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In order to study the IAA-induced modifications of the cell wall of azuki bean {Vigna angularis Ohwi et Ohashi cv. Takara) epicotyl segments, the xyloglucans were subfractionated into two components, i.e., 4K-U and 24K xyloglucans, which were obtained by extraction with 4% KOH solution containing 8 M urea and 24% KOH solution, respectively. The weight-average molecular weights of 4K.-U and 24K xyloglucans were estimated to be 40 x 10 and 106 x 10, respectively. Complete acid hydrolysis of 4K-U and 24K xyloglucans gave glucose, xylose, galactose and fucose in mole % 48.3 : 33.5 : 13.8 :4.4 and 45.3 : 30.9 : 19.6 : 4.3, respectively. Treatment of epicotyl segments with IAA (0.1 miu) caused a decrease in the amount of 24K xyloglucans and an increase in 4K-U xyloglucans, whereas the total amount of the two xyloglucans remained constant. Furthermore, TAA treatment caused a decrease in the molecular weight of 24K xyloglucans from 106X 10 to 78 X 10 without causing changes in their sugar compositions. With 4K-U xyloglucans, IAA caused an increase in the mole % of xylose and a decrease in the mole % of galactose and fucose.

SASAKI, K., INOUE, S., YOSHIDA, A., HAYASHI, F., MASUDA, Y. and HONDA, Y. Ventilatory Response and Drive Due to Carbon Dioxide Stimulation in Idiopathic Scoliosis. Tohoku J. exp. Med., 1982, 137 (2), 145-151-Ten patients with idiopathic scoliosis and seven controls were studied for the purpose of investigating the ventilatory response and drive due to CO2 inhalation by the steady state CO2 response test. To evaluate the ventilatory drive for the respiratory output mouth occlusion pressure (P0.1) was used. The ventilatory response to CO2 of the patients was not significantly different from that of the controls. P0.1 for a given PCO2 stimulation or tidal volume in the patients was significantly higher than the control. Ventilatory output against P0.1, however, was not different in the two groups. The small tidal volume of the scoliotic patients seemed to be compensated by the high respiratory frequency with a large ventilatory drive in order to maintain adequate ventilation.

Galactose inhibited auxin-induced cell elongation of oat coleoptiles but not that of azuki bean stems. Galactose decreased the level of UDP-glucose in oat coleoptiles but not in azuki bean hypocotyls. Glucose-1-phosphate uridyltransferase activity (EC 2.7.7.9), in a crude extract from oat coleoptiles, was competitively inhibited by galactose-1-phosphate, but that enzyme from azuki bean was not. A correlation was found between inhibition of growth by galactose and inhibition of glucose-1-phosphate uridyltransferase activity by galactose-1-phosphate using oat, wheat, maize, barley, azuki bean, pea, mung bean, and cucumber plants. Thus, it is concluded that galactose is converted into galactose-1-phosphate, which interferes with UDP-glucose formation as an analog of glucose-1-phosphate.

Changes in sugar compositions and the distribution pattern of the molecular weight of cell wall polysaccharides during indole-3-acetic acid (IAA)-induced cell elongation were investigated. Differential extraction of the cell wall and gel permeation chromatography of wall polysaccharides indicated that galactans, polyuronides, xylans, glucans and cellulose were present in the azuki bean epicotyl cell wall. When segments were incubated in the absence of sucrose, IAA enhanced the degradation of galactans in both the pectin and hemicellulose fractions, whereas to some extent it enhanced the polymerization of xylans and glucans in the hemicellulose fraction and an increase in the amounts of polyuronides in the pectin fraction and of a-cellulose. In the presence of 50 nw sucrose, IAA caused large increases in the amounts of all the wall polysaccharides, and enhanced the polymerization of galactans, xylans and glucans in the hemicellulose fraction. These results and an important role of galactan turnover in cell wall extension are discussed.

o) was the shortest in the upper region (0-30 mm below the apex) of the epicotyl, where vigorous endogenous growth took place, and became longer toward the basal region, which was mature and not growing. In the upper region of the epicotyl, a lower percentage of a-cellulose and a higher percentage of pectic substances than in the lower region were found. The percentage of hemicellulose content was almost constant over the whole epicotyl. Major components of noncellulosic neutral sugars in the cell wall were galactose and xylose. The percentage of the galactose content to the noncellulosic polysaccharide was highest in the upper region and lowest in the basal region of the epicotyl, and a clearly negative correlation between the galactose composition and the T o value was obtained. On the contrary, the percentage of die xylose content was highest in the basal region and lowest in die upper region, and a clearly positive correlation between die xylose composition and the To value was obtained. During die endogenous growth of die intact epicotyl, all die neutral sugars, particularly galactose, increased in die upper region, whereas in die middle and basal regions, only xylose increased. Similar changes in sugar compositions were observed during IAA-induced elongation of die segment excised from various regions of die epicotyl.

A study was made to find whether the nodding of the flower stalk in a poppy, Papaver Rhoeas L., immediately after its formation was triggered by the weight of its flower bud or by positive georeaction and the following results were obtained. (1) The direction of the nodding was mostly toward the inclined side of the stalk, which was opposite the leaf, for apical flower buds. (2) If the weight of the flower bud at stage 1 was cancelled by applying a load equivalent to the bud weight, the nodding of the stalk was not initiated. (3) The stalk at stages 1 and 2 and the upper part of the stalk (bending zone), as compared with the basal part, at later stages were highly deformable according to measurements by the bending method. (4) The cell wall of highly deformable stalks was rich in hemicelluloses and that of the basal part was abundant in pectic substances. From these results, we concluded that the initiation of the nodding in the flower stalk was caused by the weight of the flower bud and positive geotropic reaction was probably not involved.

Effects of auxin (indole-3-acetic acid), fungal β-1,3-glucanase and pectin methylesterase on expansion and on cell wall extensibility, measured by the extensometer technique, of oat coleoptile segments were studied. Pretreatment with these substances for less than 30 min promoted tissue expansion remarkably. Under osmotic stress by 0.25 M mannitol, which prevented uptake of water by the cells, auxin increased DE but not DP in 30- and 60-min incubations. β-1,3-Glucanase or β-1,3-glucanase plus pectin methylesterase also increased only DE under the same conditions. A role of cell-wall-degrading enzymes in initiating cell expansion is therefore suggested.

Auxin-induced changes in mechanical properties of the plant cell wall have been confirmed using non-automatic techniques (cf. Heyn and van Overbeek, 1931; Cleland, 1958; Masuda and Wada, 1966). A newly-developed technique using an automatic tensile testing apparatus offers several advantages in operation and in evaluation of the results obtained (Olson et al., 1965; Cleland, 1967). However, mechanical properties of the cell wall measured by a standard tensile technique, as compliance (Cleland, 1967), is not easy to interpret rheologically. We have recently developed a technique using a stress-relaxation process to determine rheological properties of the cell wall. This technique is useful for obtaining better insights into the mechanism(s) of cell growth.

This study describes the stress relaxation of the cell wall of oat (Avena sativa) coleoptiles after different periods of geotropic stimulation. The upper and lower tissues (with respect to gravity) of geotrophically stimulated coleoptiles exhibit different wall properties. The lower tissues are less resistant to deformation than the upper. The ratio of stress to strain is significatly less in the lower than in the upper tissue. Similarly, the relaxation time and the minimum relaxation time, derived from the Maxwell model which describes the physical characteristics of polymers, are also shorter in the lower tissue. However, the maximum relaxation time shows no difference between the upper and lower tissues of a geotropically stimulated coleoptile. The differences between the tissues begin at about 8 minutes after the commencement of stimulation, similar to the time for the initiation of dictyosome redistribution, and precede the onset of geotropism. The above responses of the cell wall of the lower tissue are similar to those induced by indoleacetic acid. The parameters of wall properties of the coleoptiles of both the control and the geostimulated fluctuate rhythmically with time. The periodic changes in wall properties of the coleoptile are compared to other cyclic physiological phenomena.

When the homogenate of Avena coleoptile segments was fractionated, the specific activity of β-1, 3-glucanase was remarkably associated with the cell wall, partly to be released from it by a detergent. The cell wall-bound glucanase activity was increased by the treatment of coleoptile segments with auxin. Only in 10 min of the treatment the glucanase activity and the incorporation of labeled leucine into the proteins were found to be increased in the fraction to be liberated by detergent from the cell wall fraction. These effects of auxin were inhibited by 10 μg/ml cycloheximide.

The depolymerization behavior of poly(ethylene terephthalate) (PET) to terephthalic acid (TPA) and ethylene glycol (EG) in high-temperature liquid water is examined in a batch reactor. PET is completely depolymerized in water for 10 min at 573 K. The total energy to obtain TPA and EG from a continuous PET depolymerization process with high-temperature liquid water is estimated.

Auxin-induced growth, epidermal cell length, cellular osmotic potential, and cell wall composition of coleoptile segments excised from one normal and two dwarf rice strains were studied 2, 3, 4, and 5 days after soaking. The auxin-induced growth was higher at the early stages of coleoptile growth and decreased with age, being always higher in normal than in the two dwarf strains. A good correlation between auxin-induced growth and auxin-induced decrease in the minimum stress-relaxation time has been found, suggesting that the different growth capacity in response to auxin among the three different strains is due to differences in the structure of their cell walls. In fact, cell wall analysis revealed that (1) the relative α-cellulose content of the cell walls was higher in the two dwarf strains than in the normal one, and (2) the auxin-induced decrease in noncellulosic glucose was high, compared with dwarf strains, in the normal strain, which showed the higher auxin-induced growth, showing a highly significant correlation between the decrease in noncellulosic glucose and the growth in response to auxin. Thus, the different growth between normal and dwarf strains might be attributed to their different capacity to degrade β-glucan of their cell walls.

The effects of simulated microgravity conditions produced by a horizontal clinostat on the entire life cycle of Arabidopsis thaliana ecotype Columbia and Landsberg erecta were studied. Horizontal clinorotation affected little germination of seeds, growth and development of rosette leaves and roots during early vegetative growth stage, and the onset of the bolting of inflorescence axis and flower formation in reproductive growth stage, although it suppressed elongation of inflorescence axes. The clinorotation substantially reduced the numbers of siliques and seeds in Landsberg erecta, and completely inhibited seed production in Columbia. Seeds produced in Landsberg erecta on the clinostat were capable of germinating and developing rosette leaves normally on the ground. On the other hand, growth of pin formed mutant (pin/pin) of Arabidopsis ecotype Enkheim, which has a unique structure of inflorescence axis with no flower and extremely low levels of auxin polar transport activity, was inhibited and the seedlings frequently died during vegetative stage on the clinostat. Seed formation and inflorescence growth of the seedlings with normal shape (pin/+ or +/+) were also suppressed on the clinostat. These results suggest that the growth and development of Arabidopsis, especially in reproductive growth stage, is suppressed under simulated microgravity conditions on a clinostat. To complete the life cycle probably seems to be quite difficult, although it is possible in some ecotypes.

The Japan Marine Science and Technology Center (JAMSTEC) started a study on “Wave Power Generator” in 1974. After two years of water tank experiments, the ship type buoy model seemed to be the best compared to the other models with respect to converting efficiency of wave energy into air output, easy construction and safe mooring. JAMSTEC has ordered a prototype of the system which is a massive floating structure, 80 m in length, 12 m in width, 5 m in height and 500 tons in weight. The structure consists of buoyancy rooms and air rooms, and the bottom of the air room is opened to the sea water. When a wave passes through an air room, air is pushed out of the room and sucked into the air, as the water levels rises and falls. Thus electric power is generated with the air turbine generator by the air motion in and out of the air room. The output power of the generated electricity is assumed to be about 2,000 kW, in case of 3 m wave height and 6 sec wave period, according to our theoretical calculation. The system is moored with a chain to the seabed. We have prepared many anchors and a 94-mm chain for the main mooring line of a safety load of 650 tons. A 1/10 scale model test in the water tank showed that the drag force was not so large, and it was about 100 tons to the full scale structure in the rough sea. The first open sea test will be carried out in 1978.