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Volume 63, Issue 3
Displaying 1-21 of 21 articles from this issue
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Tomizou YAMAMOTO, Kouhei TANAKA, Kazuhiro KADOSIGE1994 Volume 63 Issue 3 Pages 411-417
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIt was investigated whether the amount of ammonification could be used as an index of soil analysis for fertilizer application, which was related with the amount of soil nitrogen supplied from paddy fields. The amount of ammonificaton was shown by the amount of ammonium nitrogen released by incubation of the air-dried soils at 30°C in 4 weeks. The amount of ammonification of the top soils in the Tikugo basin was compared with the amount of soil nitrogen absorbed by rice plants, which was estimated from the nitrogen accumulated in the rice plant grown with no nitrogen fertilizer. The amount of ammonification was expressed as kg per 10a by using the depth and the volume weight of topsoil. The amount of ammonification obtained by indoor experiment was found to be correlated with the amount of soil nitrogen absorbed by rice plants. The rate of the latter to the former was 42% in 'Nishihomare' and 40% in 'Hinohikari' on the average of the experimental fields, and there was little difference of between fine textured soils and coarse textured soils. Based on the above results, it was concluded that the amount of ammonification could be used to estimate the rice yeild and to determine the optimum rate of fertilizer application.View full abstractDownload PDF (796K) -
Shigenori MORITA, Hiroyuki OKUDA1994 Volume 63 Issue 3 Pages 418-422
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSEffects of soil water stress on root development of winter wheat seedling was studied with special reference to elongation and branching of seminal roots. Japanese wheat variety Norin 61 was planted in acrylic tubes (diameter : 26 mm, length : 1 m) which were filled with gardening soil. Soil water content was adjusted to 30% for W plot and 20% for D plot at the beginning of the experiment, and irrigation was withheld afterward. Plants were grown under controlled conditions (day length: 14 hours, day temperature : 25°C, night temperature : 20°C, illumination : 10, 000 lux) and were sampled for 1 month at intervals. In D plot, the rate of leaf emergence was slower compared with W plot, whereas the root/shoot ratio was remarkably higher in D plot. The number of seminal roots was almost the same for both plots. Although W plot had more nodal roots, they were quite short. These facts suggested that the difference in root dry weight between the two plots was due to that of seminal root system development. Detailed examinations on the primary seminal root of the two plots showed that soil water stress first inhibited elongation of the main axis, then promoted the production of first-order lateral roots per main axis, and finally increased the average length of lateral roots. These sequential responses in root morphology to soil drying resulted in more-developed branching of primary seminal root in D plot.View full abstractDownload PDF (643K) -
Jiro HARADA, Si-Yong KANG, Koou Y YAMAZAKI1994 Volume 63 Issue 3 Pages 423-429
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTo characterize the root system of the Japonica-Indica hybrid rice cultivars (Milyang 23, Suweon 258), we compared the number and elongation direction of primary roots both per stem and shoot unit bases with the japonica type rice cultivars (Nipponbare, Koshihikari). The four cultivars were grown in 45-liter polyethylene containers with paddy field soil, and soil cores ( 15 cm in depth and 15 cm in diameter) were taken at the grain-filling stage. To estimate the number of primary roots of different elongation direction, soil cores were divided into four layers by different color markings. Stem numbers of the Japonica-Indica hybrids at the grain -filling stage were less than Japonica type cultivars, but the numbers of primary roots per stem were larger in the Japonica-Indica hybrid cultivars. In particular, the number of primary roots of Suweon 258 were the highest per shoot unit, per stem and per hill. The rate of primary roots of Japonica-Indica hybrid cultivars elongating deep into the soil were more than that of Japonica type cultivars. In the Japonica-Indica hybrid rice, the elongation direction of primary roots were very different between upper and lower roots in the higher shoot units of the main stem ; i.e. the upper roots elongate to the shallow layer, while the lower roots tend to elongate deep into the soil.View full abstractDownload PDF (814K) -
Tomoyuki YUKAWA, Yoshiaki WATANABE, Shinro YAMAMOTO1994 Volume 63 Issue 3 Pages 430-435
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThis study was conducted to clarify the relationship between fructan accumulation and snow tolerance by estimating the changes in degree of polymerization (DP) and concentration of fructan under treatment at 1°C in dark to mimic the conditions under snow using 3 varieties of differing wintering ability sown at optimum and late times. (1) The concentration of fructan before the cold-dark treatment in the winter hardy variety and the plants sown at optimum time was higher than the non-hardy variety and those sown late. The concentration of mono- and disaccharides in the plants sown at the optimum time was higher than those sown late, but there was no relationship between the concentration of mono- and disaccharides and wintering ability. Hardy variety contained a greater amount of long-chain fructan (DP≥9) than the non-hardy variety. The concentration of short-chain fructan (DP≤8) in the hardy variety sown late was higher than that of the non-hardy variety, but a varietal difference of this fraction was not detected in the plants sown at the optimum time. Increasing the polymerization of fructan by increasing the concentration of whole fructan is considered to be important to promote the wintering ability. (2) Treatment at 1°C in the dark was conducted to mimic the conditions under snow. The fructan decrease in the hardy variety and the plants sown at optimum time was rapid and large in the early stage of the cold-dark treatment. The decrease in long-chain fructan was greater in the hardy variety than in the non-hardy variety. The decrease in short-chain fructan was greater in the non-hardy variety sown at the optimum time and the hardy variety sown late than in the hardy and non-hardy varieties, respectively. The rate of decrease in fructan was inversely related to wintering ability. Accordingly, fructan decreased slower in the hardy variety accumulating a smaller amount of fructan than in the non-hardy variety with larger amount of fructan. These results suggest that both the fructan accumulation at early winter and the metabolism under snow affect the decrease of fructan under snow.View full abstractDownload PDF (702K) -
Toshio MABUCHI1994 Volume 63 Issue 3 Pages 436-441
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe conditions of dilute hydrogen peroxide (H2O2) solution treated on the dormancy breaking of two-rowed barley seeds soon after harvested was examined, on the varieties of Azumagoruden (light), Seijyou NO. 17 medium), and Satsukinijyou (deep dormancy). Dormancy breaking treatments were undertaken with H2O2 at concentrations of 0, 0.125, 0.25, 0.5, 1.0, 2.0 and 4.093 and soaking periods of 0, 12, 24, 36 and 48 hours. Also, the temperature conditions of soaking and germination period were 10°, 20°and 25°C. As the degree of dormancy increased higher concentrations of the H2O2 solution and longer soaking periods were required. The optimum conditions were Azumagoruden : H2O2 0.5% and 12 hours, Seijyou No. 17 : H2O2 1% and 24 hours, and Satsukinijyou : H2O2 2% and 36 hours, respectively. When the degree of dormancy was high, the dormancy breaking procedure was more effective as the temperature of seed soaking was low : Azumagoruden ; 25°C, Seijyou No. 17 ; 20°C, and Satsukinijyou ; 10°C. The viability of two-rowed barley seeds by the dormancy breaking with dilute solution of H2O2 may be assayed within 3 days.View full abstractDownload PDF (733K) -
Satoko TOMIMORI, Yuichi NAGAYA, Tetsuro TANIYAMA1994 Volume 63 Issue 3 Pages 442-451
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSAn investigation of agricultural chemicals and chemical fertilizer used by golf links were carried out from June 1991 to May 1992. Immediately after or during the rainfall, sampling for drainage was started at 6 points of 3 golf links. About 15 agricultural chemicals, nitrogen, phosphorus and potassium were analyzed. The following results were obtained. Nine agricultural chemicals including 3 herbicides (Propyzamide, Simazine, Napropamide), 4 bactericides (Flutoluanil Isoprothiolane, Captan, Tolclophos-methyl) and 2 insecticides (Diazinon, Fenitrothion) were detected. Detectable frequency was different at the 3 golf links and the 6 sampling points. The highest levels of agricultural chemicals were detected in June, and high levels of Flutoluanil, Isoprothiolane and Captan were detected. These concentrations were higher in September, and high levels of Propyzamide and Simazine were detected, and each maximum level was over 8 and 3μgL-1. Many concentrations were from 0.1 to 1.0μgL-1. Every component of the chemical fertilizer found in the drainage water from golf links were at high levels in comparison with rivers. Changes in these concentrations were closely related to time of fertilizer application for lawn management.View full abstractDownload PDF (997K) -
Hisao NAKANO, Tsuguo MIZUSHIMA1994 Volume 63 Issue 3 Pages 452-459
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTo elucidate the effect of the number of seedling per hill on yield components and yield, rice plants cv. Nipponbare and Hourei were transplanted at three levels (1, 4, and 7) and two levels (4 and 7) of the seedling number per hill in 1984 and 1985, respectively. The hill density was at two levels and the amount of fertilizers was at one or three leves. The tillering stage was divided into three or four periods and the percentage of fruitful culms and panicle characteristics were investigated in each period. In the higher seedling number per hill, the number of panicles per square meter was larger, but the number of spikelets per panicle and the percentage of ripened grain were smaller. The 1000-kernel-weight was not affected by the seedling number per hill. In every tillering period, the number of spikelets per panicle, the percentage of ripened grains and the percentage of fruitful culms showed a significant positive correlation with the diameter of the first elongated internode at the base at harvesting time. A highly negative correlation was found between the sum of the number of culms at the emergence of a tiller and the number of tillers which emerged in the same tillering period, and diameter of the first elongated internode of tillers at harvest time. The degree of the diameter decrease for the increase of sum of culms and tiller in the higher hill density was larger than the degree of diameter decrease in the lower density. The increase of the number of culms per hill decreased the rate tillering emergence, and leaf blades with a high seedling number were light green in colour. These results imply that the high seedling number per hill induces a large culm number per hill and the small growth of a culm reduces the spikelets per panicle, the percentage of ripend grains and the percentage of fruitful culms. Finally, a high seedling number per hill lowers the grain yield. The rice plant responses to three cultural factors are discussed in terms of competition in a hill.View full abstractDownload PDF (813K) -
Jian-min LI, Koou YAMAZAKI1994 Volume 63 Issue 3 Pages 460-466
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTiller survival is a primary determinant of the number of tillers per plant. This study was conducted to examine how the tiller survival was affected by their own growth and development. Winter wheat (Triticum aestivum L.) plants, cv. Norin 61, were grown under dry (D, not irrigated), wet (W, irrigated) conditions in a vinyl-house and under field (F) conditions. Ten plants per plot were selected at random as observations, the emergence, survival and mortality of tillers were observed, and the leaf number of tillers, the differences of leaf number between tillers and their mother shoots were traced at intervals of 5-7 days from tiller appearance until mid-maturity. At the same period, 3-5 plants per plot were sampled weekly, and the leaf number, stem length, nodal root number and panicle development stage of main stem and tillers were measured. By comparing to the data of observed plants, the tillers of sampled plants were divided into the group to servive and the group destined to die prematurely. A comparison of the developmental properties of the two groups revealed that the rates of leaf emergence, stem elongation and panicle development of tillers to survive were consistent with the rates of their mother shoots, while the tillers to die showed reduced rates of leaf emergence, stem elongation and panicle development after the main stem elongation stage, and finally died.View full abstractDownload PDF (796K) -
Jian-min LI, Koou YAMAZAKI1994 Volume 63 Issue 3 Pages 467-472
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn this study, two experiments were carried out to examine how the tillers survived and adapted morphologically to competition in the wheat (Triticum aestivum L.) plant population. In the first experiment, the heights (highest leaf blade height and stem length) of main stem and tillers were measured from tiller emergence to mid-maturity. It was found that, compared with the heights of main stems, the relative heights of the tillers, especially those which appeared from the leaf axils of higher positions and orders, decreased quickly after elongation of the main stems. In the second experiment, firstly, the heights of smallest tillers (ST) survived in local plant groups (about 30-40 plants), and the local shoot densities surrounding the ST were measured. A positive relationship was found between the local densities of shoots and the heights of ST. Then, analysis of the relationships between the shoot heights and the morphological features showed that, as the shoot heights decreased, the morphological features of shoots changed in the direction favorable to light competition, i.e. the specific leaf area, and the ratios of stem length to stem weight and leaf blade weight (of the uppermost 3 leaves) to stem weight inceased. In ST, these changes were closely related to the stem length differences of the main stems and their ST. These results showed that the tiller's survival was affeted not only by the competition in the plant population but also the morphological changes adapted to the competition.View full abstractDownload PDF (740K) -
Yusuke GOTO, Satoshi NAKAMURA, Kiwamu SAKAI, Kiyochika HOSHIKAWA1994 Volume 63 Issue 3 Pages 473-479
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSAn early-maturing cultivar Sucrosorgo 301 (S301) and a late-maturing cultivar Sucrosorgo 405 (S405) were grown in low population (LP : 100 cm between rows, 50 cm within rows) and high population (HP :50 cm between rows, 20 cm within rows). At the early stage, plant length was longer in HP than in LP, though at harvest time it was longer in LP. The lowest 'elongated internode (≥1 cm)' of S301 was the 6th internode (IN 6) and that of S405 was IN 7. In both cultivars, an elongated internode at the lower part of stem was longer in HP than in LP, while that at upper part was shorter in HP than in LP. The internode diameter was consistently larger in LP than in HP. To analyze the internode growth pattern, the position of a fully expanded leaf on the stem was used for counting plant age (AL) : for instance, the plant age for just expanded 10th leaf (L10) was defined as AL 10. A conceptional growth curve of internode elongation was drawn based on IN 9∼IN 12 elongation pattern. IN (n) (n : natural number) rapidly elongated at AL (n+2) and reached its maximum size at AL (n+3)∼AL (n+4). Plant density affected the rate of internode elongation. The internode thickening pattern was expressed by two different growth curves, Thickening of IN (n) was not affected by the plant density until AL (n). INn reached a maximum diameter at AL (n+5) in LP and at AL (n+2) in HP. So the diameter of IN (n) in LP was larger.View full abstractDownload PDF (721K) -
Kuniyuki SAITOH, Ryuzi INAMURA, Kuni ISHIHARA1994 Volume 63 Issue 3 Pages 480-488
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTo clarify the effect of leaf movements on the micro-environments inside the soybean canopy, the vertical distribution of several meteorological factors were compared between the rice and soybean canopy. The upper layer of the soybean canopy had higher leaf area density. In the soybean canopy, wind speed, wet filter paper evaporation rate and CO2 concentration of the air were lower, and dew point temperature of the air was higher, just below the plant cover than the rice canopy. By measuring the wet filter paper evaporation rate and the vapor density difference between the air and the filter paper at each height inside the canopy, boundary layer vapor diffusion resistance (ra) was calculated. ra increased with lowering the height above the ground inside the canopy, and decreased at each height with increase in the open field wind speed. ra was larger in the soybean canopy than the rice canopy due to lower wind speed. The relative wind speed in the upper layer of the soybean canopy became higher late in the morning. It is speculated that wind penetrate into the soybean canopy by the active leaf movement. Diurnal variation of relative light intensity was observed in each height inside the canopy. The light extinction coefficients of the whole canopy decreased as the sun altitude increased, and these changing levels of the soybean canopy were larger all day than the rice canopy. The extinction coefficients in the upper layer of the soybean canopy were smaller during the daytime due to trifoliolate compound Leaf movements. Cleary, sunlight penetrates into the soybean canopy with a decrease in the area of triangle described by the three tips of the trifoliolate compound leaf.View full abstractDownload PDF (1003K) -
Akihiro NOSE, Masaru UEHARA, Yoshinobu KAWAMITSU, Naotada KOBAMOTO, Mi ...1994 Volume 63 Issue 3 Pages 489-495
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of photosynthetic photon flux density (PPFD) and temperature on leaf gas exchange rates of ten lines of Saccharum spontaneum L. collected from the tropics to temperate regions in North-West Pacific zones, S. sinense Roxb. cv. Yomitanzan, native sugarcane in South-West Islands, and Saccharum hybrid cv. NCo310 were investigated. The relationship of gas exchange traits and rates was examined. Significant line- and species -differences (P<0.05) were found in the carbon dioxide exchange rate (CER) at high PPFD (1700 μM photon m-2s-1), leaf stomatal conductance at low PPFD (180 μM photon m-2s-1), contents of total nitrogen, soluble protein, and chlorophyll, PEP carboxylase and malic enzyme activity, and specific leaf area (SLA). CER at high PPFD (P<0.05) of Tainan, S. spontaneum was significantly higher than that of Saccharum hybrid cv. NCo 310, while CERs of JW2, JW32, and JW41 of S. Spontaneum were significantly higher than that of S. sinense Roxb. cv. Yomitanzan. CER of Tainan exhibited the highest value in a range of 20 to 35°C. Consequently, this suggests that S. spontaneum such as Tainan, is a useful germplasm source in sugarcane breeding. CER of Saccharum correlated significantly with leaf stomatal conductance (r=0.496, P<0.01), the malic enzyme activity of Mn type (r=0.838, P<0.01) and Mg type (r=0.547, P<0.01), and the chlorophyll content (r=0.466, P<0.01).View full abstractDownload PDF (844K) -
Toshihiro HASEGAWA, Takeshi HORIE1994 Volume 63 Issue 3 Pages 496-501
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe estimation of available nitrogen in paddy soil is important in order to evaluate rice productivity and to improve fertilizer management. In this study, a simplified model is proposed for estimating nitrogen mineralization in paddy soil based on incubation experiments. The main factors considered are soil moisture percentage on dry weight basis before submergence (θ) and temperature (T). Soil samples were collected from an experimental paddy field (Alluvial, SL) at Kyoto University. Incubation experiments were conducted for wet and air dried soil under four different temperatures of 15°, 20°, 25° and 30°C. To investigate the effect of preflooding soil moisture on N mineralization, we set eight levels of soil moisture before submergence, after which samples were subjected to a similar incubation experiment. Mineralized N in wet soil (NW) increased linearly, while the drying effect (ND), defined as a difference in N mineralized between air-dried soil and wet soil, was found to have an equal ceiling value over the incubation temperature conditions, though the rate toward the asymptote varied with temperature. We employed the following equations to express the N mineralization rate :dN/dt=dNW/dt+dND/dt dNW/dt=KW dND/dt=KDNOexp(-KDt) where, KW and KD are temperature dependent rate constants expressed by the Arrhenius' equation, of which the apparent activation energy was 24, 803 and 14, 058 cal·mol-1, respectively. No is the maximum effect of soil drying expressed as a function of θ before submergence as follows : NO=7.171-0.66θ+0.015θ2, θ≤19.56% =0 θ>19.56% The present model was able to estimate satisfactorily the amount of NH4-N mineralized under specific conditions. Increasing the model generality is a subject for further study.View full abstractDownload PDF (676K) -
M.T. ISLAM, Waichi AGATA, Fumitake KUBOTA, Abdul HAMID1994 Volume 63 Issue 3 Pages 502-509
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSCharacteristics related to photosynthetic rate and leaf area production of 63 mungbean (Vigna radiata (L.) Wilczek) genotypes collected from different Asian countries were evaluated in pot culture conditions. There were large genotypic differences in photosynthetic rates (Pn) and its related factors. Each of the variations was also quite large, but that of leaf conductance (Gl) was the largest. Pn was positively correlated with its related factors. Among them, mesophyll conductance (Gm) was the highest. The transpiration rate (Tr) of most of the genotypes was higher than that of other crops. Although there was a high correlation between Tr and Gl, Tr was saturated at over 0.75 mol·m-2·s-1 of Gl. As a result, genotypes with high Gl resulted in higher water use efficiency (WUE) compared with other genotypes. Based on Pn values, all the genotypes were classified into three groups, high Pn, medium Pn and low Pn. Genotypes belonging to the high Pn group had high values of related factors as compared with that of the medium and low Pn groups. Although the leaf area increasing rate (LIR) and mean area of the terminal leaflet (TLA) had a significant correlation with Pn, the leaf emergence rate (LER) did not. Specific leaf weight (SLW) significantly related with Pn. It is, therefore, considered that stomatal frequency which relates strongly to Gl, mean TLA, LIR and SLW, can be used as selection criteria for improvement of Pn in mungbean genotypes.View full abstractDownload PDF (748K) -
Tohru KOBATA, Satoru TANAKA, Motokazu UTUMI, Shinichi HARA, Tadashi IM ...1994 Volume 63 Issue 3 Pages 510-517
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn rice plants a drought at the booting stage is the event most damaging to grain yield because it drastically increases sterility. Our objective was to establish what phosiological processes caused sterility during drought. We applied several soil-drying treatments to pot-grown plants of three rice cultivars (one lowland and two upland) for 10 days during the booting phase. Flag leaf elongation rate (LER), the rate of dry matter production (DMP) and leaf water potential (LWP) decreased and sterlity increased in all cultivars as the intensity of soil drying increased. Increasing sterility was closely correlated with reduced DMP in all cultivars. It has been assumed previously that suppressed assimilate supply causes sterility. However, when DMP was strongly suppressed by shading under well-watered conditions, sterility was unaffected. Moreover, when part of the root system was partially dried at the booting stage, sterility significantly increased and leaf diffusive conductance decreased when compared with the results for well-watered plants, although there was no significant difference in LWP between the treatments. We suggest that sterility in rice plants subjected to soil drying during the booting stage occurs not by reduced assimilation or because of water deficits in the shoot, but by some chemical signal from roots to shoots.View full abstractDownload PDF (882K) -
Yoshie S. MOMONOKI, Hideo KAMIMURA1994 Volume 63 Issue 3 Pages 518-523
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSSalt stress is one of important subjects in recent agriculture. Salicornia europaes L. is well used as a comparative plant of salt resistance for many crops. However, there is no detail data for mechanism of salt resistance in Saliconia plants. In the present work, changes in growth, pH and osmotic pressure were investigated at the organ level durins at the organ level during the growth period of wild Salicornia plants. Further, glycinebetaine in the plants at the end of growth stage was determined. Plants of Salicornia around Lake Notoro-ko in the eastern region of Hokkaido, Japan germinated in the ground at the end of March. The fresh weight and the length of the aerial and root portions of the plants increased most between the end of May and the end of August. The plants bloomed at the end of July, and plants gradually changed color from green to red after the end of August. The pH in stems and branches of the plants increased from pH 7.6 to pH 8.8 during the growth period. Also, osmotic pressure in stems and branches of the plants increased remarkably from about 650 mOsm·Kg-1 to 2, 600 mOsm·Kg-1 throughout their growth period. Further, glycinebetaine was found in tissues of the aerial and root portions. These results of the accumulation of organic solutes in the cells suggests an osmotic regulatory mechanism.View full abstractDownload PDF (666K) -
Yukio KUJIRA, John H. GROVE, Pedro RONZELLI Jr.1994 Volume 63 Issue 3 Pages 524-530
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSVarietal differences in root system morphology in winter wheat (Triticum aestivum L.) were investigated using seed pack growth pouches in a greenhouse. Different genotypic cultivars, shorter B-288 D for dwarf type, Pioneer 2548, Clark and Madison for semi-dwarf type, Cardinal and Verne for tall type, were used in this experiment under two different nutrition levels (NO3-N ; 10 mg/l and 50 mg/l) with three replications. One germinated seed of each cultivar with primary seminal root less than 1.0 mm in length was transplanted into each seed pack on Dec. 5, 1991. Significant varietal differences were recognized in the spread of the root system, but there was no difference between the nutrition levels. Madison and Shorter B-288 D showed a large spread of the root system, whereas Cardinal showed a small spread. Total root length per plant was significantly different among the cultivars, with Cardinal showing the largest total root length per plant and Shorter B-288 D showing the smallest. On the other hand, there were no significant differences in stem number or leaf number per plant. These varietal differences in the lateral spread of the root system and total root length per plant were considered to be controlled by genotypic parameters. The semi-dwarf gene in wheat that affects the plant type did not influence the spread of root system and total root length per plant.View full abstractDownload PDF (650K) -
De An JIANG, Tadashi HIRASAWA, Kuni ISHIHARA1994 Volume 63 Issue 3 Pages 531-538
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSSoluble starch was applied to soil in a pot where rice plant grew at the 10th leaf stage and the initial heading stage. When root activity and leaf bleeding rate were lowered in the treated plant, photosynthesis and stomatal conductance were investigated in the morning. Immediately after that initial Rubisco carboxylation activity and Rubisco content were determined to elucidate what was predominantly responsible for the depressed photosynthesis due to low root activity. Accompanied by a decrease in root activity and leaf bleeding rate during 2-9 days after soluble starch application, the photosynthesis and stomatal conductance in the treated plants were all lowered while the initial Rubisco carboxylation activity and Rubisco content in their leaves were approached or even higher than that in the control plant. The photosynthesis was an extremely significant positive curvilinear correlation with the stomatal conductance. These results show that the depression of photosynthesis in the low -root activity plant introduced by soluble starch application is due to lower stomatal conductance in the treated plants and not due to a lower internal CO2 assimilation capacity. The decline of photosynthesis in the treated plants, however, was mitigated, in whole or in part, with prolonging the time after soluble starch application perhaps through absorbing the additional nitrogen, which was supplied with the soluble starch.View full abstractDownload PDF (820K) -
De An JIANG, Tadashi HIRASAWA, Kuni ISHIHARA1994 Volume 63 Issue 3 Pages 539-545
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn order to verify the difference in diurnal changes in photosynthesis in rice plants with different root activities, the experiment was conducted with a control plant and a soluble starch-applied plant more than 16 days after soluble starch application. There was a larger difference in the diurnal changes in the photosynthesis and stomatal conductance, due to increase in Rubisco contents resulted from the application of soluble starch and nitrogen. Photosynthesis and stomatal conductance in the low-root activity plant were higher before 10 o'clock and lower at midday and in the afternoon. The response curves of the photosynthesis to photosynthetic photon flux (PPF) expressed a significant saturable curve and were obviously different between morning and afternoon under PPF over 1000 μmolm-2s-1. An obvious diurnal change in the initial activity and activation rate of Rubisco carboxylation had been found. They all were higher at midday than in the early morning and late afternoon. The initial activity based on leaf area was significantly higher in the low-root activity rice plant, but its activation rate was obviously lower. Therefore, the difference in diurnal changes in photosynthesis between the different root activity plants can not be attributed to the difference in Rubisco activity, but mainly to the difference of the midday drop in stomatal conductance, which was significantly correlative to photosynthesis.View full abstractDownload PDF (759K) -
Somchai CHAKHATRAKAN, Vilaipon CHAKHATRAKAN, Yoshiharu MOTODA, Yasuo O ...1994 Volume 63 Issue 3 Pages 546-548
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSDownload PDF (412K) -
[in Japanese]1994 Volume 63 Issue 3 Pages 549-553
Published: September 05, 1994
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSDownload PDF (635K)
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