Showing papers in "Environment control in biology in 1996"
TL;DR: In this article, a postharvest irradiation with UV rays was attempted to enhance coloration of fruit of lightly pigmented sweet cherry (Prunus avium L. cv).
Abstract: Enhancing coloration of fruit of lightly pigmented sweet cherry fruit (Prunus avium L. cv. “Satohnishiki”) was attempted by postharvest irradiation with UV rays. UV rays irradiation at 2.35 W m-2 alone markedly promoted red color development and increased the anthocyanin content in the skin within 48 h. No additional effect was found when white light was combined with UV. The red color development proceeded even in the dark after UV irradiation, although the degree of coloration depended on the duration of the irradiation. By lowering the temperature during irradiation, from 23 to 11°C, the effectiveness of UV irradiation was suppressed. The weight loss of the fruit during irradiation increased with the intensity of irradiation, while it decreased at lower temperatures. The soluble solids content or firmness of skin and flesh were not appreciably affected.
36 citations
TL;DR: Dark storage lowered the photosynthetic capacity and, thus, lowered percent survival at transplanting and post-storage growth rate, and it would be required to store the seedlings under conditions where they have null CO2 exchange rates throughout the storage period.
Abstract: Eggplant (Solanum melongena L.) plug seedlings were stored for 3 weeks at 9°C air temperature and photosynthetic photon flux density (PPFD) of 0 (darkness), 2, 8, or 16μmol m-2s-1. The seedlings stored for 3 weeks in darkness or under 2μmol m-2s-1 PPFD reduced dry weight, while those under 8 or 16μmol m-2s-1 PPFD increased dry weight. The light compensation point of seedlings before storage was 8μmol m-2s-1 PPFD and it decreased to 4-5ymol m-2s-1 PPFD after storage regardless of PPFD in storage. All the plantlets stored under light survived at transplanting and grew successfully after storage. Dark storage lowered the photosynthetic capacity and, thus, lowered percent survival at transplanting and post-storage growth rate. For keeping seedlings at no-growth status and preventing quality degradation, it would be required to store the seedlings under conditions where they have null CO2 exchange rates throughout the storage period.
34 citations
TL;DR: In this article, low total pressure treatments were applied to spinach over the entire production period from seeding to harvest, and it was shown that the entire cultivation of spinach can be carried out at one-fourth atmospheric pressure when the O2 and CO2 partial pressures are at atmospheric levels.
Abstract: In a plant production facility designed for human life support in vacuum space, lowering total air pressures within the facilities is expected to have the engineering advantage of reducing the construction cost. In this study, low total pressure treatments were applied to spinach over the entire production period from seeding to harvest. An environment control system was constructed to grow plants under low total pressure for long durations. Spinach seeds were directly sowed on a hydroponic plant bed placed in a reduced-pressure growth chamber. The total and O2 partial pressures within the growth chamber were set at 101 and 21 kPa, 25 and 21 kPa, and 25 and 10 kPa, respectively. The CO2 partial pressure was constant at 40 Pa. At 21 kPa of O2 partial pressure, there were no significant differences in fresh and dry weights, leaf area, and shoot length of spinach at harvest between 101 and 25 kPa of total air pressure. At 10 kPa of O2 partial pressure and 25 kPa of total pressure, the dry weight was not affected, but the leaf area and shoot length at harvest were smaller than those at 21 kPa of O2. According to these results, it was evident that the entire cultivation of spinach from seeding to harvest could be carried out at one-fourth atmospheric pressure when the O2 and CO2 partial pressures are at atmospheric levels.
24 citations
21 citations
TL;DR: Cherimoya has higher adaptability to low irradiance than other two species, and under weak light condition the stomatal conductance increased for all species.
Abstract: Seedlings of cherimoya (Annona cherimola Mill.), sugar apple (A. squamosa L.) and soursop (A. muricata L.) were grown at 100, 45, 25, and 5% of full sunlight level to determine the influence of irradiance level on their growth and photosynthesis. For all species the shoot length and dry weight of wholeplant were decreased at 25% sunlight, but there was little difference in them between at 45 and 100% sunlight. Total leaf area tended to increase at 45% sunlight in sugar apple and soursop and to decrease at 25% sunlight in cherimoya and soursop. Leaf area ratio increased with decreasing light intensity in every species, and the degree of increase was the least in cherimoya. With decreasing light intensity, leaves became thinner and the specific leaf weight decreased for all species. Chlorophyll content and photosynthetic rate more decreased at 25% than those at 100 and 45% sunlight in sugar apple and soursop. There were little differences both in the chlorophyll content and photosynthesis among these light intensities in cherimoya. This indicates that cherimoya has higher adaptability to low irradiance than other two species. Under weak light condition the stomatal conductance increased for all species. At 5% sunlight, the plant dry weight was less than about 90% of that of control and photosynthetic rate almost decreased to the light compensation point.
10 citations
TL;DR: In this article, young rice plants were solution-cultured in artificially illuminated growth cabinets under combinations of 35 (ambient) or 70 (high) Pa atmospheric CO2 and 0.6, 6, 60 or 600μM phosphorus nutrition with other growth conditions of 12-h day (450μmol m-2 s-1 PPFD) /12-h night cycle at 28/23°C and about 60% RH.
Abstract: Young rice plants were solution-cultured in artificially illuminated growth cabinets under combinations of 35 (ambient) or 70 (high) Pa atmospheric CO2 and 0.6, 6, 60 or 600μM phosphorus (P) nutrition with other growth conditions of 12-h day (450μmol m-2 s-1 PPFD) /12-h night cycle at 28/23°C and about 60% RH. Generally, the growth and dry matter production were promoted by high CO2 and the effects were enlarged with elevating P level up to 60μM but the highest P (600μM) decreased the CO2 effects. At the lowest P (0.6μM), the root growth was substantially promoted at the sacrifice of shoot growth. The net assimilation rate (NAR) was largely promoted by high CO2 but not by P nutrition. The high CO2 decreased the leaf weight ratio (LWR), which indicated the relative promotion of dry matter partitioning to organs other than leaves. The mineral nutrient (P, K, Ca, Mg) content was also decreased by high CO2, probably because of the dilution effect of carbohydrate accumulation. The P use efficiency in dry matter production decreased with increasing P levels but high CO2 ameliorated the effect of P. It was concluded that the growth of rice plants in poor P conditions would be ameliorated at high CO2 levels. However, substantial amounts of P should be applied for their full growth.
10 citations
TL;DR: The growth changes caused by the increase of far-red light were investigated in pole-type and bush-type kidney beans and the length and dry weight of the stem in both the pole- type and the bush- type kidney beans increased and the proportion of thestem dry weight relative to the whole dry weight increased.
Abstract: The growth changes caused by the increase of far-red light were investigated in pole-type and bush-type kidney beans (Pheseolus vulgaris L. cv Kentucky Wonder and Celina) . Irradiation with a wavelength over 700 nm was added to the fluorescent lamps to increase far-red light. The light quality variation with supplementary far-red light was presented by phytochrome photoequilibria (Pfr/P) . To estimate the Pfr/P, the SPD method was used, which was calculated by the spectral photon flux distribution of irradiation and the phytochrome photoconversion. The calculated Pfr/P was compared with the measured Pfr/P derived from the method of Holmes and Smith (1975) . The calculated Pfr/P was expressed in a rectangular hyperbolic equation of the R/FR ratio, and this Pfr/P and the measured Pfr/P showed low level difference (<8%) . Therefore, by using the SPD method, estimation of Pfr/P could be possible without the analysis of phytochrome. As the far-red light increased and Pfr/P decreased, the length and dry weight of the stem in both the pole-type and the bush-type kidney beans increased and the proportion of the stem dry weight relative to the whole dry weight increased. The increase of stem length was great when the Pfr/P was above 0.77, and small when below 0.77. The stem length increased through increases of both the number of nodes and the internode length in the case of pole-type, while in the case of bush-type beans, only through the internode length.
9 citations
9 citations
TL;DR: In order to investigate the seasonal change of transpiration in mangrove species, the sap flow rates (Fs) in Bruguiera cylindrica were measured in southern Thailand, with a stem heat balance method and stomatal conductance in 4 species was measured.
Abstract: In order to investigate the seasonal change of transpiration in mangrove species, the sap flow rates (Fs) in Bruguiera cylindrica were measured in southern Thailand, with a stem heat balance method. From the result, the transpiration rates (Tr) normalized by leaf area in wet and dry seasons were estimated to be 0.50 and 1.04 kg m-2 d-1 on the average, respectively. Tr in the dry season was rather high compared to that in the wet season. This was probably caused by the difference of meteorological conditions, such as solar radiation and air humidity. Moreover, stomatal conductance (gs) in 4 species, Rhizophora apiculata, Ceriops decandra, Xylocarpus moluccensis and B. cylindrica, was measured in the wet season with a porometry to investigate its interspecific difference. In all the species, gs reached a plateau at the PPFD of 200 to 400μmol m-2 s-1. The plateau in R. apiculata was estimated to be between 150 and 250 mmol m-2 s-1 ; the level is similar to that in evergreen trees in Japan. However, gs in the remaining 3 species was rather low.
8 citations
TL;DR: In this paper, Ficus carica (L. cv. Masui Dauphine) cuttings were subjected with 0 or 50 mM NaCl solution for 4 weeks.
Abstract: Potted fig (Ficus carica L. cv. Masui Dauphine) cuttings were subjected with 0 or 50 mM NaCl solution for 4 weeks. Stem elongation, photosynthesis, transpiration, and mineral content in plants and latex were measured in a time course. Growth, photosynthesis and transpiration were suppressed by NaCl. Greater amounts of Na+ and Cl- ions accumulated in leaves and stems than in roots. The NaCl treatment decreased K+ and Ca2+ in all plant parts except leaves. The osmotic potential of exuded latex was significantly decreased by the NaCl treatment. Na+ content of the latex was considerably lower than that of leaves or stems, while the Cl- content was approximately equal to that of leaves or stems, suggesting a high capacity for the exclusion of Na+ by membranes of the laticiferous cells.
8 citations
TL;DR: Light in low temperature storage was shown to contribute to keeping high postharvest quality of the radish sprouted quality under conditions where light was provided throughout the pre-storage and the storage period.
Abstract: Radish sprouts (Raphanus sativus L.) harvested in a commercial operation were kept for a day at 20°C air temperature under 0 (darkness) or 50μmol m-2s-1 photosynthetic photon flux density (PPFD) (pre-storage treatment) and stored for 16 days at 5°C air temperature under 0 or 5μmol m-2s-1 PPFD (storage treatment) . The pre-storage treatment was to examine the effect of illumination during shipping conditions. For treatments under light, white light was provided continuously (24 h d-1 photoperiod) with cool white fluorescent lamps. The best quality was obtained under conditions where light was provided throughout the pre-storage and the storage period. Dark storage caused the shoot elongation and chlorophyll degradation. Light in low temperature storage was shown to contribute to keeping high postharvest quality of the radish sprouts.
TL;DR: 処理は, 濃度を変化させる時期を組み合わせて行った, 品質および生理的特性に及ぼす影響について検討した,
Abstract: 半促成NFTトマトにおいて, 生育段階に応じた培養液濃度変化が生育, 収量, 品質および生理的特性に及ぼす影響について検討した.処理は, 培養液濃度と, 濃度を変化させる時期を組み合わせて行った.濃度はEC値0.12 (L) , 0.18 (M) , 0.30Sm-1 (H) の3水準とし, 濃度処理を開始する生育時期を, 第1果房の, a) 開花期, b) 果実肥大期, c) 収穫期とした.地上部生体重は, 処理区間に有意差は認められなかった.光合成, 蒸散速度は, 高濃度で管理した区で抑制された.しかし, 初期より高濃度で管理すると吸水量とCa吸収が抑制された.また高濃度下では尻腐れ果発生が多かった.果実の糖含量と酸度は, 高濃度で管理したトマトで比較的高かった.培養液濃度を急激に変化させた場合は, 変化をさせなかった場合に比較し収量, 品質, 生理的特性に大きな影響が現れることが判明した.
TL;DR: It is shown that 60% of the population does not believe in reincarnation, while the other 40% does not.
Abstract: 茶の水耕栽培において, 日射量や昼夜の温度差が品質や生長に与える影響について, 茶中の遊離アミノ酸含量, 葉の光合成速度, 新芽の伸長度および新葉の呼吸速度の観点から検討した.本論文の要点は以下のとおりである.(1) 80%遮光区では, 新芽の葉および茎においてテアニンやアルギニン, グルタミンなどの遊離アミノ酸含量が顕著に増加し, 葉で約4倍～6.5倍, 茎で約15倍～6.5倍の値であった.この増加率は葉においてより顕著であった.また, 根でもテアニンやアルギニン, ヒスチジンなどが増加する傾向を示したが, 葉や茎に比べてわずかであった.いっぽう, 60%および25%遮光区ではどの部位でも遮光による遊離アミノ酸の増加はほとんどみられなかった.(2) カフェイン含量は80%遮光区では新芽の葉で約1.8倍, 茎で約1.5倍増加した.(3) 80%遮光区では, 新芽部分の全遊離アミノ酸含量は無遮光区に比べて約3倍増加した.いっぽう, 60%および25%遮光区では遮光の有無による差はみられなかった.(4) 茶新葉での見かけの最大光合成速度は約85mgCO2dm-2h-1と成葉の約3.5倍であった.また, 新葉での飽和光合成光強度は約800μmol m-2s-1と, これも成葉の約2.7倍であった.このように新葉と成葉では光利用効率に大きな差がみられた.(5) 新芽の伸長は昼夜の温度差が大きいほど促進されることが明らかとなった.また, 昼夜の温度差が茶中の遊離アミノ酸含量に与える影響を検討したところ, 温度差が11℃の場合, 新芽の葉ではテアニンやグルタミンの含量が約2倍増加した.また, 茎でもこれらの遊離アミノ酸含量は1.5倍程度増加していた.(6) 昼夜の温度差を変化させてもカフェイン含量には差はみられなかった.(7) 昼夜の温度差が11℃の場合には, 新芽部分の全遊離アミノ酸含量は温度差5℃および1℃に比べて約1.5倍増加していた.なお, 温度差が5℃と1℃とでは両者の全遊離アミノ酸含量に差はみられなかった.(8) 茶新葉の呼吸速度は夜間温度が高くなるほど増大し, 25℃では15℃の場合の約3倍であった.このように夜温が低いほど茶樹の代謝速度が抑えられ, このことも, 夜温が低いほど新芽の伸長度が大きく, また, 遊離アミノ酸含量も高くなる一因と考えられる.最後に, 本研究を進めるに際し茶樹の提供をいただいた埼玉県茶業試験場岡野信雄部長, 水耕栽培法についてご指導いただいた静岡大学小西茂毅教授, (株) 宇治園中川米秋工場長に深く感謝申し上げます.また, 水耕栽培茶の管理でお世話になった川西春義氏および北電興業 (株) 菅原彰敏氏に感謝致します.
TL;DR: Some calli were found to be preserved after immersing in liquid nitrogen (LN) and these results will be important to the development of cryopreservation methods of kiwifruit germplasm.
Abstract: Seeds obtained from kiwifruit (Actinidia deliciosa (A. chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward) were germinated and the calli derived from the hypocotyl of the seedlings were used to test various methods of cryopreservation. Some calli were found to be preserved after immersing in liquid nitrogen (LN) . The effective measures for preserving calli after immersing in LN are as follows ; calli were cultured with 24% (w/v) or 41% (w/v) sucrose for 2 days, and then after being dehydrated twice, first for 22 min with 60% (v/v) PVS2 (30% (w/v) glycerol, 15% (w/v) dimethyl sulfoxide, 15% (w/v) ethylene glycol and 13.7% (w/v) sucrose) and then for 23 min with 100% (v/v) PVS2, were preserved in LN. After cryopreservation, the calli were warmed in 37°C water immediately after being taken from the LN. They were washed in a liquid culture medium containing highly concentrated sucrose and then revived in a medium from which ammonium nitrate (NH4NO3) had been removed. These results will be important to the development of cryopreservation methods of kiwifruit germplasm.
TL;DR: The results indicate that the proper use of the transmitted light can provide precise quantification of leaf damage, even if it is characterized by a very complex pattern as leaf spot in Saintpaulia.
Abstract: Quantification of leaf spot (leaf damage with yellow spot) in Saintpaulia (Saintpaulia ionantha H. Wendl. cv. Ritali) was conducted by using an image analysis technique. Clear images without distortions or shadows were acquired by using a transmitted light from underneath the leaf. Quantification by the image analysis has very high correlation with that estimated by weighing the replicas of photograph. Furthermore, images analyzed by using an image editing software corresponded very well with the micrograph photographed under a fluorescence microscopy. These results indicate that the proper use of the transmitted light can provide precise quantification of leaf damage, even if it is characterized by a very complex pattern as leaf spot in Saintpaulia.
TL;DR: 1.7月20日に『福紫盃』と『あずまの雪』を播種し, 大部分の個体が本葉4枚完全に展蓉した状態に達した8週間後に12.5±1℃に3
Abstract: 1.7月20日に『福紫盃』と『あずまの雪』を播種し, 夜冷育苗, 高冷地育苗, ロゼット苗の低温処理育苗の採花率を比較した結果, 2月までに『福紫盃』ではどの育苗方法でも採花できなかったが, 『あずまの雪』は低温30日区で88%, 夜冷60日区で57%, 高冷地区で32%の株で品質のすぐれた切り花が採花できた.2.7月12日に66品種を播種し, 大部分の個体が本葉4枚完全に展葉した状態に達した8週間後に12.5±1℃に設定した保冷庫に4週間搬入後, 10月8日に定植した結果1月に4品種, 2月に29品種, 3月に29品種, 4月に4品種が開花し, 品種間差が大きかった.3.早・晩性の異なる20品種を5月15日, 5月31日, 6月14日, 7月1日に播種し, それぞれ本葉が4枚展開した後低温処理し, 8月19日, 8月26日, 8月30日, 9月10日に植え付け, 11～12月採花するための播種適期を検討した結果, 6月14日播種区が採花率と品質の点で最もすぐれていた.4.41品種を6月12日に播種して本葉が4枚展開した幼苗を低温処理して, 8月27日に定植した結果, 早生系のF1品種が11～12月採花に最も適していた.
TL;DR: In this article, the authors used the isopiestic psychrometer and pressure probe to measure the wall extensibility and effective turgor of soybean embryos under environmental stresses.
Abstract: Mechanisms of cell elongation were studied by using soybean (Glycine max [L.] Merr.) embryos subjected to environmental stresses under tissue-culture conditions. Water potential of culture media ranged from -0.02 to -0.80 MPa so that nutrient deficiency and salt stress conditions could be applied to plants grown in the media. According to Lockhart's growth equation, cell expansion is controlled by hydraulic conductance, growth-induced water potential, wall extensibility and effective turgor. All parameters were measured in elongating stems and roots of soybean embryos by using the isopiestic psychrometer and pressure probe. Wall extensibility was significantly larger than hydraulic conductance, and the effective turgor was significantly smaller than the size of the growth-induced water potential. Therefore, we conclude that cell elongation rates were primarily regulated by how much water could be absorbed by elongating cells and the size of the water potential difference between elongating cells and the water source under environmental stresses.
TL;DR: In this paper, a chopper amplifier for a potentiometer with a new DC-AC converter using metal oxide semiconductor field effect transistor (MOSFET) was developed.
Abstract: When electric potential on plant surface is to be measured, a potentiometer with high input impedance is required, because electric potential is very little. A chopper amplifier for a potentiometer with a new DC-AC converter using metal oxide semiconductor field effect transistor (MOSFET) was developed by the authors. The dynamic characteristic of the MOSFETs can be controlled by applying voltage to the substrates, so the MOSFETs are tried on the new amplifier as DC-AC converter. The four electrode type p-MOSFET is used for this chopper amplifier which has the electrode of the sauce, the gate, the drain and the substrate. In this chopper amplifier, the back of two MOSFETs are put together. The substrates of them were connected by each other, and are given square wave voltage. Then the input signal voltage is chopped into square wave and amplified differentially. The trial DC amplifier had very high impedance, more than 3.5 × 1010 Ω and 57 pF in parallel. The electric potential on a living plant surface is desired to be measured with no contact and no infiltrating for the sake of its reproducibility. Therefore conductive sponges were used as electrodes of this potentiometer, because they were made of carbon for a little polarization potential and they adhered easily to plants. Although the output impedance of the standard power source was very high, the input-output characteristic of this potentiometer had a good correlation for input voltage between -1.0 V and + 1.0 V. Surface electric potential voltages of some vegetables and fruits were measured by this potentiometer, and both electric potential voltages changed with time and their preservation ways were examined. From the results, the followings were obtained ;1. A high impedance potentiometer was designed and constructed for measuring surface potential voltage of living plant tissue.2. Electrical potential measurement was obtained noninvasively by using the sponge electrode.3. Correlation between freshness and electric potential voltage on a living plant surface was recognized by the measurements.4. Preservation in the refrigerator was effective not only for external appearance but for biological and physiological phenomena as well.
TL;DR: Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period, and these rates gradually decreased as the plant grew.
Abstract: In order to obtain basic data of evolution of ethylene from lettuce plant (Lactuca sativa L. cv. Okayama), ethylene concentration was measured in a closed chamber in which the plants were cultivated under controlled environment (25°C air temperature, 60-70% relative humidity, 200μmol m-2 s-1 photosynthetic photon flux density (PPFD), continuous lighting, 400μL L-1 CO2) . Ethylene release rates of intact lettuce plant on a fresh weight basis (Ef) and on a dry weight basis (Ed) ranged from 0.1 to 0.25 nmol g-1 h-1, and from 1.2 to 3.1 nmol g-1 h-1, respectively. These rates gradually decreased as the plant grew. The ethylene release rates on a leaf area basis (E1) remained constant (0.6 nmol dm-2 h-1), independent of leaf area. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period. Ed and E1 of lettuce plant cultivated at 2000μL L-1 CO2 were 1.4 times and 1.7 times, respectively, as much as those of the plant cultivated at 400μL L-1 CO2. Ed of lettuce plant was slightly higher in 300μmol m-2 s-1 PPFD than in 150μmol m-2 s-1 PPFD. E1s were similar to each other in both PPFD. Ed and E1 of lettuce plant cultivated at 12 h light/12 h dark period were 1.9 times and 1.7 times, respectively, as much as those of the plant cultivated at continuous lighting.
TL;DR: It can be supposed that the photosynthesis nearly compensated the respiration at a depth of 30 cm and supplied O2 to the roots in subsoil at shallower places, even when the pneumatophores were submerged in the daytime.
Abstract: The pneumatophores of Avicennia and Sonneratia species photosynthesize and the photosynthetically generated O2 is used for the respiration in the roots in subsoil. To understand the radiation environment of the pneumatophores, we measured solar radiation on the vertical surface (Rv) in the water with dye films. The Rv averaged over the daytime at a depth of 30 cm was similar to the light compensation points in the pneumatophores. From this result, it can be supposed that the photosynthesis nearly compensated the respiration at a depth of 30 cm and supplied O2 to the roots in subsoil at shallower places, even when the pneumatophores were submerged in the daytime.
TL;DR: All the Chinese cultivars had short stems, suggesting that they were suitable for pot flowers rather than cut flowers, and one Chinese cultivar in which flower buds blasted during forcing.
Abstract: Forced flowering of Chinese tree peony cultivars was tested in comparison with Japanese cultivars. All the Chinese cultivars flowered in late December as early as one of the earliest flowering Japanese cultivars. One of the most popular Japanese cultivars flowered late in January. Flower harvest rate was over 80% in all the cultivars except one Chinese cultivar in which flower buds blasted during forcing. Some Chinese cultivars produced crown or bomb type flowers which were rarely found in Japanese cultivars. All the Chinese cultivars had short stems, suggesting that they were suitable for pot flowers rather than cut flowers.
TL;DR: In this paper, the effect of dissolved O2 concentration on root water uptake in hydroponics was analyzed by measuring the stem base water flux in cucumber plants (Cucumis sativus L.) using heat flux control method (HFC).
Abstract: For analyzing the effect of dissolved O2 concentration on root water uptake in hydroponics, the stem base water flux in cucumber plants (Cucumis sativus L.) was measured by heat flux control method (HFC) in “a” newly developed system for controlling dissolved O2 concentration. At an air temperature of 25°C, a relative humidity of 70%, a PPFD of 300μmol m-2 s-1 (a photoperiod of 12 h) and a root temperature of 25°C, dissolved O2 concentration was controlled at set values of 0.01, 0.10 and 0.20 mM with an accuracy of ±0.005 mM. At each dissolved O2 concentration, the water uptake rate drastically increased by lighting the plant, and water uptake reduced in proportion to decrease in dissolved O2 concentration: Water uptakes per day at 0.20, 0.10 and 0.01 mM were 235, 186 and 164 g, respectively. This fact suggests that root water uptake in hydroponics is depressed at lower dissolved O2 concentrations by change in membrane permeability of root cells through respiration-dependent processes.
TL;DR: A method for application of the exergy concept to the optimization of greenhouse heating systems using the heat generated in composting is discussed in this paper, where exergy analysis helps to decide the optimum quantitative operating conditions under which not only the composting reaction most properly occurs but also the greenhouse heating process most effectively operates.
Abstract: A method for application of the exergy concept to the optimization of greenhouse heating systems using the heat generated in composting is discussed. It was found that exergy analysis helps to decide the optimum quantitative operating conditions under which not only the composting reaction most properly occurs but also the greenhouse heating process most effectively operates. According to the calculated results obtained for the heating process of a greenhouse on a small scale in the Hokuriku district, it was theoretically found that the optimum temperature of heat source is about 333 K and is almost equal to the optimum temperature for composting, in so far as we use a heat exchanger in which exergy dissipation due to friction is less than 10 times as much as the exergy dissipation due to friction during aeration through the compost bed.
TL;DR: A high reserve of nutrients, being available upon resumption of watering, was proposed to stimulate budbreak and subsequently to improve flower formation and a high level of ABA during water stresswas proposed to play a role in stimulating nutrient accumulation.
Abstract: Young “Riesling” grapevines were induced to produce second shoots by water stress before summer pruning. The vines, field-grown and established in isolated soil beds were subjected to water stress by disconnecting irrigation for 15 and 23 days. Water stress enhanced budbreak and cluster formation. In the early stage of water stress, abscisic acid (ABA) content increased in the canes and trunks, while it decreased in the roots. As the stress persisted, ABA content dropped in the canes and trunks, but increased in the roots. The levels of nitrogen, amino acids, and soluble sugars in the canes, trunks, and roots increased during water stress, while the levels of starch decreased. The results were discussed in relation to interactions of ABA with metabolism of amino acids and sugars. A high level of ABA during water stress was proposed to play a role in stimulating nutrient accumulation. A high reserve of nutrients, being available upon resumption of watering, was proposed to stimulate budbreak and subsequently to improve flower formation.
TL;DR: C cucumber plant growth was inhibited through leaf turgor loss caused by the depressed water uptake of roots in O2-deficient nutrient solution, and remarkable inhibition of leaf expansion was found with the decreased leaf water content.
Abstract: Dissolved O2 concentration in hydroponics was controlled at 0.01, 0.10 and 0.20 mM, and the growth of cucumber plant was analyzed in the respective dissolved O2 concentrations at a root temperature of 25°C, an air temperature of 25°C, a relative humidity of 70% and a PPFD of 300 μmol m-2 s-1 (a photoperiod of 12 h) . Growth of leaves and roots was inhibited at lower dissolved O2 concentrations, while the nodal development was not affected. At the lowest dissolved O2 concentration of 0.01 mM, remarkable inhibition of leaf expansion was found with the decreased leaf water content. These facts suggest that leaf expansion was inhibited through leaf turgor loss caused by the depressed water uptake of roots in O2-deficient nutrient solution.
TL;DR: これにより, 切り花の概形および花の密集の程度を数値化できた, 以下のようなことがわかった.
Abstract: 本報では, 処理方法を変えて栽培したスプレーギクを供試材料とし, 画像処理技術を用いて花房のフォーメーションを多角形で近似した.次に, その近似多角形を利用して評価指標を設定し, その評価指標を入力因子としたニューロによる品質評価の自動化について検討を行った.その結果, 以下のようなことがわかった.1.切り花全体および花の画像に対して, それぞれ濃度ヒストグラムより算出した異なるしきい値を利用することで適当な2値画像が得られた.また, 切り花全体の2値画像から最下位節が正確に検出できた.2.2値画像に基づき, 多角形近似を行うことで, 切り花全体および花の画像の有するフォーメーションの特徴を表現できた.3.近似多角形に基づき, 三つの評価指標の設定を行った.これにより, 切り花の概形および花の密集の程度を数値化できた.4.ニューロの入力因子として, 設定された三つの評価指標を用いて学習を行った結果, 生産者の評価結果に追従することがわかった.
TL;DR: The allowable level of ethylene for lettuce plant seemed to be about 0.1 to 1.0μL L-1 under any photosynthetic photon flux density (130, 270, and 380μmol m-2 s-1) as mentioned in this paper.
Abstract: Lettuce plant (Lactuca sativa L. cv. Okayama), which is a candidate for vegetables cultivated in Controlled Ecological Life Support Systems (CELSS), was exposed to ethylene. Effects of ethylene on the plant growth were investigated in order to determine an allowable level of ethylene. Although a few reports showed a decrease in rates of photosynthesis and transpiration of some plant species by 1.0μL L-1 ethylene, no decreases in the rates of lettuce plant were observed at 0.1 to 1.0μL L-1 of ethylene under any photosynthetic photon flux density (130, 270, and 380μmol m-2 s-1) . Then, the plant absorbed ethylene and the absorption rate increased with ethylene concentration. But the plant did not absorb ethylene under dark conditions. This fact might mean that lettuce absorbed ethylene mainly through stomata. The plant cultivated at 0.5μL L-1 ethylene for 10 days showed epinasty, chlorosis and inhibition of leaf expansion. These phenomena resulted in growth inhibition of lettuce plant. Leaf expansion of the plant cultivated at 0.1μL L-1 ethylene was also significantly inhibited. The plant growth rate was slightly lower compared with plants grown in ethylene-free air. From these results, it is obvious that a low concentration of ethylene influenced leaf expansion and chlorophyll degradation of lettuce plant, but not the rates of photosynthesis and transpiration. The allowable level of ethylene for lettuce plant seemed to be about 0.1μL L-1.
TL;DR: Familiarity, ease of access, trust, and awareness of risks and benefits will all be important.
Abstract: 庄野法を実際の作物 (トマト9個体) に適用し, 概略的形状と葉傾斜角の3次元分布の同時計測を試みた.計測した形状情報を, 統計的解析の容易な情報に簡略化し, それらの統計的な解析 (変動係数の分析, 相関分析) から, それぞれの形状情報の特性およびその有効性を検討した.この結果, 各形状情報の特性が明らかになるとともに, 供試材料の実際の形状的特徴を適切に反映し得ることが確認された.さらに主成分分析により, 簡略化した形状情報から合成指標を作成した.上位3主成分の意味の解析結果に基づき, 形状的特徴の全体的傾向および各供試材料間の位置関係を, 第三者に理解しやすい明確な形式で可視化することができた.