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Two populations of Tylenchorhynchus annulatus, recovered from loamy-soil rhizosphere of Zoysia japonica from Korea are described and illustrated based on integrative taxonomy, considering both morphological and molecular phylogenetic inferences from analyses of the 28S-rRNA and ITS-rRNA gene sequences. One of the populations manifested variation in species diagnostic characters; continuous lateral field incisures past the phasmid was not a constant character in all specimens examined, with some specimens manifesting fusion of inner incisures of the lateral field below the level of the phasmid and incomplete areolation of the lateral fields. The fusion of the inner incisures of the lateral field past the phasmid level is therefore a variable character within the group, and when used alone, may not be taxonomically reliable to delineate species within the genus. This is molecularly supported by genetic resemblance of the two populations with other characterized T. annulatus isolates based on D2-D3 expansion segment and ITS-rRNA. The overlapping disparities between the two populations are therefore herein treated as intraspecific variations within T. annulatus populations. Furthermore, comparison within all the published sequences of T. annulatus are made and recommendations for sequence corrections are given. Tylenchorhynchus thermophilus is characterized herein for the first time in Korea while T. annulatus and T. claytoni are molecularly confirmed.

Broad-leaved evergreen trees create urban forests for mitigation of climate warming and adsorption of particulate matter (PM). This study was performed to identify the species suitable for urban greening by examining the adsorption capacity of the evergreen species in urban areas in Korea, the adsorption points and the elemental composition of PM in the adsorbed tree. Leaf sampling was carried out four times (period of seven months from October 2017 to May 2018) and used after drying (period 28 to 37 days). Particulate matter (PM) was classified and measured according to size PM2.5 (0.2–2.5 μm), PM10 (2.5–10 μm), PM100 (10–100 μm). The total amount of PM adsorbed on the leaf surface was highest in Pinus densiflora (24.6 μg∙cm−2), followed by Quercus salicina (47.4 μg∙cm−2). The composition of PM adsorbed by P. densiflora is 4.0% PM2.5, 39.5% PM10 and 56.5% PM100, while those adsorbed by Q. salicina are evergreen at 25.7% PM2.5, 27.4% PM10 and 46.9% PM100. When the amount of PM adsorbed on the leaf was calculated by LAI, the species that adsorbed PM the most was P. densiflora, followed by Q. salicina, followed by Q. salicina in the wax layer, then P. densiflora. As a result of this study, the amount of PM adsorbed per unit area of leaves, and the amount of PM calculated by LAI, showed a simpler pattern. The hardwoods had a high adsorption rate of PM2.5. The adsorption ratio of ultra-fine PM2.5 by evergreen broad-leaved trees was greater than that of coniferous trees. Therefore, broad-leaved evergreens such as Q. salicina are considered very suitable as species for adsorbing PM in the city. PM2.5 has been shown to be adsorbed through the pores and leaves of trees, indicating that the plant plays an important role in alleviating PM in the atmosphere. As a result of analyzing the elemental components of PM accumulated on leaf leaves by scanning electron microscopy (SEM)/ energy dispersive x-ray spectroscopy (EDXS) analysis, it was composed of O, C, Si, and N, and was found to be mainly generated by human activities around the road. The results of this study provide basic data regarding the selection of evergreen species that can effectively remove aerial PM. It also highlights the importance of evergreen plants for managing PM pollution during the winter and provides insights into planning additional green infrastructure to improve urban air quality.

This study was carried out to provide preliminary information to grasp how many particulate matter (PM) which is a problem in urban area are absorbed and removed by street trees. The morphology, size and element composition of PM deposited on leaves of five street trees (Quercus glauca, Q. myrsinaefolia, Ginkgo biloba, Prunus serrulata var. spontanea, and Pinus densiflora) in Jinju city, South Korea were analyzed. The size of PM was classified into three as PM2.5 (0.2~2.5 μm), PM10 (2.5~10 μm), and PM100 (10~100 μm). The element composition of PM deposited on the leaves at the study sites mainly comprised of O, C, N, Si, and Al. The PM at industrial area and university campus was irregular and spherical shape, respectively. Total PM accumulated on the leaf surfaces of P. densiflora was 71.65 μg/cm² at industrial area and 40.66 μg/cm² at university campus, which was significantly higher than the other species. The ratio of PM2.5, PM10, and PM100 deposited on the leaves was 9.2%, 37.0%, 53.8% at industrial area and 15.8%, 27.1%, 57.1% at university campus, respectively. P. densiflora deposited the most PM2.5, PM10 and PM100 in leaf wax at the study sites, which was significantly higher than the other species.

In order to improve the transformation efficiency of zoysiagrass by increasing the frequency of callus formation from mature seeds and plant regeneration, the effect of pre-treatment with sea sand was examined. Mature zoysiagrass seeds were given 10 min of swelling time before sea sand treatment using a sea sand and seed ratio of 1 : 1 and a vortex shaking speed of 6 (1,000 rpm) for 10 min. The seeds showed increased callus formation that was more than 2 times the rate in the control. In addition, plant regeneration efficiency was also increased when embryogenic callus induced from sea sand-treated mature seeds was cultured in regeneration medium. These results will be very helpful for improving the genetic transformation frequency of zoysiagrass, a recalcitrant monocot grass. ( Key words : Callus, Pre-treatment, Sea sand, Zoysiagrass) Ⅰ. 서 론 우리나라를 중심으로 아시아 지역의 중국, 일본 등지에서 자생하는 것으로 알려져 있는 한국잔디(zoysiagrass)는 난지형 다년생 잔디로 알려져 있다(심 et al., 1998). 한국잔디는 지하경과 포복경에 의해 생육밀도를 높게 형성하는 특성이 있는 잔디이며, 또한 우리나라를 포함해 일본, 중국 등의 아시아 국가에서는 잔디 우점 초지를 이용하여 가축에게 방목용 초지로 활용한 예가 보고되고 있다(Dhital et al., 2010). 한국잔디로 조성된 초지는 목초생산성이 높을 뿐만 아니라 단위면적당 많은 수의 가축을 방목하는 고밀도의 방목강도에도 잘 견디는 특성이 있는 것으로 알려져 있다(Ito and Takatsuki, 2005). 잔디는 또한 다른 대부분의 C

This study was performed to determine the effects of silicon on zoysiagrass after the application of drought stress. The daily amount of water or scilicon solution was 150 ml per a pot. For 14 days, plants were treated with 0.1 and 1.0 mM silicon (Si) and with distilled water for control and the drought only-treatment. Afterward, the plants in Si and drought treatment were exposed to a 21-day under drought stress condition but the plants in control received water. The results indicated that the growth and the moisture and chlorophyll contents decreased in the drought only-treatment and 0.1 mM Si compared to the control. However, 1.0 mM Si showed an increase in the growth with a significant increase of water and chlorophyll contents. The MDA and H₂O₂ concentrations and electrolyte leakage decreased, while the radical scavenging capacity increased in 1.0 mM Si. 1.0 mM Si showed little to no differences in the growth and no differences in water and chlorophyll contents, electrolyte leakage, MDA and H₂O₂ concentrations and antioxidant capacity compared to the control. These results suggested that application of silicon is useful for drought tolerance improvement of zoysiagrass under drought that is occurring in turf fields.

화본과 식물 중 잔디는 각종 환경에 적응력이 강한 편으 로 척박한 토양을 피복할 목적으로 많이 이용되고 있으며 (Berard, 1973; Rim et al., 2003), 생활수준과 녹색환경에 대 한 관심이 높아지면서 이용범위가 더욱 다양해지고 사용 면적도 확대되고 있다(Chio and Yang, 2006). 최근 잔디 생산자들은 과학적인 잔디관리에 대한 관심이 높아지면서 잔디 생육환경(Choi et al., 1993a; Chio et al., 1993b; Lee et al., 1990)에 대한 조사와 시비방법개선(Hwang et al., 1999; Kim, 1990; Kim et al., 2003)을 통해 품질 좋 은 잔디를 얻고자 노력하고 있다. 그럼에도 불구하고 잔디 생육환경에 있어 큰 영향을 미치는 잔디 비배관리의 과학 화는 아직 부족한 상태이다(Kim et al., 2008). 잔디의 생육과 품질은 토양환경과 같은 생육환경과 병해 충 방제나 시비관리와 같은 관리기술에 따라 결정된다 (Carrow, 1980). 따라서 잔디의 건전한 생육을 위해 적절한 잔디 관리 기술이 필요한 실정이다(Kim et al., 2003). 특히 시비관리는 잔디에 영양원을 공급하는 것으로서 생육과 품 질을 결정하는데 대단히 중요한 역할을 한다고 볼 수 있다 (Kim et al., 2003). 질소는 잔디 시비에 있어서 중요한 영양분이며, 다른 필 수원소에 비해 더 많이 요구된다(Joo et al., 1997). 잔디의 생육은 질소비료의 시비 수준에 따라 큰 영향을 받으며, 질 소비료 시비량에 비례하여 잔디 조직 속에 질소함량이 높 아진다(Shim, 1989). ABSTRACT. This study was conducted to find out the optimum nitrogen fertilization for production of good quality and high yield zoysiagrass (Zoysia japonica Steud.), the changes in chemical properties of soil in pot and field experiments treated with different levels of nitrogen fertilizer. In pot experiment, the fresh and dry weights of shoots and stolons and the number of shoots increased as nitrogen levels increased, and showed no significant between 24 and 48 kg N 10 a. In field experiment, the shoot length, fresh and dry weights of shoots, roots and stolons, the number of shoots and total stolons length linearly increased as affected by increased nitrogen application, and were not significantly different between 24 and 32 kg N 10 a. In both experiments, pH and exchangeable cations (Ca and Mg) in soil decreased as the rate of nitrogen application increased. As a results, chemical properties of soil were more deteriorated in the plots of higher nitrogen fertilizer rate. Thus, these results demonstrated that the nitrogen fertilizer rate for maximum growth of zoysiagrass was 24 kg N 10 a in consideration of growth and soil condition.

In this study, 241 zoysiagrasses (Zoysia spp.) accessions naturally growing in South Korea were collected in order to investigate the seed morphological traits. One of the goals of this study was to identify the morphological characteristics and variations of zoysiagrass seed. For the 241 zoysiagrasses accessions collected, a total of 41% (99 accessions) was interspecific hybrid zoysia, which showed various types of seed variations different from zoysiagrass species. Most of these hybrids zoysiagrasses were classified into Z. sinica type and Z. japonica type. Group I and II included Z. sinica type, this group showed 30.1 and 17.5 in number of seed per spike and 4.6 and 5.2 mm in seed length. Group III and IV included Z. japonica type, this group showed 59.2 and 45.8 in number of seed per spike and 3.3 and 3.4 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the interspecific hybridization which confirmed that genetic variation from level of gene flow between the species.

It is important for genetic resources to collect and identify in native medium-leaf type zoysiagrasses species distributed in Korea. This study was conducted to investigate morphological variation and characteristics of native medium-leaf type zoysiagrasses from coastal, island and inland regions in Korea. Among them, 75 collected lines was confirmed to have various morphological variations, accessions were classified into 2 main based group coastal and inland regions by morphological characteristics and site environment. Group I included Z. sinica type, this group showed 3.7 mm in leaf width, 29 in number of seed per spikelet and 5.0 mm in seed length. Group II included Z. japonica type, this group showed 4.4 mm in leaf width, 42 in number of seed per spikelet and 3.5 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the introgressive hybridization between species which confirmed that cross-pollination is possible due to protogyny. The individuals showing variations should be preserved as valuable genetic resources for the expansion of variations in zoysiagrasses, and the results of this investigation on the genetic resources collected will be highly valuable in breeding high quality turfgrass.

After 400 mM of NaCl treatment, 0.1 and 1.0 mM of silicon (Si) were added to Kentucky bluegrass, ‘Perfection’ and ‘Midnight,’ to identify the effect of Si on the antioxidant defense mechanisms and inorganic ions as a parameter in the salt stress on grass. Compared to the control, the NaCl treatment caused a significant decrease in the shoot length and the fresh and dry weight of shoot and root of the both types of Kentucky bluegrass. Adding Si after the NaCl treatment increased the growth and dry and fresh weight of shoot and root in the grass. In both types, the Na + concentration significantly increased after the NaCl-only treatment compared to control and decreased dramatically after 0.1 and 1.0 mM Si were added following the NaCl treatment compared to the NaCl-only treatment. K + and Si concentrations remarkably increased in the shoot and root when Si was added after NaCl treatment. There was a significant reduction in the oxygen radical absorption capacity and the total phenolic compounds in the both types. Compared to the NaCl-only treatment, higher glutathione and lower proline concentrations were observed in the plant treated with Si after NaCl treatment. These results suggest that, even though Si is not generally classified as ‘essential element’, Si may have a significant involvement in the antioxidant defense mechanisms and inorganic ions in the salt stress on grass. Key words: diphenyl-1-picrylhydrazyl (DPPH), total phenolic concentration, proline, salt stress.

This study investigated the effect of exogenous hydrogen peroxide (H₂O₂) on the antioxidant responses and growth of warm-season turfgrass (Zoysia japonica Steud.) and cool-season turfgrass (Poa pratensis L.) subjected to drought stress. Compared with control plants that were not pretreated with H₂O₂, plants pretreated with H₂O₂ had significantly greater fresh and dry weights of shoots and roots, and increased water content. H₂O₂ pretreatments before drought stress significantly decreased the concentrations of malondialdehyde and H₂O₂. DPPH radical scavenging and glutathione activities were significantly increased. The responsive activities of the antioxidant enzymes superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase were also significantly enhanced. Our results suggest that exogenous H₂O₂ could improve the growth of warm-season and cool-season turfgrass under drought stress by increasing the activity of their antioxidant enzymes, while decreasing lipid peroxidation.

The study was conducted to clarify the effects of silicon on the salt-sensitive ‘Perfection’ and ‘Midnight’ Kentucky bluegrass (Poa pratensis L.). The 400 mM NaCl treatment reduced shoot length, fresh and dry weight of shoot and root as well as relative water content and chlorophyll and carotenoid content in both cultivars. The NaCl caused an increase in electrolyte leakage, malondialdehyde concentration and H2O2 in both cultivars. This physiological interferences and visually noticeable disturbances in Kentucky bluegrass were significantly alleviated by the addition of silicon after salt stress. In ‘Perfection’, for example, 0.1 mM silicon application after NaCl treatment significantly increased in the shoot length by 48%, the fresh weight of the shoot by 72%, the relative water content by 61%, and the total chlorophyll content by 57%. Compared to the NaCl-only treatment, significant reduction in the electrolyte leakage and the concentration of malondialdehyde and H2O2 were observed in silicon treatment.