, as well as by Arpc2 and Arpc3 RNAi, resulted in a range of effects. These included the failure of asymmetric division, spindle migration, and the formation and completion of oocyte cytokinesis. The formation of the actin cap and cortical granule-free domain (CGFD) was also disrupted, which further confirmed the disruption of spindle migration. Our data suggest that the Arp2/3 complex probably regulates oocyte polarization through its effect on spindle migration, asymmetric division and cytokinesis during mouse oocyte meiotic maturation

Age-dependent resistance of a perennial herb, Aristolochia contorta against specialist and generalist leaf-chewing herbivores

Plants need to balance investments in growth and defense throughout their life to increase their fitness. To optimize fitness, levels of defense against herbivores in perennial plants may vary according to plant age and season. However, secondary plant metabolites often have a detrimental effect on generalist herbivores, while many specialists have developed resistance to them. Therefore, varying levels of defensive secondary metabolites depending on plant age and season may have different effects on the performance of specialist and generalist herbivores colonizing the same host plants. In this study, we analyzed concentrations of defensive secondary metabolites (aristolochic acids) and the nutritional value (C/N ratios) of 1st-, 2nd- and 3rd-year Aristolochia contorta in July (the middle of growing season) and September (the end of growing season). We further assessed their effects on the performances of the specialist herbivore Sericinus montela (Lepidoptera: Papilionidae) and the generalist herbivore Spodoptera exigua (Lepidoptera: Noctuidae). Leaves of 1st-year A. contorta contained significantly higher concentrations of aristolochic acids than those of older plants, with concentrations tending to decrease over the first-year season. Therefore, when first year leaves were fed in July, all larvae of S. exigua died and S. montela showed the lowest growth rate compared to older leaves fed in July. However, the nutritional quality of A. contorta leaves was lower in September than July irrespective of plant age, which was reflected in lower larval performance of both herbivores in September. These results suggest that A. contorta invests in the chemical defenses of leaves especially at a young age, while the low nutritional value of leaves seems to limit the performance of leaf-chewing herbivores at the end of the season, regardless of plant age

Auxin mediates the touch-induced mechanical stimulation of adventitious root formation under windy conditions in Brachypodium distachyon

Abstract Background It is widely perceived that mechanical or thigmomorphogenic stimuli, such as rubbing and bending by passing animals, wind, raindrop, and flooding, broadly influence plant growth and developmental patterning. In particular, wind-driven mechanical stimulation is known to induce the incidence of radial expansion and shorter and stockier statue. Wind stimulation also affects the adaptive propagation of the root system in various plant species. However, it is unknown how plants sense and transmit the wind-derived mechanical signals to launch appropriate responses, leading to the wind-adaptive root growth. Results Here, we found that Brachypodium distachyon, a model grass widely used for studies on bioenergy crops and cereals, efficiently adapts to wind-mediated lodging stress by forming adventitious roots (ARs) from nonroot tissues. Experimental dissection of wind stimuli revealed that not bending of the mesocotyls but physical contact of the leaf nodes with soil particles triggers the transcriptional induction of a group of potential auxin-responsive genes encoding WUSCHEL RELATED HOMEOBOX and LATERAL ORGAN BOUNDARIES DOMAIN transcription factors, which are likely to be involved in the induction of AR formation. Conclusions Our findings would contribute to further understanding molecular mechanisms governing the initiation and development of ARs, which will be applicable to crop agriculture in extreme wind climates