Environment Control in Biology
Online ISSN : 2185-1018
Print ISSN : 0582-4087
ISSN-L : 0582-4087
Volume 36, Issue 3
Displaying 1-8 of 8 articles from this issue
  • Yasuhiro ITANI, Yuichi YOSHIDA, Yukihiro FUJIME
    1998 Volume 36 Issue 3 Pages 125-129
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    This experiment was carried out to investigate the effects of CO2 enrichment on growth, yield and fruit quality of strawberry (Fragaria×ananassa Duch. cv. Ai-Berry) grown with two types of rockwool (RW : slub and granule) . The growth and development of plants were hastened in flowering date, maturing days and harvesting date by CO2 enrichment in both RW media. Between the RW media, the growth was more vigorous and yield was higher in granule compared to those in slub. CO2 enrichment increased total yield by 50 and 30% in RW slub and granule, respectively. Soluble solid content and titratable acidity of fruits were also increased by the CO2 enrichment. Although the leaf area of plants grown with CO2 enrichment was larger compared to the control, the rate of water absorption was almost equal. The electric conductivity of nutrient solution was also markedly decreased by CO2 enrichment. In midwinter, the CO2 concentration in the control greenhouse was lower than outside especially on fine and cold days, and much lower than those in the usual soil cultured greenhouses. Because in greenhouses for soilless culture where no organic substance is applied, only a small amount of CO2 can be expected to be supplied from the soil, CO2 enrichment may be necessary when strawberry plants are grown without soil.
    Download PDF (634K)
  • Toshio SHIBUYA, Toyoki KOZAI
    1998 Volume 36 Issue 3 Pages 131-136
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    In the production of plug seedlings, the air current speed around the seedlings is an important environmental factor affecting the rates of net photosynthesis (P) and evapotranspiration (E) . In the present experiment, a plug sheet consisting of tomato plug seedlings and soil mix was placed in a wind tunnel with artificial lights, and the P and E rates of the plug sheet were examined under different air current speeds, at an air temperature of 29-30°C, relative humidity of 60-70%, CO2 concentration of 340-360 μmol mol-1 and photosynthetic photon flux density of 270 μmol m-2s-1 At the inlet and outlet of the wind tunnel, absolute humidities (yin and yout, respectively) and CO2 concentrations (Cin and Cout, respectively) were determined with a dew point analyzer and an infrared CO2 analyzer, respectively. The weight of the plug sheet was measured with an electronic balance. The E was estimated based on the change with time in the weight of plug sheet. The air flow rate in the wind tunnel, F, was determined using an equation : E = F (yout-yin) /A, where A is the area of plug sheet. The P was determined using the equation : P=F (Cin - Cout) /A. The P and E increased as the air current speed and LA! (leaf area index of the seedlings) increased. However, the increase in P with the increase in LAI was less than the increase in E with the increase in LAI. Eleven days after seeding, when LAI=0.43, the P and E at an air current speed of 0.6 m s-1 were 1.4 and 1.9 times those at an air current of 0.1 m s-1, respectively.
    Download PDF (667K)
  • (1) Effects of Hydrogen-Ion Concentration Exponent and Free Effective Chlorine Concentration on the Control of Powdery Mildew on Cucumber Leaves
    Kazuhiro FUJIWARA, Mitsuo IIMOTO, Mikiko FUJIWARA
    1998 Volume 36 Issue 3 Pages 137-143
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    The effects of spraying water with different hydrogen-ion concentration exponents (pHs) and free effective chlorine concentrations (ECCs) on the incidence of powdery mildew (Sphaerotheca fuliginea Pollacci) on leaves of cucumber (Cucumis sativus L. cv. Shapu 7) grown in a plastic house were investigated as a fundamental research for the establishment of a crop disease control system with electrolyzed strong acid water. pH-regulated waters (pH: 2.0, 2.3 or 2.6; ECC : 0 ppm ; oxidation-reduction potential (ORP) : almost constant at 510 mV), ECC-regulated waters (ECC : 30, 40 or 50 ppm ; pH : 2.3 ; ORP : almost constant at 1 170 mV), or well water (pH: 7.8, ECC : 0 ppm, ORP : 460 mV) were sprayed, 4 times in 9 days, onto the leaves once every third day. The incidence of powdery mildew on cucumber leaves showed a tendency to decrease with decreasing pH or with increasing ECC of the sprayed water over the 12 days of observation. Water with a pH of 2.0 suppressed the incidence significantly at the 5% level against water with a pH of 2.6 and well water on day 12, which is 3 days after the last spray. Water with an ECC of 50 ppm suppressed the incidence significantly at the 5% level against water with an ECC of 30 ppm and well water on day 12. These results indicate that pH lower than a certain level can be a factor independently capable of controlling powdery mildew on cucumber leaves in spraying electrolyzed strong acid water, and that ECC higher than a certain level under a low pH can be a primary factor capable of controlling it.
    Download PDF (960K)
  • Yasuhiro ITANI, Yuichi YOSHIDA, Yukihiro FUJIME
    1998 Volume 36 Issue 3 Pages 145-150
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    This experiment was carried out to investigate the effects of CO2 enrichment (700-800 ppm in the day time) on the absorption of water and mineral nutrients in strawberry (Fragaria × ananassa Duch. cv. Nyoho) grown by nutrient film technique. The concentration of major elements in the nutrient solution were NO3- : 5, NH4+ : 1, H2PO4- : 1, K+ : 3, Ca2+ : 1, Mg2+: 1 mmol·L-1. Vigorous growth and high yield were obtained by CO2 enrichment. In control (ambient CO2, 200-400 ppm), the uptake concentration (each mineral absorbed per unit volume of water absorbed, n/w) was almost equal to the concentration of the solution, throughout growing period. However, under CO2 enriched condition, n/w and total uptake amount of minerals increased by 30-60% compared to control, especially, from November to February when the temperature and light intensity were low. The n/w of minerals were also 50-100% higher than the concentration of the nutrient solution. Total-N concentration in leaves was markedly decreased by CO2 enrichment, while there was little difference in P, K, Ca and Mg. To keep the concentration of nutrients in the solution, the concentration of nutrients should be kept 50-100% higher than those previously reported, when strawberry plants are grown with CO2 enrichment.
    Download PDF (660K)
  • Hajime ONODA, Teruo ONODA, Tsutomu SHIMODA, Ken ONODA, Tetsuo IWANO, T ...
    1998 Volume 36 Issue 3 Pages 151-157
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    To establish a year-round hydroponic method and a highly productive cultivation technique of paddy rice, we performed three cultivation tests in 1) completely controlled facility equipped with high pressure sodium lamps (HPS) and metal halide lamps (MH), 2) a facility with HPS using together with sunlight, 3) a facility with HPS and MH together with sunlight, 4) a facility with MH lamps together with sunlight and 5) a facility with only sunlight in 1994 and 1995. Photosynthetic photon flux density (PPFD) was greater in the completely-controlled facility with supplemental lighting, facility with HPS, facility with MH and HPS, facility with MH, and facility with only sunlight, in these order. The PPFD had significant positive correlations with the number of panicles, panicle length, number of grains and weight of brown rice, and had a negative correlation with the percentage of abortive kernels. When incorporated in the first stage of the multiple regression equation by a stepwise method that determined the brown rice weight, the contribution of PPFD was 96%. Particularly in the completely controlled facility and the facility equipped with MH and HPS, the increased photosynthesis brought about better growth and yield. Though the overall mean illuminance during rice growth also had a positive correlation with the weight of brown rice, its contribution by the multiple regression method was markedly low.
    Download PDF (869K)
  • I. Effects of Irradiation and Day/Night Air Temperature
    Masaharu KITANO, Takuya ARAKI, Hiromi EGUCHI
    1998 Volume 36 Issue 3 Pages 159-167
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    Dynamics of fruit growth and photoassimilate translocation in tomato plants (Lycopersicon esculentum Mill.) as affected by irradiation and day/night air temperature were analyzed in relation to respiration, photosynthesis and transpiration of the fruit and the leaf. Fruit growth was explained by about 80% of sap flux imported into the fruit and was scarcely affected by transpirational water loss from the fruit. Irradiation clearly enhanced fruit growth and photoassimilate translocation, and about 70% of fruit growth and about 80% of photoassimilate translocation were brought during the light period with highly activated leaf photosynthesis and fruit respiration under day/night air temperature of 25/15°C. In particular, when air temperature around fruits rose to 25°C in the light period, remarkable increases in fruit growth and photoassimilate translocation were found with the activated fruit respiration. On the other hand, decreases in fruit growth and photoassimilate translocation were found during the dark period without effects of air temperature. From these results, it was suggested that energy-dependent transport process of sugar in fruits is one of the determinant processes regulating fruit growth and photoassimilate translocation in tomato plants under light.
    Download PDF (1160K)
  • Yasuomi IBARAKI, Takahiko NIKAIDO, Kenji KURATA
    1998 Volume 36 Issue 3 Pages 169-176
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    Acridine orange was used as a fluorescent probe for nucleic acids to investigate the establishment of polarity during somatic embryogenesis of carrot (Daucus carota L.) . The fluorescence emitted by acridine orange in cell clusters and somatic embryos was observed using a confocal laser scanning microscope. The fluorescence was split into a green component and a red component by optical filters. The green fluorescence emitted by acridine orange, which intercalated into double-stranded nucleic acids, was observed mainly in the nucleus. An increase in intensity of the red fluorescence emitted by acridine orange, which bound to single-stranded nucleic acids, was observed after the somatic embryo induction treatment without 2, 4-D in the medium. In addition, the biased distribution of the red fluorescence was observed in cell clusters before the formation of globular embryos. The biased distribution of fluorescence suggested that there were physiologically different cells in these cell clusters and supported the notion that physiological polarity appeared prior to the formation of globular embryos.
    Download PDF (4925K)
  • Noriko TOMITA, Takashi HIRANO, Makoto KIYOTA
    1998 Volume 36 Issue 3 Pages 177-181
    Published: September 30, 1998
    Released on J-STAGE: June 22, 2010
    JOURNAL FREE ACCESS
    In order to know the effect of supplemental UV-A irradiation on the growth of lettuce (Lactuca sativa L. cv. Okayama) and radish (Raphanus sativus L, cv. Comet), these plants were grown under artificial irradiation with 3-band fluorescent lamps and additional UV-A lamps. The UV-A irradiation promoted shoot growth of both plants, and reduced the bitter taste intensity of mature lettuce leaves. However, the UV-A effects varied with stage of vegetative development. Moreover, there was no significant effect of the UV-A on the hypocotyl growth of radish plants.
    Download PDF (522K)
feedback
Top