• Journal of Photoscience
• /
• 제9권2호
• /
• pp.158-161
• /
• 2002

UV-B radiation gives harmful effects on plants, such as production of several types of DNA lesions, and growth inhibition. On the other hand, plants have some protective mechanisms, including filtering effect due to accumulation of phenolic compounds in epidermal cells and reactivation of DNA lesions, which are enhanced by UV-B irradiation. We have investigated the mechanism of UV-B effects on plants using cucumber seedlings as plant materials. Cucumber plants were cultivated in an artificially lit growth chamber. Supplemental UV-B irradiation, of which intensity was almost equal to the level of natural sunlight, retarded the growth of first leaves. The growth retardation must result trom the inhibition of cell division and/or cell growth. Microscopical observation of leaf epidermis suggested that the growth retardation might be mainly caused by cell growth inhibition. The retardation was, however, restored within 2 or 3 days after the termination of UV-B irradiation. It is known that UV-B irradiation lowers the activity of photo system II (PS II). In the present experimental conditions, however, UV-B irradiation has little effect on PS II activity as estimated by chlorophyll fluorescence. The stomatal conductance, a major factor determining photosynthetic rate, of first leaves increased during the growth. The increase of stomatal conductance was suppressed by UV-B irradiation and restored by termination of the irradiation. It has not been clear, however, what mechanisms are involved in the suppression of increase of stomatal conductance.

• 한국산림과학회지
• /
• 제87권1호
• /
• pp.50-56
• /
• 1998

오존에 약(弱)하거나 저항성(抵抗性)을 가지는 포플러 개체(個體)를 선발(選拔)하기 위해서 36개의 잡종(雜種)포플러 클론을 오존에 노출(露出)시켰다. Open-top chamber를 이용(利用)하여 하루에 6-8시간, 3개월 동안 90-115ppb의 농도(濃度)로 오존을 노출시켰다. 수고(樹高), 직경(直徑), 엽수(葉數), 물질생산량(物質生産量), root/shoot비율(比率), 낙엽률(落葉率), 기공반응(氣孔反應) 조사(調査)하였다. 수고, 직경, 엽수, 물질생산량, root/shoot비율, 기공 conductance는 오존 때문에 감소(減少)하였고, 낙엽률은 증가(增加)하였다. 이 연구에서는 기공 conductance와 물질생산량과의 관계(關係)는 아주 낮게 나타났다. 오존환경(環境)에 대해서 저항성을 갖는 것은 기공(氣孔)의 개폐(開閉)와 항상(恒常) 관계(關係)가 있는 것은 아니라고 사료(思料)되며, 아마도 생화학적(生化學的)이고 생리적(生理的)인 다른 요인(要因)에 대(對)한 연구(硏究)가 포플러 클론이 갖는 저항성을 이해(理解)하는데 도움이 될 것이다.

• Journal of Plant Biology
• /
• 제30권1호
• /
• pp.43-57
• /
• 1987

The epidermal structure and stomatal types in vegetative and reproductive organs of three species of Bryophyllum(B. crenatum, B. diagremontion, B. tubiflorum) were described. The epidermal cells were polygonal, isodiametric, and rectangular in the leaves and stems, and elongated cells in the stamens, styles, and ovaries. These cells were commonly thick, and arched or sinuous in the leaves, epiphylous bunds, petals and ovaries. They were straight in the stems, petioles, pedicels, and peduncles. In both vegetative and reproductive organs, the subsidiary cell walls were commonly thin and mostly arched in all the organs. The great majority of the mature stomata in all the organs were helicocytic type with a helix of four to six subsidiary cells. The mature stomata varied from organ to organ with regard to the number and arangement of subsidiary cells. The ontogenetic type of stomata in all the organs was mostly helico-eumesogenous type. This type was subdivided into three subtypes such as parahelico-eumesogenous, anomohelico-eumesogenous, and diahelico-eumesogenous stomata on the basis of the division angle fo the guard mother cell. Sometimes, the anisoeumesogenous type was found in various organs. This type was subdivided into three subtypes such as paraniso-eumesogenous, anomoaniso-eumesogenous, and dianisoeummesogenous stomata. The tetra-eumesogenous and duplotetra-eumesogenous types were rarely found; the former in the leaf of B. crenatum and the latter in the leaf of B. diagremontiana. Anomometric patterns in the mesogenous categorry of stomatal types was observed in a few organs of all the materials. A new stomatal type with tetra-eumesogenous stoma within a girdle of three subsidiary cells fo aniso-eumesogenous in the leaf of B. diagremontiana was firstly observed in the vascular plants. This stoma was termed the cotetra-aniso-eumesogenous type. Anormal stomata such as aborted stomata, single guard cells, stoma with a constricted part in the middle of large guard cells, and arrested stomata were found in the various organs of all the materials.

• Journal of Ginseng Research
• /
• 제17권3호
• /
• pp.240-245
• /
• 1993

This study was conducted with ginseng plants to investigate photosynthetic response to changes of light intensity and leaf temperature. $CO_2$ uptake in diurnal course was highest in the first phase (8 00~5 : 30 Am.) on May 30, 1992. In $CO_2$ uptake related to stomatal conductance, these relationship was synchronized in diurnal course, but relationship between TEX>$CO_2$ uptake and intercellular $CO_2$ concentration in diurnal course was synchronized oppositely. Leaf temperature and light intensity at the highest $CO_2$ uptake were in the range of 23~$24^{\circ}C$) and 95$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ , respectively. In response to an increasing light intensity under a constant leaf temperature ($18^{\circ}C$), $CO_2$ uptake was increased throughout the light intensity sequence up to 250$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ When $CO_2$ uptake was measured with a series of leaf temperature under a constant light intensity (250 $\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ uptake was highest at $18^{\circ}C$ as a 4.1$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ . Similar changes were also observed in stomatal conductance and intercellular $CO_2$ concentration. Evidences from several approaches indicate that synchronization of $CO_2$ uptake, stomatal conductance and intercellular $CO_2$ concentration were closely inter-related and changes of leaf temperature iuluenced the photo-response in photosynthetic processes.

• Journal of Plant Biology
• /
• 제30권2호
• /
• pp.79-94
• /
• 1987

This study was carried out to investigate the epidermal structure, the stomatal types, the ontogeny of stomara in various parts of each organ of K. blossfeldiana, K. kewensis, and K. tometosa belonging to Kalanchoe. The epidermal cells were polygonal or isodiametric ones in the leaves, and mostly rectangular, tetragonal, and elongated ones in the leaves, and mostly rectangular, tetragonal, and elongated ones in the other organs. The candelabrum-like, triradiate stellete trichomes in the aerial parts of all organs of K. tomentosa were found. The cuticular striations and square crystals of calcium oxalate in the epidermal cells of petals of K. blossfeldiana were observed. The great majority of the mature stomata in various parts of all the organs were commonly helicocytic types. This type was subdivided into three subtypes such as parahelicocytic, anomohelicocytic, and dianisocytic stomata on the basis of the division angle of the guard mother cells. Somethies, the anisocytic type was found in most organs. This type was subdivided into three subtyes such as paranisocytic, nomoanisocytic, and dianisocytic stomata in the same way as the helicocytic type. A new stomataltype with anisocytic stoma within a girdle of four subsidiary cells of tetracytic type in the leaf of K. kewensis was firstly observed in the vascular plants. This type was termed the coaniso-tetracytic type. The anomomeristic pattern in the mesogenous category of stomatal types was found in various organs of all the material plants. Developmental mode of stomata was constant in all the parts of each organ within the same plant. The stomata was observed to be a few similar stomatal types in various parts of each organ within the same plant. The ontogeny of all the types is eumesogenous or mesogenous type. The ontogenetic type of stomata was mostly helico-eumesogenous type in all the organs of all the material plants. The mature stoma varied from organ to in regard of the number and arrangement of subsidiary cells.

• 생물환경조절학회지
• /
• 제26권3호
• /
• pp.151-157
• /
• 2017

본 연구는 정식 후 토양의 수분 함량에 따른 배추의 생장과 토양 수분에 따른 배추의 생리 반응 모델 개발을 위한 유효 매개변수를 알아보고자 수행되었다. 처리는 5개 수준으로 각각 0, 200, 300, 400 및 500mL/d/plant로 매일 1회 관수하여 토양 수분 함량 차이로 구분하였다. 토양수분과 기공전도도를 정식 후 10일부터 6일 간격으로 총 5회 측정하였으며(단, 0과 200mL/d/plant 처리구는 총 3회 측정), 광합성기구 활성을 알아보고자 정식 후 25일에 충분히 관수된 처리구(500mL/d/plant)와 결핍 처리구(0mL/d/plant)에서 이산화탄소 포화 곡선을 작성하였고, 정식 후 38일에 생장을 조사하였다(단, 관수량 처리구 0과 200mL/d/plant는 위조되어 정식 후 29일에 생장 조사함). 토양수분과 배추의 기공전도도는 밀접한 관계가 있었으며($r^2=0.999$), 직선의 정의 상관관계로 y = 6097.4x - 4.2984였다. 충분히 관수된 배추의 이산화탄소 포화곡선은 정상적인 포화 곡선을 보였으나, 토양수분이 극도로 결핍된 배추는 체내로 이산화탄소가 확산되어 들어가지 않으며, 광합성 속도도 약 $6.5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 미만으로 급격히 감소하였다. 충분히 관수된 처리구(500mL/d/plant)에 비하여 토양 수분 결핍구(0mL/d/plant 처리)에서는 약 6.8배 이상 건물생산량이 감소하였다. 그리고 토양의 수분 함량에 따라 엽면적 지수가 로그함수적(y = 16.573 + 3.398 ln x)으로 증가하였고, 결정 계수 $r^2=0.913$로 높은 상관 관계가 있었다. 결과적으로, 정식초기의 토양 수분 함량이 결핍되면 배추의 생장이 지연되며, 광합성 속도와 기공전도도가 낮아지는 것으로 밝혀졌다. 또한, 토양수분 함량과 배추 생장 반응 모델을 기공전도도와 엽면적 지수를 변수로 활용하면 정확도가 우수한 모델을 개발할 수 있을 것으로 기대된다.

• 한국산림과학회지
• /
• 제89권2호
• /
• pp.198-207
• /
• 2000

전광처리구에서 2-6%의 상대투광량을 보이는 최강피음구까지 총 5수준의 인공피음 처리 하에서 자라는 자작나무, 느티나무, 고로쇠나무, 산벚나무 1년 생 묘목의 수분 특성을 밝히기 위해 기공증산저항과 수분포텐설의 일 변화와 계절 변화를 조사하였다. 활엽수 4종에 대해서 측정한 기공증산저항은 오전 9시에 1.7 ~25.1s/cm, 오후 1시 2.3~33.3s/cm, 오후 5시에 1.1~36.8s/cm의 범위 내에서 수종과 계절에 따라서 피음처리 수준별로 다양한 변화를 보였다. 기공증산저항은 조사된 대부분의 수종에서 피음도가 강해질수록 증가하였으며 6월이나 7월에 비해 9월에 더 높았다. 느티나무, 산벚나무와 고로쇠나무에서는 전광처리구에 비해 최강피음구의 증산저항 측정치가 약 3~4배 높았다. 수분포텐셜 또한 오전 9시에 -0.17~-1.20MPa, 오후 1시 -0.30~-2.03MPa, 오후 5시에 -0.18~-1.34MPa의 범위 내에서 수종과 계절에 따라서 피음처리 수준별로 다양한 변화를 보였다. 수분포텐셜은 조사된 대부분의 수종에서 9월의 측정치가 6월이나 7월의 측정치보다 낮은 값을 보였으며 그 계절적인 차이는 다른 수종에 비해 느티나무에서 현저하게 커지고 있었다. 수분포텐셜은 전광처리구에 비해 최강피음구에서 약 2~3배 더 높았지만 그 차이는 기공증산저항에서 보이는 차이보다는 다소 작은 것으로 분석되었다. 5 수준의 피음도 구배에 따른 수분포텐셜의 차이는 자작나무의 경우에 다른 수종보다 상대적으로 작았다. 내음성이 다소 안정되는 고로쇠나무나 산벚나무에서는 전광처리구에서 상대투광량 22-28% 의 중피음구까지 피음도를 높이면서 한낮을 중심으로 수분포텐셜이 급속하게 증가되었으나 최강피음구에 접근하면서 수분포텐셜의 증가는 둔화되었다. 양수에 속하는 자작나무나 느티나무의 경우에는 전체적으로 피음수준이 높아지면서 수분포텐셜이 점진적으로 증가하였으며 그 증가폭은 자작나무보다는 느티나무에서 더 컸다.

• The Korean Journal of Ecology
• /
• 제19권5호
• /
• pp.453-463
• /
• 1996

Diurnal changes of microclimatic conditions and tissue water relations were measured at two sites where Carpinus laxiflora and C. cordata were allopatrically distributed. The microclimatic conditions at a site where C. laxiflora was distributed produced severe water stress condition during summer months. Daily maximum temperature reached $30.4^\circC$ and the highest vapor pressure deficit was 1.31 KPa when 13 rainless days were continued. During this period soil water content decreased to below the field capacity even at a depth of 20 cm and xylem pressure potential also decreased to ­2.04 MPa. However, turgor potential was maintained more than 0.4 MPa. Patterns of stomatal conductance were changed with evaporative demand and soil water availability. On the other hand, microclimatic conditions at a site where C. cordata was distributed were moderate water strees condition compared with those at a site C. laxiflora was distributed. Though soil water content was maintained above field capacity C. cordata showed a remarkable decrease in turgor potential and stomatal conductance throughout the experiment. These results indicate that there is a difference in habitat characteristics between the two species and C. laxiflora is more resistant than C. cordata to water stress.

• The Korean Journal of Ecology
• /
• 제7권3호
• /
• pp.99-108
• /
• 1983

Diurnal acid fluctuation, stomatal resistance, and solar radiation with regard to the cladode orientation were investigated in Opuntia lanceolata Haw. growing at WPeolryeong-ri, Hallim-eup, Chejudo, Korea. Diurnal changes of titratable acidity showed the typical CAM pattern in all investigated cladodes. Water tissue in the cladode had the same pattern of acid fluctuation as mesophyll tissue. Stomatal resistance was low during the night, increased rapidly to be a peak right after sunrise and decreased again thereafter. The southern side of the cladode showed higher stomatal resistance than the northern side during the day time. It suggests that the stomata of the northern side opens under diffuse radiation. The amount of solar radiation varied depending upon the cladode orientation. It is thought that C4 acids move inter and intra mesophyll tissues in the cladode through the unknown pathways. RuBP carboxyulase activity in the cladode was very high at 14:00, but was not significant at 01:00. PEP-carboxylase had high activities both at 14:00 and at 01:00. The results of this study showed the possibility that O. lanceolata Haw. had the C3, C4 and CAM photosynthetic patterns under the environmental conditions at Weolryeong-ri.

• 한국대기환경학회지
• /
• 제14권6호
• /
• pp.537-544
• /
• 1998

We selected Spathiyhyllum patinii and Pachira aqkatica, since the former has high O3 absorption while the latter low absorption, and analyzed physiological factors such as diffusive coefficient, transpiration rate, photosynthetic rate, and CO2 absorption rate, which affected O3 absorption capacity There was significant relationship between gas absorption capacity and the other factors; photosynthetic rate, diffusive resistance, stomatal resistance and CO2 absorption rate. Therefore model formula for estimation of O3 absorption rate in plant was formulated by making use of these factors. There was difference for the estimation of O3 absorption rate according to plant species. In case of Spathiphyllum patinii, photosynthetic rate is an optimal factor for estimation of O3 absorption capacity. On the other hand, stomatal resistance and diffusive resistance are optimal factors of Pachira aquatica among various physiological ones. And we knew that CO2 absorption rate is a potential factor to evaluate gas absorption capacity regardless of plant species. But considering efficiency and practicality, diffusive resistance was the most effective factor for the estimation of O3 gas absorption.