Environment Control in Biology

Large-Scale Transplant Production by Somatic Embryo Culture and Its Environmental Control

Teruaki SHIMAZU, Kenji KURATA

2002 Volume 40 Issue 2 Pages 133-146
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.133

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Somatic embryogenesis has been recognized as the theoretically most effective method for micropropagation of transplants and the material of artificial seeds. The main advantages of somatic embryogenesis over axillary or adventitious shoot propagation are that the procedures of cutting plantlets into segments and transferring segments onto new media in the proliferation phase are not necessary. The main problems restricting the commercial application of somatic embryogenesis for plant micropropagation are poor productivity and quality of embryos produced in liquid culture. Induction of somatic embryogenesis in liquid culture using bioreactor systems offers opportunities for bioprocess automation and environmental control, and consequently is expected to reduce manual labor and costs. This review gives an overview of research on large-scale transplant production by somatic embryo culture and its control of environment, mainly for bioenvironmental and bioprocess engineers.

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Effects of Cell Shape on the Growth of Plug Transplants in Several Vegetable Crops

Jie CHEN, Tadashi ITO, Yutaka SHINOHARA

2002 Volume 40 Issue 2 Pages 157-166
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.157

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Effects of cell shape on the growth of plug transplants of lettuce, cucumber, tomato and sweet corn were investigated. Round, pentagonal, square and triangular cells with the same volume of growing medium were used. In lettuce and cucumber plug transplants, round cell promoted root circling while triangular cell retarded compared to pentagonal and square cells. Before root ball formation, round cells promoted plant growth. On the contrary, they inhibited plant growth after root ball formation compared with square and pentagonal cells. Triangular cell inhibited plant growth at each growth stage. In tomato plug transplants, the rate of root circling was increased in order of round, pentagonal, square, and triangular cells. However, cell shape did not affect the plant growth before root ball formation, while the growth of plants in triangular cell was inhibited compared with all other cells after root ball formation. In sweet corn plug transplants, root circling and plant growth were unaffected by cell shape at each growth stage. In conclusion, square or pentagonal cells are more suitable for lettuce and cucumber plug transplants than round and triangular cells. Except triangular cells, the cells with other shapes are suitable for the production of tomato plug transplant. The cell shape is not an important factor in sweet corn plug transplant production.

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Effects of Nutrient Solution Levels on the Growth, Yield and Mineral Contents in Hydroponically-Grown Bush Snap Bean

Manolo Toledo VALDEZ, Tadashi ITO, Yutaka SHINOHARA, Toru MARUO

2002 Volume 40 Issue 2 Pages 167-175
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.167

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This study was conducted to determine the influence of nutrient solution levels on the growth, yield, mineral contents and some physiological characters of bush snap bean, and to determine their effects on water and nutrient uptake. The treatments used were 1/4, 1/2, 1, 11/2 and 2 times of the standard Enshi-shoho solution concentration. Increasing nutrient strength reduced vine length, but increased plant fresh and dry weights, leaf chlorophyll, photosynthetic rate, transpiration rate and stomatal conductance at flowering and early pod development stages. Water and nutrient uptake increased with increasing nutrient levels. N, P and K contents in the leaf blades and young pods increased while Ca and Mg decreased with increasing nutrient strength. Leaf blades had higher total-N, Ca and Mg contents, while pods did higher P and K. Percent pod set was slightly improved in 1/2 to 2-strength treatments. Pod yield was comparable among 1/2, 1, 11/2 and 2-strength treatments. The results indicate that 1/2 strength is sufficient for high yield of bush snap bean.

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Effects of Root Zone Temperatures and N-K Nutrition on the Growth, Flower and Pod Abscissions, Pod Production and Mineral Contents of Bush Snap Bean

Manolo Toledo VALDEZ, Tadashi ITO, Toru MARUO, Yutaka SHINOHARA

2002 Volume 40 Issue 2 Pages 177-186
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.177

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Bush snap bean cv. Torukatto was used to investigate the effects of root zone temperatures (RZTs) and N-K levels on the growth, abscissions of flowers and pods, pod production and mineral contents. The effects of RZTs were more pronounced than N-K supply on the vegetative as well as reproductive performance in this cultivar. RZTs at 20, 25 and 30°C enhanced plant growth while 35°C RZT reduced it producing plants with less vegetative growth of vine, greener leaves and smaller leaf area. Moreover, photosynthetic activity tended to increase with an increase in RZT up to 30°C in combination with either of the N-K levels. Higher number of pods was obtained from plants grown with 20, 25 and 30°C RZT. Increased total-N, Ca and Mg contents were observed in leaf blades while P was higher in the pods and K was similar in both organs. The results suggest that maintaining the root zone temperature within the range of 20 to 30°C may act more effective for growth performance regardless of N-K supply in the nutrient solution. High RZT of 35°C has an adverse effect on root growth that can lead to the death of root tissues.

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Effects of Leaching Rate and Renewal of Nutrient Solution on Cucumber Growth in Recirculating Hydroponics Using Organic Medium

Shoko HIKOSAKA, Masaaki HOHJO, Toru MARUO, Yutaka SHINOHARA, Tadashi I ...

2002 Volume 40 Issue 2 Pages 187-194
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.187

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Cucumbers were grown in bag cultures with bark and peat medium to establish an appropriate administrative method of nutrient solution. Different volumes of nutrient solutions with a 2.4 dS⋅m^-1electric conductivity (EC) were supplied to control the leaching fraction (LF) at 0, 15 and 30% of the applied solutions. The renewal frequencies in reservoir were set at zero or twice. The yield, leaf area, chlorophyll and N content of the leaves were greater in the 15 and 30% LFs than those in the 0%, with no difference between the 15% and 30% LFs. Solution renewal did not affect these parameters, EC and nutrient composition in the reservoir. The poor growth in the 0% LF could be ascribed to osmotic stress because the EC of the nutrient solution in the medium significantly increased. However, there were few differences in the nutrient accumulation inside the medium in all treatments. More than 20 to 40% of the nutrients, except for NH₄-N, applied to the plants was discarded by the renewal. These results suggest that if EC 2.4 dS⋅m^-1 was adopted for this growing system, more than a 15% LF should flow out to avoid an increased EC in the medium. The renewal of the nutrient solution in reservoirs is not beneficial for the increasing yield.

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Varietal Differences of Rice (Oryza sativa L.) Growth to Low Nitrogen Supply

S.M. Nurul AMIN, Naotsugu UCHIDA, Tomoko HATANAKA, Tetsushi AZUMA, Tak ...

2002 Volume 40 Issue 2 Pages 195-200
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.195

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Appropriate and effective nitrogen (N) use is an important factor to realize the sustainable rice production and to avoid environmental pollution. In this study, the low N conditions were induced by two different treatments; the restricted supply of N fertilizer by soil culture and the sudden depression of N by water culture. The growth responses of eight varieties of indica rice to low N supply were analyzed using fundamental growth parameters and specific nitrogen utilization rate (NUR) . The relative growth rate (RGR) was generally higher in the local varieties than improved varieties in both experiments. The net assimilation rate (NAR) showed a close correlation with RGR, whereas the specific leaf area and leaf weight ratio did not. A highly positive correlation was found between RGR and NUR. Among the local varieties, Pokkali showed the highest RGR, NAR and NUR in both experiments. These results indicated that under low N supply, the growth rates of the local varieties were higher than those of the improved varieties due to their higher NAR and NUR.

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Partitioning of Absorbed Nitrogen to Chloroplast, Soluble Protein and Rubisco in Rice Leaves under Low Nitrogen Supply

S.M. Nurul AMIN, Naotsugu UCHIDA, Chisato MASUMOTO, Tomoko HATANAKA, H ...

2002 Volume 40 Issue 2 Pages 201-206
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.201

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Nitrogen (N) fractions such as chloroplast, total soluble protein and ribulose-1, 5-bisphosphate carboxylase (Rubisco) in rice leaves were determined for 8 cultivars of indica rice at two N supply levels. The conversion rates from absorbed N to chloroplast-N ranged from 78 to 84%, and the rates depended not on the exogenous N levels but on the cultivars. The amounts of total soluble protein and Rubisco increased linearly with increasing leaf N content, and their correlation coefficients were significantly high. The proportion of total soluble protein-N to total leaf N was different among cultivars, and their values varied from 59 to 75% in the control plot and from 43 to 61% in the low N plot. The Rubisco-N accounted for about 24 to 45% of total leaf N in the control plot and varied from only 5.8 to 27% in the low N plot depending on cultivars. The partitioning rate of total leaf N to the Rubisco-N was influenced most severely by low N supply among the N fractions examined.

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Diurnal and Annual Variations in the Spectral Photon Flux of Daylight at Gifu City

Yukitsugu ISHII, Keisuke YAMAZAKI

2002 Volume 40 Issue 2 Pages 207-213
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.207

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Photon flux (PF) in the spectral regions of 300-400 nm (UV), 400-500 nm (B), 500-600 nm (G), 600-700 nm (R) and 700-800 nm (Fr) were observed almost daily with a spectroradiometer (LI-1800) at noon in from Jan. 2000 to Mar. 2001 at Gifu (lat. 35°25' N and long. 136°46' E) . The spectral ratio of B/photosynthetic photon flux (PPF) and R/PPF on clear days changed reversibly during the morning and in the evening; variability was less during the daytime. Whereas G/PPF was almost constant during the whole studies period irrespective of fine or cloudy weather. The B/PPF ratio increased rapidly from 24.6% on the winter solstice to 27.1% on the vernal equinox. After reaching a peak of 27.3% on the first day of autumn, it decreased gradually from the autumnal equinox to the winter solstice. The seasonal changes in R/PPF showed opposite tendencies for B/PPF. This cycle of spectral photon flux probably assists plants in making a distinction between spring and autumn season. We found that the PPF as well as UV, B, G, R and Fr values were nealy equal in vernal equinox and autumnal equinox. The R/PPF ratio for the fine days was high and B/PPF was low in comparison with the cloudy days.

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Intelligent Control of Heat Stress to Reduce the Water Loss of Fruit during Storage

Testuo MORIMOTO

2002 Volume 40 Issue 2 Pages 215-222
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.215

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In this study, an optimal control of heat stress was applied to minimize the water loss of fruit during storage using an intelligent control system. The control system consists of a decision system and a feedback control system. In the decision system, the dynamic change in the rate of the water loss, as affected by temperature, is first identified using neural networks and then the optimall-step set points of temperatures that minimize the rate of the water loss are sought through simulation of the identified neural-network model using genetic algorithms. Here, anl (=6) -step control process was supposed. The length of each step was 24 h. Two optimal values, a single heat stressT= {40, 15, 15, 15, 15, 15°C} and double heat stressT= {40, 15, 40, 15, 15, 15°C}, were obtained as the optimal values under the range of 15 to 40°C. Especially, a temperature operation first rising to the highest level and then dropping to the lowest level in the given range provided a lower rate of the water loss than by keeping constant at the lowest level through whole the control process.

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Effect of Soil Compost on Bulblet Growth of Lilium japonicum Thunb

Masanori OHKAWA

2002 Volume 40 Issue 2 Pages 223-227
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.223

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Experiments were conducted to determine the effect of soil compost on growth of leaf, root and the regenerated bulblet from bulb scales ofLilium japonicumThunb. in vitro culture. The bulblets, subcultured on MS-medium under continuous light of 40 μmol m^-2s^-1at 20°C in vitro, were taken out from a culture tube and transplanted into four kinds of soil compost used in the experiment. They were cultured for 120 d in a glasshouse. Soil of equivalent volume of perlite and vermiculite was the most effective for leaf emergence rate, rooting and bulblet growth in the four kinds of soil. The mixture of perlite and vermiculite was considered to be in suitable humidity, aerial and nutritional conditions. On the other hand, soil of equivalent volume of perlite and vermiculite was ineffective.

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Rosetting Characteristics-Based Classification of Eustoma grandiflorum (Raf.) Shinn. Cultivars Sown on Different Dates

Jie LI, Yohko NOTSU, Makiko OGAWA, Hajime OHNO, Kiyoshi OHKAWA

2002 Volume 40 Issue 2 Pages 229-237
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.229

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Eustoma grandiflorumseedlings become rosetted under high temperature conditions. This characteristic varies among cultivars. To classify 241Eustomacultivars based on their rosetting characteristics, the bolting rates were checked weekly after sowing in May, June or July. When seeds were sown in May, the bolting rate was generally higher, but in June sowing, bolting rates ranged from high to low values. The bolting rate in July sowing was the lowest. Abnormal bolting was observed in all of the three sowing months. In evaluating bolting rate, the bolting rate of abnormally bolted seedlings was multiplied by 0.5 and that of rosetted ones was regarded as 0. Based on the calculated rosette index using this evaluated bolting rate, we ranked all the 241 cultivars as A-E (rosette index : A<20, 20≤B<40, 40≤C<60, 60≤D<80 and 80≤E) . As a result, 17, 35, 122, 56 and 11 cultivars were ranked as A, B, C, D and E, respectively.

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Volatile Constituents and Free Amino Acids in Ethylene-Treated Citrus grandis [L.] Osbeck Fruits

Kazutaka NISHIKAWA, Hidenori OKABAYASHI, Masayoshi SAWAMURA, Masahiro ...

2002 Volume 40 Issue 2 Pages 239-243
Published: June 30, 2002
Released on J-STAGE: June 22, 2010

DOIhttps://doi.org/10.2525/ecb1963.40.239

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‘Tosa-buntan’ (Citrus grandis [L.] Osbeck) fruits were treated with 0, 20, and 40 ppm ethylene for 96 h in the dark in order to ripen the fruit and improve the color. As a result, the 20 and 40 ppm ethylene-treated fruits showed a decrease in their chromatic component (L value), and an increase in their a value and free amino acids (especially, asparagine and glutamic acid), compared with the untreated fruits. The effectiveness of ethylene treatments showed no difference between 20 and 40 ppm. Volatile constituents were analyzed by capillary GC and GC-MS, respectively. The amount of flavor compounds in the fruits showed no change regardless of the administration of the ethylene treatment or the storing period. The content of nootkatone, the characteristic flavor compound of pummelo, increased in all treatments. These results suggest that the ethylene treatment of‘Tosa-buntan’is a useful storing method for shipment to the market.

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