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Volume 62, Issue 2
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Osamu SASAKI, Atsuhiko YUDA, Kenji UEKI1993 Volume 62 Issue 2 Pages 157-163
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThis study was conducted to present a quantitative analysis of the branching pattern of the sweet potato over growth time and its varietal differences of the two cultivars, Shiroyutaka and Minamiyutaka. 1. Primary and secondary branches in Shiroyutaka were developed significantly during 30 to 60 days after planting. Most of such branches were formed at the base of the plant, and they tended to have grown more rapidly than in the branches formed on the other part of the plant axes. In Minamiyutaka, on the other hand, branching ability was relatively low, especially very few branches were formed at the base of the plant. Based on the difference in such a branching habit of the two cultivars, the dry matter of the vegetative top in Shiroyutaka showed heavier than that of Minamiyutaka through all the growth period. 2. The diameter at the base of the main stem was observed to increase in close relation to the development of the branches formed at the base of the plant. Shiroyutaka, compared with Minamiyutaka, increased its diameter significantly during the growth periods of both primary and secondary branches. This increase was owed mainly to the increase in the secondary vascular tissues. 3. The tuberous root yields in Shiroyutaka were higher than in Minamiyutaka through each time of the growth stage. Based on these results, it is suggested that early development of the branches formed at the base of the plant promoted the growth rate of the vegetative top and the yield of tuberous roots. Additionally, the increase in diameter at the base of the main stem might have some advantage in relation to the translocation of the substance.View full abstractDownload PDF (878K) -
Yoshiaki KAMIJI, Shigekazu HAYASHI, Takeshi HORIE1993 Volume 62 Issue 2 Pages 164-171
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSFactors for causing variations in lower internodes length of rice were investigated in relation to lengths of synchronously extending leaf blade, LAI and radiation environment in the canopy for a cultivar 'Nipponbare' grown under different split application conditions of N fertilizer. The N application conditions included light basal and heavy top-dressings from the panicle initiation stage onward (L), and heavy basal and heavy top-dressings from the spikelet formation stage onward (V). Lengths of lower internodes showed no or negative correlations with those of upper leaf blades which were synchronously extending with the internodes. Under the same amount of total N application, the lengths of lower internodes at L were shorter than those at V. Since N top-dressing at L was applied at the lower internodes elongation stage, N is not likely to be the direct cause for the lower internodes elongation. Lengths of lower internodes correlated positively with LAI at 30 days before heading, and negatively with accumulated solar radiation at the stem base during the lower internodes elongation stage. Shading treatment given to the stem base of the plants elongated lower internodes. These results indicate that the primary factor for the variation of lengths of lower internodes in rice is solar radiation conditions in the canopy through the promotions of LAI development.View full abstractDownload PDF (759K) -
Tetsuro TSUCHIYA, Toshiaki MATSUDA, Nobuo CHONAN1993 Volume 62 Issue 2 Pages 172-182
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSBy making serial sections, the distribution and connection of vascular bundles in the potato tubers were observed by light microscope. The vascular bundles entered from stolon into the rose end of tuber separate to the external phloem of cortex, to the bundles of vascular bundle ring, and to the internal phloem in perimedulla. Each of the external phloem in cortex and the bundle of vascular bundle ring have the anastomosing network which runs parallel to periderm. The internal phloem in perimedulla contains each of phloems which run to the direction of eye and to the center of tuber, forming three-dimensinal network. The external phloem and the internal phloem of vascular bundle ring have radial connetions respectively to external phloem in cortex and to internal phloem in perimedulla. Perimedulla is separated by the rays into the clusters which homologize to the vascular cylinder of aerial stem, and those clusters separate and join each other at the base of eyes. From observations of the tuber in rapid development, it was suggested that the starch grains density of each tissue is related to the distribution of vascular bundles, the starch grains are more densely accumulated in parenchyma cells around phloem in cortex and perimedulla, than those in the central medulla and the ray containing no vascular bundle. From the observations of the distribution and connection of vascular bundles in tuber, it was assumed how the pathway of assimilate transport exist in tuber at stage of tuber development, and the relation was discussed between the distribution of vascular bundles and accumulation of starch grains in the tissues.View full abstractDownload PDF (2034K) -
Akiko SATO, Atsushi OYANAGI, Michihiro WADA, Toshiaki MATSUDA1993 Volume 62 Issue 2 Pages 183-187
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWe investigated the fine-structure of endosperm and flour of wheat cultivar Norin 61, grown in different soil types and in different nitrogen fertilizer conditions with scanning electron microscope ; compared with hard wheat imported from Canada (1CW), it had high flour yield. The endosperm and flour of Norin 61 having low protein content grown in Red Soil had numerous openings and few protein matrix and primary and secondary starch granules were distinctly visible compared with those of Norin 61 having middle protein content grown in Gray Lowland Soil. On the other hand, the endosperm and flour of Norin 61 having high protein content grown in Andosol had few openings and numerous protein matrix and the trace of which starch granules drawn out were distinctly visible on more protein matrix. Nitrogen topdressing on Norin 61 in Red Soil increased protein content in wheat grain and the openings among starch granules were filled with more protein matrix. Though there were many differences of the fine-structure of endosperm of Norin 61 due to soil type or nitrogen topdressing, the flour yield and specific surface area of flour of these Norin 61 did not differ. In the endosperm and flour of 1CW, starch granules were not visible and embedded in plate of protein matrix. Some granules in flour of 1CW were cell itself. The physical nature of protein matrix joining starch granules together probably affects flour yield and shape of flour.View full abstractDownload PDF (636K) -
Akira FUKUDA, Satoshi YAMATANI, Tohru KOBATA, Tadashi IMAKI1993 Volume 62 Issue 2 Pages 188-192
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTea leaf sometimes receives serious damage as leaf blight or defoliation by winter cold wind in Sanin region of Japan. When wind of 4-7ms-1 blew, air temperature decreased to 0∼-4.4°C and a little snow remained on the ground, leaf water potential (ΨL) of tea plant (cv. Yabukita) was lowered to -1.2MPa in mid night and decreased to -2.3MPa in daytime of the next day. Leaf blight appeared one or two days after the condition. This temperature is a little higher than that causing freeze damage of tea leaves. However, when wind speed was lower that, air temperature was near 3-5°C and there was no snow, ΨL decreased only to -1.0MPa and leaf injury was not observed. ΨL did not decrease under -1.1MPa even in a hot summer day. We observed relationships between pressure rate and leaf injury of tea leaves pressurized with a pressure chamber in order to make analogous comparisons with decreases of ΨL by the cold winter wind. Leaf death started from pressurized rate 1.0MPa and 1.8MPa in winter and summer tea leaves, respectively, and the death was urged by more increase of pressurization rate. We suggested that the cold wind injury is caused by water deficiency of tea leaf as indicated by decrease of ΨL under the strong cold wind and low temperature condition, and, in particular, winter tea leaves more easily receive damage because winter leaves are sensitive to decrease of ΨL more than other seasons leaves.View full abstractDownload PDF (593K) -
Akira FUKUDA, Satoshi YAMATANI, Tohru KOBATA, Tadashi IMAKI1993 Volume 62 Issue 2 Pages 193-198
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn the previous report, we indicated that cold wind injury of tea leaf in Sanin region occurred under decreases of leaf water potential (ΨL) caused by low temperature and strong wind. We attempted to clarify why ΨL decreases under the environments and tried to simulate the cold wind injury under artificial condition in order to know whether decrease of ΨL truly causes leaf injury. Under a combination of low soil and air temperature (0.5/-1.5°C) with strong wind (4.5ms-1), ΨL decreased to -0.6MPa under a dark condition and to -1.8MPa under a light condition. Leaf injury appeared under the light condition. Water flow resistance (R) inside the plant increased when low soil and air temperature (0.5/-1.5°C) was maintained under changing wind speed below the light condition. R in leaf and roots increased with decreased plant body temperature when R of the parts was directly assumed by the slope between pressurization rate with a pressure chamber and water flow rate through the plant parts under several temperatures. We concluded that the cold wind injury in Sanin region may be caused by decrease of leaf water potential because low soil and air temperature drastically increase water flow resistance inside the leaf or the roots, and strong wind and short wave radiation accelerates transpiration rate.View full abstractDownload PDF (651K) -
Makoto TSUDA1993 Volume 62 Issue 2 Pages 199-205
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of water stress on the grain growth of rice appear to depend on the stages of plant development. The plants which were subjected to water stress during the grain-filling period produced more imperfect rice kernels than those subjected to water stress before heading. Since the grain growth of rice is affected by dry matter supply to the grain, one can expect that the production of imperfect rice kernels changes with dry matter production during the grain-filling period in rice subjected to water stress. To prove this hypothesis, an experiment was conducted in which the relationship between the production of imperfect rice kernels and the dry matter production during the grain-filling period was examined. A rice cultivar, Koshihikari, was grown in 4liter pots containing sandy loam soil. Plants were subjected to water treatment in which daily evapotranspiration was replaced by 60% for a week. The treatment was started either at fifteen days before heading, or two or twelve days after heading. Control plants were kept continuously submerged. The dry matter increase during grain-filling period was not affected by water stress before heading, whereas it was decreased by water stress after heading. Water stress before heading reduced the number of spikelets per plant and the size of single spikelet, resulting in the decrease of panicle weight per plant. After heading, the decrease of panicle weight per plant by water stress was associated with dry matter production during the grain-filling period. Also found was the increase of the number of spikelets wherein specific gravity ranged from 0.84 to 1.06. These spikelets enclose imperfect rice kernels. The rcsults suggest that winnowed paddy yield is coupled with the number and size of spikelets under water stress before heading. After heading, the effect of starch deposition is predominant.View full abstractDownload PDF (757K) -
Akiko SATO, Kazuhiro SUENAGA, Kazumi KAWAGUCHI1993 Volume 62 Issue 2 Pages 206-210
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effect of shading at different growing stage on wheat was examined to confirm the stage when the spike number and the character of spike were determined. Spike number decreased by shading to full heading date. T3 showed a marked decrease in the spike number compared with M, T1 or T2. Spikelet number decreased to floret differentiation stage of tillers by shading. Since floret differentiation stage was delayed in T3 than in comparison with that in M, T1 or T2, spikelet number of T3 decreased later than M, T1 or T2 by shading. Sterile spikelet number of tillers decreased to full heading date by shading. Grain number per spikelet of tillers was affected by shading from two weeks before full heading to ripening stage. Grain weight of tillers was affected by shading at ripening stage.View full abstractDownload PDF (575K) -
Kazumi MAEDA1993 Volume 62 Issue 2 Pages 211-221
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn groundnut (Arachis hypogaea L.), it is presumed that stem-system has no substantial mechanical role in supporting the pods. In order to assess whether a reduced partitioning of dry matter to stems (includes petioles) is associated with an increased seed yield, a 3-year field trial was conducted using 27 cultivars (cvs.). In this study, correlations between seed yield and major agro-physiological characteristics, including yield components and botanical groups of the cvs. were analyzed. It was concluded that seed yields above 3000 kg ha-1 in cvs., including Japanese Norin cvs., developed by inter-subspecific hybridization, were associated with high seed/stem ratio (2∼3), harvest index (30∼40%), by decrease of the number of branches and large seed size (above 70 g/100-seed weight). A further analysis indicated that these cvs. were early in flowering and maturation and erect in growth habit. Based on these results, a contribution of subsp. fastigiata to increase seed yield was noted and the characteristics of a groundnut ideotype were proposed.View full abstractDownload PDF (1207K) -
Susumu ARIMA, Jiro HARADA, Noriyuki TANAKA, Seiji OKA1993 Volume 62 Issue 2 Pages 222-227
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effect of photoperiod on the distributing pattern of flower buds along a stem and the growth of leaves in Trapa bispinosa Roxb. was examined by the photoperiodic treatments of seven artificially changed day-lengths, 9, 11, 13, 13.5, 14, 15, 17 hours in 24 hours cycle. The treatments were conducted for two months, from 26th June to 26th August, using the plants in the late floating leaf stage. Flower buds initiated under the short-day conditions of 14 hours or less. The distributing pattern of flower buds formed along a stem under the short-day condition was affected by photoperiod ; that is the number of flower nodes (FN) in a flower node group (FNG) increased and the number of non-flower nodes (NFN) in a non-flower node group (NFNG) decreased by the shortening of day-length, though no significant change was observed in the length of cyclic appearance of FNG and NFNG along a stem. In consequence, the number of FN per unit number of nodes on a rosette increased with the shortening of day-length. Moreover, the growth of leaves was suppressed and the size of a leaf become smaller. In a rosette, although the number of leaves increased, the size of rosette tended to become smaller. Similaly, the size of flower buds or flowers immediately before or after flowering, respectively, was decreased by short-day treatment. The results obtained in the present study suggest that development of fruit may be suppressed by excessive short-day conditions.View full abstractDownload PDF (745K) -
Liu-Fu JIN, Kiichi HANADA1993 Volume 62 Issue 2 Pages 228-235
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWe observed the efffects of kinetin absorbed from roots on the growth of main stem and tillers in rice plants grown in solution culture. The growth of the plants in plant length, plant age expressed by the number of leaves, length of leaves, number of roots and length of roots were inhibited, with a few exceptions, by kinetin irrespectively of light intensity and nitrogen concentration in the culture solution. The effects on the development of tillers were dependent on the light intensity. Kinetin inhibited the increase in number of tillers of the plant, the age of tillers expressed by the number of leaves and length of tillers with a few exceptions under natural light intensity. Under low light intensity, on the other hand, kinetin promoted the increase in number of tillers of the plant and the development of tillers in number of leaves and length. The development of the tillers at lower nodes such as the 2nd and 3rd nodes, whose development seemed to have stopped at the time when kinetin was absorbed, were promoted by kinetin. No relationship was observed between the nodal position of the roots supplied with kinetin and the nodal position of the tiller affected by kinetin.View full abstractDownload PDF (922K) -
Minoru NISHIMURA1993 Volume 62 Issue 2 Pages 236-241
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSStudies were conducted to clarify the relation between the rooting ability from flag leaf node and the cool tolerance at the booting stage in rice. Panicles with the flag leaf nodes were taken from plants just after the heading and kept in water, cutting out the stems at 3 to 5 cm below the flag leaf nodes. Days from the start of the treatment to the rooting were evaluated as the rooting ability. In the 15°C treatment, rooting was not found. In the 25°C and 30°C treatment, the rooting ability of varieties from the flag leaf nodes was closely correlated with the cool tolerance. Rooting from the flag leaf nodes was rarely found when panicles were taken after heading. On the contrary, rooting ability was higher when panicles were taken before heading than just after heading. Although rooting ability became lower when panicles were taken after irrigation with cool water before heading, rooting ability of the varieties with the cool tolerance was higher than that of the varieties with cool sensitivity. The rooting ability of F2, F3 and F4 progenies between two varieties of high and low tolerance for cool temperature at the booting stage were tested. Relation between the rooting ability and cool tolerance was not clear, probably because the fixation degree of these progenies was not enough. It is necessary to investigate this relation using the more advanced progenies.View full abstractDownload PDF (628K) -
Minoru NISHIMURA1993 Volume 62 Issue 2 Pages 242-247
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSSterility was induced by low temperature at the booting stage in early maturing varieties in 1986, and in medium and late varieties in 1987, particularly in the varieties without cool tolerance at Hokkaid Agricultural Experiment Station, Sapporo. Eating quality also was greatly lowered in these varieties. The present study was conducted to clarify the relation between these two phenomena. Thirteen to 31 varieties grown in the paddy field and the cool water irrigation field were used in this experiment. Amylose and protein content of milled rice were measured. Eating quality was evaluated by a panel of fifteen members. Eating quality of the varieties with high sterility caused by low temperature in 1986 and 1987 was much lower than in the year with little damage by cool temperature at the booting stage. Protein contents of these varieties were much higher than that of the varieties with low sterility. When sterile spikelets were induced by low temperature stress in the cool water irrigation field, protein content of the varieties became higher, in proportion to the spikelet sterility. It was suggested that the main cause of lowering of eating quality found in the rice plants with high sterility was increases in protein content due to the increases in nitrogen translocation per fertile grain. Therefore, it is important to improve the cool tolerance at the booting stage in order to improve the eating quality of rice.View full abstractDownload PDF (661K) -
Fumitake KUBOTA, Keiji IIZUKA, Waichi AGATA1993 Volume 62 Issue 2 Pages 248-256
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSPhotosynthesis and root weight production in single leaf grafts were discussed from the point of view of sink-source balance. Cultivars used were Koganesengan (K), Siroyutaka (S), Beniaka (B) and Tsurunasigenji (T). Scion (leaf+petiole) and stock (petiole+roots) of the four cultivars were reciprocally grafted in 16 combinations. To elucidate the single and compound effects of sink and source on root weight (RX/Y), mathematical models were derived, from which scion effect (EX/*), stock effect (E*/Y) and their combination effects, general combining effect (GCEX/Y) and specific combining effect (SCEX/Y), were calculated. The relationships of these components were shown as the following equations. RX/*=EX/*+R*/*;R*/Y=E*/Y+R*/*GCEX/Y=(EX/*+E*/Y)/2;RX/Y=GCEX/Y+SCEX/Y+R*/*:where RX/* and R*/Y are the average root weights of the grafts with cv. (X) scion and cv. (Y) stock, respectively. RX/Y is the root weight of a graft with cv. (X) scion and cv. (Y) stock. R*/* is the average root weight of all the plants of 16 graft combinations. When K or B was used as scion, the root weight of grafted plants highly increased ; the scion effects of both cultivars were positive. Also the stock effect of K was positive. While both scion and stock effects of T were negative and the lowest. A positive linear relationship was detected between GCE and SCE, but T/S and T/B were excepted from the tendency. Photosynthetic rate increased in the plants grafted to K-scion or K-stock, while in T/S and T/T the rates significantly reduced. Root weight production was positively related to photosynthetic rate within a limited range. In T/S and the grafts with T-stock, peitole weights increased ; the petiole functioned as a sink when the tuber sink capacity was limited.View full abstractDownload PDF (1015K) -
Akiko SATO, Atsushi OYANAGI, Michihiro WADA1993 Volume 62 Issue 2 Pages 257-260
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSRelation between phosphorus, nitrogen and potassium contents and the emergence rate of T1 (tiller in axils of the first leaf on main stem leaf) in wheat varieties having different adaptability to low available phosphoric-acid was examined in Andosol. Three varieties of wheat were cultivated in low available phosphoric acid field and improved field by the application of additional phosphoric-acid and stable manure. Phosphorus content of shoot and root of three varieties in low available phosphoric-acid field. In cv. Asakazekomugi and Norin 61 having low adaptability to low available phosphoric-acid soil, the emergence rates of T1 were decreased at shoot phosphorus content less than 0.5%. In cv. Norin 64 having high adaptability to low available phosphoric-acid soil, the emergence rate of T1 was sustained at 0.3% phosphorus content. The application of additional phosphoric-acid and stable manure increased not only phosphorus content, but also nitrogen and potassium contents of wheat plants. Partial correlation coefficient between phosphorus, nitrogen and potassium contents and the emergence rate of T1 indicated phosphorus content predominantly affected the emergence of T1. It is considered that the high emergence rate of T1 of Norin 64 in low available phosphoric-acid soil was due to high tillering ability to low phosphorus content in plants.View full abstractDownload PDF (509K) -
Hiroshi HASEGAWA, Tadao KON, Yasuhiro KONO1993 Volume 62 Issue 2 Pages 261-266
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSVigorous growth of F1 hybrid of rice (Oryza sativa L.) may be partially attributed to the development and function of the root system, but only a few studies have been conducted in this aspect. This study was carried out to elucidate the root system development of heterotic F1 hybrid seedlings grown in culture solution for 30 days. Dry weight of a single nodal root (SNR) of F1 hybrid was always greater than that of parents, except 10 days after planting. Each representative root system of 20-day-old F1 hybrid and parents was quantitatively analyzed. Total root length and total number of root apices of SNR were also greater than those of parents. From the viewpoint of the entire root system, F1 hybrid surpassed parents in the total root length, root dry weight and total number of root apices, and each heterobeltiosis was 168, 123 and 139, respectively. As a result, the root system of F1 hybrid was not only heavier in the dry weight but also greater in length/dry weight ratio (specific root length) than that of parents. We interpreted this result that F1 hybrid had high efficiency in converting dry matter into root length increment, which may possibly ensure high nutrient collection capability.View full abstractDownload PDF (661K) -
Takahisa AMANO, Qingsen ZHU, Yulong WANG, Naoto INOUE, Hidehiko TANAKA1993 Volume 62 Issue 2 Pages 267-274
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSAnalysis of the characteristics of grain production of 965 gm-2 obtained by Shan You 63 (F1 hybrid rice) in 1991 was carried out Absorption of nitrogen reached 21 gm-2 up to the time of heading, and a large capacity of grain yield (50, 360 spikelets per m2) was obtained. Efficiency of increase in spikelet number per m2 by absorbed nitrogen up to heading was essentially the same as in west Japan. Mean Leaf Area Index 10 days before heading became exceptionally large (10.18). A large amount of translocation of accumulated assimilation products before heading improved the percentage of ripened grain. Increase in translocation of assimilated products stored in the culm and leaf before heading may remarkably increase yield in China.View full abstractDownload PDF (794K) -
Takahisa AMANO, Qingsen ZHU, Yulong WANG, Naoto INOUE, Hidehiko TANAKA1993 Volume 62 Issue 2 Pages 275-281
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSTo clarify lodging resistance of high yield examples, characters related to lodging of Shan You 63 (F1 hybrid rice) with 965 gm-2 of a brown rice weight were analyzed. There were various factors for early lodging regarding external morphological characters. The lodging index (a distance between fulcra in 5 cm) at the 4th internode from the top (N4) at maturity was more than 200. High yield of Shan You 63 was obtained under quite dangerous conditions as regards lodging. The reason for increase in the lodging index at N4 was low breaking resistance. This phenomenon could be explained by a high rate of translocation of non-structural carbohydrate (NSC) and total nitorogen (N) from the culm and leaf to ear, and an extreme decrease in dry weight per unit length of the portion lower than N4 at maturity. To consistently obtain a yield exceeding 965 gm-2 in Shan You 63, it is necessary to develop cultivation techniques to store more NSC, N and dry matter in the culm and leaf sheath and ear.View full abstractDownload PDF (718K) -
Hajime SATO1993 Volume 62 Issue 2 Pages 282-287
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSLeaflet movements in response to a reduction of leaf temperature by water spray was examined under severe plant water stress at fine midday, using the lateral leaflets of the third trifoliolate leaves in potted plants of two kidney bean (Phaseolus vulgaris L.) cultivars : Hime-tebo and Taisho-kintoki. All lateral leaflets not sprayed with water (the control) largely inclined and oriented themselves to their terminal leaflet. The water spray (the spray treatment) rapidly decreased the twisting angles of the leaflets, but did not change the vertical angles. In the control, stomata closed completely (except for abaxial surface of cv. Taisho-kintoki) and water saturation deficit was much higher. However, in the spray treatment, although not significant, the stomata of leaflets slightly opened and the water saturation deficit rose rather slightly. The decrease of the twisting angle synchronized with a reduction of leaf temperature. The change in the twisting angle of the lateral leaflets seemed to be associated with leaf temperatures, not with leaf water potentials. Further, this response was discussed to be caused directly by the change in temperature of the pulvinule rather than the leaf blade.View full abstractDownload PDF (808K) -
Saneaki TANAKA, Akira YAMAUCHI, Yasuhiro KONO1993 Volume 62 Issue 2 Pages 288-293
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe aim of this study was to examine the effect of various NH4-nitrogen concentrations in culture solution on the seminal root elongation of the rice plant. Ten rice cultivars with differing adaptabilities for heavy manuring were grown in Kasugai rice culture solution at 30°C for 12 days. First, the nitrogen concentration was set at four levels, 0, 4, 40 and 240 mg L-1. In all the cultivars, seminal root elongation was exponentially inhibited with increasing nitrogen concentration and thus the inhibitory effect per unit increase of nitrogen concentration was much greater in the range of 0 to 4 mg L-1 than in the higher range. In a separate experiment, nitrogen concentration was set at six levels, 0, 0.4, 1, 2, 3 and 4 mg L-1. In this range, seminal root elongation was linearly inhibited with increasing nitrogen concentration. Comparing the cultivars, a clear trend was seen. The seminal root elongation of the rice cultivars, which are reputed for their low adaptability for heavy manuring, was more severely inhibited as nitrogen concentration increased compared to cultivars with high adaptability. Additionally, the seminal root axis length of the former cultivars tended to be greater than that of the latter cultivars when nitrogen concentration was at 0 mg L-1.View full abstractDownload PDF (645K) -
Kana NAKAHISA, Eiji TSUZUKI, Takashi MITSUMIZO1993 Volume 62 Issue 2 Pages 294-299
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSAllelopathic effects of alfalfa (Medicago sativa L.) plants were investigated using soil previously grown with alfalfa (alfalfa soil). Alfalfa soil inhibited the emergence of alfalfa seeds and also the growth of alfalfa and radish. Methanol extracts from the alfalfa soil markedly inhibited the elongation of radish hypocotyl and alfalfa radicle, suggesting the presence of allelopathic substances. The incorporation of cut pieces of alfalfa shoots in the soil reduced seed emergence, hypocotyl elongation and dry weight in radish seedlings to 65, 73 and 81%, respectively, compared to the control. Aqueous extracts of alfalfa plants inhibited the elongation of radish hypocotyl and alfalfa radicle. Inhibition increased with increasing concentrations. Inhibition of radish hypocotyl and alfalfa radicle elongation was greater in root extracts than in shoot extracts. The presence of phenolic compounds as allelopathic substances in alfalfa soil, as well as in the alfalfa plant, was suggested using color reaction with diazotized sulfanilic acid.View full abstractDownload PDF (561K) -
Akihiro ISODA, Takao YOSHIMURA, Toshio ISHIKAWA, Hiroshi NOJIMA, Yasuo ...1993 Volume 62 Issue 2 Pages 300-305
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of leaf movement of peanut on radiation interception were examined. A peanut cultivar (c.v. Nakateyutaka) was planted at three planting densities (20 cm, 30 cm and 40 cm equidistant spacings). In the treatment plots, the upper layer of the conopy was covered horizontally with a nylon net to restrain the movement of the leaflets. Intercepted radiation of each leaflet was measured by integrated solarimeter films for two consecutive days. It was observed that the leaflets of the upper layer oriented paraheliotropically to the sun rays in midday. Intercepted radiation per unit leaf area and unit ground area of the control were larger in the 20 cm spacing, almost similar in the 30 cm spacing and smaller in the 40 cm spacing as compared with the treatment. The leaf movement of the upper layer of the canopy played a significant role in radiation interception in the 20 cm plot, no discernible effect in the 30 cm plot and a rather adverse role in the 40 cm plot. Leaf area of the 20 cm spacing was concentrated densely at the upper layer. Leaf area of the 30 cm and 40 cm spacing was larger at the middle layers. It was assumed that effectiveness of the leaf movement of the upper layer would depend mainly on spatial leaf area distribution and density.View full abstractDownload PDF (686K) -
Akihiro ISODA, Takao YOSHIMURA, Toshio ISHIKAWA, Peiwu WANG, Hiroshi N ...1993 Volume 62 Issue 2 Pages 306-312
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe effects of the leaf movement on radiation interception were examined by a treatment which restrained the leaf movement in the upper layers of the canopy. Two determinate soybean cultivars with different canopy structures (c.v. Nanbushirome and Miyagishirome) were grown at two planting densities in the field. A pot experiment was also used to evaluate radiation interception under the conditions of no mutual shading. Intercepted radiation of every leaflet of two plants within the canopy and one plant in the pot experiment was measured by the integrated solarimeter films for two consecutive days. The amount of intercepted radiations per unit ground area in the treatments were larger than those in the controls of both cultivars and indicated the ineffectiveness of the leaf movement on radiation interception. In general, Nanbushirome intercepted larger amount of radiation in every layer of the canopy in both field and pot experiments. The differences between the control and the treatment in Nanbushirome were large as compared with Miyagishirome. The leaf temperature of the uppermost layer of the canopy in Nanbushirome was higher than the air temperature in the treatment, whereas it was at par with the air temperature in the control. The leaflets of the upper layer moved paraheliotropically to the sun rays during most of day time, it was therefore assumed that the leaf movement would regulate leaf temperature.View full abstractDownload PDF (736K) -
Tadashi TAKAHASHI, Kimio NAKASEKO1993 Volume 62 Issue 2 Pages 313-318
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn order to understand the relationship between solar radiation and biomass production within crop canopies, penetration, reflection, and interception of photosynthetically active radiation (PAR) were measured in the canopy of a spring wheat variety called Haruyrutaka. The relationship was evaluated by looking at the plant and canopy architecture, the amount of intercepted PAR, the crop growth rate (CGR), and the conversion of PAR into dry matter (EPAR). The interception (%) of PAR increased rapidly from seedling emergence to flag leaf emergence. It was more than 90% from flag leaf emergence to maturity. Within the canopy, the interception of PAR by the ear was more than 30% after anthesis. The interception of the flag leaf increased from anthesis to milk ripe stage as the flag leaf reclined from an erect to a horizontal position. Interception decreased from the milk ripe stage to maturity as the flag leaf further drooped. Two regression lines fit the relationship between the amount of intercepted PAR by the living plant and the CGR for canopy. The slope of the line after heading was higher than the one before heading. This is because the ear covered the upper layer of the canopy so that assimilation increased under high PAR conditions and consumption increased under low PAR conditions. EPAR changed throughout the growing season as the plant and canopy configuration changed.View full abstractDownload PDF (653K) -
Tadashi TAKAHASHI, Naoyuki TSUCHIHASHI, Kimio NAKASEKO1993 Volume 62 Issue 2 Pages 319-323
Published: June 05, 1993
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe ability or activity of assimilated organs in wheat canopy was estimated by measuring nitrogen content and water soluble sugar content (WSC) of leaves and ear in spring wheat canopy (cv. Haruyutaka) under field conditions. The relation of these organs to assimilation activity was also determined. Nitrogen content of leaf was closely related with carbon exchange rate (CER) in leaf, when measured under intensive radiation of more than 1500 μmol m-2s-1 of PAR (r=0.963***). This indicated that nitrogen content showed potential photosynthetic ability. Daily increase of WSC of leaf was closely related with CER in leaf under natural canopy (r=0.760***), showing the real-time activity of assimilation in canopy. The activity of assimilation in second leaf was lower than in flag leaf owing to shading by the latter, although photosynthetic ability in both was the same. Although CER of ear was not measured in this study, we assumed that photosynthesis in ear contributed considerably to grain growth as found in other recent work, because the amount of nitrogen and the daily increase of WSC in ear were higher than those in leaf.View full abstractDownload PDF (591K)
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