Since the Kyoto conference, new frameworks for greenhouse gases (GHGs) reduction, such as the Clean Development Mechanism (CDM), Joint Implementation (JI), and International Emissions Trading (JET) have been proposed. Implementation of these emerging concepts will change the perspective for biological CO₂ mitigation strategies. For example, conducting the CO₂ mitigation projects in non-Annex I countries rather than in the Annex I countries will lower both capital and operating costs of CO₂ mitigation projects. In addition, in some non-Annex I countries sufficient land might be available for the biological CO₂ mitigation, which may not be available in land-short Annex I countries. In this study, the impact of this new framework on feasibility of microalgal CO₂ mitigation technology was assessed and the feasibility of microalgal CO₂ mitigation for Japan in non-Annex I countries was examined. The results showed that implementing new frameworks will improve the feasibility of open-pond microalgal CO₂ mitigation systems. Even with conservative assumptions of productivity of 30 tCO₂/ha/yr with no revenue from the byproducts, open-pond microalgal CO₂ mitigation is competitive to alternative CO₂ mitigation technologies. With some favorable assumptions, CO₂ mitigation cost can be within the range of estimated international CO₂ prices.

View full abstract

The computational methods to detect the coding regions of genes and specific sequences of the transcriptional control region using stochastic models such as the hidden Markov Model have been developed. But there are still aspects of the control of the gene expression based on a sequence of the transcriptional control region that have not been described. We report here our attempt to apply texture analysis to a sequence surrounding a transcriptional starting site to extract the features. We developed the features extraction program by employing texture analysis based on the gray level run length matrix and applied it to sequences surrounding transcriptional starting sites of genes coding the heat shock proteins. Thus we could successfully represent features extracted from a sequence surrounding transcriptional starting sites as specific patterns of them.

View full abstract

This work was undertaken to investigate response of callus and the water status of Sturt's desert pea (Swainsona formosa) in vitro under various environmental stress conditions. Water potential of culture media ranged from -0.27MPa to -1.05MPa so that salt and osmotic stress and different concentration of sucrose could be applied to Sturt's desert pea calli grown in the tissue culture media. The percent increase in calli was highest in standard MS medium with 30g L^-1 sucrose but was not so when the water potential of medium was adjusted to the same water potential using standard MS plus mannitol. The water potential of callus tissue was almost the same as that of culture media at any range of MS and sucrose concentrations. Turgor of callus tissue did not alter significantly under any stress conditions. It is concluded that the optimum concentration of salt, sucrose and water status of medium could be estimated by this method and that standard MS concentration and its water status are suitable for the formation of Sturt's desert pea calli.

View full abstract

Tolerance to fusarium wilt, caused by Fusarium oxysporum f, sp. fragariae (Fof), in strawberry (Fragaria×ananassa Duch., cv. Nohime) plants infected with arbuscular mycorrhizal (AM) fungi (Gigaspora margarita, Glomus fasciculatum, Gl. mosseae, Gl. sp. R10, Gl. aggregatum) was estimated under capillary watering conditions. Thirty days after Fof inoculation, the incidence of fusarium wilt ranged from a minimum of 22.2% in Gl. mosseae plot and a maximum of 100% in non-AM one ; the incidence varied, depending on AM fungal species. Incidence and severity of browned vessels and roots became lower in AM plots than in non-AM one. Non-diseased and diseased AM plants had higher dry weight of shoots and roots than did diseased non-AM plants. No significant difference in phosphorus concentration in plants appeared between non-AM and AM plots 11 weeks after AM fungus inoculation (just before Fof inoculation) and 30 days after Fof inoculation. These findings suggest that tolerance to fusarium wilt occurred in AM fungusinfected strawberry plants, and the effect had less association with phosphorus concentration in plants.

View full abstract

Hydraulic properties related to growth of flower stalks, leaves and roots in tulip (Tulipa gesneriana L.) plants were studied after bulbs were stored at 20°C continuously or under low temperature for 4-, 7- or 9-week periods. The shorter cold storage periods in the bulbs resulted in the reduced growth of roots, leaves and flower stalks. Differentiation and development of vascular bundles in flower stalks of growth-reduced plants caused by the shorter cold storage periods were similar to those of rapidly growing tulip plants. A decrease in hydraulic conductance was associated solely with reduced cell elongation rates, but not with the processes of cell division and tissue differentiation. Sizes of the water potential gradient between the water source and the expanding cells were linearly related to speeds of growth rates in all organs. Further, the shortage of cold periods led to lower hydraulic conductance in the zone of elongation of those tissues. Therefore, reduced growth in the elongating zone of all tulip tissues was associated with the reduction of both the hydraulic conductance and the size of the growth-induced water potential regardless of the period of low temperature treatments.

View full abstract

The present study was undertaken to clarify the relationship between tepal growth and the hydraulic properties of expanding tulip (Tulipa gesneriana L.) tepals. The growth rate of outer tepals was measured with an extensiometer while growth of the tepals was altered by feeding sucrose solution or trehalose solution to cut tulip flowers. Feeding sucrose to the flowers increased cell elongation rates of tepals and feeding trehalose to the flowers decreased the cell elongation rates. Simultaneously, turgor of the epidermal cells in the zone of elongation of intact outer tepals was measured with a cell pressure probe. Cell osmotic potentials were measured with the isopiestic psychrometer after extracting cell solution of similarly treated cut flowers. Cell water potential was obtained by summing cell turgor and its osmotic potential. When the hydraulic conductance of intact growing tepal tissues was calculated by dividing the growth-induced water potentials by the relative growth rates at the steady states, it was found that the hydraulic conductance was significantly decreased by trehalose feeding. Therefore, it was thought that changes in the hydraulic conductance were responsible for rapid changes in growth rates in tulip tepals when components in the vase solution were modified in cut tulip flowers.

View full abstract

In soilless culture, control of nutrient solution is very important for production of the high quality tomato fruits. The control will be efficient by taking the information of internal properties of growing fruits into account. Therefore, nondestructive measurement method for these properties is highly required. Nondestructive near infrared (NIR) methods have already been used effectively in many crops such as mango, apple, peach, however, no studies have been reported on growing tomato fruit. In addition, tomato fruit has a great variation in internal structure that consists of flesh and pulp. It causes ununiformity in texture and chemical compositions within a fruit and hence significantly affects NIR spectra. Therefore, specially assembled NIR instrument is required for accurate nondestructive determination of constituents in the fruit. Three halogen lamps as a light source of the instrument illuminated almost the whole fruit surface from the upper side. Then the spectrum of transmitted light through the bottom of the sample was measured by spectrometer. The performance of this instrument was investigated by developing calibration model for determination of the soluble solids content (SSC) in the whole fruit from the spectrum. This method successfully determined the SSC of tomato fruits with correlation coefficient between predicted and actual values (r) of 0.91, standard error of performance (SEP) of 0.73%, and bias of 0.17%.

View full abstract

In order to examine the short-term response of tomato (Lycopersicon esculentum Mill.) plants to water stress, we investigated the dynamics of fruit growth and water balance in growing fruits under the well-watered and the water deficit conditions. Under the well-watered condition, most (84%) of pedicel sap flux toward the fruit contributed to fruit expansion, and the residual (i.e. only 16%) was lost by transpiration from the fruit and its calyx. The most dominant component of the fruit water balance was the phloem sap flux, since a major part (i.e. 70%) of the sap delivered into the fruit was brought by phloem transport. On the other hand, xylem transport made a lesser contribution to the fruit expansion and exhibited larger susceptibleness to water stress. Under the water deficit condition, the fruit growth rate was depressed to 36% of well-watered plants, while phloem sap influx to the fruit was less affected. Xylem sap backflow occurred frequently under the water deficit condition, and the net influx of xylem sap during the whole day was nearly zero. The phloem transport solely sustained the fruit growth under water stress. This study quantitatively demonstrated that water deficit results in smaller fruits with higher sugar concentrations through different responses of phloem and xylem transport to water stress.

View full abstract

‘Meiwa’ kumquat (Fortunella crassifolia Swingle) trees were subjected to water stress in order to increase first-flush flowers by withholding water until the soil water content reached about 35% and maintained 2 weeks, 3 weeks and 4 weeks. In all treatment subjected to water stress increased first-flush flowers as compared with non-treated control trees. The number of first-flush flower increased with the prolonged duration of water stress. Early fruit develop-ment in water stressed trees were promoted and fruit diameter at harvest increased significantly. In rind color of the fruit at harvest, a value of the rind increased significantly suggested promotion of fruit maturation in water stressed trees. Total soluble solids of the fruit in water stressed trees were not different from the control trees, while yield per tree in water stressed trees were significantly increased as compared with the control trees. These results indicate that the number of first-flush flowers increases under water stress after termination of new shoot growth and yield increases significantly without degrading fruit quality.

View full abstract

The effect of purple nonsulfur bacteria (Rhodobacter sphaeroides) application on the growth and quality of Komatsuna (Brassica campestris) was investigated under different light qualities using blue (470 nm) and red (660 nm) light emitting diodes (LED) . Freeze dried purple nonsulfur bacteria (PTBP) were used for the investigation. Komatsuna plants were grown for 21 days with or without PTBP application under 3 different light qualities (blue-100%, red-100%, blue 20%-red 80%) at 20°C in a growth chamber. The PTBP application significantly promoted root growth under the blue-100% treatment, whereas the no PTBP application under the same light quality reduced root growth compared to the other light quality treatments. Moreover, the PTBP application under blue-100% increased chlorophyll and carotenoid contents, and reduced total sugar and ascorbic acid contents. On the other hand, the PTBP application under red-100% reduced nitrate and ascorbic acid contents. These results indicate that PTBP application significantly promotes growth and quality of Komatsuna under blue light, and may also compensate for red light.

View full abstract