While many of the practical problems concerning dormancy in the potato tubber have been solved, the internal physiological factors that govern this state are little understood. One of the more obvious methods of approaching this basic problem is to determine what changes occur in the enzymatic activity. In the present investigation, with a desire to obtain some further understanding of the physiology of dormancy, particular attention was paid to the interrelation between ascorbic acid, phophorylase and phophatase in the potato tubers during the storage period. The experimental results obtained may be summarized as follows: 1). Generally speaking, the activities of phosphorylase and phophatase showed little variation during the rest period. On the other hand, the ascorbic acid contents (reduced- and oxidized-forms) in the tuber decreased gradually with the again of the tuber during this peiod. 2). After the termination of the rest period, concomitant with the increase of the reduced ascorbic acid content in the apical bud of the tuber, remrkable high activities of phosphorylase and of phophatase were recognized, except for the phosphorylase activity in the pith of the tuber. 3). When considering the physiological role of the ascorbic acid in the germination and the biochemical action of the ascorbic acid as the activator of phosphatase enzyme, these increases in the terminal bud noted above, may be intimately related to the termination of the dormancy of potato tubers.

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The present report deals with the variability of coleoptile nervation in the kernels obtained under different environments. The author grew a strain of rice variety "Tokyo-Tozomochi (glutinous)" under several emvironmental conditions. Kernels obtained were germinated and the number of vascular bundles in their coleptiles were determined. The results and the conculusions are as follows: 1. The numbers of the bundle were smaller in the kernels obtained under nitrogen-deficit, probably being due to the diminution of cell activity to differentiate into vascular bundles. They were larger under phosphate-deficit and, probably, under potassium-dificit. 2. The number was smaller in the kernels obtained from the plants grown under short-day conditions, and was larger under long-day conditions. 3. Their number was larger in the kernels when the area of the leaf was reduced by cutting out a portion of it, after the heading period. 4. The number of the bundles increased when the soil was treated. with chemicals such as fratol (sodium-salt of monofluoracetic acid) and 2.4-D, accompanied by delay of heading. But there were no chemicals effecting decrease of the number of bundles. 5. From the above observations, the author considers the phenomena of increasing of coleoptile nervation as may be regarded as the sign of adaptation or compensation for the unfavorable internal conditions in the course of the embryo development.

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To elucidate the relation between the resistance of the rice varieties to Hellminthosporium leaf spot and "Akiochi" and the resistance to the root-rot caused by hydrogen sulphide, the authors carried out a solution culture experiment in which five varieties, differing in the degree of resistance to the diseases and "Akiochi", were grown with and without hydrogen sulphide. The result of the expriment was as follows: (1) Irrespective of the varieties, the addition of hydrogen sulphide to nutrient solution caused the root-rot, and the top growth of the plant was retarded. Normal development of the flower and grain was, therefore, inhibited, resulting in the loss of yield. The susceptibility of the plant to the disease was also increased by hydrogen sulphide. (2) The degree of root-rot infestation, the retardation of top growth and the increase in the susceptibility to the disease by hydrogen sulphide were all lower in Norin-37, a variety which is highly resistant to the disease and "Akiochi", as compaired with the other varieties, less resistant or more susceptible to the disease. (3) Varietal differences in the susceptibility to the disease were observed more clearly in the plants grown with hydrogen sulphide than in those grown without it. (4) From the result of the chemical analysis of the plants of the two varieties (Norin-37 and Norin-8), differing from each other in the degree of resistance to the disease and root-rot, no clear difference was found between them either in the nutrient contents or in the susceptibility to the disease. (5) In rice varieties, the loss of yield caused by hydrogen sulphide appeared to have a more intimate relation to the root-rot rather than to the increase of the susceptibility due to hydrogen sulphide.

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At a glance at a map of the paddy fields in Hokuriku District, we may easily be acquainted with that about sixty three per cent of the total area is occupied by ill-drained fields. Il-drained paddy fields are unfavorable not only for culture of rotation crops of paddy rice but also for growth of rice plant when compared with well-drained one. The fact may be partially attributed to root decay and reduction of absorption of nutrients such as silica and potassium. In order to ascertain the fundamental differences between ill-drained paddy field and well-drained one, that is, to make clear the differences in the plant growth caused by the difference in aeration of the soil, several experiments were carried out, in which growth of seedlings, morphology and respiration of root, and content of silica in leaves were observed. Results are summarized as follows: (1). In the plant grown under well aerated soil, compared with that grown which worse aeration, no remarkable differences in height of seedlings and length and width of leaf blades were observed, but the vigorousness of development in stem and root was distinguished. (2). Good aeration of the soil promoted elongation of root, resultting in the deep development of root system and numerousness of roots. (3). With good aeration of the soil, the formation of lysigenous aerenchyma and deterioration in root were suppressed and number of silicified cells leaves increased very remakably presumably owing to high oxidation-reduction potential.

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In order to make clear the peculiarity of growth habit of rice plant in warmer regions, and to obtain fundamental data of clinical diagnosis based on its external characteristics, the present investigation concerning with growing process of leaves according to the leaf order was carried out. The results obtained are summarized as follows: 1. Elongation process of the leaves (blades and sheaths) according to their leaf orders were shown in Fig. 1 (in nursery bed period) and Fig. 2 (in transplanted field period). 2. Elongation periods of the leaves are shown in Fig. 3. These periods increased in length gradually according to the leaf order from the 1st blade to the 7th blade, where the firstpeak occured, and then decreased sucessively until the 10th blade which showed the minimum length of period. In higher odered leaves than the 11th blade, these periods were increased again gradually. Elongation period of each leaf sheaths coincides almost with that of the next higher ordered leaf blades. 3. Leaf period of each leab showed a tendency to increase gradually from the lower to the higher. The difference in the life duration between the 1st and the 9th leaves was not so great, but those among the upper order leaves beyond the 12th were of some significance.(Fig. 3) 4. Blade-weight per leaf changed regularly according to the leaf order as shown in Fig. 4 (A). The weight increased regularly according to the elongation of blade, and the maximum weight was reached shortly after the completion of elongation. The decrease of the blade weight from the maximum was not so large as that of sheath. 5. sheath-weight per leaf changed in the similar way as that of the blade as shown in Fig. 4 (B). The difference of weight between the sheath and the blade according to the growing stage seemed to show heavy decrease after the maximum weight was attained, and this tendency was especially remarkable in sheaths of 12∼15th leaves. This decrease of weight correlated closely with starch translocation in sheath. 6. Between the two groups of the leaf, i. e. a lower group of 1∼11th leaves and the upper one of 12∼16th, the authors found a distinct difference in the sheath blade weight ratio. It might be related to the growth phase transition from the vegetative to the reproductive stage of the plant. 7. Developmental changes of leaf number and weight per plant were shown in Flg. 5. the number of green leafblades was largest at the developing stage of young ear, but their weight was heaviest at the time immediately before heading. The number and weight of green leaf sheaths were largest at the same time as the former.

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This experiment was carried out to make sure the seasonal changes of starch content in leaf-sheath according to the leaf orders with the same object as shown in Report I, especially in relation to the developing process of rice grain. The results obtained are summarized as follows: 1. Starch content in sheath of the sucessive leaves is changed regularly according to the leaf order as shown in Fig. 1. The content was rather much in the 6th sheath, minimum in the 8th one and successively increased in upper ones up to the 13∼14th orders which showed the maximum content. Above the 15th sheathes the content showed decending tendency again. The 16th sheath (the uppermost leaf) showed far smaller content. 2. The minimum content of starch in the 8th sheath might be due to the vigrous growth of vegatative parts and to the high nitrogen content of the leaves in the unavailable tillering stage; and the maximum content of starch, put in temporary storage in the 13∼14th sheaths was correlated with the highest cabohydrate assimilation and immature stage of ear which should later induce the translocation of starch. Small content of starch in the 16th sheath is caused by the direct translocation of carbohydrates to ear in develsping period of grain. 3. Starch content in each leaves changed with their life process, and increased according to the development of sheath and decreased with the decaying. 4. Changes of starch content per plant were shown minimum at early unavailable tillering stage and gradually increased immediately before earing time which showed maximum content of starch, and later decreased gradually again. The investigation of the starch content in the culm must be the subject of future research to obtain a conclusion.

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(1) 耐湿性の大なる蔓豆は湛水状態では第一次根の腐死に伴い, 茎根部に顕著な通気組織を形成し, 之を貫通して多数の不定根が生ずる. 通気組織は栓皮形成層と同質なる第二次形成層から発生する. (2) 耐湿性の小なる白大豆では皮目の如き通気組織を局部的に形成するに過ぎず, 且つ, 不定根の発生も少い. 第二次形成層の分化は不明瞭である. 大豆に見られる通気組織は一種の呼吸根或は皮目の如き作用を営む. (3) 大豆茎部の厚皮中には通気組織と認むべき顕著な細胞間隙は認められず, 従つて大豆は本質的に茎葉から根部え多量の酸素が運搬され易い形態を具えていないと考えられる. (4) 栓皮形成層は環境に応じ, 乾燥時には栓皮を生じ, 湿潤時には通気組織を形成する. 斯る第二次形成層の活動はホルモンの影響によるものと考える. (5) 水中に生育する不定根の先端部に於ける厚皮は分離細胞間隙に富み, 且つその古い部分では内鞘の分裂により通気組織が形成されている. 之等の不定根も酸素不足の土壤中に深く進入することは不可能である. (6) 大豆の耐湿性の大小は通気組織及び不定根の発生の難易により或る程度決定されるものと考える.

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In order to obtain some informations on the behavior of translocation and storage of nitrogen compounds in the seed tuber of sweet potatoes during the hot-bed nursery period, the present investigation was undertaken with the variety "Gokoku" as material. The experimental results obtained may be summarized as follows: 1. At the sprouting stage of the seed tubers, the protein-N contents fluctuated slightly, while the soluble-N contents increased considerably; and consequently the total-N contents became larger as compared with those at the time of imbedding. 2. Being accompanied with the deveolpment of sprout, both the protein and sluble-N contents decreased remarkably, which in turn caused a rapid falling of the total-N contents in the seed tuber. 3. In the later stages of growth in the hot-bed nursery, both the protein-and soluble-N contents increased steeply and the total-N contents rose consequently.

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In the present paper, there are described the behavior of carbohydates and nitrogen compounds both in the basal and the apical parts of sweet potato slips of the variety "Okinawa No. 100" during their rooting period, The experimantal results obtained may be summarized as follows: 1. At the time of planting, the nitrogen compounds were abundant in the apical parts and little in the basaal parts of the slip, while the carbohydrates showed a reverse gradient though it was not so evident as in the case of nitrogen compounds. 2. At the pre-rooting period, translocation of nitrogen compounds and of carbohydrates to the basal parts were recognized. 3. After the rooting had once begun, more striking accumulation of nitrogen compounds and carbohydrates in the basal parts took place, while in the apical parts both nitrogen compounds and carbohydrates increased only slightly as compared with those at the pre-rooting period.

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(X) On forecast of the weight of 1, 000 rice-kernels. In the former report it has been made clear that weight of 1, 000 rice-kernels is determined primarily by the size of lemma and palea, and secondarily by the development of caryopsis filling up the inside of them, and, moreover, the former depend upon the environmental condition during the period prior to heading and the latter upon that after heading. Basing upon these facts, the authors have made some experiments to find out the methods for forecasting the weight of l, 000 rice-kernels. The rsults are summarized as follows: (1) As number of spikelets per head is greatly influenced by the environmental condition in the period prior to heading, weight of l, OOO kernels can be forecast roughly from the number of spikelets per head. The method is available in early stage, but its goodness of fit is not so high as the other methods. (2) Where the environmental condition in the period after heading is normal, there are found high correlation coefficients between weight of hulls and that of rice-kernels at the time of maturity, and, moreover, between weight of hulls at the time of maturity and that of hulls at the 7th day after heading. Therefore, where the environmental condition in the period after heading is normal, it will likely be possible to forecast the weight of 1, OOO rice-kernels from the weight of hulls at heading-time. (3) Whenever specific gravity of gains reaches to a certain value (the value is about 1.05, excluding grains lighter than 0.84 in specific gravity), final weight of 1, 000 rice-kernels can be forecast from the weight of developing caryopsis, irrespective of varieties, cultivating methods and stages subjected to cutting treatment of leaf-blades. Especially, it can be clearly forecast from the weight of developing caryopsis at the time when the rate of increase in specific gravity of grains begins to decrease, after reaching to its maximum rate. The period in which weight of 1, 000 rice-kernels can be forecast, so far as this present experiments are concerned, is at about 17th day for early maturing variety, 22-27th day for medium and late variety after heading.

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(XI) On forecast of fruit bearing percentage in rice. In 1951 and 1952, the authors tried to find out methods for forecasting fruit bearing percentage in rice plant, making experiments to ascertain, on the one hand, the period in which fruit bearing percentage is finally determined and, on the other hand, to trace up the process in which the percentage is destined. Various degrees of fruit bearing percentage were obtained by cutting leaf-blades at different growing stages of 3 varieties differing in earliness of maturity. Tracing up the fruiting process of grains was made by measuring specific gravity of developing grains (air dried) at an interval of 5-7 days after heading. Results obtained are summarized as follows: (1) The period in which fruit bearing percentage of medium maturing variety is finally determined, in most cases, is about 33-38-days after heading, and 20 days prior to maturity. But the period varies with varieties and years to a considerable extent. (2) It has been made clear that there exists the period in which the fruit bearing percentage is destined and the period is considerably previous to that in which the percentage is finally determined. And the period has been proved to be at about 17th day after heading for the early maturing variety, and 22-27th day after heading for the medium and late variety used. Moreover, in all cases differing in cultivating conditions or in stages and in degrees subjected to cutting treatment of leaf-blades, fruit bearing percentage of medium variety used has been observed to be destined at about 21st day after heading. (3) As number of days from heading when fruit bearing percentage is destined varies with varietes and with years, it seems to be unavailab1e in forecasting the percentage. Therefore, it is necessary to find out a method by means of which fruit bearing percentage can be forcast in every case differing in vgrieties and years. In consequence of examining the data here obtained, the authors have ascertained that fruit bearing percentage in every case will be able to be forecast by investigating the developing preocess of grains as follows. (4) Taking a given value of specific gravity for a standard, the percentage of grains heavier than the standard specific gravity to total number of sampled grains always increases with maturity. And the period when the rate of increase in the percentage above mentioned reaches a maximum and thereafter the rate begins to decrease remarkably has been proved to be the period in which fruit bearing percentage is destined. (5) At this critical period, the persentage of grains heavier than a standard specific gravity is always highly correlated with final fruit bearing percentage in evry case differing in varieties and in cultivating conditions or in stages and in degrees subjected to cutting treatment of leaf-blades. Accordingly, this present correlation is considered to be utilized as a criterion for forecasting fruit bearing percentage of rice plant. (Whatever value of specific gravity one may take as a standard, one can obtain almost identical results. But, it is recommendable to use the value 1.00 as a standard for getting most exact results.)

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In the previous report**, the mote formation of cotton seeds has deen classified into following 3 types : (i) the ovule itself was defective, lacking in embryosac formation; (ii) the ovule was normally formed, but the pollen-tube, although reaching to ovule, failed in completing the fertilization; (iii) the fertilization was normally functioned, but the successive development of ovule was arrested. In the present paper, further investgation was added to get the actual frequencies of above mentioned 3 types. Using one variety of each upland and Chinese cotton, embryonal development was traced at each stage of 7, 10 and, 15 days after flowering and at maturation. Formaline acetic alcohol was used for fixation, and longitudinal sections of 10 to 15μ thick were stained with DEL-AFIELD'S haematoxylin. It was determined that the non-fertilized motes, wherein the above No.1 and No.2 types are included, were almost constant in their frequency throughout the various stages, meanwhile the fertilized motes, that is the type No. 3, increased gradually in number as showh in Table 2. Therefore, the increasing occurrence of motes shown in Table 1 should be due to the latter case. When the non-fertilized motes are divided into the types, No. 1 and No. 2, each may play some role but be of rather less importance in formation of motes, because the frequency of each one is merely less than 3 percent respectively as shown in Table 3. As to the embryonal development of fertilized motes, when observed in comparison with the normally growing ovules, following facts were confirmed (Table 4, 5, 6). 1. The fertilized motes begin to occur from an earlier stage, and the majority of them are observed before 15 days after flowering. 2. Some of fertilized motes are arrested in their development immediately after fertilization, and are deformed into tiny structure. The others continue to develop slowly for a while, but cease to grow soon or late, and remain as they are in mature bolls,

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1. From our previous studies, it is evident that if the seeds sown sparsely in seed-bed they can produce higher yield, even when transplanted later than usual. But this method needs wide acreage and much labour to manage the seed-bed and there are some troubles in applying this. Then we tried to sow seeds lately in seed-bed and transplant seedlings lately to paddy fields because this method needs less acreage and labour. 2. Two varieties were used: "Sekiyama-No.2" is a heavy-panicle type and Ou-No.195" a mediate type. Seeds were sown at six different times to seedbed with ten days interval from 16th of April to 5th of June, and the seedlings were transplanted 20 or 30 days later than usual. 3. Seedlings Were transplanted individually with the rate of six hills per 3.3m (90.9 × 60.cm) in a paddy field in order to give a good enough space for growing. 4. Both varieties showed low yields when it was transplanted lately owing to decreasc of pancle numbers. 5. Wnen the both varieties were transplanted 30 days later than usual, and also "Sekiyama-No. 2" transplanted 20 days later than usual, the length of nursery period gave no influeuee on the yield. In other words there is no difference of yields between the rice crop derived from the seedlings grown for only 30 days and that derived from seedlings grown for as long as 70 days in seed-bed, when they were transplanted 30 days later than usual season.

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Investigation were made on the blooming habits of severals pecies of Sorghum, Lolium and Trifolium on a panicle or a head basis. In Sorghum blooming time in a day of the 4n species, Johonson grass, differed distinctively from that of the 2n ones, Sudan grass and seed sorghum, (c.f.Fig.1). In Trifolium species, however, there was little difference. The order of blooming was specific to each genus (c.f.Fig. 2and4), within which there was recognized little interspecific difference. The duration of blooming periods varied with the size of infloresence within a species (c.f.Table 1). A great interspecific variation was observed especially in Trifolium whose species had distinctly different numbers of florets (c. f. Tabel 2), the maximum being 12-14 days in crimson clover and the minimum being 1-2 days in sub clover. The most favorable condition of cultural medium for pollen germination was searched for on some speies of Lolium, Trifolium and Melilotus, with special reference to sucrose and agar concentrations. The sucrose concentration for the highest pollen germination percentage varied evidently among the clover species (c.f. Table 5 and Fig. 6), but not so clearly among the ryegrasses (c.f. Table 4).

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