Immature fruits of Japanese pear, Pyrus serotina, were picked and homogenized with 70% ethanol. The homogenate was extracted with 70% ethanol three times and filtrated. The filtrate was concentrated, the residue adjusted to pH 8.4 with 1N NaOH and then extracted with n-butanol. The butanol phase was evaporated and aqueous extract of the residue was added to a Dowex-50(H⁺ form) column and eluted with water, 1N NH₄OH and 5N NH₄OH successively. Cytokinin activities in the three fractions were tested by tobacco(Wisconsin No. 38) pith callus assay. Cytokinin activities were detected in both 1N and 5N NH₄OH fractions, but not in the water. Based on these results, the NH₄OH fractions (Am-fraction) were combined and analysed by microcrystalline cellulose thin layer and gas liquid chromatographies. The fraction separated by TLC for the bioassay of cytokinin revealed activities at Rf values 0.5 and 0.7. Analyses of TMS derivative of Am-fraction by GLC gave four peaks. Mixture of the TMS derivative with that of authentic zeatin analyzed on GLC revealed that peak 2 coincides with zeatin, and peak 1 was considered to be dihydrozeatin.

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In the previous paper significant correlations were reported between air temperature and diurnal increment or diurnal amplitude of fruit growth at Stage I. In the present investigation, young fruits of Nijusseiki pear were grown under different night temperature conditions, and effects of night temperature on the diurnal fluctuation of fruit diameter, mostly of transverse one, changes in organic components of fruit, period of maturation, and quality of harvested fruit were examined.
Night temperatures were regulated at 15, 20, and 30°C during the period of 65 days from fruit set to June 29. Trees exposed to natural temperature conditions served as controls. The results obtained are described as follows:
1) High night temperature exerted more prominent effects on the diurnal fluctuation of fruit diameter at the time of a month after anthesis (about May 25) than at the other periods of growth. The higher the night temperature the greater the amplitude of diurnal fluctuation (both expansion and contraction). These effects were more marked at earlier than at later stages of fruit development and they became more vague as the time progressed.
2) The higher the night temperature the more shortened the duration of the former half of fruit development (Stages I and II), and a distinct demarcation period from Stage I to Stage II was observed. Duration of fruit development at Stage I was 46, 44, 41, and 31 days in controls and 15, 20, and 30°C treatments, respectively, that is, decrease in maturing period was 5, 15, and 30 days in the 15, 20, anb 30°C night temperature treatments, respectively.
3) In the 30°C treatment, high night temperature at early stages of fruit development stimulated the metabolism of organic components within the fruit, which may be due mainly to the maturation of fruit. Before the maturation period, the surface of the peel was kept quite smooth. The size of fruits harvested was uneven and most of them reached maturity with small sizes. Below 20°C, higher night temperature seemed to produce fruit of rather superior quality. In general, fruit exposed to night temperature of 20°C were most excelent in size, exterior appearance, and internal quality, though the maturing period (duration of development from fruit set to harvest) was not so shortened.
4) At a later period of fruit development, after Stage III, diurnal fluctuation of fruit diameter reflected the internal physiological features such as accumulation of elaborated materials and conversion of sucrose into inverted sugars. The relation between external phenomena and internal metabolic activity seems to be meaningful from the viewpoint of fruit development. When both the diurnal growth and the contraction of fruit diameter were prominent, more reducing sugars were accumulated within the fruit, whereas nonreducing sugar (sucrose) was predominantly accumulated when the contraction was gradually diminished and finally stagnated.

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The distributions of micro-meteorological elements in relation to sprouting, flowering, and development of shoots, leaves and fruits were studied with the tree crowns of 17-year-old Satsuma mandarin (cv. Miyagawa-wase) trained to the modified central leader, semispherical and open-center forms.
1. The distributions of micro-meteorological elements in the tree crown depended closely on the tree forms. That is, as the position in each tree crown shifts from the top toward the bottom, and from the outside toward the inside, light intensity and air temperature were significantly decreased, whereas relative humidity was significantly increased.
2. As the position in each tree crown shifts from the top toward the bottom, and from the outside toward the inside, sprouting, leafing and flowering were correspondingly retarded. Consequently, differences of about three days were found between the top to middle of the outside and the lowest position of the inside.
3. Leaves at the top of each tree crown were small and thick, while those at the bottom were large and thin and the thickness and number of layers of the palisade tissue varied with positions in the tree crown. Furthermore, the water content of spring flush leaves was high at the bottom, though their water saturation deficit (W. S. D.) was low. A decreasing order of stomata per unit leaf area was found to be the top, middle and bottom. Consequently, the number of stomata was significantly decreased in the bottom, and the ratio of open to closed stomata was low.
4. The chlorophyll content in leaves was highest at the bottom followed by the middle and teen the top, particularly, chlorophyll a content was markedly high at the bottom where light intensity was low. The contents of N, P, K and Mg in leaves varied with the position in the tree crown.
5. The growth and quality of fruits at the bottom were inferior to those of the middle and the top. These results appeared to be closely related to the distributions of micro-meteorological elements such as light intensity and air temperature in the tree crown.

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With decreasing moisture supply, the ¹⁴C activity of the ethanol soluble fraction in the fruit increased in comparison with that of the ethanol insoluble fraction. Sugars may be major constituents of the former fraction, and polysacharides those of the latter. It appears that the suppression of polysacharide synthesis may result in more sugar accumulation in the juice. Although the translocation of photosynthates was depressed by withholding water, sugar content per fruit was rather higher than that of the controls. Thus, it was tentatively supposed that the hydrolysis of cell wall constituents may also occur leading to the high sugar content in the fruit under moisture stressed conditions.

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Diurnal fluctuations in diameter or satsuma mandarin fruit were precisely measured and recorded by means of a differential transformer. The fruit enlargement was found to be conspicuous from the middle of daytime to about 8:00 p.m. Thereafter a slight but steady expansion continued until the sunrise of the next morning. About an hour after sunrise, the fruit was gradually decreased in diameter. The rate of contraction and the time of expansion within a day depended mainly on the meteorological conditions. It was also clarified that on a fine day there observed short-period rhythmical fluctuations of expansion and contraction in diameter which were superposed on a general increasing trend of fruit growth. The period was about 20 to 30 minutes and the amplitude was about 40 to 60μ. However, when the whole tree was covered with black cheesecloth, these fluctuations disappeared and the fruit showed only a monotonous enlargement. When it was cloudy, there appeared no rhythmical fluctuations. Further, it was noticed that several minutes after the initiation of illumination the fruit responded to it quickly, i.e., when irradiation was decreased, the fruit immediately expanded and vice versa. Variations in leaf thickness also coincided with those in fruit diameter. The translocation of photosynthates was always decreased with low intensity of irradiation.
From the results obtained, it may reasonably be concluded that the apparent enlargement of young satsuma mandarin fruit is closely associated with the moisture content within a tree. Thus, the magnitude of stomatal opening seems to be an important factor with respect to the induction of short-period rhythmic fluctuations of young fruits.

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(1) In order to elucidate the mechanism of gall formation caused by the root-knot nematode, an egg mass of Meloidogyne incognita var. acrita was inoculated on the second internode of balsam plant (Impatiens balsamina L.), and investigation of the process of gall formation and histological studies of galled stem tissue were made during 8 weeks after inoculation.
(2) The gall swelling could be distinguished externally 2 weeks after inoculation. The tissue thickness on the inoculated side increased gradually after inoculation, in particular, it increased markedly between 4 and 8 weeks after inoculation.
(3) Among the histological observations, the first reactions of plant tissue infected with nematodes were cell enlargement and cell division in the pith, vascular bundle and cortex. Increases in the pith and cortex thickness resulted from cell division. However, in the cortex, cell division was followed by cell enlargement 7 weeks after inoculation. An increase in the area of vascular bundle tissue resulted from both cell division and cell enlargement.
(4) The length of life cycle in this nematode was about 4 weeks under the experimental conditions.

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1. Tomatoes, cv. ‘Shin-Hogyoku No. 2’ were grown at six levels of light intensities and 2 levels of fertilizers in combination during the growing season (1961) to study the interaction of these factors on flower bud differentiation and their subsequent development.
2. The decreasing order of height of seedlings in 2 (NPK) and NPK plots was as follows: the plants shaded with three cheese cloths (fine; 35% light)<with one cheese cloth (68% light)>natural sunshine (100% light)>with five cheese cloths (19% light)>with seven cheese cloths (10% light)>with ten cheese cloths (5% light). The fresh weight of seedlings in the 2 (NPK) and NPK plots showed the same tendency as their height except that it was the greatest in the plots shaded with one cheese cloth.
3. The time of floral differentiation and their subsequent development in both 2 (NPK) and NPK plots in natural sunshine and in 68% to 35% light under the screen with cheese cloths were earlier than in other shaded plots. The lower the light intensity, did the flower bud differentiation delay.
4. The number of flower buds per seedling in both 2(NPK) and NPK, plots with relatively high level of light intensity, e.g. full light, 68% to 35% light under the screen with cheese cloths was the highest. The plot in 19% light under the screen with cheese cloths was medium in the number of flower buds. Two plots, e.g. 10% to 5% light under the screen with cheese cloths has lower in it.
5. In the same light intensities, the seedlings in 2 (NPK) plots grew faster, differentiated flower clusters earlier, and had the number of flower buds greater consistently than those in the NPK.

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As a series of studies on chemical emasculation, the results of repeated applications of Dalapon were represented. Sweet pepper, cultivar., Shosuke, was used as the test plant. The plants were sprayed six times with aqueous solutions ranging in concentration from 100 to 300ppm at one week intervals. Repeated applications markedly reduced injury to foliage and continued a suppression of anther dehiscence for a longer period than a single application. On the other hand, these concentrations caused an abnormal expansion of the ovary. A counterplan to reduce this toxic effect was discussed. A screening test of some Dalapon homologues was also investigated in this paper. The results indicate that sodium salts of chlorinated lower fatty acids generally induce the suppressive effect on anther dehiscence. Among these substances, the effect of a-chloropropionate was as reliable as Dalapon.

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Sands have a single grained structure, therefore the amount of its total porosity or its water holding capacity is usually characterized by such fractional systems as the shape and size of constituting particles, or the packed condition of the particle. In order to get a more adovanced insight to these properties, the author made a study using the commercial quartz sands as well as naturally occurring sands from Tottori and Fukuoka prefectures.
1. In each case of four kinds of sands having a single fraction system, the total porosity attained to ca. 52% in a loosely packed condition and to ca. 45% in a compactly packed one. The three different kinds of coarse sands, i.e., Very coarse sand (particle size was ca. 2-1mm in diameter), Coarse sand (1-0.5mm), and Medium sand (0.5-0.2mm), were usually provided with larger pores, which resulted in pF values less than 1.7. On the other hand, Fine sand (0.2-0.02mm) consisted of smaller pores, which induced pFvalues larger than 1.7 in ca. 70% of its total porosity.
2. The physical property of two fraction system of coarse sands showed only a slight change according to their different mixing proportion. However, on the mixing proportions of coarse and Fine sands in the fractional system the physical property changed remarkably. When the larger particles were mixed with the smaller ones at the ratio of 60: 40, the total pore space took the minimum value, but the mode of the frequency distribution of various pore sizes always showed the middle value of those of the respective single particle system.
3. The total porosity in the three fraction system sands showed a similar tendency with the two fraction system sands. When Very coarse and Fine particle sands were mixed together, the porosity changed remarkably, ranging from 42% to 53% in a loosely packed condition and from 32% to 46% in a compactly packed condition according to their mixing proportions.
4. The particles composing the natural sands were more or less uniform in their size and most of them belonged to the category of coarse sands. The total porosity averaged 45-50% of the total volume, being 1-5% less than that of the commercial quartz sands employed. The water holding capacity of certain natural sands took a slightly larger value than that of the commercial quartz sands. The values of certain natural sands were about the same as those suspected from the mechanical constitution of the commercial quartz sands. Thus, the total porosity as well as the water holding capacity of the natural sands could be duly estimated from the data on their mechanical constitutions.

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To get a clearcut insight into the evaporation features of sand beds when we use them for crop raising, experiments on the evaporation procedure of sand beds and the relationship between the water contents of the bed under full saturation and under field capacity conditions were performed. In addition, some mechanical properties of particles composing sand beds were investigated.
1. At bed depth of 10cm, two kinds of sands, Very coarse sand (the particle size was ca. 2-1mm in diameter) and Fine sand (ca. 0.2-0.02mm), attained to similary high evaporation ratios, ranging from 95 to 65% as their surface were drier. In the bed of larger sand particles (Very coarse), the surface dried more rapidly than that of the bed of smaller particles (Fine). The water content at that occasion was about 60% in the Very coarse and about 20% in the Fine sand.
2. When sand beds were set at 2cm in depth, there were no differences in the evaporation ratio, the time of surface drying, and the water content among Very corse, Coarse (1-0.5mm), Medium (0.5-0.2mm) and Fine.
3. The relationship between the evaporation ratio (Y) and the water content (X) at the commencement of drying on the surface of the sand bed of 10cm in depth were as follows:
Very coarse 100% ……Y=1.56 X-32.7
Coarse 100% ……Y=1.15X-2.99
Medium 100% ……Y=0.498X+48.6
Fine 100% ……Y=0.06X+89.48
Very coarse 20%+Fine 80% ……Y=0.113X+98.52
Very coarse 80%+Fine 20% ……Y=1.028X+4.33
4. In the case of Very coarse sand, the water content from the upper to lower layer of the sand bed showed a remarkable difference; while in the case of Fine sand bed; it showed only a small change. When the average water content was ca. 60%, the surface layer of Very coarse sand bed was quite dry and the layer below 6cm from the surface was saturated with water. On the other hand, in a similar water content, ca. 60%, Fine sand bed retained ca. 25% of the water on its surface and almost 100% in the layer situating under 8cm or more in depth. Furthermore, when the average water content in the beds was close to 30%, the amount of water contained in sand layers showed a definitely decreasing pattern from upper to lower. In the bed of Very coarse sand the layer below 9cm from the surface was quite saturated, while in that of the Fine sand, drying occurred at first in the near surface layer, and in the layer at 10cm deep from the surface the water content was ca. 50% at the highest.

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In order to investigate the effect of iron concentration in the nutrient solution on zinc toxicities of vegetable crops, welsh onion, spinach, bean, and cucumber were grown in solution culture with varying zinc and iron levels. Hoagland′s No. 1 solution was used as the basic nutrient solution. The concentrations of zinc supplied were 0.05, 1, 3, 10, and 30ppm. At each of the zinc level iron was supplied at rates of 1, 3, 10 (or 9), and 30ppm. Iron chelate (Fe-EDTA) was used as the iron source. All of the solutions were adjusted to pH 6.
1. At the 1 and 3ppm iron levels, plants treated with excess zinc revealed interveinalc hlorosis in upper leaves. The symptom became more progressively severe with decrease of the iron supply and with increase of the zinc supply; and in the severe case plants were entirely chlorotic and showed markedly inhibited growth.
2. The increase of iron supply in the solution was markedly effective to prevent the development of the chlorosis and to reduce the inhibition of growth, provided the zinc level was not too high. Normal growth was obtained when the ratio of iron to zinc in the solution was in the optimal range, from 1 to 3 or more, depending on the zinc level in the solution. It was also suggested that the excessive iron supply might cause iron toxicities.
3. Although the chlorosis observed was considered to be zinc-induced iron chlorosis, there was no evident relation between the development of the chlorosis and the iron content in leaves in most case. However, the ratio of iron to zinc or to zinc plus manganese within leaves was definitely low with plants which showed chlorosis or inhibited growth due to zinc toxicities.
4. The increase of iron supply in the solution had also the effect to suppress the excessive accumulation of zinc in the plants.

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The unstability of growth initiation from bud-meristem explants of Cattleya alliance in vitro is considered to be a great problem to establish a technique of clonal propagation by tissue culture method. So some factors which affect survival or growth of the explant were studied. The meristems were excised from apical or lateral buds of new shoots and cultured on RM-1962 medium under continuous llumination of fluorescent lamps about 2000lux and 25°C.
1. NAA or 2, 4-D is essential for the growth initiation of explants and the optimum concentration is found each at 0.1ppm.
2. The culture medium of RM-1962 in liquid state is better both for the survival rate and growth amount of explants than that of Knudson C. The organic components of RM-1962 had little effects on the growth and so the mineral part of the medium is supposed to be effective. The effect of addition of coconut milk at 10% to the medium differed among the hybrids used.
3. When the explants were cultured in liquid standing, liquid rotating at 0.86 rpm, liquid shaking at 90rpm and on agar-solid media, the former two were confirmed to have a good effect for survival and suppression of tissue-browning and the latter two to promote tissue-browning and then to decrease the survival rate of the explants.
4. The explants from apical bud and lateral buds on upper nodes of a shoot tended to be inferior in the survival and growth rate to the explants from middle and lower nodes.
5. The growth response of meristems seemed to differ by each species and hybrid used even if cultured under the same condition.

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Effects of warm and cold storage temperatures on sprouting and flowering of bulbs in Lilium longiflorum THUMB., ‘Georgia’ and ‘Hinomoto’, were studied. Quantitative changes of RNA content and mitosis in the apical meristem of bulbs during, storage were observed by histochemical procedure.
The results obtained were as follows:
1. A large amount of RNA, demonstrated by methylgreen-pyronin method, was observed in the cytoplasm of cells at the site of leaf initiation. The measurement by microspectrophotometry showed that the RNA content of cells in the apex of daughter bulb decreased progressively from June, and almost disappeared in middle August in field conditions.
2. Mitosis in the apical meristem of daughter bulbs decreased gradually from flowering time, and nearly disappeared at the beginning of July in the field.
3. Sprouting of early lifted bulbs, which contained a large amount of RNA in the cells of the meristem, was promoted by warm storage (30°C for 30-35 days). The RNA content in the meristem of bulbs was decreased by the warm treatment.
4. The plant grown in 20°C phytotron in summer, continued to differentiate scally leaves in their daughter bulbs until November. And hence sprouting of daughter bulbs was delayed extremely.
5. The RNA content of cells in the apical meristem of bulbs increased progressively after the beginning of cold storage, cells in the mitotic state appeared in the apical meristem of the bulbs.
6. In the experiment of cold storage, the earliest cell division in the apical menstem was observed in 15°C treated bulbs. In those bulbs, the number of cells in mitotic state reached its maximum two weeks after the start of cold storage. On the other hand, cell division was not observed for a long time in bulbs stored at 3°C, in spite of the increase of RNA content in the apical tissue.
7. The earliest sprouting of buds was observed in the bulbs stored at 15°C, and the earliest flowering was observed in the lot of 9°C.

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Since citrus fruits juice abundantly, physical and chemical properties of the juices are considered to play an important role in determining the quality of citrus fruits and in processing.
In the present study, viscosity of the juice prepared from satsuma mandarin (Citrus unshiu MARC.) fruits was investigated in relation to the various properties of the juice. The viscosity showed high positive correlation with refractometer index, Specific gravity, total Sugar contents, that is, their correlation coefficients were 0.87, 0.80, and 0.88 with Wase unshiu (early maturing cultivar), and 0.91, 0.81, and 0.81 with Futsu unshiu (medium maturing cultivar), respectively. On the contrary, there was negative correlation between viscosity and water content of the juice, showing -0.80 with Wase unshiu and -0.81 with Futsu unshiu. The correlation between viscosity and pH value was considerably lower, showing 0.51 and 0.57 with Wase and Futsu unshiu, respectively.
It seems that the viscosity of juice would be a good index to the quality citrus fruits.

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Changes of the activity of several glucose catabolism catalyzing enzymes in tomato fruits during the after-ripening of them and the effect of packaging them with a polyethylene bag on the activity of the enzymes were investigated. The activity of succinate dehydrogenase (SDH), one of the enzymes in TCA cycle was also investigated.
1. Determination of the activity of the enzymes in each part of fruit (gelling-pip and flesh) revealed that aldolase, glucose-6-phosphate dehydrogenase (G-6-PDH), 6-phosphogluconate dehydrogenase (6-PGDH), and SDH in gelling-pip have higher activity than those in flesh do.
2. In gelling-pip the activity of aldolase decreased rapidly with the ripening of fruit, and this led to the presumption that glucose catabolism by way of EMP pathway declined. Whereas when the after-ripening of fruit was controlled by packaging them with a polyethylene bag, the activity of the enzyme was kept on the original level.
3. Although changes of the activity of G-6-PDH and 6-PGDH, the enzymes in HMP pathway, were rather small their activity contrary to aldolase showed the tendency to increase temporarily with the after-ripening of fruit. This led to the following presumption: glucose catabolism in tomato fruit particularly in gelling-pip converts from EMP into HMP pathway during the after-ripening of fruit.
4. When fruits were packaged with a polyethylene bag, the activity of G-6-PDH and 6-PGDH was controlled to rise.
5. The activity of SDH in gelling-pip was low at the preclimacteric stage of respiration, increased with the climacteric rise, and decreased again after the climacteric maximum. When fruits were packaged with a polyethylene bag the activity of SDH was kept on the original level without increasing.

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