Multiple regressions of six malting barley cultivars between yield and climatic conditions in Kyushu region over years were computed by backward and forward procedure. Phenotypic correlations between yield and mean temperature, total precipitation and total sunshine duration during the whole growing period (Dec. 1-May 20) were generally negative, negative and positive, respectively. Multiple regression analysis showed, however, that only precipitation contributed yield adversely. The negative phenotypic correlations between yield and temperature suggested that high temperature caused yield decrease, but this was because of the positive correlation between temperature and precipitation, and the influence of temperature on the yield was little. The influence of sunshine duration to yield was also little. Regression coefficients showed that yield decreased at the rate of 4-6 kg/ha per additional 1mm precipitation. The number of ears was restricted by precipitation, resulting in yield decrease. Growing period was devided into two stages; before heading and after heading. Regressions were computed between yield and climatic conditions before and after heading for three cultivars. Precipitation in both of the growing period before and after heading date caused yield decrease. Therefore, high precipitation or wet injury was the main restriction to higher yield of malting barley in Kyushu region.

View full abstract

The experiment was conducted to evaluate the difference in nutrient uptake of different ecospecies and ecotypes of rice plant. Fifty one japonica cultivars composed of 32 lowland and 19 upland cultivars, and 25 indica lowland cultivars were used. The uptakes of ammonium-N (NH₄-N), nitrate-N (NO₃-N), phosphorus and potassium (in nutrient mg·dry wt g^-1·h^-1) were determined by using 25-day-old seedlings. The result revealed that : (1) Ammonium-N and phosphorus uptakes were higher in indica compared with japonica. On the other hand potassium uptake was higher in japonica than in indica. There is no difference between the two ecospecies in nitrate-N uptake. (2) Lowland rice showed higher uptake than upland rice in four nutrients, especially in nitrate-N and potassium. (3) Nutrient uptake was in the order of: nitrogen, potassium, phosphorus. This order of uptake was consistent on ecospecies and ecotypes. (4) Correlations between dry weight and potassium uptake, and between ammonium-N and nitrate-N uptake, phosphorus uptake were not significant japonica, but positive and significant in indica. Correlation between root number and ammonium-N uptake was not significant in upland rice, but negative and significant in lowland rice. (5) Nitrate-N uptake showed a positive and significant correlation to potassium uptake regardless of ecospecies and ecotypes. (6) It can be concluded that inorganic assimilation of rice plant depends on the ecospecies and ecotypes.

View full abstract

The present investigation was carried out to clarify the meteorological environment in the rice population of 40×100 meters. The temperature, water vapor pressure and CO₂ concentration in the population were measured every hour from 9:00 to 17:00, 6 times during the cultivation period. [Horizontal distribution] In the case of the west wind or the north wind, blowing toward the population, the temperature in the population decreased gradually from the border to about 10 meters inside the population, while water vapor pressure increased from the bordering area to 5∼25 meters inside. The temperature and water vapor pressure were constant around the center of the population. In the case of the east wind, blowing across the population, the temperature and water vapor pressure did not vary in the population. CO₂ concentration decreased from the bordering area to 25∼50 meters inside irrespective of the wind direction. [Vertical distribution] In the plant population, temperature rose and water vapor pressure dicreased with height. The difference between the upper and lower part of the border of the population was larger in temperature and smaller in water vapor pressure than that of the inside.

View full abstract

In order to study the relationship of flour and starch qualities to cultivar, producing prefecture, and grade, 46 domestic wheat samples of 17 cultivars and 8 imported wheat samples were tested. Domestic wheat, as compared with imported wheat, had special characters in the medium protein content of flour, and high amylose content of defatted starch. As for the qualities of domestic wheat, the geratinization values of starch and its defatted starch showed low GT (geratinization temperature) and MVT (maximum viscosity temperature), and high MV (maximum viscosity) and BD (break down). Chihokukomugi (cultivar of Hokkaido area) was low in protein and amylose contents and high in the ratio of large granule size of starch among cultivars, and was similar to those qualities of ASW (Australian standard white), which is suitable for Japanese noodle (Udon) making. The grains showed heavy kernel weight and high amylose content in the eastern prefectures. The low grade wheat had light kernel weight, high protein content, and high ratio of large size of starch. The relationship between the values of tested items was further studied. From the results, it is presumed that medium protein content, low amylose content, high ratio of large size of starch, and suitable gelatinization of the starch were important characters in rendering domestic wheat suitable for making Japanese noodles.

View full abstract

The varietal differences in the optimum soil temperature for rooting and the rooting ability under the low soil temperature were investigated under the controlled environment (air temperature: 25/16°C, soil moisture: 70% of field capacity). The optimum soil temperature for the total root length at 1 week after transplanting was about 30°C in 8 cultivars. In another cultivars, i.e. Kokei 14, Norin 2, Tamayutaka and Benikomachi, it was about 35°C. Thus the optimum soil temperature for the establishment of cut-sprouts seems to be higher in these 4 cultivars. In all cultivars the optimum soil temperature was higher than 29°C. The ratio of the total root length under 18°C to that under 28°C, differed among cultivars, and it was higher in Norin 1, Minamiyutaka, Kokei 14 and Benikomachi and lower in Tamayutaka, Norin 2, Shiroyutaka and Shirosatsuma. The total root length per unit weight of cut-sprouts under the critical soil temperature, 15°C, also differed among cultivars. It was higher in Norin 1 and Minamiyutaka, and it was lower in Benikomachi and Kokei 14 etc. Thus it seems that the rooting ability under low soil temperatures is higher in Minamiyutaka and Norin 1.

View full abstract

Longitiudinal and transverse distribution of sugars in petiole of sugar beet (Beta vulgaris L. var. saccharifera Alef.) were investigated. A sampling of leaves was conducted in the evening (E) of a fine day and during the following morning (M) in the fall season. After extraction was conducted in the usual manner with 80% ethanol, sugars were analyzed by the enzyme (HK-G6PDH) method using an F-kit, manufactured by BMY. Results: In the leaves with petiole, glucose and sucrose contents were higher in the basal part than the upper part. In contrast, fructose content was higher in the upper part. These three sugars increased during the night at the 2∼4% level per dry matter in the basal part of the young petiole. On the transverse distribution of the sugars in the petiole, glucose increased during the night in the adaxial side called "white part" which consists mainly of pith parenchyma cells, in the content level from E13% to M20%. On the other hand, it was not changed in the level of 5∼6% at E and M in the abaxial side called "green part", which consists of mainly vascular bundle and cortex parenchyma. The sucrose content was higher in the "green part", increasing during the night (E5%→M12%). The result of the present studies indicates that the photosynthates translocate transversely between the conductive tissues and the pith parenchyma cells with alternative diurnal changes.

View full abstract

Silking stages of three corn varieties (Wasehomare, Hokuyu and P3715) were estimated according to the concept of DVI (Horie et all), using the Nonparametric method recently proposed (Takezawa and Tamura). The Growth data obtained at Tokachi Agricultural Experiment Station at 5 seeding times in each year through 1979 to 1985 were used. The results are: 1) Curves showing the relationships between Developmental rate (DVR) and air temperature were similar to sigmoid. We termed the curve as DVR-T curve. The shape of DVR-T curve differed among varieties. At low air temperature regimes, the curve was more linear in Wasehomare than in other two varieties. On the other hand, the rate of decrease in DVR at high air temperature regimes was higher in the order Wasehomare<Hokuyu<P3715. Especially in P3715, the curve gradually declined as the temperature reached higher than about 23°C. 2) Although ranges of the silking stage observed in the experiment were very wide (33∼40 days), differences in days between observed and estimated silking stages were less than three days in Wasehomare and Hokuyu. Estimation in those varieties was accurate. In P37l5, the differences are somewhat larger than those of the two varieties. 3) The length of the silking stages were more accurately estimated using the Nonparametric method than by the Accumulative temperature method. This was probably because a more correct evaluation of temperature response is possible by useing the Nonparametric method.

View full abstract

Allometric relationships between axial and radial stem growth in rice plants (cvs. Nipponbare, Musashikogane and Dobashi 1) were examined based on developmental studies on successive stem segments (=frusta) composing the main stem. During the vegetative phase of the plants, the development of each stem segment followed an uniform pattern represented by an allometric regression of its diameter v. length. At the beginning of the reproductive phase, however, most of immature stem segments shifted from this allometric to more elongating side. Such abrupt change in segment shape was mainly caused by the concurrent activity of intercalary meristem located in the lower part of stem segments whose corresponding leaf had just emerged. However, in the upper stem segments, which also exhibited the same tendency to elongate though less pronounced, the growth prevailed throughout the whole organs and definite intercalary meristems were not yet recognized. These results suggest that the characteristic stem development associated with the transition from vegetative to reproductive phase of the plants does not necessarily depend upon activities of their intercalary meristems alone.

View full abstract

The properties of the growth curves of the tiller number per plant in case of the single-planted rice plants in a pot culture were investigated. The tiller number increased with time, and the pattern fitted the logistic curves. On the other hand, when the tiller number was plotted against the plant age expressed by leaf number (the number of spread leaves plus the ratio of the length of the emerged part of the emerging leaf blade on the main stem), the exponential curves fitted to it closely. Therefore, as a time-scale, we used the age expressed by leaf number to calculate the relative rate of increase in tiller number (Rt). In a rice plant, there are differences (D) in growth speed between the main stem and each tiller. In the previous paper, we supposed the "synchronous growth" (the leaf of each tiller and that of the main stem expanded synchronously in a plant) to rid the tillering pattern of the influence of D. The increasing pattern of tillering against the plant age expressed by leaf number in the "synchronous growth" more closely fitted the exponential curve. Therefore, we expressed the all-inclusive Rt of the tillering stage by using the coefficient of the formula of the exponential curves.

View full abstract

In the previous three papers, we have obtained the methods of growth analysis about the tillering behavior of a rice plant. Using the methods, the temperature effects were investigated in the present paper. Plants (cv. Sasanishiki, 1 plant/pot) were grown in different temperature conditions as 30 (6:00-18:00)-25 (18:00-6:00)°C (plot H), 24-19°C (plot M), 17-12°C (plot L), respectively, after 5.8 plant age expressed by leaf number (the number of spread leaves plus the ratio of the length of the emerged part of the blade of emerging leaf on the main stem). The rate of increase in tiller number against time was H>M>L plot, but the rate against the plant age was L>M>11 plot. It was possible to analyze the tillering behavior into two factors: one is the differences (D) in growth speed between the main stem and each tiller, and the other is the tillering pattern at the synchronous growth (the leaf on each tiller and that on the main stem expanded synchronously in a plant). D of the second-order tillers was L>M>H plot, and D of the third-order tillers was M>H plot. Tillering curves of the three plots at synchronous growth was corresponded with each other. Therefore the temperature influenced the balance of' growing speed between tillers and main stem, and had no effect on the position of tiller emergence.

View full abstract

Three cultivars of rice plants were grown in pots in a shading frame of 50% light intensity and on shadowed place at high altitude of 303m in hillside during the different period from tillering to early ripening stage in order to compare the photosynthetic activity, root respiration and nitrogen absorption with those of control plants. After the period of tiller number determined, the shading-treatment promoted leaf area developing through the both ways of increase in leaf length and specific leaf area; it could contribute to enhancement of the photosynthesis per plant. Also photosynthetic rate per leaf area in the treated plant was higher than in the control plant due to higher N% in the leaf. Dry matter production was more depressed than nitrogen absorption by the shading, i.e., decreased rates of the former and the latter in average were 30.3% and 3.7%, respectively. The result of a multiple regression analysis for dark respiration of plant per leaf area (r^^-) showed that r^^- had a high positive correlation to N% in leaf and high negative correlation to C/F ratio (C: Stem weight, F: Leaf area), therefore, r^^- of treated plants did not increase owing to the low C/F value. Multiple regression analysis between root respiration and two factors, N% in root and C/F ratio, showed high correlation coefficient as R=0.817^**: the root respiration of the shaded plant had higher rate than that of control. The amount of nitrogen absorbed during treated period was sustained with the root respiration and the dry matter production.

View full abstract

In the previous paper it was reported that the yield of rice was increased by the foliar application of triacontanol (TRIA) at early growth stages. However, as the range of TRIA concentration used was not so wide, the effect of concentration was examined in this report. Main results obtained are as follows: 1. The range of effective concentration was found to be wide, from 0.2 to 10ppb, and the highest yield, 16% over the control, was obtained by 10 ppb sprayed at the early tillering stage. 2. By TRIA-spraying, growth of the top was slightly inhibited, but the root system during the ripening period remained considerably heavier than the non-treated control. 3. In most cases, yield increase was brought about by increases in the percentage of ripened grains and in 1000-grain weight. 4. Both the dry weight increase and NAR during the ripening period were higher in the TRIA-treated plots than in the control plot. A high, positive correlation was found between these two growth parameters. From these results it was inferred that TRIA-application increased the number of panicles and grains and, in addition, helped maintain a large and healthy root system during the grain-filling period, which contributed to promoting ripening by increasing dry matter production after heading.

View full abstract

Changes with time in dry weight of each part and dry matter partitioning were investigated for three wheat varieties, tall Haruhikari, semi-dwarf Haruyutaka and tall late Selpek. The seasonal pattern of dry matter partitioning was quite similar among the varieties, and the growth was divided into five main phases based on the pattern of partitionings as reported in the previous paper. The dry matter partitionings to each part (Y) were simply presented by the regressions against the days after emergence (X) as follows (Fig. 3). In growth phase I (emergence to flag leaf initiation) and growth phase II (flag leaf initiation to flag leaf emergence), the partitioning to leaf blade was represented by a linear regression, Y_l1 = b₁X+c₁ and Y_l2=-b₂X+c₂. In growth phase III (flag leaf emergence to anthesis), the partitioning to ear (chaff plus rachis) was represented by a quadratic equation, Y_e=-a₃(X-b₃)²+c₃. In growth phase IV (anthesis to milk ripe stage), the partitioning to grain was represented by a linear regression, Y_g=b₄X-c₄. The varietal differences in partitionings were explained by using these regressions (Table 2). In growth phase II, tall Selpek had a smaller coefficient b₂ than the other two varieties, because Selpek had a longer term in this phase. In the growth phase III, semi-dwarf Haruyutaka had the highest value of constant c₃ than others, but that of coefficient a₃ did not differ among the varieties, indicating that the rate of partitioning to ear was higher in Haruyutaka than in others.

View full abstract

Rice pollen grains germinated more than 80% with low variation (standard deviation less than 10%) and their pollen tubes elongated to more than 150μm within one hour with a simple medium composed of 1% agar, 20% sucrose and 20μg·ml^-1 (ppm) boric acid, using a Petri dish (4.5 cm in diameter). In addition to the composition of the medium, it is important that the incubation temperature should be around 20°C and that the pollen grains should be shed directly on the medium from the anthers as soon as the flowers begin to open. Under these conditions, their pollen grains began to germinate 2 to 3 min after shedding and attained maximum growth rate within 20 min. After that time, the length of pollen tube increased at a linear rate of ca. 7.5μm·min^-1 over the next 15 min.

View full abstract

To establish a method for isolation and culture of rice protoplasts, enzyme solution compositions, culture conditions, and the selection of cultivars and tissues as materials were examined. The results suggested that the 1st and 2nd leaf sheath of 6-day old seeldings, which were cultured in the medium containing only minerals and vitamines of MS medium under 23°C, 16.2 W/m², and light length 14 h, were found suitable as materials. The materials were treated without shaking for 4 h in an enzyme solution (pH 5.6) containing 0.25% macerozyme R-10, 1% cellulase "Onozuka" R-10 and 1% BSA in a MS medium which contained MS-minerals, MS-vitamines, 1.0 mg/l 2, 4-D, 2.5 mg/l kinetin and 10 g/l sucrose. The isolated leaf sheath protoplasts were cultured in a MS medium (0.42 M) containing 1% BSA. All protoplasts from 11 cultivars kept their cell activity through the culture for 2 weeks or more. The addition of BSA in both the enzyme solution and culture medium was especially effective for the maintenance of protoplast viability. The vacuoles developed in the protoplasts during the culture period; after 5 days in the culture the protoplasts enlarged to a diameter 1.75 times greater compared with that just after the isolation. The chloroplasts in protoplasts began to dedifferentiate during the culture, and both chloroplast size and chlorophyll content decreased. Protoplast division was not observed in this medium throughout the culture process.

View full abstract

Soybean plants show diversity in stem growth habit ranging from determinate type to indeterminate type. Stem growth of determinate type plants abruptly terminates near flowering, while that of indeterminate type plants continues after flowering. In order to elucidate endogenous factors controlling such growth habit of soybean plants, ABA levels in leaves and pods of determinate and indeterminate isolines were compared. No differences were found in ABA levels, which suggests that ABA in not involved in stem termination of soybean plants. Some unknown factors seem to cause the stem termination.

View full abstract

The time course of respiration in the continuous dark was examined with soybean plants having experienced various preceding light conditions, aiming to elucidate the determination mechanism of changes with time in respiration rate. The initial value of respiration rate per unit dry weight (RPW) observed immediately after the onset of dark period was dependent on the light intensity in the preceding light period, and it was not affected by the length of light period. However, the bottom level of RPW observed after the initial decrease was affected by the length, with the lower levels in the plants exposed to the shorter light period. Furthermore, the magnitude of midnight rise of respiration, the temporal rise in the dark period, was affected by both light intensity and length of light period. It showed the linear relationship against cumulative light intensity which was obtained from light intensity multiplied by length of light period. RPW in nitrogen-depleted plants did not respond to length of light period. In this experiment, it was found that the time course of respiration consisted of two different phases. One was in the initial part of the dark period and dependent on light intensity. The other was in the following part and dependent on cumulative light intensity in the preceding light period. From this observation, it was considered that respiration in the dark period was regulated by two different physiological processes.

View full abstract

Morphogenesis of panicle and spikelet in paddy rice, cultivars Yuhkara and Fujihikari was studied by SEM. Germinated seeds planted in containers with submerged soil were cultured under natural conditions. The young panicle and spikelet were dissected and fixed every day until heading with modified Karnovsky's solution with 5% aclorein, dehydrated with acetone, and were dried at critical point, and then coated with gold for investigation. At the panicle primordium differentiation stage (PDS), the ratio of height to width (H/W) in the apical meristem (AM) decreased from one to 0.4 and 0.2 at the palea and stamen PDS respectively. Before the lemma and palea completely covered the inside floral organs, the stamen primordium differentiated to the anther and filament, and pistil primordium to ovule and ovary wall. A central stamen in the lemma side was located at the lowest position among all stamens. This indicated that the three stamens located in the lemma side may be situated at lower positions than the palea-sided organs. When the ridged cuticle (RC) in the anther epidermis began to develop at the meiotic stage of pollen mother cell (PMC), stigma cell started to differentiate, forming stigma hairs when RC covered the anther epidermis. RC changed to a more complicated structure almost at the same time as xylem vessel differentiated in stigma vascular bundles. Therefore, this structural change was considered to have some correlation with sclerification or shrinking of inner anther wall cells. Development of orbicules on the surface of pollen and tapetum cells was discussed.

View full abstract

In order to obtain basic information regarding improvement of potato root characters through breeding using its wild relatives, morphology, respiration activity, dry weight (DW), length and surface area of the roots of 12 potato cultivars and lines and 8 wild relatives (Table 1) were investigated during the flowering stage under field conditions. The roots of the wild potato species were thinner but their dry matter percentages were higher than those of the cultivars and lines (Table 2). From observation of root monoliths (Fig. 1), it appeared that the number, diameter and length of the lateral roots differed among the materials (species) used. The cultivars exhibited relatively high root respiration rata compared to the wild species on the basis of either root DW or root length (Table 2). Some wild species had a considerably larger root DW, root length and root surface area, and higher ratio of root DW to leaf DW than the cultivars and lines (Table 2 and 3). From the results it can be seen that some wild species have good potential to be used as parents in the breeding for the improvement of root characters in potato.

View full abstract