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Volume 70, Issue 1
Displaying 1-16 of 16 articles from this issue
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Kazuhiko KOBAYASHI2001 Volume 70 Issue 1 Pages 1-16
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESS -
Youji NITTA, Yoshinori YAMAMOTO, Takehide KAWAMURA, Aki SEKINO, Toshia ...2001 Volume 70 Issue 1 Pages 17-22
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSStorage of rice nursling seedlings berore transplanting is thought to be a cost-saving technique in rice culture. The objective of this study is to clarify the morphological changes of inner structures of stored rice seedlings under low temperatures(5.0, 10.0 and 12, 5°C) by means of observing every serial cross-section through the stem with a light microscope. Compared with the nursling seedlings just after raising at 5.O °C storage temperature, the stored seedlings showed a thinner leaf sheath and a decrcase in the number and size of the 2nd nodal tiller, but an incrcase in the number of crown root primordia. In the storage temperatures of 10.0 and 12.5°C, no changes occurred on the stemlength and size, on the size and number of nodal tillers, and on the inner strucures of leaf sheath and stem compared with the nursling seedlings just after raising, however, the number of crown root primordia incrcascd. After transplanting, the crown root primordia that had incrcased during storage emerged.These results indicate that in comparison with the nursling seedlings just after raising, the storage under low temperature before transplanting increases the number of crown root primordia of seelings without morphological changes of stem, leaf sheath, or tillers. Storage under 10.0 or 12.5°C before transplanting is available for rooting and growth after transplanting for rice nursling seelings.View full abstractDownload PDF (1398K) -
Keisuke SUGAI, Yusuke GOTO, Mitsuo SAITO2001 Volume 70 Issue 1 Pages 23-27
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of stepwise raising of the water level on tiller growth in rice plants were examined. When the plant age in leaf number of the main stem was 7.5, the plants were submerged to a level of the 7th leaf collar. Thereafter, as the plant's age advanced, the water level was raised to the level of the uppermost leaf collar. The length or the second tiller(T2), T3, T4, T7 in a deepwater plot was higher than in the control plot from the 6th or 18th day after the start of deepwater treatment. The response of tiller length to the treatment was similar to the main stem. Changes in age counted by the leaf numbers of T2, T3, T4 were simllar to the main stem, but the changes of T7 were not. The differences in relative tiller age between tillers(T2, T3, T4) and the main stem in the deepwater plot were smaller than in the control plot. The younger the tiller age at the start of treatment, the larger the difference in relative tiller age between the deepwater plot and the control plot. The starts of panicle differentiation in primary tillers were delayed by the treatment. In the treated plants, the starts in the primary tillers were more delayed than in the main stem. Therefore the effects of the deepwater treatment on tiller growth varied with the tiller growing stage at the beginning of treatment.View full abstractDownload PDF (829K) -
Yoriyuki NAKAMURA, Hiroshi TAKANO, Akio MORITA2001 Volume 70 Issue 1 Pages 28-33
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSA scrious loss of soil occurs during the transplanting of tea cuttings grown in bottomless paper pots. To minimize this, the effects of the application of sodium alginate solution to yellowish soil and the difrerent pot sizes (diameters of 4cm to 6cm) on the soil loss were examined. The prevention rate of soil in the smaller pots (4cm) was higher than in the larger pots (6cm). The optimal concentration and volume of sodium alginate solution for the prevention of soil loss was more than 0.3% and 80mL per pot (diameter of 6cm, length of 15cm), respectively. When the water was not added to the pots after the sodium alginate application, the high prevention rate more than 80% to 90% of soil was kept for about 10 days. Without the application of sodium alginate solution, the prevention rate or soil in the pots varied among the nine soil types. Sandy soil, a 4:6 mixture of yellowish red soil and peat moss, and a 4:6 mixture of yellowish red soil and rice husk charcoal showed the high prevention rates. The application of sodium alginate solution decreased the loss of soil regardless of soil type.View full abstractDownload PDF (846K) -
Kazuhiro KOBAYASI, Hiroko NAKASE, Tadashi IMAKI2001 Volume 70 Issue 1 Pages 34-39
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSDense planting is an important cultural technique to increase the number of spikelets per unit area, and is thought to be favorable for grain filling because it increases the percentage of spikelets on the primary rachis-branches(PBs) to the total spikelets. The objective of this experiment was to analyze the relationship betwee nplanting density and spikelet number with reference to the percentage of spikelets on the PBs. An active tillering cultivar, Nipponbare was used. Four planting densities(11.1 to 44.4 hills m-2) were combined with four rates of nitrogen topdrcssing(O to 7.5gm-2). Denser planting increased the number of differentiated and final spikelets. The effect of the denseplanting on spikelet number was more prominent, the higher the rate of nitrogen application at panicleinitiation. The denseplanting increased panicle number per unit area, but decreased the number of differentiated PBs per panicle. The number of differentiated secondary rachis-branches per PBs and the percentage of spikclet degeneration were scarcely affected by the density. Contrary to the expectation, the denser planting did not increase the percentage of spikelets on the PBs. This is because the number of differentiated secondary rachis-branches per diffcrentiated PB was not changed by planting density and the degeneration of spikelets on the PBs increased with increasing planting density. This experiment suggests that denseplanting does not necessarily increase the percentage of spikelets on PBs.View full abstractDownload PDF (1058K) -
Hisao NAKANO, Kyoichi KOMOTO, Kikuo ISHIDA2001 Volume 70 Issue 1 Pages 40-46
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSField experiments were conducted to investigate the effect or planting pattern on the development and growth of the branch from each node on the main stem. Soybean, cv. Tamahomare and Toyoshirome, were sown in square(35cm×36cm) or rectangular(70m×18cm) patterns, one or two seeds per hill on 20 June, 1990, and two seeds per hill on 22 June, 1991 and 1992. Gindaizu was also used in 1991 and 1992. In all three cultivars, the numbcrs of branches and nodes per plant, and yield in the square planting plot tended to be greater than those in the rectangular planting plot. Square planting compared with rectangular planting resulted in significantly higher light intensity at the ground surface of hills, but the reverse was true between rows on 26 July. On 12 August, there lationship between planting pattern and light intensity of the ground surface was similar to that on 26 June, though the light intensity were markedly lower. At the nodes 5 and 6(counted from cotylendon node) on the main stem in all three fultivars, the branching percentage was higher in the square planting plot than in rectangular planting. The number of branch nodes on nodes 3 to 6 (similar to the above) on the main stem in square planting tended to in rectangular planting. Moreover, podding efficiency on thec lower main stem nodes was higher in the square than in rectangular planting. Consequently, it was suggested that a higher yield was obtained by the square planting compared to rectangular planting as a result of the higher numbers of branches and branch nodes and higher podding efficiency in the lower nodes of the main stem due to reduced mutual shading.View full abstractDownload PDF (997K) -
Katsunori TAKAHASHI, Toshiaki MATSUDA, Youji NITTA2001 Volume 70 Issue 1 Pages 47-53
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSFine structural changes accompanied with the gelatinization of starch granules in milled rice grain during cooking were observed with a scanning electron microscope using three rice cultivars, Koshihikari, Kirara397 and Thailand rice (Indica type). In cv. Koshihikari, the change of starch grains started from the surface of the amyloplast envelope after 10 minutes of cooking(temperature at the central part of rice cooker was 45°C). After 15 minutes of cooking(51.3°C), starch granules in the first cell layer of a milled rice grain became swollen and a fibrous structure was observed on the surface of each starch granule. By the development of the mesh-like structure on the surface of starch granules, each amyloplast changed to one unit body after 20 minutes or cooking(98.5°C). Then, the bodies in each endosperm cell were fused and developed into the unit of irregular gel-like structure. The swelling of starch granules and the formation of irregular gel-like and mesh-like structures during cooking proccsses were faster in the outer layer than at the central part of a grain. These changes occurred faster in cv. Koshihikari than in Kirara 397 and Thailand rice. The pore size in the mesh-like structure was larger in the outer layer or agrain. We suggest that, in the gelatinization proccsses of starch, water molecules are incorporated into the insoluble high density amylopectin molecules as the main components of a starch grain resulting in swelling of starch and change to the soluble structure with a low molecular density.View full abstractDownload PDF (2312K) -
Hideki YOSHIOKA2001 Volume 70 Issue 1 Pages 54-58
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSHeading time of rice cultivars, Koshihikari and Kirarimiyazaki, in the early-season-culture depends on climatic factors during the period from transplanting stage to panicle formation. Effect of short days given at various stages was examined by pot-experiments in Miyazaki Prefectural Experiment Station. When the two cultivars were grown in short days from transplanting, Koshihikari, which normally heads later than Kirarimiyazaki headed one day earlier than Kirarimiyazaki. It was thought that this reversed heading between Koshihikari and Kirarimiyazaki was due to the difference in photoperiodic sensitivity, Koshihikari was sensitive to photoperiod from 30 days before the first panicle formation stage to panicle formation, especially 18-19 days before the first panicle formation. The same was also the case in Kirarimiyazaki, but the heading of this cultivar was less hastened by short-day treatment than that of Koshihikari. It was thought that the reversed heading between Koshihikari and Kirarimiyazaki in 1998 was due to the high temperature during April and May, which accelcrated the vegetative growth(panicle formation) and made Koshihikari more responsive to short days than Kirarimiyazaki.View full abstractDownload PDF (739K) -
Michihiko FUJII, Takeshi HORIE2001 Volume 70 Issue 1 Pages 59-70
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSRelative contributions of drought tolerance and drought avoidance to drought resistance in the dry-matter production of different rice cultivars at different fertilization levels were evaluated based on a pot experiment with three cultivars subjected to drought and fertilization treatments and in a field experiment with 10 cultivars subjected to drought treatments. Drought tolerance was expressed as leaf water potential(LWP) at which dry-matter production declined to 50% or 20% of that under flooded conditions. The cultivar difference in drought tolerance was about O.21MPa, and the difference in fertilization levels was 0.74MPa in midday LWP, indicating that the fertilization effect is larger than the cultivar effect. However a large cultivar difference was observed in leaf death and plant survival. The cultivar difference in the avoidance in field experiment, defined as LWP maintained under drought conditions, was about 0.29MPa in the midday LWP, which was more than about 50% larger than that in the tolerance. In the pot experiment, the avoidance was about twice as large as the tolerance. These facts revealed that differences in dry-matter production in the field experiment were closely correlated with diffrerences in the avoidance. And a close relation was revealed between yields and dry weight at harvest under continuous drought conditions. Because differences in drought avoidance were more than about 50% larger than in drought tolerance, LWP is suggested to be a good index of drought resistance.View full abstractDownload PDF (1719K) -
Daigo MAKIHARA, Makoto TSUDA, Yoshihiko HIRAI, Toshiro KUROSA2001 Volume 70 Issue 1 Pages 71-77
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effect of salinity stress on grain filling was studied in two rice varieties(Kala-Rata 1-24 and IR28) with different resistances of yield to salinity. Plants were subjected to saline irrigation(150mM sodium chloride) during the grain-filling period in combination with the primary rachis-branch clipping. Saline irrigation decreased whole plant dry-matter production during the grain-filling period. A dry-matter increase of hulled rice was retarded because of the insufficient supply of dry-matter during the mid grain-filling period by saline irrigation; however it later recovered because of an increase in the compensatory translocation of stem reserves to the panicle. The final panicle dry weight did not decreass because of saline irrigation. The retardations of the dry-matter increases of hulled rice were markedly in the inferior spikelets of plants with intact primary rachis-branches, but not in the plants with half primary rachis-branches. The dry-matter increase of hulled rice that was retarded by saline irrigation recovered after the saline water was removed. These results in dicated that the potential of grain growth and the carriage of assimilates might not be affected by saline irrigation. The insufficient supply of dry-matter to hulled rice during saline irrigation may have resulted from a decrease in the production of low-molecular sugars for translocation because of the suppression of carbohydrate metabolism under salinity.View full abstractDownload PDF (969K) -
Daigo MAKIHARA, Yoshihiko HIRAI, Makoto TSUDA, Kenji OKAMOTO2001 Volume 70 Issue 1 Pages 78-83
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSSalinity tolerance at the seedling stage of rice(Oryza sativa L.) is related to the ability to maintain photosynthesis under salinity. Sensitivity or photosynthesis to sodium accumulation in leaf blade was evaluated in 13 rice varieties differing in salinity tolerance at the seedling stage. Leaf blades were excised at the leaf base, the cut end immersed in 50 mM sodium chloride solution, and the rates of photosynthesis and transpiration were measured. Photosynthetic rate decreased in parallel to stomatal closure until leaf sodium content reached 3 to 5 mg g-1. However, in the leaves with sodium content of over 3 to 5mg g-1, the transpiration rate was even, while photosynthetic rate decreased further due to another factor related to sodium accumulation in the leaf blade. Vulnerability of photosynthesis to sodium accumulation measured using exeised leaves varied with the variety, similarly to that measured using the leaves of intact plants. These results in dicated that salinity tolerance at the seedling stage in rice could be evaluated by measuring photosynthetic rate in excised leaf blades.View full abstractDownload PDF (914K) -
Zujian ZHANG, Teiji NAKAMURA, Iwao NISHIYAMA2001 Volume 70 Issue 1 Pages 84-91
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSPreviously, we reported that the amount or activity of the root relative to shoot was an important fact or relating to the sterility caused by cool temperatures. To elucidate the causal relationship between the relative amount or activity of roots and the cool-weather resistance, we modified the amount or activity or roots experimentally. When about 75% of roots or all tillers were cut off at the pollen mother cell formation stage just before the young microspore stage, there was no reduction in the fertility of the plants cooled at the young microspore stage. Howecver, the fertility of the cooled plants was significantly reduced by the root cutting at the primary rachis branch differentiation stage, and also by the treatment or roots with a respiratory in hibitor or addition of glucose to the pots, which was expected to reduce the root activity through a reduction of soil. These results indicated that there was a causal relationship between the amount or activity of roots and the cool-weather resistance. In addition, the cool-weather recsistance was reduced by the root cutting at the primary rachis branch differentiation stage but not by similar treatment given just before the critical(cool-weather sensitive) stage. These facts suggest that the root does not affect the cool-weather resistance at the critical stage, but affccts it at a stage earlier than the critical stage, for example, through the effect on the process of pollen formation.View full abstractDownload PDF (1300K) -
Hideki SUGIMOTO2001 Volume 70 Issue 1 Pages 92-98
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThree types or eddoe plants(Colocasia esculenta(L.) Schott), i.c., daughter-tuber type(cv. Uhan and Ishikawawase), mother-and daughter-tuber type(cv. Akame), and mother-tuber type(cv. Taiwan-imo), we recultivated in a drained paddy field. The daughter-tuber leaves of each cultivar were removed to estimate the role of the leaves. The rate of canopy photosynthesis of cv. Uhan was measured in mid-October using a closed chamber system, and then plant was fed with 13CO2 to estimate the contribution ratio of daughter-tuber leaves to total canopy photosynthesis. The rate of canopy photosynthesis in the plant with and without daughter-tuber leaves was 24.6 and 17.5μmol m-2S-1, respectively. The ccontribution ratio of the photosynthesis of the daughter-tuber leaves to total canopy photosynthecs is was 29.1%. Total tuber yield in control plants was 16% higher and the markctable tuber yield was 34% higher than those in the plants without daughter-tuber leaves. The photosynthate of daughter-tuber leaves greatly contributed to the enlargement of each tuber, and hence tuber weight per plant.View full abstractDownload PDF (1025K) -
Partitioning of 13C-labeled Photosynthate in Eddoe Plants with Special Reference to Source-sink UnitHideki SUGIMOT02001 Volume 70 Issue 1 Pages 99-104
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe partitioning of 13C-labelled photosynthate in eddoe plants(Colocasia esculenta(L.) Schott) was studied. At various stages of development, the whole plants of cv. Uhan were fed with 13CO2.The 13C-labeled photosynthate at an early development stage was distributed mainly to the leaves and petioles, that at the middle developmental stage to the leaves, petioles and tubers, and that at the late developmental stage to the tubers. When secondary tubers began to enlarge, mother-or daughter-tuber leaves in three types of eddoe cultivars classified as daughter-tuber type(ev. Uhan), mother-and daughter-tuber type(ev.Akame), and mother-tuber type(ev. Taiwan-imo) were fed with 13CO2. A great part or 13C-labeled photosynthate from mother tube rleaves was distributed to daughter tubers in Uhan, both to daughter and mother tubers in Akame, and to mother tuber in Taiwan-imo. This tendency was the same even in the plants from which daughter leaves had been removed. The 13C-labeled photosynthate from daughter-tuber leaves was distributed to daughter and secondary tubers but not to the mother tuber in Uhan and Akame. However it was also distributed to the mother tuber in Taiwan-imo. It was revealed that photosynthates from daughter-tuber leaves contributed greatly to the enlargement of the tubers, especially daughter and secondary tubers. The partitioning pattern 13C-labeled photosynthates from mother-and daughter-tuber leaves reflected the charaeteristics or tuber growth and showed existence of source-sink unit specific to each cultivar.View full abstractDownload PDF (854K) -
Tomohiko NIWA, Takatsugu HORIUCHI, Sinya OBA, Kunji YAMAMOT02001 Volume 70 Issue 1 Pages 105-110
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSCarbonized sewage sludge has more advantages in terms of storage and transportation than dewatered sewage sludge, but no detailed studies have so far been conducted on the former. Dewatered sewage sludge was collected from Gifu City and Takasu Village in Giru Prefecture. The dewatered sewage sludge was heated to several temperature ranges(300-700 °C) top roduce the carbonized sewage sludge. Then, their chemieal and physieal properties were measured. Total nitrogen, EC, C/N ratio, etc. were found to vary with the site and time of collection, and the carbonizing temperature. For example, the total nitrogen content varied from 3% to 7%. Furthermore, the carbonized sewage sludge from Takasu Village was two times harder and 1.5 times denser than that from Gifu city. Thus, the carbonized sewage sludge from Gifu city was higher in porosity than that obtained from Takasu Village. Upland rice, grown in 1/5000a Wagner pot, was used as an indicator for evaluating the effect of the fertilizer. The rice seeds were sown in the pots with different amounts of 300 °C carbonized sewage sludge, 3g and 6g of total nitrogen per pot. Thirty days after sowing, top dry weight and SPAD(Soil & Plant Analyzer Development: measurement apparatus for chlorophyll content) value were higher in the sewage sludge from Gifu city compared with that from Takasu Village. The observed difference in fertilizer effect between the two sewage sludges on rice growth may be explained by their difference in chemical properties and porosity amount.View full abstractDownload PDF (925K) -
[in Japanese]2001 Volume 70 Issue 1 Pages 111-114
Published: March 05, 2001
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSDownload PDF (1274K)
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