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Volume 28 (1959 - 196･･･
- Issue 4 Pages 333-
- Issue 3 Pages 259-
- Issue 2 Pages 157-
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Volume 28, Issue 3
Displaying 1-20 of 20 articles from this issue
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Giichi HASEGAWA1960 Volume 28 Issue 3 Pages 259-261
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSConnected with the previous report, the present one deals with the seasonal changes of Ca, Mg, Fe and Mn contents within the main culm of rice plant, the pattern of their accumulation and translocation and the interrelations among those elements. The results obtained were as follows: 1) The Ca percentage was highest in L.B. than in other parts, and it increased continuously with leaf age on every position, that is, being high in the lower leaves and becoming low in the upper ones in proportion to their positions on the culm. The Ca in L.S. was much lower than that in L.B., though its behaviour was similar to that in L. B.. Ca was contained largely in L. B., it being highest in the 13th L.B.. In L.S. and I.N. Ca contents were small; in some of them it was recognized to have been translocated away. Though Ca was considered not to play a prominent role in grain ripening, Ca absorption by root was assumed to have continued till the yellow ripe stage at least, as Ca was found accumulated in the upper vegetative parts till full ripe. 2) The Mg percentage in L.S. and I.N. was nearly equal, being slightly higher in L.B.. especially that of middle leaves max. in the 13 or 14th L.B. Accumulation and translocation of Mg in L.B. as well as in L.S. occurred on and after their expansion. With regard to L.S., the largest amount of Mg was contained in middle leaves, too. Mg in I.N. was observed to be translocated into grain after heading time. The role of Mg in grain ripening process was as great as that of N or P. Hence the largest role in the grain ripening was assumed to be played by Mg in the middle parts. 3) Fe percentage was highest in the lower L.S., lower in the upper L.B. and L.S., and lowest in the hull and grain. Fe amount was highest in the 11-13th leaves. Accumulation and translocation of Fe were made in L.B., L.S. and I.N. respectively as the parts became aged. The Fe in L.S. and I.N. of the upper part was recognized to play a role in ripening. 4) Mn percentage was generally high in L.B., medium in L.S., and low in I.N.; higher in the lower leaves and lower in the upper ones. The behaviour of Mn in eachleaf was much the same as that of Ca. Mn amount was similar to Ca, but in L.S. the former was found to be much more than the latter. The role of Mn in ripening was assumed to be as little as that of Ca. 5) As a result of the consideration of the relation among K-Ca-Mg, the relations of Ca+Mg/K to Ca/Mg seemed to be antagonistic in all parts within the main culm. 6) The relation between P and Mg was also found to be interactive. 7) The Fe-Mn relation was also regarded to be similar to the Mg-Ca relation. 8) The general order of accumulation in all parts is assumed as follows: [P, N, Dry matter, K] [Mg, Fe] [Mn, Ca]. But especially in the upper I.N., the order changed as follows: K, Fe [N, P, Dry matter, Mg, Ca, Mn]. 9) Physiological functions of successive leaves and elements concerned with ripening were diagrammatized as follows:[table]View full abstractDownload PDF (480K) -
Koou YAMAZAKI1960 Volume 28 Issue 3 Pages 262-265
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThese experiments were carried out to examine the formation of lateral buds in rice and wheat plants, and also to find its relationships to the leaf development on the main stem. In rice plants, when the base of a leaf margin grows as far as the opposite side of the shoot apex, the lateral bud primordium first appears at its outer position. The primordium is recognized by the repeated periclinal divisions of the inner cells. The bud primordium thus formed remains in the same state until the adjacent upper leaf begins to emerge from the adjacent lower leaf sheath, when the bud primordium suddenly grows up and forms a prophyll. In wheat plants, the same phenomena were observed, in spite of the conspicuous changes in the number of leaf primordia involved in the apical bud. All these phenomena were found in every leaf bases observed except in the first and the second leaf bases of rice plants. At the first leaf base, the lateral bud primordium is first observed, but it does not grow any more and degenerates. At the second leaf base, the primordium develops, but sometimes it fails to form a prophyll and becomes a parenchymatous protuberance. In rice plants, neither the amounts of nitrogen fertilizer applied nor the plant spacings were effective on the formation of lateral buds mentioned aboveView full abstractDownload PDF (1489K) -
Tomowo HOSODA, Fumio IWASAKI1960 Volume 28 Issue 3 Pages 266-268
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe experiments were carried out to study relationship between flower formation and elongation of internode in cereals. In the present report, especially, the effects of temperature on flower formation and elongation of internode in paddy rice plants are concerned. In the experiments, rice varieties NORIN No.11, RIKU No.132 and ZUIHO were used as materials. Seeds of each variety were sowed several times in a thermo-controlled green house (18-25°C) and in the open air (15-30°C), respectively. The time of flower formation was indicated by the double-ridge stage of main shoot apex. But, we have no suitable index for elongation of internodes. So the formation of vacant space (inside the tissue of the node) was taken for a sign of elongation of internodes. Dissected stem tips were fixed in F.A.A., and were embedded in paraffin wax. Serial sections cut (at about 15 μ) of them were stained with 1% gentian violet solution. In an early stage of vegetative growth, we observed none of the nodes in the shoot apex. However, small cell bands were observed below the growing point of the apex nearly at the middle stage of vegetative growth. The authors termed it node formation (Plate B). Moreover, the small cell bands splitted then and there appeared so-called vacant spaces among those bands. (Plate C). Finally, visible elongation of internodes was observed. The elongation of internodes in highly thermo-sensitive varieties began at an earlier stage than that in low thermo-sensitive varieties. Namcly, the elongation of internodes in NORIN No.11 occurred at 6-leaves stage, while that in RIKU No.132 and in ZUIHO took place at 10-leaves stage. We observed no alteration in the time of these stages by applying high or low temperatures. So, it could be concluded that temperature has no influence on the node formation in paddy rice, though the growth of plant was remarkably delayed at lower temperatures. On the contrary, the flower formation in high thermo-sensitive varieties (NORIN No.11) were delayed by low temperatures. But, the flower formation in low thermo-sensitive varieties is rather photo-controlled than thermo-controlled. Thus we may conclude that there is no close relations between flower formation and beginning of elongation of internodes in paddy rice plants, though visible elongation of internodes is stimulated by flower formationView full abstractDownload PDF (685K) -
Masayuki INOSAKA1960 Volume 28 Issue 3 Pages 269-270
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSSome experiments were carried out to make clear the relation between the vascular connection of the individual leaves with each other and with the tillers, and the growth of the individual leaves and tillers in rice plant. The results obtained are summarized as follows: 1) It was considered by the writer that the time of emergence of the (N+3)rd leaf was influenced by the activity of the (N) th leaf, being maintained at maximum against the other leaves during the period from the emergence of the (N+2)nd leaf to that of the (N+3)rd leaf and also by the activity of the (N+1)st leaf which is closely connected by vascular strand with (N+3)rd leaf. The ordinal numbers above mentioned mean the position of the leaves or tillers on the main culm, that is, (N)th leaf (tiller) means a certain leaf (tiller), (N+1)st leaf (tiller) is the leaf (tiller) above the (N)th leaf and so on. 2) The growth of the (N+2)nd leaf was correlated with the (N)th one that showed the maximum activity during the development of the former one and was connected by the vascular strand with it. 3) The time of emergence of the 1st and 2nd leaves on the (N)th tiller was affected by the culm leaf showing the highest activity during their growth and by the activity of (N+1)st leaf connected with them. The (N)th leaf had an influence on the emergence of the 1st leaf of (N)th tiller. 4) The growth of the 1st and 2nd leaves on the (N)th tiller was found similar to the result mentioned aboveView full abstractDownload PDF (419K) -
Tetsuya HIRANO, Hiroshi SHIMADA1960 Volume 28 Issue 3 Pages 271-274
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn order to study the agronomical capability of rice plants in differently transplanting cultivation, such as early, usual or late, the authors investigated changes of chemical components and morphological characters which constitutes their yields by controlling the number of tillers. The results obtained were as follows: 1) Rice plants transplanted early on paddy field were lower in the percentage of ripened grains and the grain weight, but more in number of tillers, as the result of it, they brought about the highest yields as well as the most numlerous panicles per unit area. The yield of the late transplanting cultivation was the least, because of a small number of panicles and the decrease of the percentage of ripened grains and the grain weight due to the delay of heading. 2) The percentage of ripened grains and the grain weight showed good results when rice plants were transplanted early with the controlled number of tillers. 3) Starch and total sugar percentages in leaf sheath were the highest in the early transplanted plants with the controlled number of tillers, and the carbohydrates were most easy to be translocated to the ears. On the contrary starch and total sugar percentages in leaf sheath were the lowest and nitrogen percentages the highest in the plants lately transplanted with the controlled and non-controlled number of tillers, and the carbohydrates were most hard to be translocated to the earsView full abstractDownload PDF (694K) -
Kazuo NAGATO, Morie EBATA1960 Volume 28 Issue 3 Pages 275-278
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSLowland rice plants (Norin-17) of early and sermi-late cultivations, and the ears of the same variety of late cultivation were treated during night time with high (30°C) and low (20°C) temperature (15°C -30°C for the ear treatment) for certain periods in various stages of kernel development. Investigations on maturation, fruiting and specific gravities of the seeds, and some microscopic observations on bran layer and starchy tissue of the kernels were conducted. The results are summmarized as follows: 1) High night temp. accelerated the kernel development and maturation. 2) Chalky kernels and partially-chalky kernels markedly occured in the plots of high night temp. around 1O days after flowering. That was presumably due to an unbalance in supply and demand of nutrients, and to increased consumption of storage foods in the weak kernels, which were caused by high temp. 3) Both high and low night temp. 5 to 15 days after flowering caused milky-white kernels which considered to be due to the temporary hindrance of ripening. Many of milky-white kernels due to hindrance in early ripening stages had an opaque part (white-core-like but different from that of white-core kernel in shape and location) in their tissues. 4) Measurements on specific gravities of paddy, brown rice and parts of kernel revealed insufficiency of storage matter accumulation in the outer parts of kernel under high night temp. conditions. But as for the inner parts, they had larger s.g. values than those from low temp. plots, indicating good accumulation in these parts in earlier stages of seed development. 5) High night temp. in early stages of seed growth increased aleurone cells and thickness of bran layer on back side of kernel. Low temp. decreased these measurements. 6) On the cross sections of kernels from high night temp. plots a well-ar-ranged radial starch tissue (characteristic of Koshitsu-Mai) was observed. 0n the other hand, remarkable development of flatish cells along the dorso-ventral diameter of kernel (typical for Nanshitsu-Mai) was noticed in the kernels from low night temp. plotsView full abstractDownload PDF (1014K) -
Shin'ichi HASEGAWA, Kanenori NAKAYAMA, Keiji USUI1960 Volume 28 Issue 3 Pages 279-280
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWith a view to determining the quantity and frequency of irrigation adequate for paddy rice when it is grown on upland fields, water use by the plant and its root distribution were investigated in comparison with those of upland rice, in 1957-'58. The results obtained were as follows: 1) Water requirement of paddy rice was 280-290 and rather less than that of upland rice (290-300). 2) Though the ratio of the amount of water transpired after heading time to its total amount transpired during the whole life, in both cases of paddy rice and upland rice, was higher under the paddy field condition than under the upland field condition, and the earlier the heading the higher was this ratio, this ratio was higher in paddy rice than in upland rice in every case. 3) The number of roots distributed in the 0-10cm. soil layer were more and in deeper layers it was fewer in paddy rice than in upland rice, with the result that the water content of the soil of the field where paddy rice was grown was lower in the shallow layer and higher in the deep layer than that of the field planted with upland rice. The weight of roots of the paddy rice were less than those of the upland rice both in the shallow and deep layers. These results led us to the conclusion that it should be necessary to irrigate paddy rice on upland fields with somewhat shorter intervals and with larger quantities of water, especially for the period after heading time as compared with upland riceView full abstractDownload PDF (397K) -
Seiichi IZUMI, Toshiaki OIKAWA, Masami HIMEDA1960 Volume 28 Issue 3 Pages 281-282
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSFor the purpose of simplifying the seeding of the winter wheat or barley in paddy field, a method putting the mannures and seeds into the soil by plowing with Rotary power tiller was examined. Results obtained were as follows: 1) On the new method, as the depth of plowing became deeper, the number of plants was less numerous per unit amount of sown seeds. Compared with the plant growth by the common method, the growth by the new method was slower in early stages, but the weight of grains was heavier than that of the common method. 2) In case of properly adjusted number of spiks by the amount of sown seeds and depth of plowing, the weight of grains of the simplified method was much increased than that of the common methodView full abstractDownload PDF (412K) -
Takao SATO, Hideo ODA, Miyosi KIRIHARA1960 Volume 28 Issue 3 Pages 283-285
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSWe have reported by the statistical study that the correlation coefficients between the yield-constitutional factors of winter wheat and atmospheric and soil temperatures before and after severe winter were very high in highlands. Therefore we studied experimentally the influence of raising atmospheric and soil temperatures during December to April upon the growth and yields of wheat. The results were as follows: 1) Higher atmospheric temperature and higher soil temperature treatments in early March to late March increased the number of ripened grains per ear, probably as the results of the recovery effect resulted from the vigorous vegetative growth and also healthy differentiation induced by higher temperature. Higher temperature in early to mid-April increased the number of ears, probably as the results of effective spring tillering. By these reasons the yields were increased by the above two treatments. 2) Though higher temperature in December to February increased the number of stem in early spring period, it was decreased at the harvest time on account of the death of spikelets by subsequent cold weather. Consequently the yields were not increased by these treatment, although the growth of wheat was promotedView full abstractDownload PDF (520K) -
Ichiro KATO, Yasuo NAITO, Risaku TANIGUCHI, Fukuya KAMOTA1960 Volume 28 Issue 3 Pages 286-288
Published: 1960
Released on J-STAGE: February 14, 2008
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Keishi URANO, Koichi OTAGIRI, Toshisada MATSUSHITA, Tatsu YOSHIZAWA, T ...1960 Volume 28 Issue 3 Pages 289-290
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn order to know the effects of irrigation, deep ploughing, heavy rate application of fertilizers and their combined treatments on the nutrient uptake by crops and physical and chemical properties of soil, the present studies were carried out. The results obtained are as follows: 1) Generally, the amounts of nutrients absorbed by the upland rice and soybean increased with increasing the rate irrigation, deep ploughing and heavy application of fertilizers, especially the effect of irrigation was most conspicuous. The promotive effects were observed evidently between these treatments one another and the increments of nutrient absorption by the crops were very remarkable with combinations of two or three. 2) By deep ploughing, the soils underlain the top layer, which had very poor physical and chemical properties, were improved strikingly, especially increase of porosity and fertility were observed. Furthermore, it was recognized that the amelioration of acidity, increment in exchangeable bases and so on caused by irrigation were more remarkable in deep soil layer when treated together with deep ploughing. 3) From a stand point of status of nutrient absorption by crops and physical and chemical properties of soil, it was clarified that there was interaction among irrigation, heavy application of fertilizers and deep ploughingView full abstractDownload PDF (404K) -
Kiyochika HOSHIKAWA1960 Volume 28 Issue 3 Pages 291-295
Published: 1960
Released on J-STAGE: February 14, 2008
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Isamu MORIMOTO1960 Volume 28 Issue 3 Pages 296-298
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESS1) With a view to illustrate the yield of various food crops obtained by the Japanese agricultural technique, at its highest level, the author collected the yield records of them from all the Prefectural Agricultural Experiment Stations in Japan. Fluctuation curves of the yield from unit area of many crops, such as; paddy rice, upland rice, barley, naked barley, wheat, barley for brewing, sweet potato, white potato, corn, foxtail millet, barnyard millet, proso millet, buckwheat, soybean, azuki bean, peanut, repereed and sesame, were studied. 2) By comparing the fluctuation in the yield of each crop by variety tests at every Prefectural Agricultural Experiment Station, the author considers that he call illustrate the sum of ycarly fluctuation, local fluctuation and varietal fluctuation of the crop concerned. 3) Every crop has its own fluctuation curve, which is a normal monomodal symmetric one. 4) From his point of view of Japanese agriculture as an occupation work the author illustrates the per-tan yield in calories, and from his point of viwew of Japanese agriculture as an enterprise work he illustrates the per-tan yield as monetary income, and also in protein, in starch or in oil and fat products. 5) By illustrating the per-tan-calory yield of sweet potato and that of paddy rice in the records of varietal yield tests at every Prefectural Agricultural Experiment Station and those in the governmental statistics, the author demonstrated the fact that the superiority of the sweet potato as a heavy yielder crop may only be local. We must submit after all to the conviction that the best is the fittestView full abstractDownload PDF (485K) -
Toshiro OTA1960 Volume 28 Issue 3 Pages 299-300
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSBy seeding various seeds with ion exchange resins in petri-dishes, the percentage of germination and growth of root after germination were improved or inhibited. There were many illustrations of improvement in Amberlite IRC-50 and IRA-410, and of inhibition in Amberlite IR-120 and IR-4B. Moreover, there was likely a cortain relation between the botanical classification and the classification according to the response to ion exchange resinsView full abstractDownload PDF (377K) -
Sadakichi FUJII, Osamu OKAGAKI1960 Volume 28 Issue 3 Pages 301-304
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThis study has been concerned with the effects of high temperature during various stages of growth on the growth and development of plants and the oil formation of seeds in the three rape varieties. Generally, the growth and development of plants were accelerated by the high temperature during each stage of growth. The high temperature, especially during seed maturing stage, hastened the maturity of seeds and decreased the oil content of seeds. Thus the oil content per dry weight of seed of the variety "Norin No.3"or"Norin No.14"was 42% or 45% respectively under low temperature, while under high temperature, 36% or 39% respectively. It is worthy of notice that there is a parallelism between the yield of seed and the content of oil in the seed in these two varieties. In the variety "Aburamasari" noted for its high content of oil, however, the decrease in oil content of seeds under high temperature was not so remarkable as in the other two varieties, and no difference was found among the yields of seeds of each plot. The relation between oil content of seeds and temperature during maturation of seed was discussed in connection with characteristics of varietiesView full abstractDownload PDF (577K) -
Tokuzo MIYAZAKI1960 Volume 28 Issue 3 Pages 305-308
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSIn the previous experiments by the present author, it had been recognized that the nitrogen amounts contained in tobacco seedlings possessed a high correlation to activity of growth after transplanting. The fact suggested that photosynthetic ability, the principal cause of dry matter production, should be affected by the amounts of nitrogen in the seedlings. With a view to studying this point, tobacco seedlings having different levels of nitrogen content were grown, and the photosynthetic ability of them was measured at the growth stages of 9, 9∼10, 10, 11, 12, and 13 leaves during the seedbed period, at the transplanting day and at 6, 13, 20th days after transplanting, respectively. The photosynthetic ability in the seedbed period was lowered as seedlings grew up. The phenomenon may have been caused by the increase of carbohydrates accompanied with lowering density of proteinic nitrogen in the tissues. Throughout the seedbed period and after transplanting, it was recognized that the increase of carbohydrates in tissues strongly and negatively correlated to photosynthetic ability, but on the other hand, the increase of proteinic nitrogen affected positivebly only through the function of increasing active substances in the tissue maintaining its juvelinity. The increase of carbohydrates and lowering of nitrogen levels in the tissues led to physiological decay in photosynthesis. Therefore, it was considered that nitrogen contents of seedlings should be held at high levels in order to avoid physiological decay of tissues throughout the seedbed period, the seedlings recover normal growth after transplantingView full abstractDownload PDF (551K) -
Iwao NIKKI, Masaaki USHIYAMA, Isamu MORITA1960 Volume 28 Issue 3 Pages 309-310
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe object of this experiment is to study the ecological effects of altitude on orchard grass (Dactylis glomerata). Details of the four locations used for this experiment and the method are mentioned in the first report of this series. Results obtained are as shown in Table 1 and 2. At the lowest location the summer depletion of the plant growth was the most prominent and the survival percentage after summer passing was much less than at the other locations. And the plant showed progressively more vigorousg rowth, higher survival percentage, larger dry weight, less injury by plant diseases and higher content percentage of crude protein and crude fiber with increasing altitudeView full abstractDownload PDF (367K) -
Mosaku SAKURAI, Sumio KUMAI, Matasaburo HIROSE, Tadashi SANADA1960 Volume 28 Issue 3 Pages 311-312
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe present study was designed to clarify the changes in respiration of root of orchard grass, Italian ryegrass and Ladino clover by cutting. The results were as follows : 1. About the changes in the respiration of root of Italian ryegrass by the late fall cutting, it was showed that the respiratory activity was decreased rapidly, and thereafter continued a low level during the winter. 2. In relation to the seasonal fluctuation of root respiration by cutting treatment in orchard grass, it was showed that by repeating the cutting the respiratory rate was decreased considerably. By the first cutting the rate of respiratory activity of roots was depressed most severely and thereafter it maintained a low level untill the 2nd cut. Though the reduction by the 2nd cut was not so severe as that by the first cut, the respiratory rate of roots was lower than that in the time of the first cut, and it recovered a little before the 3rd cut. As the 3rd cut was conducted during mid summer, the respiratory activity showed considerable decline and regrowth was delayed because of the higher temperature. The decline in respiratory rate by the 4th cut was not so severe that the activity recovered rapidly, but it was obtained that the recovery of respiratory activity in the case of non-treatment of the 4th cut was better than that with the 4th cut treatment. 3. The respiratory activity of root of Ladino clover was depressed by the 3rd and 4th cutting treatments, but in general it recovered about two weeks after cuttingView full abstractDownload PDF (414K) -
Kinjiro SUGAWARA1960 Volume 28 Issue 3 Pages 313-315
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSAs one of the causes of the sterility of buckwheat it may be taken up that the fruiting causes the plant to prevent the smooth inverting and transforming of assimilated starch. Namely, in spite of the fertilization taking place completely, on account of the starch accumulated in the vegetative parts being incapable of translocating for fruiting, the ovares can not develop. When the pollinated ovaries are plucked in the early fruiting stage the rest of the other young pollinated ovaries begin to develop. When the ovaries are not plucked, they make it a rule to fructify according to a certain definite order, and, when they reach a certain number, the other ovaries do not grow to fructify, even if they are pollinated. If we periodically pluck the ovaries which have begun to fructify, the percentage of fruiting or that of an immature ear of wheat is not much different from that of the ovaries, which are not plucked at all. But the number of the ovaries, which have begum to develop for friting, decreases in proportion to the number of the plucked ovaries. Through the observation on the starch in the stem which was done to prove the fact stated above, it has made clear that the grains of starch grow in proportion to the growth of the vegetative parts, and have a tendency to be layers. The sum-total of stocked starch increases as the plant grows and the sum of starch in the stem never diminishes in any growth-stages. These phenomena prove that the invertion and the transformation of carbohydrates take place very slowly in buckwheat, so it is most indesirable for the crops in which only their fruited grains are aimed at harvesting for actual useView full abstractDownload PDF (552K) -
Aiya ISHIHARA1960 Volume 28 Issue 3 Pages 316-320
Published: 1960
Released on J-STAGE: February 14, 2008
JOURNAL FREE ACCESSThe experiments were carried out to follow the process of vernalization in winter wheat plants, var. Norin no. 64, under the field condition in late autumn and winter seasons. At successive stages, some of the growing plants in field were removed to the continuous light condition under the temperature of about 20°C, and the affected degree by natural vernalization in the plants was estimated by counting the number of leaves newly formed before flowering in the main stem, subtracting the number of determinate leaves at the time of the removing from the final leaf number. It was found that the vernalization progressed almost to the completion during one or one and a half month from sowing time. The results indicated that the vernalization under the field condition proceeded with a similar rate as that of seeds treated at 5°C, even though the temperature in the field was higher than 5°C, f.i., the daily mean temperature was 15∼7°C during the vernalization period in one experiment. From the examination of shoot apex development, it was suggested that in the vernalized plants the production of leaf or bract primordium is activated, which in turn leads to the spikelet initiationView full abstractDownload PDF (760K)
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