• Journal of Ecology and Environment
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• v.33 no.2
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• pp.121-131
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• 2010

Betula platyphylla var. japonica and Betula ermanii segregate vertically at an elevation of approximately 1,850 m on Mt. Neko in Nagano Prefecture, Japan. B. platyphylla var. japonica and B. ermanii were the dominant species below and above this altitude, at which the mean-annual and growing-season air temperatures were $4^{\circ}C$ and $14.1^{\circ}C$, respectively. Based on a modification of Kira's warmth index which employs cumulative temperature represented as $^{\circ}C$ day, leaf unfolding in both species was observed to be initiated at $58^{\circ}C$ day and $169^{\circ}C$ day, respectively. In 1996, leaf unfolding was initiated on 18 May in B. platyphylla var. japonica (+/-6 days) and on 5 June in B. ermanii (+/-8 days), shortly after the last frost which occurred on 5 May 1995 above 1,850 m; below this elevation there was no risk of frost at the time. At elevations above 1,850 m, the unfolded leaves of B. platyphylla were damaged by late frost, while B. ermanii escaped injury because the leaves were still protected by winter buds. The optimum temperature for seed germination in both B. platyphylla and B. ermanii was $30^{\circ}C$. Temperature alternation from 10 to $30^{\circ}C$ and moist storage of seeds at $4^{\circ}C$ (stratification) prior to incubation increased germination rates in both species. The seedlings of B. ermanii had a greater survival rates than those of B. platyphylla var. japonica when planted above 1,850 m. Comparisons of the timing of leaf unfolding and the latest frost at a site appeared to be the main factors affecting the vertical distribution of these species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.195-201
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• 2001

Sowing date experiments were carried out by employing a rice variety "Kwanganbyeo" in both field and phytotron with natural daylength. In phytotron, temperatures were controlled at daily mean of 21$^{\circ}C$ and 24$^{\circ}C$. The responses of final leaf number and beading date were analyzed in relation to daylength during photo-sensitive period (PSP). Based on the component models predicting the final leaf number and leaf appearance rate, a rice phenology model was established and verified. Days from sowing to flowering (DSF) were shortened and final number of leaves (FNL) increased as sowing dates were delayed from 25 April to 5 June in field and phytotron. The increased leaf appearance rate (LAR) and the reduced FNL, respectively, due to the higher temperature and the shorter daylength in delayed sowings in the field brought about greater shortening of DSF than in the phytotron where only FNL was reduced by shorter daylength in delayed sewings. FNL showed very close relationship with the average daylength during PSP of six-leaf stage to panicle initiation, being well fitted to the following rational function ($R^2$=0.98):(equation omitted) where D is daylength and a, b, and c are the constants that were estimated as 14.694, -0.992, and -0.068 in Kwanganbyeo, respectively. The rice phonology model, which was composed of two component models for LAR and FNL, predicted DSF very accurately. The differences between the observed and predicted DSF was less than two days in the sewing date field experiments in 1999 and 2000 of which data were not used for the model construction.struction.

• Korean Journal of Remote Sensing
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• v.31 no.1
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• pp.11-20
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• 2015

This study aimed to investigate the canopy growth conditions and the accuracy of phenological stages of paddy rice using ground-based remote sensing data. Plant growth variables including Leaf Area Index (LAI) and canopy reflectance of paddy rice were measured at the experimental fields of Chonnam National University, Gwangju, Republic of Korea during the crop seasons of 2011, 2012, and 2013. LAI values were also determined based on correlations with Vegetation Indices (VIs) obtained from the canopy reflectance. Three phenological stages (tillering, booting, and grain filling) of paddy rice could be identified using VIs and a spatial index (NIR versus red). We found that exponential relationships could be applied between LAI and the VIs of interest. This information, as well as the relationships between LAI and VIs obtained in the present study, could be used to estimate and monitor the relative growth and development of rice canopies during the growing season.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.319-331
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• 2013

Recent climate change, which is mostly ascribed to anthropogenic activities, is believed to be a major factor leading to biodiversity decreases and ecosystem service deteriorations. I have reviewed recent studies on climate change effects for many ecological processes involved with plants, in order to improve our understanding of the nature of ecological complexity. Plants in general have better growth and productivity under high levels of $CO_2$, although the long term effects of such $CO_2$ fertilizers are still controversial. Over the last 30 years, the Earth has been greening, particularly at higher latitudes of the Northern Hemisphere, perhaps due to a relaxation of climatic constraints. Human appropriation of net primary productivity (NPP), which corresponds up to 1/3 of global NPP, is ultimately responsible for climate change and biodiversity decreases. Climate change causes phenological variations in plants, especially in regards to spring flowering and fall leaf coloring. Many plants migrate polewards and towards higher altitudes to seek more appropriate climates. On the other hand, tree mortality and population declines have recently been reported in many continents. Landscape disturbance not only hinders the plant migration, but also makes it difficult to predict the plants' potential habitats. Plant and animal population declines, as well as local extinctions, are largely due to the disruption of species interactions through temporal mismatching. Temperature and $CO_2$ increase rates in Korea are higher than global means. The degree of landscape disturbances is also relatively high. Furthermore, long-term data on individual species responses and species interactions are lacking or quite limited in Korea. This review emphasizes the complex nature of species responses to climate change at both global and local scales. In order to keep pace with the direction and speed of climate change, it is urgently necessary to observe and analyze the patterns of phenology, migration, and trophic interactions of plants and animals in Korea's landscape.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.95-101
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• 2014

This study was conducted to analyze the pattern of growth and phenological characteristics of Mankyua chejuense B.-Y. Sun, M.H. Kim & C.H. Kim, which belong to the Ophioglossaceae family. M. chejuense asexually reproduced using rhizomes, and a clone of the species grew up to 52 cm based on root growth and new leaves was produced from rhizomes. The development of leaves were divided into four stages; leaf emergence-separation and growth of leaf-sporophyll maturation-senescence. Most leaves emerged in July and August with high temperatures and precipitation and most leaves reached full expansion during September-October and died during April-May next year. The life span of leave was 10 months, from July to April, and the start of leaf senescence varied depending on the habitat environment and this might result from micro environmental differences among the habitats.

• Korean Journal of Environment and Ecology
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• v.24 no.1
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• pp.62-68
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• 2010

This study was conducted to find out how the germination, phenology and leaf morphology of Phytolacca insularis(endemic species of Korea) and P. americana(alien species) react to the global warming situation. Seed and seedlings of two species were sampled and placed under two separate conditions for the experiment. One of the seed and seedlings was treated in the glass house with control(ambient $CO_2$+ambient temperature, (AC-AT), and the other with control(elevated $CO_2$+ elevated temperature, EC-ET), over the period of one year, 2008-2009. The germination rate of two species was fast, and the time of their germination started early, when they were treated at EC-ET than at AC-AT. Furthermore, the germination rate of Phytolacca insularis(endemic species of Korea) was found to be comparatively lower than that of P. americana(alien species). The former showed only vegetative growth whereas the latter showed both vegetative growth and reproductive growth in one year period. The more $CO_2$ degree and temperature increased, phenological responses of two species, including leaf growth, the formation of flower stems, flowering, and fruit maturing, became much faster, and the time of their leaf-yellowing was delayed. The lamina length of P. insularis was not significantly affected by elevated $CO_2$ and temperature. The lamina length of P. americana, on the other hand, became longer at EC-ET than at AC-AT, but the leaf width of both species increased at EC-ET. As for the number of leaves, both species showed no difference. Finally, the ratio of the leaf area of P. insularis was high at AC-AT, but P. americana was high at EC-ET. These results indicate that P. americana, aliens species, reacts more sensitively to global warming than P. insularis, endemic species, does.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.23-30
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• 2008

The relationship between three phenological parameters and somatic embryogenesis was investigated during a two-year period. Staminodes and petals from six hybrids and two clones as controls were sowed on three distinct primary callus growth media. Flowering level, fructification level, and leaf thrusts rhythm as phenological parameters were measured simultaneously during the weekly harvest of flower buds. Mean and coefficient of variation of the measured parameters highlighted stable phenological phases. The relationship between phenological parameters and somatic embryogenesis was investigated first by comparing the variation of somatic embryogenesis and that of the phenological parameters, and second by using Pearson's linear correlation. Except for the fructification level in both control clones the first year, the other parameters recorded stable phenological phases, regardless of the genotype and year. Favorable and unfavorable phases for the somatic embryogenesis were identified. In hybrids, favorable phases included February, August, September, and October. In both control clones, time interval propitious to embryogenesis stretched from February to December. The significance of the coefficient of correlation seemed to establish a relationship between somatic embryogenesis and phenology. However, a causal link could not be established. Leaf thrusts rhythm was revealed to be the phenological parameter most linked to somatic embryogenesis. Attempts to optimize embryogenesis during unfavorable phases, showed that a correction of 2.4 D/TDZ concentration is not the solution.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.2
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• pp.47-57
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• 2011

This study monitored forest plant species vulnerable to climate change in Jiri Mountain, one of Korea's representative alpine regions, in order to securely preserve plant genetic resources susceptible to climate change and to utilize the results as basic data for bioclimatology prediction and management on a long-term basis. A majority of indicator plants tended to blossom one week to one month later in 2010 than in 2009. As with the blooming dates, the falling dates of blossoms became later in most species, with the exception for Weigela florida and Oplopanax elatus. Leaf bursting as well fell on later dates in a majority of species excluding Carpinus laxiflora and Cupressus sempervirens, displaying the most obvious differences among the data of analysis of the 2009-2010 physiological cycle changes. It is believed that was due to the fact that temperatures in February, March and April, which affect plants' blossoming and leaf bursting, were lower in 2010 than in 2009 and that cold temperatures in the winter lasted for a longer period in 2010 than in 2009. The dates of leaves being changed to red were similar in 2009 and 2010 by being or later or earlier by several weeks in 2010 than in 2009 without any regularity. Most species' leaves began to fall at similar dates in 2009 and 2010 or at later dates by one to two weeks in 2010 than in 2009. The temperature differences in late 2009 and late 2010 were not so large, resulting in similar dates of falling leaves, and gaps in several indicator plants' physiological cycles without any regularity can be attributed to each individual plant's physiological and environmental characteristics.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.197-206
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• 2001

The depletion of stratospheric ozone is regarded as a major environmental threat to plant growth and ecosystem. The ozone depletion has caused plants to be exposed to an increased penetration of solar ultraviolet-B (UV-B) radiation in the 280-320 nm wavelength range. Enhanced UV-B radiation may have influence on plants biological functions in many aspects including inhibition of photosynthesis, DNA damage, lipid peroxidation, changes in morphology, phenology, and biomass accumulation. To cope with the damage by UV radiation, plants have evolved to have protective mechanisms, such as photorepair, accumulation of UV-absorbing compounds, leaf thickening and activation of antioxidative enzymes. The objective of this review is to address the effects of enhanced UV-B on plant growth, UV-B action mechanisms and protection and protection mechanisms in plants.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.420-432
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• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.