Hoduck Kang

Phenotypic and Genotypic Analysis of Rice Lesion Mimic Mutants

Lesion mimic mutant (LMM) plants display spontaneous necrotic lesions on their leaves without any pathogenic infection. Specific rice LMMs designated as spotted leaf (spl) including spl1, spl3, spl4, spl5 and spl6 are genetically known as lesion resembling disease (lrd) mutant. The inheritance patterns in the and progenies of these mutants are controlled by recessive genetic factors. Lesion development in the rice LMMs were controlled by both development stages and environmental factors. The rice LMMs exhibited higher numbers of spots under temperature than those under . Contents of chlorophyll were drastically reduced at 60 days old LMM leaves when the spot formation was severe. The levels of endogenous hydrogen peroxide were highest at 45 days old mutants but reduced at 60 days old. Transcription levels of stress related genes including thioredoxin peroxidase and protein disulfide isomerase were reduced in spotted leaves than those of non spotted leaves. It could be suggested that scavenging system against reactive oxygen species induced by either stresses or innate metabolisms may not work properly in the rice LMMs. As these rice LMMs autonomously expressed clear lesions of lrd phenotype without pathogen infection, it could be useful to understand stresses responses in plants.

Comparative phenotypic and physiological characteristics of spotted Leaf 6 (spl6) and brown leaf Spot2 (bl2) Lesion Mimic Mutants (LMM) in rice

Spontaneous necrotic lesions were found in a lesion mimic mutant brown leaf spot 2 (bl2) without pathogenic infection. Small spots in the seedlings appeared at the four leaves stage and gradually grew into a large round and black area with a gray center on the leaf surfaces. Lower growth habit and lower agronomic trait values with reduced stature, tiller, and panicle number, as well as lower yield potential were noted in the mutants relative to the trait values of the wild-type plants. Microscopic analysis revealed that mesophyll chloroplast was severely damaged or absent in the spotted area of the mutant leaves. Total chlorophyll content, hydrogen peroxide level, and catalase activity were increased at up to 45 days after germination and were dropped at 60 d in the mutant leaves. However, the total protein contents were reduced slightly with a growth period of up to 45 days and were increased at 60 days after germination. A gradual increment of the total ascorbic acid contents in the mutants were observed with advanced plant age, but increased until 45 days and dropped comparatively at 60 days in the wild-type leaves. Increased gene transcriptions of OsPDI and OsGPX1 were noted in the spotted leaves as compared to the non-spotted leaves of the mutant and wild-type leaves, whereas transcripts of OsTPX were transcribed at lower levels in the spotted leaves as compared to the non-spotted leaves. The genetic nature of the bl2 mutant indicated that the F1 plants evidenced the wild-type phenotype and that bl2 was governed by a single recessive gene.

Mixed heavy metal stress on photosynthesis, transpiration rate, and chlorophyll content in poplar hybrids

The present work aimed to study the physiological effects of mixed heavy metals, cadmium (Cd), copper (Cu), chromium (Cr), and zinc (Zn) in four poplar hybrids. Poplar hybrids were treated once with six different concentrations (0, 5, 50, 100, 200, and 500 ppm) of mixed heavy metals for a period of 3 months. The photosynthetic and transpiration rates were measured before and during treatment using an LCi–SD portable photosynthesis system whereas the photosynthetic pigments were analytically determined. According to the results obtained, poplar hybrids exhibited a decrease in chlorophyll content and carotenoids except for hybrid 1 (Eco 28) which showed an increase at 200 and 500 ppm heavy metal concentrations. The photosynthetic rate decreased with increasing heavy metal concentrations; however, an increase was observed at the highest concentration of 500 ppm at 14.54 µmol m−2 s−1. Transpiration rates were significantly affected by increased heavy metals. Hybrid 1 (Eco 28) was deduced as the hybrid that has the ability to tolerate high levels of mixed heavy metals. Among the four poplar hybrids tested, hybrid 1 (Eco 28) was the best candidate for phytoremediative experiments under greenhouse conditions. These results are valuable in understanding how various tree hybrids respond to mixed heavy metal stress, especially when using them as bio indicators for phytoremediation experiments.

Antioxidant and antibacterial behavior for sediment removed ethanol extract from sea buckthorn seed

The purpose of this study was to develop the separation process removing sediment in sea buckthorn seed ethanol extract, and to investigate the antioxidant and antibacterial behavior for the sediment removed ethanol extract (SBS extract). Sediment such as low solubility materials and oil component was simply removed by filtering after storing the crude extract containing celite for 16 h in a refrigerator at 4 °C. The SBS extract displayed strong antioxidant activity in the stability test as a function of both storage time and temperature when compared to vitamin C and BHA (Butylated hydroxyanisole) as typical antioxidant ingredients. The bactericidal ratio of the SBS extract against E. coli increased with an increase in the addition of the test agent, and this was particularly significant at concentrations greater than 1,000 μg/ml addition. The bactericidal ratio of 1,000 μg/ml SBS extract against B. subtilis, S. aureus, P. aerusinosa and E. coli was 96.4, 98.6, 91.5, and 52.2% after 2 h, and 98.2, 99.7, 99.3, and 82.6% after 4 h, respectively. These results suggest that the SBS extract may be used as a functional food, pharmaceutical, and cosmetic agent.

Inhibitory effects of sea buckthorn (Hippophae rhamnoides L.) seed on UVB-induced Photoaging in human dermal fibroblasts

Sea buckthorn (Hippophae rhamnoides L.) seed, which has very high nutraceutical, cosmetoceutical and therapeutic properties, has been widely used to treat diseases in Tibetan and Mongolian traditional medicines. In this study, we measured the antioxidant activities of the solvent-dependent SBS (Sea buckthorn seed) extracts using the DPPH and Folin-Ciocalteu assays and we investigated the efficacy of SBS in protecting skin against UVB-induced damage using cultured human dermal fibroblasts. In addition, the inhibitory effects of SBS on UVB-induced skin photoaging were examined by determining the level of Metalloproteinase (MMP)-1 and procollagen after UVB-irradiation. The antioxidant capacity of the SBSE (alcoholic) extract was significantly higher than the SBSH (hexane) and SBSW (water) extracts, as measured based on the free-radical scavenging activity and total phenolic content. SBSE was chosen as the most suitable candidate antioxidant. In human dermal fibroblasts, the cell viability of SBSE extract at doses of 2.5, 5, and 10 μg/mL was higher than the UVB-treated control. By RT-PCR and Western blot, SBSE treatment inhibited UVB-induced IL-1β expression in cultured cells. In addition, SBSE restrained UVB-induced IL-6 and COX-2 gene expression in cultured fibroblasts in a dose-dependent manner. Treatment with the SBSE extract after UVB irradiation in human dermal fibroblasts significantly reduced MMP-1 expression and increased procollagen synthesis when compared with UVB-irradiation only. In this study, SBSE was shown to increase the synthesis of procollagen, decrease the expression of MMP-1, and inhibit the production of IL-1β, IL-6, and COX-2 in UVB-irradiated human fibroblasts. These findings suggest that the SBSE extract may be a potential therapeutic agent for preventing and treating skin photoaging.

Economical synthesis of complex silicon fertilizer by unique technology using loess

Loess processed material (LPM) was produced as a substitute for silicon, clay and minerals, and applied to tomato and cucumber cultivation. LPM was produced by using a NaOH addition ratio of 30%, a reaction temperature of 1,200 °C, a reaction time of 1 h, and an alumina ball diameter of 10 mm. Treatment with a 200-fold diluted LPM solution resulted in respective increase of 7.8% and 8.3% in the weight and quantity of the tomato fruit, and a 31.7% increase in the quantity of cucumber fruit produced, when compared to the control. On the other hand, commercial silicon fertilizer (CSF), with a price that is estimated to be four times that of LPM, did not significantly increase the yield of tomato or cucumber in terms of weight or quantity. Thus, it is suggested that LPM may be used as a potential complex silicon fertilizer.

Early fertilization and absorbent treatments continuously enhanced windbreak tree growth and soil properties in the Hetao Plain of Inner Mongolia, China

Intensive and continuous management has rarely been applied in forestation designed to combat desertification, except for a few instances of fertilization and irrigation in the early stage in northern China. We hypothesized that early and discontinuous fertilization and absorbent treatments would continuously increase tree growth and improve soil properties in an arid region. In 2003 and 2004, treatments of nitrogen fertilization and absorbents were applied to Populus alba var. pyramidalis trees in an experimental windbreak site in the Hetao Plain of Inner Mongolia, China. Nevertheless, the current study results have demonstrated that early and discontinuous nitrogen fertilization and absorbent treatments continuously increased tree growth (2003–2009) without any significant improvement in soil properties in 2010. The study results suggest that early and discontinuous fertilization and absorbent practices may be sufficiently effective in forestation aimed at combating desertification in arid lands where continuous maintenance cannot be expected.

Characterization of potato vegetative MADS-Box gene,POTM1-1, in response to hormone applications

We used petiole/leaf cuttings from potato (Solanum tuberosum L) to study the effect of plant hormones on expression of the vegetative MADS-box gene,POTM1-1. Transcript levels were constitutive after treatments with exogenous ABA, GA3, methyl jasmonate (Meja), and NAA. However, transcripts amounts were reduced when tissues were treated with BA. High levels of cytokinin disrupted apical dominance and promoted axillary-bud formation. Therefore, based on these results, thePOTM1-1 gene may conceivably be involved in maintaining the proper development of vegetative axillary meristems.

Phytoextraction potential of four poplar hybrids under greenhouse conditions

ABSTRACT The present work aimed to determine the phytoextraction potential of four poplar hybrids when treated with mixed heavy metals, cadmium (Cd), chromium, (Cr), copper (Cu), and zinc (Zn) under greenhouse conditions. Poplar hybrids were treated once with six different concentrations (0, 5, 50, 100, 200, and 500 mg L−1) of mixed heavy metals over a period of 3 months, after which the plants were harvested, dried, digested using the aqua regia method and the heavy metal concentrations in the roots, stem, and leaves were determined. Individual heavy metal analysis using ICP-AES of separate heavy metals in plant parts demonstrated higher Zn accumulation in leaves, compared to all other heavy metals. As for Cd, Cr, and Cu the concentration accumulation in the leaves, stem, and roots varied across hybrids. Based on the phytoextraction potential of the four hybrids, hybrid 1 (Eco 28) was determined as a suitable candidate for phytoextraction of multi-contaminated sites, with DN 034 also showing selective phytoextraction potential in the early stages of growth.

Quality Characteristics of Radish Treated with Environmentally-friendly Red Clay-processed Materials

ABSTRACT Quality characteristics of radish treated with red clay-processed materials (RCPM) were investigated. Two different types of treatments using RCPM including a control were farm-raised in identical environments. General components, texture, nutrients, and antioxidant activities were performed. For general components analysis, total amounts of crude fat and ash were higher in radish treated with RCPM than in control. RCPM-treated radish showed higher contents of minerals (P, Mg, K, Zn, Mn, and Na) and vitamins (vitamin C, thiamin, and riboflavin) than those of control. RCPM-treated radish exhibited higher DPPH radical scavenging activities and total polyphenol contents than those of control, indicating higher antioxidant activities of radish raised by RCPM. In the textural analysis following refrigeration for 4 weeks, RCPM-treated samples showed a more stable texture and higher hardness values than those of control. Therefore, these results indicate that RCPM can be used to produce high-value radish of premium quality.