• 한국작물학회지
• /
• 제48권2호
• /
• pp.81-88
• /
• 2003

Soybeans [Glycine max (L.) Merr.] are frequently exposed to unfavorable environments during growing seasons and water is the most important factor limiting for the production system. The purpose of this study was to determine the leaf water potential changes by irrigation, and to evaluate the relationships of leaf water potential, growth and yield in soybeans. Three soybean cultivars, Hwangkeumkong, Shinpaldalkong 2, and Pungsannamulkong, were planted in growth chamber and field with irrigated treatments. Leaf water potential of three soybean cultivars was positively correlated with leaf water content during vegetative and reproductive growth stages in growth chamber and field experiments. Leaf water potentials measured for three soybean cultivars under growth chamber were higher than those of under field conditions. Higher leaf water potential with irrigated plots under field was observed compared to conventional plots during reproductive growth stages. Leaf water potentials of three soybean cultivars were continually decreased during reproductive growth stages under field and there was no significant difference among them. Number of leaves, leaf water content, pod dry weight, number of seeds and seed dry weight with irrigated plots were higher than those of conventional plots. The results of this study suggested that leaf water potential could be used as an important growth indicator during the growing season of soybean plants.

• 생명과학회지
• /
• 제8권5호
• /
• pp.557-562
• /
• 1998

토양수분이 한발상태에서 적습상태로 변동되었을 때, 콩의 광합성속도, 증산작용, 기공전도도 및 엽내수분의 변화와 이들 형질간의 상호연관성을 구명하기 위하여 본 실험을 수행하였던 바 그 결과를 요약하면 다음과 같다. 한발상태에서 적습상태로 토양수분 함량을 변동시켰을 때, 광합성속도, 증산작용, 기공전도도 및 잎의 함수량은 재관수후의 시간이 경과함에 따라 증가하는 경향이었는데, 광합성속도는 증산작용보다 빠른 회복을 보였고 품종간의 일정한 경향은 보이지 않았다. 광합성속도와 엽내수분, 기공전도도와 엽내수분 및 광합성속도와 기공전도도간에는 모두 정(正)의 상관관계가 인정되었는데, 특히 광합성속도와 엽내수분간의 상관계수가 가장 높아 양자간의 밀접한 관계를 나타내었다.

• Journal of Ginseng Research
• /
• 제4권2호
• /
• pp.197-221
• /
• 1980

Habitat observation, cultural experience of old and present plantation, weather factors in relation to crop stand and water physiology of root and leaf were reviewed. According to habitat observation ginseng plants love water but plate wit talus well grow at drained place with high moisture content in air and soil while ginseng plants were not found in dry or wet place. According to cultivation experience ginseng plants require abundant water in nursery and main field but most old planters believe that ginseng plaints are draught-loving thus require little water. The experience that rain especially in summer i.e unfavorable might be due to mechanical damage of leaves arid leaf disease infection, or severe leaf fall which is caused by high air temperature and coinsided with rain. According to crop stand observation in relation to weather factors abunsant water increased each root weight but decreased total yield indicating tile increase of missing root rate. Rain in summer was unfavorable too. Though rain in June was favorable for high yield general experience that cloudy day and rain were unfavorable might be due to low light intensity under shade. Present leading planters also do loot consider the importance of water in main field. Water content is higher in top than in root and highest in central portion of root and in stem of top. For seedling the heavier the weight of root is tile higher the water content while it reveries from two years old. Water potential of intact root appeared to be -2.89 bar suggesting high sensitivity to water environment. Under water stress water content severly decreased only in leaf. Water content of leaf appeared to be 78% for optimum, below 72% for functional damage and 68% for perm anent wilting. Transpiration or curs Principally through stomata in lower side of leaf thus contribution of upper side transpiration decreased with the increase of intensity. Transpiration is greater in the leaves grown under high light intensity. Thus water content is lower with high light inte nsity under field condition indicating that light is probable cause of water stress in field. Transpiration reached maximum at 10K1ut The decrease of transpiration at higher temperature seems to be due to the decrease of stomata aperture caused by water stress. Severe decrease of photosynthesis under water stress seems to be principally due to functional damage which is not caused by high temperature and Partly due to poor CO2 supply. Water potential of leaf appeared to be -16.8 bar suggesting weakness in draught tolerance. Ginseng leaves absorb water under high humidity. Water free space of leaf disc is %mailer than that of soybean leaf and water uptake appears to be more than two steps.

• The Korean Journal of Ecology
• /
• 제13권1호
• /
• pp.59-66
• /
• 1990

Changes in water potential, lethal temperature and carbohydrate content in the leaves of wintergreen (Pyrola japonica) during overwintering were investigated. Leaf water potential was kept at -2 bars in the tender stage before October, decreased to -46 bars in the dormancy stage and increased to -2 bars again after dehardening Lethal temperatures of the leaf tissue were $-7^{\circ}C$ in the tender stage and $-7^{\circ}C$ in the dormancy stage, but did not recover up to that of the tender stage during dehardeding. Peak of soluble sugar content coincided with the nadir of the leaf water potential. There were close relationships among daily minimum air-temperature, leaf water potential and lethal temperature in changing patterns during overwintering.

• 생명과학회지
• /
• 제8권5호
• /
• pp.492-496
• /
• 1998

$eta$선투과율을 이용하여 식물잎의 수분함량을 측정하기 위하여 1/5000a 와그너 폿트에 생육시킨 벼와 콩및을 대상으로, 정상적으로 생육한 개체만을 선별하였다. $^{99}$Tc(100 $\mu$ci)과 G-M detector사이를 10cm로 두고 그 사이에 잎을 놓아 잎을 통과한 $eta$선량(I)과 잎을 제외시켰을 때의 $eta$선량(Io)을 각각 측정하여 $eta$선투과율(I/Io)를 구하였고, 잎의 생체중과 건물중, 비엽면적을 측정하여 잎의 함수량과 $\beta$선 투과율(I/Io)과의 관계를 구하였다. 1. 잎 절단후 시간이 경과함에 따라 $eta$선투과율(I/Io)은 증가하는 경향이었으며, 토양수분결핍후 수분공급에 의해 $eta$선투과율(I/Io)은 감소하는 경향이었다. 2. 잎의 함수량과 $eta$선투과율(I/Io)과의 직선회귀관계식은 고도의 유의성이 인정되어, 잎의 함수량이 감소할수록 $eta$선투과율(I/Io)은 증가하였다. 3. 잎의 함수량을 종속변수로, 비엽면적(SLA)과 $eta$선투과율(I/Io)을 각각 독립변수로하여 다중회귀를 분석한 결과, 편회귀계수가 SLA는 벼 0.007, 콩 0.004이었고, I/Io는 벼 -0.863, 콩 -0.904로 수분함량에는 $eta$선투과율(I/Io)의 영향이 지배적이어서, $\beta$선투과율(I/Io)에 의한 식물잎의 수분함량이 측정이 가능하였다.

• 한국환경과학회지
• /
• 제27권4호
• /
• pp.275-279
• /
• 2018

Water status of intact plants has been optically estimated by measuring reflectance at the wavelengths 1,450 nm and 1,900 nm based on their signal strengths. Although another water band at 970 nm is considered to have very small signals, the band apparently lies within the detection range of inexpensive spectrometer and plain charge-coupled device (CCD) camera used in wild fire studies. However measurement of the reflectance at 970 nm has been rarely applied to estimate the water status of dead plant materials such as fallen branch, twig, and leaf. To test the possibility of applying water reflectance at 970 nm to estimate the water content (WC) in leaf litter, the reflectance in various WC values were measured in the leaf litter of three Quercus species (Q aliena, Q aliena, Q mongolica, and Quercus variabilis). The results showed that the WC in the leaf litter can be determined by reflectance water index (WI) in the three Quercus species ($WC=1,450{\times}WI-1,378.8$, r=0.865). However, there was no interaction effect in the relationship between WI and WC among the litter of the three Quercus species.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제35권2호
• /
• pp.77-82
• /
• 2017

We studied on improvement method of rutin content using mulberry leaf powder. Mulberry leaves were collected and then hot-air dried and powdered for experiment. As a result, we have developed a pre-treatment method that extracts mulberry leaf powder with water or fermented alcohol with reflux extractor and then increases the rutin content by improving the process. Citric acid (0.1 ~ 1%) and 1000 ml fermented alcohol (50 ~ 95%) or water (10 ~ 50 times) was extracted with 100 g of mulberry leaf powder using a reflux extraction device ($80{\sim}90^{\circ}C$, 1 hour, twice). The extracts were collected, filtered and concentrated. For the recrystallization, the concentrate was dissolved by adding distilled water and allowed to stand at a low temperature. Then, the supernatant was discarded by centrifugation, and only the residue was lyophilized to prepare a final powder. As a result, regardless of the concentration of citric acid added, the content of rutin was higher in 90% fermented alcohol extract. Whereas, in the case of extracting with water, citric acid 0.5% was added to water 25 times as much as the weight of mulberry leaf powder, and 2274.4 (mg / 100g) of rutin content was highest in the case of refluxing twice at $80^{\circ}C$ for 1 hour. The powder with increased rutin content is expected to be applicable to various foods as a food additive. In addition, it can contribute to the improvement of the farm income by promoting consumption of mulberry leaf while satisfying the consumers' desire for functional food intake.

• 한국작물학회지
• /
• 제39권3호
• /
• pp.223-231
• /
• 1994

콩의 내한발성 품종육성 및 선발에 대한 기초자료를 얻고자 팔달콩, 새알콩 및 단엽콩을 공시하여 수경재배에서는 수경액을 PEG처리로, pot 실험에서는 단수처리하여 수분부족을 유기하고 PEG 농도, 품종 및 생육시기별로 엽의 수분 potential, 질산환원효소의 활성 및 ABA 함량을 조사하였다. 1. 엽의 수분 potential은 PEG의 농도가 높을수록 낮았으며 생육시기에 따라서는 제1엽기보다 제3엽기와 제5엽기에 높았는데, 품종간에는 차이가 없었다. 엽의 수분 potential은 단수처리 3일후에 무처리에서보다 약 2.2배가 감소되었다. 2. 질산환원효소의 활성은 PEG의 농도가 높을수록 낮았고 제1엽기보다 제3엽기와 제5엽기에 높았으며, 품종간에는 팔달콩이 새알콩과 단엽콩 보다 높았다. 단수처리에서는 처리 3일후에 질산환원효소의 활성이 무처리에서보다 약 47%가 감소되었다. 3. ABA의 함량은 PEG의 농도가 높을수록 높았고 제1엽기와 제3엽기보다 제5엽기에 높았으며 품종간에는 팔달콩이 새알콩과 단엽콩보다 높았다. 단수처리에서는 처리 3일 후에 ABA의 함량이 무처리에서보다 약 1.7배가 증가하였으며 생육후기보다 생육초기에 더욱 증가하였다.

• 한국자원식물학회지
• /
• 제11권3호
• /
• pp.307-314
• /
• 1998

The response of water stree under high and low temperatures, was shown differently according to the longer the suspension period of water supply. Leaf photosynthetic rate(LPS), leaf water potential(WP), relative leaf water content and relative soil water content were lower. At the higher temperatures, the percentate of reduction in LPS and WP was greater than at low temperatures. It is suggested that evaporation rate should be higher in the high temperature than the lower temperature. Also leaf water potential was lower at high temperature than at low temperature. After the 9 th day of treatment , LSP was remarkably reduced at high temperature, but the reduction of LPS was not significant at low temperature. Solidago virga-aurea var. asiatic that maintained LPS of 3rd day after treatment was more strong than other varieties at low temperatures. The silting and curling of leaves were observed symptoms of stress on the 9th day at the both temperatures. The leaves of aster scaber and Ligularia fischeri turned red on the 9th day after treatment at low temperature.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
• /
• pp.7-10
• /
• 2005

Plant water deficiency during drought season causes physiological stress and can be a critical indicator of forest fire vulnerability. In this study, we attempt to analyze the spectral characteristics of water stressed vegetation by using the laboratory measurement on leaf samples and the canopy reflectance spectra extracted from satellite hyperspectral image data. Leaf-level reflectance spectra were measured by varying moisture content using a portable spectro-radiometer. Canopy reflectance spectra of sample forest stands of two primary species (pine and oak) located in central part of the Korean peninsula were extracted from EO-l Hyperion imaging spectrometer data obtained during the drought season in 2001 and the normal precipitation year in 2002. The preliminary analysis on the reflectance spectra shows that the spectral characteristics of leaf samples are not compatible with the ones obtained from canopy level. Although moisture content of vegetation can be influential to the radiant flux reflected from leaf-level, it may not be very straightforward to obtain the spectral characteristics that are directly related to the level of canopy moisture content. Canopy spectra form forest stands can be varied by structural variables (such as LAt, percent coverage, and biomass) other than canopy moisture content.