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Volume 69, Issue 3
Displaying 1-23 of 23 articles from this issue
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Yutaka UNE2000 Volume 69 Issue 3 Pages 277-285
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESS -
Takayoshi TERAUCHI, Makoto MATSUOKA2000 Volume 69 Issue 3 Pages 286-292
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSA slow growth during the early stage in sugarcane yields low productivity in spite of its long cropping duration, though the photosynthesis ability is high. A small specific leaf area(SLA)is the main reason it takes longer for the canopy structure to complete. To investigate the enhancement of the early growth in sugarcane, six commercial varieties were grown for this experiment. Ninety-four sugarcane genetic resources were also applied in measuring the leaf characteristics. SLA sal negatively correlates with leaf thickness and leaf length per width ratio(leaf index). It is appropriate to make leaf blades short, wide, and thin to get high SLA. Dry matter per stem was obviously higher in the lesser tillering variety because the number of tillers did not affect the total dry matter production in early growth. By filling the stem numbers per area using high density planting, the rapid stem growth of the less-tillering variety enables quicker growth in the early stage in the sugarcane community. A shortening of the sugarcane growing seasons is required for an effective field usage of crop shifting. As well as the effective canopy structure for solar radiation, the morphological characteristics for rapid growth in the early stage were regarded as an important selection point in breeding.View full abstractDownload PDF (992K) -
Katsuya MATSUBA2000 Volume 69 Issue 3 Pages 293-305
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn any theory on rice cultivation, methods for controlling the plant type form the core. An analysis identified the most suitable leaf-internode unit for targeting to control the plan type and the appropriate stage to do this. The growth of the shoot is determined by the units, consisting of an internode and the leaf connected to that lower node. The leaf with the largest increase in elongation rate after top-dressing is not the elongating young leaf, but the leaf primordium positioned above that leaf. Therefore the most effective control of the plant type is achieved by targeting the particular unit that is in the differentiation atage. This model could explain the following. (1) Contrary to Matsushima's theory, a decrease in nitrogen absorption results in shortening the upper lamina without affecting the lower internodes. (2) Excessive fertilization in the early growth period results in spindly growth of the lower internodes. Therefore if the nitrogen absorption declines from the middle period, the lower internodes and lamina show excessive growth, but the upper internodes and lamina stay short, as in the "akiochi" type. (3) If the fertilization levels in the early growth period are kept low and topdressing is applied in the middle growth period, a plant type with a reverse triangle shape caused by well-developed upper internodes and lamina in contrast to short lower internodes is formed.View full abstractDownload PDF (1636K) -
Jing CUI, Akihito KUSUTANI, Masanori TOYOTA, Koh-ichiro ASANUMA2000 Volume 69 Issue 3 Pages 306-313
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe relationships between the early growth after transplanting and several seedling characteristics of 10 high-yielding varieties bred in Asian countries(H group)were compared with those of 10 Japanese varieties(J group). There were sighnificant differences between the seedlings of the two groups in plant length, root dry weight and the percentage of endosperm consumption. Plant length was shorter, root dry weight was heavier and the percentage of endosperm consumption was higher in the H group than in the J group. The seedling character index(SCI)shown by(the seedling age in leaf number)×(the ratio of top dry matter weight to plant length)of the H group was higher than that of the J group. The relationship between the number of days affer sowing(X)and the leaf number of seedling(Y1)was shown by Y1=a1+b1X and the relationship between X and the percentage of endosperm consumption(Y2)by Y2=100-a2·exp(-b2X). There was no significant difference between the H and J groups in the constant b1(leaf number increase coefficient, LNG), but the constant b2(endosperm consumption coefficient, ECC) of the H group was significantly higher than that of the J group. SCI was positively correlated with LNC and ECC. Top dry matter weight(TW)and leaf area(LA)at 28 days after transplanting were greater in the H group than in the J group. Significant positive corrlations were found between SCI and TW, LA, From these results, it was considered that the high yielding varieties with higher SCI have large LA and superior early growth affer transplanting.View full abstractDownload PDF (1231K) -
Jing CUI, Jusheng ZHAO, Akihito KUSUTANI, Masahiro MOROKUMA, Masanori ...2000 Volume 69 Issue 3 Pages 314-319
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn order to raise highly palatable rice cultivars in the Huabei region, palatability characteristics were compared between 10 cultivars grown in Tianjin district(Tianjin cultivars)and 10 new and old Japanese cultivars (Japanese cultivars). The score of overall eating-quality in the sensory test on cooked rice was the highest in the Japanese cultivar Koshihikari and the lowest in the Tianjin cultivar Jinyou 9701. The average value of overall eating-quality of Tianjin cultivars was -0.42 and that of Japanese cultivars was -0.04. By using the score of overall eating-quality, all cultivars were classified into 3 groups i.e., H group(≩+0.35), M group(+0.35∼-0.35)and L group(≨-0.35). Among the Japanese cultivars, Koshihikari, Kinuhikari and Okuhikari belonged to the H group, Shinriki, Aikoku and Norin 18 to the L group, and the other cultivars to the M group. In Tianjin cultivars, only Huayu 13 belonged to the H group. Jinzhu 1, Jindao 779 and Jinyou 29 belonged to the M grouo, and all others to the L group. There were no significant differences among groups in amylose content, protein content and maximum viscosity. Amylose contents and protein contents of Jindao 779 and Huayu 13 were close to those of Koshihikari and/or Kinuhikari. From these results, it was concluded that although the Tianjin cultivars had satisfactory physicochemical properties, they wae inferior in overall eating-quality in the sensory test. This may be because only a few Tianjing cultivars possess a low amylose content, low protein content and high maximum viscosity in combination. However, Jindao 779 and Huayu 13 possessed comprehensively good characteristics, and these cultivars are expected to be very useful breeding materials for raising new palatable cultivars in the Huabei region.View full abstractDownload PDF (934K) -
Hiroomi ASANO, Fumitoshi HIRANO, Katsunori ISOBE, Hidetoshi SAKURAI2000 Volume 69 Issue 3 Pages 320-323
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSPreviously, we suggested that cultivation of paddy rice by Aigamo duck farming system, delayed the harvest time by about 10 days and improved the taste of rice due to the increased grain yield accompanied with the decrease in the number of green-kernel rice and protein content in brown rice. In this study, we examined the content and composition of protein and amylose content in the grain samples used in our previous report. The total protein content in brown and milled rice tended to decrease with the delay of the harvest time, irrespective of the cultivar(Koshihikari or Kinuhikari)by both the standard and Aigamo duck cultivation methods. The protein in the brown rice harvested either at maturity, 10 days earlier or 10 days later, consisted of 66.0-67.7% glutelin, 18.8%-20.8% albumin+globulin and 12.5-14.5% prolamin. The composition of protein varied slightly with the cultivar and the method of cultivation, but scarcely with the harvest time. The same was also the case for the protein in milled rice. Thus, the 10-days later harvest time did not affect the protein composition markedly even in the rice cultivated by Aigamo duck farming system. Amylose content in milled rice tended to decrease with the delay of harvest time in both cultivars and cultivation methods examined. These results suggest that late harvest in Aigamo duck farming system improved the rice taste to the decrease in the number of green-kerneled rice and the contents of protein and amylose.View full abstractDownload PDF (687K) -
Zhichiao ZHAO, Kiyoshi TAKAHASHI, Iwao NISHIYAMA2000 Volume 69 Issue 3 Pages 324-331
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWe investigated the relationship between the forms of emergence and the seedling growth of rice(Oryza sativa L.)and the effects of plant growth regulators on the forms of emergence and seedling growth. In the first experiment, two cultivars of M type(Tchampa, Hei Chiao Chui Li Hsiang Keng)and two of S type(Haginomae Mochi, Shan Kiu Ju)were used as materials according to the results of the previous experiments. All cultivars were sown at a depth of 5.5cm. The mesocotyl growth was promoted in the case of M type, whereas the elongation growth of coleptile and the first leaf were inhibited when compared with S type. The growth of mesocotylar toots was also stimulated. The emergence rate of cultivars of S type was smaller than that of M type, but the growth after emergence was faster. The leaf number of seedlings of S type was greater than that of M type at 15 days after seeding. In the second experiment, we studied regulation of the forms of emergence and seedling growth by using five plant growth regulators, including three plant hormones, ABA, GA3 and ET, and two inhibitors of gibberellin biosynthesis, BX-112 and PP-333. The sowing depth was 5.5cm. As a result, in S type or F type cultivar, the form of emergence was changed to M type by an application of ABA. In F type, the form of emergence changed to S type by BX-112 or PP-333 application. These results suggest that the form of emergence is determined by plant hormones.View full abstractDownload PDF (1237K) -
Junichi KASHIWAGI, Kazuto IWAMA, Toshihiro HASEGAWA2000 Volume 69 Issue 3 Pages 332-336
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWe examined the stability of phenotypic variations of root length(RL)in the seedling genration of a cross between Norin 1(large RL)and Konafubuki (small RL)in different growing seasons and soil water conditions. Seedlings were grown in pots in a greenhouse, and RL was measured when six leaves were expanding. Mean RL largely differed among the environments, i.e., larger in the summer crop season than in the winter crop season and larger in the moderate water condition than in the dry of wet soil condition. The pattern of phenotypic variation of RL was similar, however, in all environments. The distribution of RL had a large peak in the smaller side, and the seedlings seemed to be separated into two groups, small RL and large RL. These results indicate that the pattern of phenotypic variation of RL in the seedling generation of the hybrid population is relatively insensitive to growing seasons and soil water conditions, suggesting that a selection of RL in the seedling generation may be possible in any of these growth conditions.View full abstractDownload PDF (795K) -
Akihito KUSUTANI, Jing CUI, Masanori TOYOTA, Koh-ichiro ASANUMA2000 Volume 69 Issue 3 Pages 337-344
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe varietal difference in bleeding rate was investigated using 10 Japanese varieties(J group)and 10 high-yielding varieties of rice bred in Asian countries(H group). The relationship between bleeding rate and yied characters was examined. Bleeding rate at the heading time(BR1)and maturing time(BR2)ranged from 2.20 to 3.92, and from 1.50 to 2.62(g h-1 hill-1), respectively. There were no significant differences in BR1 and BR2 between the two groups. The reduction rate of bleeding rate(RRB)during the ripening period shown by 1-BR2/BR1 was significantly higher in the H growp than in the J group. BR1 was not signifcantly correlated with the number of the phytomers(TPN), but showed a significant positive correlation with BR1/TPN. BR1 also showed a significant positive correltion with the shoot dry weight at the heading time. There was a significant positive correlation between RRB and the decline of leaf color(DLC)during the ripening period. Moreover, a significant negative correlation was found between RRB and the percentage of ripened grain. These results imply that the variety with a higher RRB and DLC has a lower ripening ability.View full abstractDownload PDF (1125K) -
Hiroshi TSUYUZAKI, Kazuyoshi TAKEDA, Tomoaki KOMAZAKI2000 Volume 69 Issue 3 Pages 345-350
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSBarley husbandry was investigated in the east part of Tibet plateau where the Tibetans are cultivating local varieties as their staple food. Barley lines collected there were grown in Japan to examine the heading date, yield component and so on. Almost all varieties cultivated were naked six-rowed barley. The nakedness seemed to have been selected by Tibetans, as it is a favorable trait for milling. They cultivated barley at small fields on the riverside and mountain slopes by hand using cows for plowing. Organic fertilizer was commonly used as basal dressing. Seeding time ranged from the middle of March to the beginning of April, and harvesting period was in August. These times differed according to the altitude. The harvested barley was dried, and then thrashed by human trampling or using a simple instrument. The heading time of the barley lines varied over a period of nearly one month when grown in Japan. The plants collected at 2900∼3100m tended to head later than those collected at a lower of higher place. The genetic differentiation may have derived from the difference in the climate and crop husbandry in each altitude zone. The kernel weight of collected lines belonged to the biggest grain size group in the naked six-rowed barley varieties of the world. Some proposals for the yield improvement in the explored area are presented.View full abstractDownload PDF (1302K) -
Jing CUI, Akihito KUSUTANI, Masanori TOYOTA, Koh-ichiro ASANUMA2000 Volume 69 Issue 3 Pages 351-358
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSVarietal differences harvest index (HI) and yield (Y) were examined using 60 Japanese varieties (J group) and 20 high-yielding varieties bred in Asian countries (H group). HI varied from 36.8% to 53.4%. Mean values of HI were 43.5% in the J group and 48.8% in the H group. Y ranged form 22.6g/plant to 40.0g/plant. The mean value of Y in the J group was 27.8g/plant, and that in the H grouo was 34.1g/plant. A significant positive correlation was found between HI and Y in the H group, but the correlation was not significant in the J group. There was a significant negative correlation between HI and total dry weight at the maturing time (W2) in the J group, but the correlation was not significant in the H group. The relationship between HI and dry matter production was examined by dividing HI into the following three components, based on the number of spikelets (N) and total dry weight at the heading time (W1), and W2. HI=Y/W2=[W1/W2]×[N/W1]×[Y/N] HI showed a negative correlation with W1/W2 in both groups. HI also had a positive correlation with N/W1 in the J group and with Y/N in the H group. W1/W2, N/W1 and Y/N are presumed to be indicators of the balance of dry matter production around heading time, the efficiency of spikelet production and the ripening ability, respectively. Therefore, these results suggest that varieties with relatively higher dry matter productivity after heading have higher HI in rice. Furthermore, HI was assumed to be affected by the efficiency of spikelet production in the J group and by the ripening ability in the H group.View full abstractDownload PDF (1192K) -
Jing CUI, Akihito KUSUTANI, Masanori TOYOTA, Koh-ichiro ASANUMA2000 Volume 69 Issue 3 Pages 359-364
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTo find useful indexes for the selection of new rice varieties having a high harvest index, the correlation of harvest index (HI) with morphological characteristics and leaf color was examined using 60 Japanese varieties (J group) and 20 high-yielding varieties bred in Asian countries (H group). In the J group, HI showed a positive correlation with leaf color (SPAD value, SV) and a negative correlation with plant length (PL) at the heading time. In the H group, HI showed a positive correlation with SV, but the correlation coefficient between HI and PL was not significant. The correlation berween HI and culm length (CL) was similar to that between HI and PL. HI showed a negative correlation with ear length (EL) in the J group, but significantly positive correlation in the H group. There was a significantly positive correlation between EL/CL and HI in the H group. A multiple regression analysis was conducted to clarify the relationship berween morphological characteristics and HI. A significant multiple correlation coefficient was obtained between HI and SV (X1), PL (X2) or EL/CL (X3). The ratio of standard partial regression coefficient of X1, X2 and X3 to HI was 54:15:31. Consequently, it is considered that these morphological characteristics are useful indexes to select varieties with a high harvest index.View full abstractDownload PDF (946K) -
Ryouji SASAKI, Zhichao ZHAO2000 Volume 69 Issue 3 Pages 365-371
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSRice seedlings (Oryza sativa L.cv.Sasanishiki) with plant ages of 2.0, 2.3, 2.5, 2.7, and 3.4 in leaf number were transplanted and completely submerged for 0, 5, and 10 days. Plant length and total root length were measured 10 days after transplanting (DAT), and the percent survival and total dry weight of the survived plants were recorded at 25 DAT to evaluate the difference in submergence tolerance among the seedlings. When the seedlings were submerged for 5 days, all survived. When they were submerged for 10 days, however, the elongation of plant length was promoted and growth of the roots was conversely suppressed. The percent survival of the seedlings with a plant age of 2.0-2.7 ranged from 53% to 81%, and it was higher than the 22% of seedlings with a plant age of 3.4. In particular, the percent survival of seedlings with a plant age of 2.5 was highest among seedlings. When endosperm reserves were removed from the seedlings just prior to transplantation, the reduction of elongation growth and the percent survival was hardly observed in the seedlings, except for those with a plant age of 2.0. The results indicate that the difference in percent survival among the seedlings was not caused by the amount of the residual endosperm reserves at the start of submergence.View full abstractDownload PDF (1309K) -
Ryouji SASAKI, Zhichao ZHAO2000 Volume 69 Issue 3 Pages 372-379
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe adverse effect of elongation growth and the beneficial effect of carbohydrate supply on tolerance to complete submergence for 10 days were evaluated in five kinds of transplanted rice seedlings, with plant ages of 2.0, 2.3, 2.5, 2.7, and 3.4 in leaf number in 1993 and 1994. The percent survival of seedlings with a plant age of 3.4 was lowest, and seedlings with a plant age of 2.5 showed the highest level of submergence tolerance among the seedlings in both years. The percent survival of seedlings positively correlated (r=0.951*) with the increase in shoot dry weight during submergence. In contrast, a negative correlation berween elongation growth (% of nonsubmerged seedlings) and percent survival was observed in each year. When the length of leaf sheath was longer than that of the leaf blade under submergence, the percent survival decreased and the percent survival in both years was reflected by a regression line (r=0.757*). Furthermore, a strong positive correlation (r=0.998***) was found between the ratio of increase in shoot dry weight to length of leaf sheath at the end of submergence and the percent survival. These findings suggest that the difference in submedrgence tolerance among seedlings is due to the difference of elongation growth, depending on the developmental stage of a leaf and the supplied carbohydrates to the growth zone of elongating leaves.View full abstractDownload PDF (1234K) -
Shao-Hui ZHENG, Miho KAWABATA2000 Volume 69 Issue 3 Pages 380-384
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSExudation from imbibing seeds is an indicator of seed vigor and influences seedling emergence. The objective of this report was to determine the substance of exudation from the seeds and its differences among crops and cultivars. The amounts of amino acids and sugars exuded from the imbibing seeds of 66 cultivars in 8 leguminous crops were measured by HPLC. Sixteen amino acids were detected from the seeds in soybean, and 14 in kidney bean. Only two were detected from the seeds in rice bean. The amount of exudates was greatest in soybean (1020μg per gram seed), and least in rice bean (71μg per gram seed). Arginin exuded in high frequency, however, it accounted for 32%(kidney bean)to 80% (rice bean) of total amino acid exudation. The sugars exuded from the seeds were mostly fructose and glucose. The frequency of sugar exudation was high in soybean and kidney bean, but low in mung bean and rice bean, and no detection in black gram. A great deal of exudates was found in soybean(2065μg per gram seed)and kidney bean(1297μg per gram seed). It doubled the amount of amino acids exuded in these two crops. No correlation between the exudation of full seeds and crushed seeds indicated that the exudation is independent of the contents of exudates in the seed. Dramatic difference was found among 29 cultivars in soybean, since the exudation presented from no detection to the greatest deal of exudation in some cultivars. Furthermore, the large seeds were very likely easy to exude, but no significant correlation was found between exudation and thickness of seedcoat.View full abstractDownload PDF (766K) -
Kuniyuki SAITOH, Takasi OHNAKA, Toshiro KURODA2000 Volume 69 Issue 3 Pages 385-390
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe dry matter production, dark respiration rate, and growth efficiency of early-(Koshihikari), medium-(Nipponbare)and late-(Akebono)maturing rice cultivars, were examined. The yield was lowest in Koshihikari than the other two cultivars because of poor ripening. The phytomass yield was in the order of Akebono > Nipponbare > Koshihikari because of the larger leaf area and the longer growth duration in later cultivars. The crop growth rate was higher in Koshihikari during the early growth stage in spite of its lower leaf area. The dark respiration rate (Rs) in the whole plant was highest at the rooting stage and rapidly decreased until the heading time;it decreased gradually thereafter. Rs in the panicle was highest at 7-14 days after the heading time and decreased to nearly zero by the maturing stage. In Koshihikari, however, it was maintained above zero at maturity. The respiratory loss as land areal basis was highest at about the heading time in all cultivars and decreased thereafter. The later the maturing time of the cultivar, the longer the period with high respiratory loss. The growth efficiency (net production/gross production) was above 60% at the rooting stage, but it was lowered during the grain-filling period, especially in Koshihikari and in Akebono. These were attributable to the higher atmospheric temperature in Koshihikari and larger plant body in Akebono, both requiring more respiration to be maintained. The growth efficiency in the panicle was higher in the order of Akebono>Nipponbare>Koshihikari, implying that the higher temperature during the grain-filling period increased the respiratory loss independent of the growth of grains.View full abstractDownload PDF (998K) -
Satoshi MORITA2000 Volume 69 Issue 3 Pages 391-399
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of high temperature(32°C/23°C max/min;27.5°C, daily mean temperature), which is common in August in Fukuyama city, Japan, on the grain weight and the grain quality of rice plants were examined. Air temperature was controlled artificially in growth chambers. The grain weight at 32°C/23°C was lower than at 28°C/19°C as a control in all primary branches at a panicle. The proportion of normal grains relative to all grains was smaller at 32°C/23°C. Moreover, the grain weight and the proportion of normal grains relative to all grains at 35°C/26°C were smaller than those at 32°C/23°C. The decrease in grain weight at high temperature accompanies the decrease in grain thickness. The proportion of imperfectly ripened grains relative to all grains at 32°C/23°C was higher than that at 28°C/19°C, and the proportion of nonfertilized grains at 35°C/26°C was higher than that at 32°C/23°C. The cultivars for which the ratio of grain weight at 35°C/26°C to that at 28°C/19°C was lower than 90% were Moritawase, Arborio as a large grain, and Akenohoshi, which tended to have a bad ripening performance. In contrast, the cultivars with a ratio higher than 95% were Koganemasari, Lakhi Jhota as a small grain, and Hoshiyutaka, known as a good ripened cultivar.View full abstractDownload PDF (1350K) -
Satoshi MORITA2000 Volume 69 Issue 3 Pages 400-405
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of high temperature in August in Fukuyama city, Japan, on the grain weight and the grain quality of rice plants were examined. Air temperature was manipulated by 1) changes in cropping seasons by different planting dates adn 2) transferring pots from lowland to upland at the heading stage. In the first experiment, no significant differences were found among the mean grain weights and the grain quality of any cropping seasons. In the second experiment, not significant difference was found in the mean grain weight between the two treatments, but significant differences in the grain quality and the weights of grain with a thickness of more than 1.9mm were observed. In experiments 1) and 2), the grain weight/mean solar radiation during 20 days from the 4 days after flowering stage at the top of the panicles(=S20)correlated negatively with the mean temperature at that stage. The rate of normal grains/S20 did also. These results suggest that the neggative influence of high temperature, 27∼28°C, on grain weight is counteracted when solar radiation increases, accompanied by remperature increase. When temperature increases without increases in solar radiation, however, the grain weight and grain quality were adversely affected.View full abstractDownload PDF (956K) -
Takahiro TANIMOTO, Ryoichi ITOH2000 Volume 69 Issue 3 Pages 406-412
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe aim of this study is to estimate the effects of leaf rolling on the transpiration, photosynthesis, dry matter production and water use efficiency(WUE), of four rice cultivars that differ in the degree of leaf rolling. Leaf rolling was assessed with a ruler as the leaf rolling rate(LRR). LRR(%)=(1-RLW/FLW))×100, where RLW and FLW were the width of the rolling and flattened leaves, respectively. Transpiration in Koshihikari, Koganemasari and Akihikari was significantly larger than in C-115, and the transpiration of C-115 was increased by unrolling of the leaves. There was a negative correlation between the transpiration and the LRR. These results suggest that the rolling of leaves inhibits transpiration. Among the leaves with the same stomatal conductance, leaves exhibiting more than 10% LRR transpirated less than those exhibiting less than 10% LRR. However, photosynthesis was not influenced by LRR. These results indicate that WUE of a single leaf is improved by a higher LRR. The LRR had no effects on stomatal conductance and leaf temperature. Therefore, it is thought that the transpiration was decreased by leaf rolling through the decrease in the boundary-layer conductance. Comparable to the WUE of a single leaf, WUE per plant was improved by increasing LRR. Transpiration in normal C-115 was significantly increased by the unrolling of leaves. The dry matter in normal and the leaf-unrolled C-115, however, was not different until 20 days after heading, showing that WUE of normal C-115 was larger than that of the leaf-norolled C-115. WUE was decreased by evaporative demand in all cultivars and the unrolled C-115. Under the same evaporative demand, however, WUE of C-115 was larger than that of other cultivars.View full abstractDownload PDF (1042K) -
Tohru KOBATA, Makoto SUGAWARA2000 Volume 69 Issue 3 Pages 413-418
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSA shortage of carbon assimilate supply to rice grain during the first ten days after heading(DAY0-10)has been considered to reduce the potential grain dry-matter increase(ΔGP). It was, however, uncertain whether assimilate supply after the shading period was sufficient to support ΔGP when the reduction of grain dry-matter increase(ΔG)was observed. Our objective was to demonstrate that ΔG after the shading treatments was reduced not through the decrease in ΔGP but through a lack of assimilate supply, based on our model analysis. In our model, ΔG is determined by assimilate supply(current dry-matter production(ΔW)plus reserved assimilate in straw(SP)and the ΔG has an upper limitation defined by ΔGP. In this study ΔGP was estimated under a sufficient supply of assimilates which were provided by periodical thinning of the plants. By the shading during DAY0-10, ΔG as well as ΔW were reduced even after the end of the shading treament. Observed ΔW and SP at the heading were input to the model to calculate ΔG and straw dry-matter increase(ΔS). The calculated dry weight of the grain and straw coincided closely with the actual observed data. We herewith suggest that the grain dry-matter increase by shading during DAY0-10 was not suppressed by inevitable reduction of ΔGP but rather by a lack of assimilate supply during the active ΔG period.View full abstractDownload PDF (961K) -
Takayuki NAKANO2000 Volume 69 Issue 3 Pages 419-423
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSA non destructive method using Plant Canopy Analyzer(LAI-2000, LI-COR, Inc.)was applied to estimate a leaf area index(LAI)for mature tea(Camellia sinensis L.)bushes. The LAI estimated by PCA showed a positive correlation(n=51, r=0.951, p<0.0001)with the orthodox stratified clip method using a leaf area meter. A bias was observed, however, with PCA, since an LAI value of 3 was noted with no leaf. The positive LAI observed in the absence of leaves suggests that the PCA method may sense a branch ares as a leaf area. Thus the estimation of LAI using PCA dose not seem appropriate. When the same methodology was applied for total weight of a bush, a better correlation was found with PCA(n=51, r=0.973, p<0.0001)than LAI. Thus the PCA appears to be a method of choice for measuring the total weight of a tea bush.View full abstractDownload PDF (952K) -
Haruhiko YAMAMOTO, Kiyoshi IWAYA, Kenji SUZUKI, Seiji YAHAKAWA, Yoshin ...2000 Volume 69 Issue 3 Pages 424-430
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTyphoon 9918 passed through the Kyushu District and the western part of Chugoku District on September 24, 1999. A gust higher than 20m/s was recorded in the middle and southern parts of Kyushu District. The typhoon caused gust and storm surge disasters in the western part of Japan. The agricultural loss in the Kyushu District exceeded 91 billion yen. The peak gust recorded at Onoda Fire Station of Yamaguchi Prefecture was 58.9m/s. The sea level in Ube port was 560cm at 8:00, which was 209cm higher than the expected value(351cm). In Aiofutajima of Yamaguchi City, the gust and storm surge caused the bank to collapse, The rice plants received salt damage from the sea water and did not yield any rice that year.View full abstractDownload PDF (1998K) -
[in Japanese]2000 Volume 69 Issue 3 Pages 431-434
Published: September 05, 2000
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSDownload PDF (845K)
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