• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.357-364
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• 1999

This study measures the influence of grass cover on water use and shoot growth of apple trees growing under different soil water regimes in temperate climate conditions and evaluates monthly crop coefficients of such conditions during four months of the growing season in 1995. To do so, double pot lysimeter experiments of 3-year-old Fuji' apple (Males domestica Borkh.) trees under a transparent rain shield were designed and installed. Trees were triplicate under three soil water regimes: (A) drip-irrigation at -50 kPa of soil matric potential (IR50). (B) drip-irrigation at -80 kPa of soil matric potential (IR80), and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, two soil surface conditions were tested: the soil surface bare, and covered with turf grasses. Mean monthly water use increased with increasing soil matric potential for drip irrigation and was greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees ($r^2$ values of $0.953^{***}$ for turf grass-covered system and of $0.862^{***}$ for bare surface system), while those obtained in the WT45 treatment fluctuated, Duncan's multiple range tests for shoot growth showed that grass-covered IR50 was most favorable to apple trees. while bare surface waterlogged situation was most adverse at least in part due to a lack of oxygen in the root zone. Mid-season leaf Kjeldahl-N was higher in drip-irrigated apple trees than in WT45 trees, while soil Kjeldahl-N was not different irrespective of treatments.

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.309-315
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• 2011

Rice grown in anaerobic waterlogged soil accumulates ammonium as a major source of nitrogen (N). We have compared the physiological symptoms of rice seedlings subjected to N-starvation stress with those receiving sufficient N, based on measurements of shoot/root length and weight and an analysis of protein expression patterns. N starvation marginally increased root growth but notably decreased shoot biomass. N uptake was reduced by >50% in the roots and shoots of N-starved seedlings. To better understand the mechanism of N starvation in rice, we performed a comparative proteome analysis of proteins isolated from rice leaves. Twenty-five differentially expressed proteins were analyzed by matrixassisted laser desorption/ionization time-of-flight (TOF) mass spectrometry and electron spray ionization quadrupole TOF. Functional analysis of the N-starvation response proteins suggested their involvement in protein synthesis and fate, metabolism, and defense. These results indicate that these proteins may play important roles in regulating the plant's complex adaptation responses for N use during N starvation. The proteins may be useful for further characterization of protein function in plant N nutrition.

• Journal of Wetlands Research
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• v.11 no.1
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• pp.39-48
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• 2009

Wetland plants are an important component for wetland design and construction because they determine functions of wetlands through interactions with the abiotic environment such as wetland soil and hydrology as well as with other wetland organisms. In this study, germination experiments with soils from a natural wetland that contain seeds of wetland plants were conducted in wetland mesocosms to investigate the applicability of natural wetland soils for introducing and establishing wetland plants into constructed wetlands. Seven species were germinated in the experiment, with two new species that were not found in the field survey of wetland plants in the West Nakdong River area, Korea. The number of plant individuals germinated in submerged conditions (15 individuals) was much greater than that in waterlogged conditions (2 individuals). In experiments in which soils from a natural wetland and a wetland construction site were mixed at different ratios, the largest number of plant individuals was observed in the condition with 100% natural wetland soil. The highest growth was observed at 50% natural wetland soil for Hydrilla verticillata and 100% for Ceratophyllum demersum. These results suggest that 1:1 mixture of soils from natural wetland wetlands and wetland construction sites would provide an appropriate condition for secure establishment of submerged plants in constructed wetlands.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.142-147
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• 2009

The effects of short-term waterlogging on physiological responses, fatty acid compositions and yield components of rapeseed at both the vegetative growth and the reproductive growth stages were assessed in this study. Waterlogged plants were treated for a period of 10 days at the vegetative growth stage and 4 days at the reproductive growth stage. The results show that photosynthesis and stomatal conductance at both the vegetative growth and the reproductive growth stage were significantly reduced during the waterlogging period and after the recovery period. When the plants were removed from water, photosynthesis and stomatal conductance progressively restored similar values to those of control plants within $2{\sim}3$ days. Fatty acid compositions were unaffected by waterlogging treatment. However, yield components (pod number and pod length) of the waterlogged treated plants at the reproductive growth stage were significantly reduced. These results suggest that short-term waterlogging may thus influence oilseed yield component.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.255-261
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• 2016

The present study was conducted to characterize physiological responses of aerial part according to soil water stresses in 'Mihong' peach trees. Discolorations, wilting and falling of leaves were observed in chronological order as response for waterlogging and no irrigation and the phenomena started from basal to end of shoots. Shoot growth in elongation and thickness decreased and fallen leaves were severe in waterlogged trees. Function of water uptake by roots and photosynthesis and leaf respiration decreased by waterlogging. Leaf chlorophyll contents decreased in both treatments. In waterlogging treatment, decrease of chlorophyll was observed in normal leaves with waterlogging using light microscopy. Starch content was lower in both treatment and carbohydrate content was lower in root with waterlogging. These results demonstrated that waterlogging weakened the function of soil water uptake and movement and decreased photosynthesis and fallen leaves. Finally the peach trees would wither or suffer low temperature damage through the shortage of reserve accumulations. We suggested that waterlogging damage in peach trees could be reduced to take notice of irrigation and install drainage facility to improve soil condition.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.327-332
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• 1986

Laboratory experiments were conducted to estimate extractable nitrogen by buffer phosphate solution of pH 7. A series of experiment soils were a) Sandy soil applied with compost, lime, and Wallastonite every years for 32 years. b) Sandy soils with and without waterlogging for 70 days before transplanting. c) Normal soils produced high and common yields. The results were summarized as follows: 1. Extractable organic nitrogen by pH 7 phosphate buffer solution was increased in order of NPK + compost > NPK > NPK + compost + lime + Wollast-onite > NPK + compost + lime > NPK + wollastonite > no fertilizer plot. 2. Extractable organic nitrogens at plots of NPK and NPK + compost were decreased as the growth stage processed regardless of tretments. 3. In case of normal soils having high and common yields the content of total N, organic matter and $NH_4-N$ were increased in high productive soil, while, only $NO_3-N$ content was increased in common productive soil. Especially, there was a highly positive correlation between extractable total nitrogen and $NH_4-N$ content submerged for 4 weeks under incubated condition. 4. Organic nitrogen content of soil was increased on the condition of non-waterlogging, however, nitrogen uptake by rice plant was increased in waterlogged paddy. 5. The content of extractable total nitrogen increased in the order of normal soil, sandy soil, unmatured soil, saline soil, and estimation of optimum nitrogen rates by extracted organic nitrogen was in order of saline soil, unmatured soil, sandy soil, normal soil.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.7-11
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• 1968

A high and low productive paddy soils were waterlogged at $30{\pm}2^{\circ}C$ for 35 days in the laboratory. The relation of pH and Eh changes, ferrous iron and ammonium nitrogen of these soils was studied. The results obtained are summarized as follows: 1. pH value has been increased for 13 days of incubation and after 13 th day, they maintain their pH value without marked change, and pH value of high productive soil is higher than that of low productive soil by 0.25-0.30. 2. Eh value has been decreased for 10 days of incubation and then they also maintain their Eh value without marked change. Eh value of high productive soil is lower than that of low productive soil by 50-70 mv. 3. In both soils ferrous iron formed under submerged condition increased steeply within 4-5 days of incubation and after that they maintain their content without marked change. The $Fe^{+{+}}$ content of high productive soil is higher than low productive soil by 1.0 mg/1 gr soil. 4. $NH_4{^{-N}}$ formed under submerged condition rapidly increased in the early period of incubation and after that decreased to a certain level and maintain their content, but its content of high productive soil is higher than that of low productive soil by $20-25{\gamma}/1\;gr$ at the early stage and lower at the latter period by $10-15{\gamma}/1\;gr$.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.336-342
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• 2010

In a pot experiment, we studied the effect of nitrification inhibition on Fe reduction and P release in paddy soil and growth and nutrient uptake of rice plant. Recommended level of fertilizers, 6 kg N, 5 kg $P_2O_5$ and 4 kg $K_2O$ per 10a, were applied, and for N fertilizer urea, urea+N-serve, and $KNO_3$ were included. Four 30-day-old seedlings were transplanted in a waterlogged 9 L pot filled with Yuga series soil, and 3 pots were prepared in each N fertilizer treatment. Changes of soil redox potential and concentration of ${NH_4}^-$, ${NO_3}^-$, $Fe^{2+}$ and ${PO_4}^{3-}$ in soil solution at 10 cm depth were monitored, and also the growth and nutrient uptake of rice plants were measured. Concentration of ${NH_4}^+$ in soil solution was highest in urea+N-serve treatment, and followed by urea and $KNO_3$ treatments. Addition of N-serve could effectively inhibit nitrification in the soil. In the treatment of $KNO_3$, relatively higher ${NO_3}^-$ concentration was found at 10 cm depth soil. In urea+N-serve treatment redox potential was lower than -100 mV during the experiment, but in the treatment of $KNO_3$ the potential was maintained above 0 mV until ${NO_3}^-$ remaining in soil solution. Reduction of Fe(III) and solubilization of P were highly correlated with redox potential changes in the three N fertilizer treatments. Concentrations of Fe(II) and ${PO_4}^{3-}$ in soil solution at 10 cm depth were much higher in the urea+N-serve treatment. The most vigorous rice seedling growth was found in the urea treatment. Although the availability of N and P in soil was enhanced in the urea+N-serve treatment through the suppression of nitrification, excessive solubilization of Fe could limit the growth of rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.77-82
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• 1998

Aerenchyma development in rice (Oryza sativa L.) roots is quite important for adaptation to waterlogged or reduced soil conditions. Anatomical observations were carried out to clarify the development of schizogenous and lysigenous aerenchyma in elongating crown roots of rice. The crown roots of 3rd and 4th phytomer were taken from rice plants of the 8th leaf stage grown by hydroponic culture. The schizogenous intercellular spaces in the cortex of crown root tip were observed using a light microscope with semi ultra-thin sections and the lysigenous aerenchyma in mature tissue of crown root were observed using a cryo scanning electron microscope (cryo-SEM) with freezing fracture method. The schizogenous intercellular spaces in the root tip exist obviously in the middle portion of cortical cell layers close to the root-root cap junction, but not in root cap, stele and outer cell layers of cortex. The air spaces were formed at the junction of four neighbouring cells of inner cortex in the transverse sections, and between longitudinal cell layer connected along the root axis. Although many of those spaces were filled with liquid, some spaces seem to exist as air spaces. The lysigenous aerenchyma in the cortex, which hardly filled with liquid, emerged at 3-4 cm segment from the root tip and increased toward the basal region of root axis. The developing process of lysigenous aerenchyma was primarily separation of a radial row of cells caused by the shrinking and collapsing of cortical cells and then formation of septa along the radial cell rows by the fusion of cell wall with each other. These results suggest that the schizogenous and lysigenous aerenchyma playa role as a passage for the movement of oxygen into the root tip region where oxygen is required for respiration.