• Horticultural Science & Technology
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• v.32 no.1
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• pp.18-25
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• 2014

This study was conducted to investigated effects of water relation of mulching and trickle irrigation on the external and internal fruit quality in Satsuma mandarin grafted on trifoliate orange rootstock in a orchard assigned to randomly three groups; whole period of Tyvex mulching (TM), Tyvex mulching with trickle irrigation once a week from October 22 to harvesting season (WM) and non-mulching treatment (NM). The average soil moisture content in the TM was lower than the WM during the time of trickle irrigation from Oct. 21 to Nov. 28. The leaf water potential was at the level of ${\Psi}max$ of -1.5 to -2.5 MPa during whole period of Tyvex mulching treatment but gradually increased at the point of supplement of water. The water and osmotic potential in juice vesicle was decreased by drought but increased again in response to the supply of water in WM. The total soluble solids (TSS) in fruit juice was increased by drought stress, but diminished in response to supply of water after drought. The content of titratible acidity was increased by drought stress but gradually decreased due to supplement of water after drought, reached it at the level of 1%. It was suggested that the accumulation of the total soluble solids compensates the degree of active osmoregulation and the decrease in content of acidity accounts for the fast respiration and water uptake resulted of the water after drought.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.210-219
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• 1991

This study is to diagnose the drought tolerance of twenty broad-leaved tree species by the pressure-volume(P-V) curves. As for the diagnosis of drought tolerance, the valuable water relations parameters obtained from P-V curves are the osmotic potential at full turgor, ${\Psi}_0{^{sat}}$, osmotic potential at incipient plasmolysis, ${\Psi}_0{^{tlp}}$, maximum bulk modulus of elasticity, $E_{max}$, and relative water content at incipient plasmolysis, $RWC^{tlp}$. Also, the figures related to the diagnosis of drought tolerance are the free water content (FWC) versus leaf water potential(${\Psi}_L$), volume-averaged turgor pressure ($P_{vat}$) versus leaf water potential (${\Psi}_L$), and H$\ddot{o}$fler diagram. In this study, the relatively high drought tolerant species are Fraxinus rhynchophylla, Quercus acutissima, Quercus serrata, Quercus aliena, and Populus alba${\times}$glandulosa ; the relatively low drought tolerant species are Fraxinus mandshurica, Betula platyphylla var. japonica, Populus euramericana, Kalopanax pictum, Carpinus loxiflora, Carpinus cordata, Prunus sargentii, Prunus leveilleana, and Cornus controversa ; medium species are Quercus mongolica, Acer mono, Acer triflorum, Acer pseudo-sieboldianum, Ulmus davidiana, and Zelkova serrata.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.263-268
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• 2000

The effect of $Cd^{2+}$ on stomatal apertures of epidermal strips and intact leaves in Commelina communis L. was investigated. Cadmium stimulated stomatal opening. The stomata, treated with 100 $\mu$M $Cd^{2+}$ opened to a degree of about 8.38 fm, but the stomata, treated with no cadmium opened to 3.74 ${\mu}{\textrm}{m}$. In order to show that there was no mechanical or osmotic impediment preventing the stomata in the epidermal strips, salicylic acid (SA) and abscisic acid (ABA) were used. The treatment of 100 $\mu$M SA and 1 $\mu$M ABA inhibited 14% and 28% of stomatal opening, respectively. Other heavy metals such as $Al^{3+} and Ag^{2+}$ were also used to investigate the effect of the stomatal apertures. The treatment of $Al^{3+} and Ag^{2+}$ also stimulated 19% and 41% of stomatal opening. To understand how cadmium open stomata, the effect of cadmium on the K+ influx into the epidermal strips was investigated. $Cd^{2+}$, SA, ABA inhibited 98%, 28%, 34% of K+ uptake respectively. 3-weeks old Commelina was transferred to and grown in Hoagland solution (0,5 mM $Cd^{2+}$, 10 mM $Cd^{2+}$) for 4 days and stomatal conductance were measured. The treatment of 5 mM $Cd^{2+}$ and 10 mM $Cd^{2+}$ showed about 51% and 70% inhibition of stomatal conductance, respectively Therefore, it could be concluded that stomata in epidermal strips and intact leaves behaved differently and cadmium- stimulated stomatal opening was due to the result of cadmium uptake into the epidermal strips instead of K+. [cadmium, stomata, stomatal conductance]

• Horticultural Science & Technology
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• v.28 no.4
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• pp.561-566
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• 2010

The effects of calcium concentrations of coating bag treatment to reduce berry cracking were investigated through the changes of pericarp structure and berry cracking rate in 'Kyoho' grape. The soluble solids and anthocyanin contents in harvested grapes were highest at $18.1^{\circ}Brix$ and $2.56{\mu}g{\cdot}cm^{-2}$ in non bagging group compared with those of calcium coating bag treatments. The firmness of pericarp was lowest in non bagging group ($1.18kg{\cdot}5mm^{-1}{\O}$) compared with bagging treatments (1.23, 1.24, 1.27, $1.35kg{\cdot}5mm^{-1}{\O}$) which increased effectively in proportion to calcium concentration. As a result of histological observation of the fruit skin, the bagging with higher calcium concentration developed thicker epidermal and sub-epidermal layer of cell wall than that of non bagging. Moreover, the strengthened berry skin of calcium treatments effectively decreased berry cracking rate under critical turgor pressure. However, the 9% calcium coating bag treatment which was the most effective for cracking reduction seriously decreased marketability of harvested grape with white color staining on berry skin caused by eluted calcium from the coated paper bag. Based on our results, we recommend that 6% calcium coating bag be available for berry cracking reduction and higher quality production.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.131-135
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• 2010

This study was carried out to establish a proper cultivation condition and diagnose the drought-tolerance of three wild edible greens belonging to genus of Ligularia by using pressure-volume curves methods. The result of the original bulk osmotic pressure at maximum turgor ${\Psi}_{\circ}{^{sat}}$ was -0.8 MPa in Ligularia fischeri and L. stenocephala, which was somewhat lower than the value, -0.7 MPa, in L. fischeri var. spiciformis. In addition, the values of the osmotic pressure at incipient plasmolysis ${\Psi}_{\circ}{^{tlp}}$ in L. fischeri and L. stenocephala, both of which were -0.9 MPa, These were slightly lower than that of -0.8 MPa in L. fischeri var. spiciformis. On the other hand, it appeared that the values of maximum bulk modulus of elasticity $E_{max}$ of L. fischeri and L. stenocephala were approximately two times higher than that of L. fischeri var. spiciformis. However, There was a distinct difference between the values of the relative water contents in these three species. Therefore, Ligularia spp, occurring incipient plasmolysis in the high water contents, have a relatively low property of drought-tolerance, suggesting that growth of those Ligularia spp. are appropriate for relative moisture forest.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.461-468
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• 2012

This study was conducted to study the seasonal changes of relative water relations parameters by pressure-volume curves of Korean mistletoe (Viscum album var. coloratum) leaves for understanding ecological characteristics. In growing season, the osmotic potentials at full turgor (${\Psi}_o^{sat}$) and at incipient plasmolysis (${\Psi}_o^{tlp}$) decreased, while increased the maximum bulk elastic modulus of the cell wall ($E_{max}$) and relavive water content ($RWC^{tlp}$). Korean mistletoe in Quercus variabilis and Korean mistletoe in Quercus mongolica in November showed best maximum perssure potential (${\Psi}_{P,\;max}$). Pressure potential (${\Psi}_P$) and water potential (${\Psi}_L$) in Korean mistletoe in Quercus variabilis were rapidly decreased with decreasing of relative water content. The values of $RWC^{tlp}$ in November were all above 84% showing that the function of osmoregulation is somewhat better, and symplastic water content (Vo/DW) and maximum water content (Vt/DW) were variable seasonally. Thus, responses to water relations of Korean mistletoe in Quercus variabilis and Korean mistletoe in Quercus mongolica such as ${\Psi}_o^{sat},\;{\Psi}_o^{tlp},\;E_{max},\;{\Psi}_{P,\;max},\;RWC^{tlp}$ showed increaing drought tolerance with increasing of leaf aging.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.451-457
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• 1983

This study was conducted to estimate the effect of the drought on the changes of chlorophyll, protein and proline content of upper three leaves, and the grain yield components of barley plant (CV. baegdong) subjected to water stress at four stages: late vegetative, boot, anthesis early grain filling. 1. In comparison with leaf posititions in water stress, the first leaf below flag leaf maintained the highest relative turgidity, chlorophyll and protein content and showed the least proline accumulation. And, in terms of growth stages in water stress, chlorophyll was shown to be highest at anthesis stage, protein being highest at boot stage and proline being least at boot stage. 2. In boot stages, culm and spike length, and Number of grains per spike were remarkably decreased. And the weight of 1000 grains was at least level in the early grain filling stage, and also the grain size was comparatively decreased at boot and two following stages. 3. The protein content of grain by water stress, apart from early grain filling stage, was not significantly affected by water stress at different growth stages. 4. The rate of sterility was particularly increased at boot and anthesis stages. 5. It was eventually concluded that the boot stage among four growth stages, and the flag leaf in 3 leaf positions were mostly damaged by water stress at reproductive growth stage.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.942-947
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• 2010

In the present study, pollen tube growth and fruit set in Asian pear ($Pyrus$ $pyrifolia$) were examined upon the mechanical damage on the stigma and style following the artificial pollination. When the upper middle part of style was cut off at 48 h after the artificial pollination, pollen tube grew to the middle of the style and the subsequent pollen tube elongation and fruit set normally occurred. When the style was cut off before the pollen tube reached the middle of the style, however, no pollen tube elongation and fruit set occurred. With the pollen tube elongation through the style, callose plugs at the basal part of the pollen tube were formed to the direction of the elongation at regular intervals. When the upper part of pollen tube attached pollen grain was cut off, however, callose plugs were formed defectively in the pollen tube, and the pollen tube opened and lost their turgor pressure. These facts might be the reason for the ceased or delayed pollen tube elongation and ultimately the failure of the fertilization.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.374-378
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• 2010

Determining plant moisture characteristics is an essential study not only for cultivation, but also for ex-situ conservation. In this study, employing pressure-volume curve we examined moisture characteristics of Rhododendron micranthum, known as rare plant, with the aim of its ex-situ conservation. Several individuals growing in Mt. Worak, Youngwol-gun Yeonha-ri and Bongwa-gun Seokpo-ri were selected for this study, from which we collected leaves. The original bulk osmotic pressure at maximum turgor(${{\Psi}_o}^{sat}$)was -1.5 MPa in those of Mt. Worak and Seokpo-ri, which is somewhat lower than that of Yeonha-ri(-1.2 MPa). It appeared that the osmotic pressure at incipient plasmolysis(${{\Psi}_o}^{tlp}$) of leaves collected in both Mt. Worak and Seokpo-ri were -1.29 MPa, and -1.26 MPa, respectively, which are lower than that of Yeonha-ri(-1.02MPa). Maximum bulk modulus of elasticity($E_{max}$) was 14.0 MPa, 8.67 MPa in leaves collected from both Seokpo-ri and Mt. Worak, respectively, those value of which were approximately 3 times higher than that of Yeonha-ri(4.00 MPa). The values of $RWC_{tlp}$(Relative water content at incipient plasmolysis) of leaves collected in three areas, were roughly 83%, suggesting that Rhododendron micranthum has relatively high capability of containing water. Our finding on moisture characteristics of Rhododendron micranthum is similar to those of other Rhododendron spp. We suggest that individuals growing in both Worak and Seokpo-ri, are preferable to those in Yeonha-ri for ex-situ transplantation since those individuals are found to have better drought resistance.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.381-386
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• 2010

The berry growth and pericarp characteristics were characterized to confirm the effects of bagging periods on berry cracking during berry development in 'Kyoho' grape. The berry weight was the highest at 13.4 g in late period of bagging treated at 7 to 9 weeks after full bloom (WAFB) as compared with the lowest of 12.3 g in total period bagging. The berry cracking rate under critical turgor pressure in the non-bagging control was 53.3%, while those of bagging treatments were decreased in the order of 42.7%, 37.3%, 33.3%, and 18.7% in bagged during 3 to 9, 3 to 5, 5 to 7, and 7 to 9 WAFB, respectively. In the results of observation on histological characteristics of pericarp, berry lenticels of whole bagging treatments had smaller and normal shape compared with non-bagging control treatment. Especially on the pericarp of late period bagged during 7 to 9 WAFB, suberization around stomata and micro-cracking were not observed and structural strength of pericarp was increased with thicker sub-epidermal layer and cell wall. Therefore, the results indicate that bagging treatment for two weeks just before the veraison when the day length and daylight is relatively longer and stronger can effectively reduce berry cracking by strengthening structure of pericarp in 'Kyoho' grape.