Sim-Hee Han

Composted sewage sludge can improve the physiological properties ofBetula schmidtii grown in tailings

We investigated how the application of composted sewage sludge to tailings affects the physiological response of woody plants growing on abandoned coal-mining sites. Twenty seedlings ofBetula schmidtii were transplanted to pots containing various combinations of artificial soil plus nursery soil, tailings, composted soil, or tailings amended with composted soil. Dry weights, shoot to root ratios, relative growth rates (RGR), chlorophyll content and fluorescence, and carbohydrate concentrations were assessed at the end of the experiment. Growth responses differed significantly among soil types. For example, dry weights were greatest for seedlings grown in composted soil and smallest for plants raised in pure tailings. Shoot to root ratios were higher for seedlings in composted soil compared with those in either tailings or nursery soil. Leaf chlorophyll content was twice as high for seedlings from composted soil than for those in the nursery soil or tailings; chlorophyll fluorescence (Fv/Fm) was lower for seedlings in either nursery soil or tailings than for those in composted soil. In contrast, plants grown in either nursery soil or tailings had higher starch concentrations in their stems, whereas the carbohydrate allocation of seedlings in composted soil was highest in the leaves, followed by stems and roots. Overall, the carbohydrate content was highest in the leaves, except for seedlings treated with tailings. Therefore, we believe that composted soil can improve the physiological and biochemical properties of trees growing in tailings when appropriate nutrients are supplemented.

Three-dimensional surface topography of the needle stomatal complexes of Pinus rigida and its hybrid species by complementary microscopy.

Three-dimensional surface topography of needle stomatal complexes was investigated in Pinus rigida, Pinus taeda, and their interspecific hybrid Pinus rigitaeda. The stomatal complexes of P. rigida appeared to be sunken and ca. 15 microm deep by white light scanning interferometry. Stomatal grooves were evident in P. taeda along the stomata and amounted to ca. 5 microm deep. The centers of stomata maintained the similar height to the stomatal apertures. Meanwhile, the stomatal complexes of P. rigitaeda (ca. 15 microm deep) were characterized by distinct stomatal grooves and sunken stomatal chambers. In addition, field emission scanning electron microscopy revealed the stomatal complexes of P. rigida partially filled with epicuticular waxes. It was common to observe distinct stomatal grooves and chamber-filled stomata on P. taeda needles. The stomatal complexes of P. rigitaeda had the distinct stomatal grooves and were partially filled with wax tubules and rodlets. Surface roughness measurements of stomatal complexes showed higher levels of roughness from P. rigida and P. rigitaeda than that from P. taeda. These results indicate that the hybrid species P. rigitaeda showed intermediacy in surface characteristics between the parent species, suggesting the genetic control of needle stomatal complexes in the hybrid species.

Expression of both CuZnSOD and APX in chloroplasts enhances tolerance to sulfur dioxide in transgenic sweet potato plants

We have previously reported that transgenic sweet potato (Ipomoea batatas) plants overexpressing both CuZn superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) under the control of a stress-inducible SWPA2 promoter in chloroplasts (referred to as SSA plants) showed increased resistance to methyl viologen-mediated oxidative stress and chilling. To investigate whether SSA plants show enhanced tolerance to air pollutants, they were exposed to 500ppb of sulfur dioxide (SO2). SO2 caused visible damage to the leaves of sweet potato, but damage in the leaves of non-transgenic (NT) plants was more severe than in those of SSA plants. The photosynthetic activity (Fv/Fm) of the SSA plants decreased by only 7% on the 5th day after the treatment, whereas that of NT plants severely decreased by 63% after 5days of recovery. Moreover, the chlorophyll content in the oldest leaf of NT plants decreased by 69%, whereas that of SSA plants remained at a high level. APX activity in NT plants increased about three times under an SO2 stress, and in SSA plants about five times compared to the case with no stress conditions. These results suggest that the overexpression of both CuZnSOD and APX in chloroplasts reduces the oxidative stress derived from SO2.

Long-term Climate Change Research Facility for Trees: CO 2 -Enriched Open Top Chamber System

The open-top chamber (OTC) system is designed for long term studies on the climate change impact on the major tree species and their community in Korea. In Korea Forest Research Institute (KFRI), the modified OTC system has been operating since September 2009. The OTC facility consists of six decagon chambers (10 meters in diameter by 7 meters high) with controlled gas concentration. In each chamber, a series of vertical vent pipes are installed to disperse carbon dioxide or normal air into the center of the chamber. The OTC is equipped with remote controlled computer system in order to maintain a stable and elevated concentration of carbon dioxide in the chamber throughout the experimental period. The experiment consisted of 4 treatments: two elevated levels ( and ambient ) and two controls (inside and outdoors of the OTC). Average operational rate was the lowest (94.2%) in June 2010 but increased to 98% in July 2010 and was 100% during January to December 2011. In 2010~2011, concentrations inside the OTCs reached the target programmed values, and have been maintained stable in 2011. In 2011, concentrations of 106%, 100% and 94% of target values has been recorded in control OTC, -enriched OTC and -enriched OTC, respectively. With all OTC chambers, the difference between outside and inside temperatures was the highest () at 10 am to 2 pm. Temperature difference between six OTC chambers was not detected. The relative humidity inside and outside the chambers was the same, with minor variations (0~1%). The system required the highest amount of for operation in June, and consumed 11.33 and 17.04 ton in June 2010 and 2011, respectively.

A neutral cubane with a ZnII4O4 core: tetra­benzoato­tetra­kis(μ3-hydroxydi-2-pyridylmethano­lato)tetra­zinc(II)–acetone–methanol (1/2/1)

In the title compound, [Zn4(C11H9N2O2)4(C7H5O2)4]·2(CH3)2CO·CH3OH, the tetranuclear molecule lies on a fourfold inversion axis. ZnII ions and μ3-O atoms in the cubane core occupy alternating vertices, forming two interpenetrating tetrahedra. Each ZnII ion is further coordinated by two N atoms from two different (py)2C(OH)O ligands (py is pyridyl) and one O atom from a monodentate benzoate ligand, forming a distorted octahedral environment. The (py)2C(OH)O ligand acts in an η1:η3:η1:μ3 manner, forming two five-membered ZnNCCO chelating rings with two different ZnII atoms sharing a common C—O bond, and an alkoxide-type bond to a third ZnII ion. There are four symmetry-related intramolecular O—H⋯O hydrogen bonds between the two types of ligands. In the asymmetric unit, there is a half-occupancy acetone solvent molecule and a half-occupancy methanol solvent molecule that lies on a twofold rotation axis.

Bioaccumulation and Physiological Response of Five Willows to Toxic Levels of Cadmium and Zinc

We evaluated the phytoremediation potential of Salix spp. exposed to high cadmium (Cd) and zinc (Zn) concentrations to select feasible plant materials for restoration and revegetation of mining soil contaminated by heavy metals on the basis of their Cd and Zn accumulation, Cd-Zn interaction on bioaccumulation, and the changes of photosynthetic parameters. The Cd and Zn concentrations were in the order of root > leaf > stem, regardless of the species. In the combined Cd and Zn treatment, the leaf and stem Cd concentration in all species were higher relative to Cd-alone treatment. In contrast, the Zn concentration in plant tissues when exposed to the combined Cd + Zn treatment decreased relative to the Zn-alone treatment. The translocation factor (TF) of Cd and Zn from root to leaf was generally higher compared to TF from root to stem than those in the single treatment. The Cd + Zn treatments resulted in enhanced translocation of Cd from root to aboveground tissue (synergistic), while the same treatment suppressed the Zn translocation from root to leaf and stem (antagonistic). The reduction of photosynthetic parameters in Zn alone and Cd + Zn treatments was generally higher than that of Cd-alone treatment. Among the different species, S. caprea and P. alba×glandulosa have the lowest photosynthetic reduction relative to the control. Overall, S. caprea could be a potential candidate for phytoremediation of Cd- and Zn-contaminated sites.

Changes on Initial Growth and Physiological Characteristics of Larix kaempferi and Betula costata Seedlings under Elevated Temperature

Larix kaempferi and Betula costata seedlings were grown under an elevated temperature () for four weeks to understand initial changes on physiological characteristics caused by temperature rising in connection with global warming. At the end of the treatment, growth performance, leaf pigment content, antioxidative enzyme activities and malondialdehyde (MDA) content were measured and analyzed. Relative growth rates of the height of two tree species grown under elevated temperature () were lower than those of control () and dry weights of leaves, stems and roots were also reduced at higher temperature. Particularly, the root growth reduction of two tree species increased markedly at over the study period, which increased the ratio of shoot to root. Under higher temperature, leaf pigment contents decreased, whereas anti-oxidative enzyme activities such as ascorbate peroxidase (APX) and catalase (CAT) increased as compared with the control. But MDA content was not affected by elevated temperature. In conclusion, the elevated temperature leads to root growth reduction, restriction of nutrient uptake from soil and the reduction of leaf pigment contents, which can inhibit the aboveground growth. In addition, higher temperature might act as a stress factor that causes growth reduction through the increase of energy consumption during a growth period.

Changes on Growth, Photosynthesis and Pigment contents of the Maackia amurensis and Viburnum opulus var. calvescens under Enhanced Temperature and CO 2 Concentration

The impacts of elevated temperature and were studied on the seedlings of Maackia amurensis and Viburnum opulus var. calvescens. The seedlings were grown in controlled-environment growth chambers with four combinations of temperature and treatments: + ambient (400 ppm), + elevated (800 ppm), + ambient (400 ppm), and + elevated (800 ppm). Under elevated temperature and concentration, the dry weight decreased in seedlings of M. amurensis, but increased in seedlings of V. opulus var. calvescens. In addition, the shoot to root (S/R) ratio in M. amurensis reduced but that of V. opulus var. calvescens increased under elevated concentration. The S/R ratios of two tree species increased under higher temperature. M. amurensis represented lower carboxylation efficiency under higher temperature and concentration and that of V. opulus var. calvescens showed lower values under the only higher temperature. Photosynthetic pigment content of in the leaves of M. amurensis was lower under higher concentration and higher under the increase of temperature, but that of V. V. opulus var. calvescens decreased according to the increase of temperature. Chlorophyll a/b ratios of M. amurensis and V. V. opulus var. calvescens decreased obviously with the increase of concentration and temperature, respectively. In conclusion, the growth and physiological responses under the environmental changes such as temperature and concentration depend on the tree species. Therefore, more studies are needed to predict the response of each tree species against the climate changes.

Effects of Fertilization on Physiological Parameters in American Sycamore (Platanus occidentalis) during Ozone Stress and Recovery Phase

American sycamore seedlings were grown in chambers with two different ozone concentrations (-free air and air with additional ) for 45 days. Both the control and the chambers included non-fertilized and fertilized plants. After 18 days of fumigation, seedlings were placed in a clean chamber for 27 days. Seedlings under ozone fumigation showed a significant decrease in pigment contents and photosynthetic activity, and a significant increase in lipid peroxidation. Fertilization enhanced physiological damage such as the inhibition of photosynthetic activity and the increase of lipid peroxidation under ozone fumigation. During the recovery phase, the physiological damage level of seedlings increased with ozone fumigation. In addition, physiological damage was observed in the fertilized seedlings. Superoxide dismutase (SOD) and glutathione reductase (GR) activities of -treated seedlings increased up to 33.8% and 16.3% in the fertilized plants. The increase of SOD activity was higher in the fertilized plants than in the non-fertilized plants. Negative effects of ozone treatment were observed in the biomass of the leaves and the total dry weight of the fertilized sycamore seedlings. The -treated seedlings decreased in stem, root and total dry weight, and the loss of biomass was statistically significant in the fertilized plants. In conclusion, physiological disturbance under normal nutrient conditions has an effect on growth response. In contrast, in conditions of energy shortage, although stress represents a physiological inhibition, it does not seem to affect the growth response.

Photosynthetic Inhibition in Leaves of Ailanthus altissima under O 3 Fumigation

We investigated the enect of on the photosynthetic characteristics of tree of heaven (Ailanthus altissima) that is naturalized plant and used as restoration plant for contaminated area. Two-year-old seedlings were planted to pots and transferred into closed chamber. Photosynthetic pigments contents and photosynthetic characteristics were measured every three weeks under 100 pub fumigation. There was no visible foliar injury by exposure and contents of photosynthetic pigments did not show significant differences between control and -treated seedlings. Also there were no significant differences in stomatal conductance, and water use efficiency. But photosynthetic rate and apparent quantum yield (AQY) of treated seedlings were reduced after nine weeks of ozone fumigation. In addition, the reduction of carboxylation efficiency and photorespiration were observed in the leave of treated seedlings after six weeks. In accordance with our result, carbon fixation system of A. altissima was most sensitive to stress to evaluate physiological damage induced by .