1. Rice kernels may be divided into eight classes, namely, ordinary, white belly, white core, green, rusty, milk-white, partial chalky and chalky kernel. Amongst them, rusty kernels, milk-white kernels and chalky kernels are the grains somewhat injured in their developing process, and may be called as trash rice, owing to their undesirable characters. 2. For the purpose of establishing standards suitable for eliminating trash rice, the following characters and the correlations among them were investigated: -Spetific gravity and weight of husked kernel; specific gravity, weight, length, width and thickness of unhusked kernel. 3. According to the results, it was elucidated that rice might be sorted efficiently by their weight, specific gravity or thickness of chalky kernel, above the upper limits of them the greater part of trash rice being removed practically.

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This paper deals with the "lysigenous intercellular space" in the culm, its distribution and process of development and its ecological and specific variations in rice and other graminaceous plants. As one of the ventilating systems in the internode of the rice plant, we can recognize aerenchyma in the lower unelongated internodes and "Lysigenous Intercellular Space" in the elongated ones. The lysigenons intercellular spaces in the culm and sheath are connected anatomically through the aerenchyma of the node with each other and also with the cortex of the root tissues. The development of the lysigenous intercellular spaces in the rice culm are affected by the environmental conditions. They develope rather better under excessively moist or "akiochi" -O₂ lacking- conditions. It was found that, of gramineae, the lysigenous intercellular spaces in the culm of the speces particularly adapted to moist or excessively moist conditions were generally larger than those in the species adapted to dry or semi-dry conditions and that they develop more extensively according to the moistness of growing environments.

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Deformation in rice flowers has hitherto been known to be induced by drought, hideri-aodachi (straighthead), cool weather, submergence of the plant, conversion of the field from upland to paddy conditions, deterioration of soil, or even by mutation. The authors found the fact that the same phenomenon would be caused by the salt injury. The rice variety "Kyoto-asahi" was sown on July 13, in 1954 (later than the ordinary sowing time), and was grown in pots by sand-culture with the Nacl solution of various concentrations. In plots of both 0% (control plot) and 0.1% salt concentration, the heading was started on Sept. 21st and continued up to the middle of Oct. after that some panicles stopped however to emerge out of the leaf sheath, and no deformed flower was found on the plot. In plot of 0.3% salt concentration, however, the heading was delayed by 3 or 4 days compared with that in the control plot, and deformed flowers were observed in all panicles. Illustrations of a panicle and flowers are shown in Figs. 1 and 2. These flowers can be classified as follows: (0) Normal flowers (1) Flowers with gigantic or abnormal glumes (2) Flowers with beak-formed lemma or abnormal glumes (3) Flowers with small and abnormally developed glumes (4) Flowers with small and extremely abnormal glumes (5) Flowers with degenerating palea, or lacking in palea (6) Flowers with many small glumes (7) Flowers similar to (5) and (6) but extremely small (8) Flowers with either lemma and palea degenerating or lacking in glumes (9) Flowers scarcely developed Abnormal flowers rather appeared few in the panicle which headed early, and the later the panicles headed, the more and the severe was the deformity. On the other hand, in the case of the plot that was sown on the usualy time, that is, May 27th even in plot of 0.3% of salt concentration (the headint time was from 6th to 16th Sept.), no deformity was found at all. It can be presumed, from this fact, that occurrence of deformity might be due to the harmful effect of low temperatures at the critical stages of panicle development and heading, in addition to salt injury.

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In Sep. 1954, the typhoons No. 12 and No, 15 caused severe injuries in the rice plants cultivated on fields in the coastal districts of Hyogo Prefecture. In normal condition the leaves of rice plants contain usually about 0.4% Cl. at the heading time. After the typhoon No. 12 had passed, it was observed that the Cl. content of the leaf reached up to 9.3% at the sea-side and 0.8% at the inland that is 4km from the sea coast. The salt attached to the leaf surface had been washed away by rain. But the ratio of the amount of salt, remaining on the leaves after the rain, varied according to the distance of the field from the coast. With regard to the yield constituting factors, the number of empty grains was found to have increased, the growth of the rice kernels having been disturbed remarkably by the typhoons. It was presumed that, at the district nearest the sea-coast, the damage causing the occurrence of empty grains had been severer than that disturbing the growth of kernels, and that, at the inlands far apart from the sea, the damage disturbing the growth of kernels had been more remarkable causing the emptyness in grain. The weight of 1, 000 kernels was observed to increase according to the distance of the locality from the sea, but, at the place 4km far from the sea the weight was lighter about 20% than that of normal plants.

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MATSUSHIMA, one of the authors, Suggested the fact in the previous paper that the mumber of spikelets per panicle in rice plants is determined by the balance between the number of differentiating spikelets and that of degererating ones. The purpose of the present paper is to reaffirm the above mentioned fact. 1. Tracing up the increasing process of the number of spikelets on young panicles at an interval of two days, the authors found a maximum, in the number of spikelets at about the midst of reduction division stage. The spikelets which degenerated could be distinguished more and more clearly, and they increased in their number as the young panicles grew longer. (cf. Fig. 1) 2. From the results of thinning-out experiments, in which every other hill was thinned out in the rice-fields of 3 varieties at an interval of 10 days, and from the results of water-culture experiments, by which we could apply a sufficient fertilizer to rice-plants in a given 10-day perios through the whole growing season after transplanting. it was elucidated that the good conditiond in the 10-day period from the differentiating stage of 1st bract primordia to the beginning stage of differentiation of spikelet primordia were most effective on increasing the number of differentiating spikelets, and good conditions during the period after that were of no effect to increase it (cf. Fig. 2 apd 3) These facts led the authors to conclude that the top-dressing of fertilizer at the stage of young panicle formation which has been generally practised in Japan should be of little effect to increase the number of differentiating spikelets, but be of a great value for preventing the degeneration of spikelets so far as the number of spikelets per panicle is concerned. 3. The reason why the 10-day period from the differentiating stage of 1st bract primordia to the beginning stage of differentiation of spikelet primordia is most effective in increasing the number of differentiated spikelets, and the periods after that, are of no value in increasing it, can be explained by the fact that the number of spikelets per panicle is strongly correlated with the number of branches of 2nd order. (cf. Fig. 4) As thb 10-day period above mentioned contains the stages of differentiation of 1st and 2nd order, good conditions in the period are considered to have good effects upon the differentiation of branches of 2nd order, and consequently their number increases. 4. From the investigation of branches and spikelets, which degenerated it was made clear that spikelets which once differentiated might degenerate in those three ways as follows: the most common way is to degenerate with branches of 2nd order, the second way is to do with branches of 1st order, though the latter is not so common as the former, and the third is to do by spikelets alone, the percentage of degenerating spikelets induced by the last case being the least of those by all the three ways. (cf. Table 1) 5. Basing upon the principle mentiond above, the authors suggested that it would be a recommendable method for increasing the number of spikelets per panicle to fertilize the plant at two stages, one being the differentiating stage of 1st bract primordia, and the other being the stage just before the reduction division when spikelets are apt to degenerate most easily.

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1) This experiments has been carried out in order to clarify the various effects of continuous presoaking of rice seed from winter season up to sowing time. 2) The germination and viable seedling percentage decreased in treated plot and the rice seeds which died during the treatment period were found mostly in weak grains. 3) It was found that the seeds sown before 25th April, after the treatment, showed a remarkable increase in grain yield as compared to those sown without treatment. Bnt on the other hand reverse results were obtained, when the seeds were sown later than the above mentioned date. 4) The presoaking treatment might not be the only factor, responsible for the increase of grain yield, bnt the early and thin sowing should also be taken into consideration.

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In the rice plant infested by the rotten-neck disease at early or middle stages of its ripening, the fertilizing and ripening abilities of flower decrease to 60%-80% of that in healthy plant. When the plant is attacked at later stages, these abilities were kept at higher levels than those above mentioned. The aspects vary, however, according to the location of the infested part on the pancile.

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The experiments were undertaken with water-cultured rice seedlings of 14 varieties as materials, the absoption of oxygen being measured by the method of WINKLER, and the results obtained were as follows: 1. The absorption of oxygen in late maturing varieties was found faster than that in early ones. 2. The transference of oxygen from above-ground parts to roots in late maturing varieties was found faster than in the early ones. 3. From the results it was considered that late maturing varieties are more tolerable than early ones against oxygen deficiency.

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(1) The rate of thickening of directly planted seed roots themselves was found to pe larger when they had been produced by the plants which were grown up from slips lately set out. But the total yield per plant was larger by the seed roots grown by early season cuttage. (2) Shading treatment of the mother plants resulted in heavier thickening ability of the seed roots when directly planted. Higher soil temperatures during the growth periods of mother plants caused the latters to produce seed roots of larger productive ability in the variety Gokuoimo while in the variety Okinawa No.100 the effect was reversed. As for the soil moisture, the higher, the moisure centent the larger was the thickening rate in the seed roots by the variety Norin No.1. (3) Nitrogen supply for the mother plant showed no effect. On the other hand, the less the amount of phosphorous or potassium supplied to the mother plant, the larger thickening ability in direct planting shown by the seed roots produced by formers.

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In order to make clear the basic principles of high yield of sweet potato, variety Norin No. 10 was planted for this experiment in the year of 1953, in which, the increase or decrease of essential components, in the different organs, during their growing period have also been carefuly dtudied. The reaults obtained are as follows: 1. N or K₂O percentage in the leaf-blade reach to the maximum, in the middle of July respectively and during this period, the formation of tuberous root is also observed with naked eye. 2. Immediately after the N amount in the leaf-blade or K₂O amount in the petiole attains the maximum, that is, after Aug. 20, and at that time starch in the tuber increases very rapidly. This period is the leading thickening stage of tuberous root. 3. The starch percentage in leaf-blade becomes constant after July 11, so that it is presumed that assimilated stach is transfered directly to the tuber without being stored in the aerial part of plant body like other crops. 4. In order to make survey on the growth of tuberous root, it will be appropriate to investigate the maximum percentage of N and K₂O in leaf-blade, and also maximum amount of N in leaf-blade and K₂O in petiole with reference to various environmental conditions. 5. Some portions of components in the tuberous root are presumed to be transfered from the aerial parts of plant body after a short stay. Their proportions are as follows: [table]

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Shirobana-sai No. 1, an early variety of soybean, was grown under usual conditions in order to be exemined for total sugars, starch, total nitrogen, phosphorus, potassium and crude ash of each organ. Samples were taken at every tenth day throughont the growing period. The results obtdined are as follows. In stages prior to the flowering, the increase of all the constituents took place very slowly. During the flowering period, there was a remarkable increase in the accumulation of carbohydrates (Sugars+Starch) and potassium in the aerial parts of the plant. This was followed by the increase in nitrogen, phosphorus and crude ash, and rapid absorption of the above mentioned constituents took place in the pod-developing stage. The phosphorus absorption was almost similar to that of nitrogen. The absorption of these elements continued strikingly upto the maturity period in order to fulfil the necessary requirement for the growth of the seeds. In the stems the leaves and the pods, all the above mentioned constituents attained to their maximum amounts between 10-20 days after the end of the flowering period. Comparing these results obtained from Shirobana-sai No. 1 with those of other varieties, no significant results have been obtained in the accumulation of nitrogen and ash. But in regard to phosphorus and potassium, chemical analysis has not been made. In all the varieties examined the leaves played an important role, with few exceptions, both in accumulation process and also in the translocation of those constituents to the seeds. Therefore, the yield analyses of these varieties may be possibly acomplished by investigating the amount of principal constituents accumulated in leaves, at the stage accomplished certain days (10-20 days in Shirobanasai No. 1) after the end of flowering, and also by observing the level of accumulation changes which may be effected by environmental conditions. In this experiment, however, the behaviour of carbohydrates seemed to be one of the varietal characteristics. therefore, these differences among the varieties should be considered before the observation is made.

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This experiment was carried out in 1954 at the Kanto-Tosan Agricultural Experiment Station, as a step in a series of studies on the adaptability of green manure and forage crops for paddy field. Twenty-nine species, including Leguminoceae, Gramineae and Cruciferae were used as materials; and the effects of duration of soaking the seeds on their germination were examined. The results obtained are summarized as follows;- 1) Seeds of white clover, Ladino clover as well as hairy vetch were observed to be capable of germinating under submerged conditions. It has been said that the seeds of small-seeded species of plants generally show some tendency to germinate under water. But it was found that the fact was not always so. 2) According to the relationship between the length of soaking period and germination capacity of the seed, those crops might be classified into the following three groups; tolerable, medium and non-tolerable. Generally speaking, the seeds of Cruciferae belong to the tolerable group, the germination being not reduced through a long period of soaking. The seeds of species of Gramineae belong to the non-tolerable group. And of Leguminoceae, some species blong to the tolerable group and others to the non-tolerable. 3) These facts should be useful for the breeding of green manure and forage crops, or for the selection of crops suitable for paddy field condition.

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The most favourable condition for preservation of tea plant pollen were found to be that with lower temperatures and relative humidity of abont 60%. The pollen preserved in such conditions maintained good germinating capacity even for 31 days without showing any difference among varieties. But its fertilizing capacity was lost within a short period in the actual practice not withstanding the retained germinating power which was proved on the germination medium. By all the preservation methods tested, the pollen was reduced its fertilizing ability about to the half of that in its fresh condition, within 10 to 18 days.

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[in Japanese]

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