Effect of autumnal application of N, P and K on photosynthesis and the translocation and distribution of photosynthates was studied with Delaware grapes grown in pots, using ¹⁴CO₂. The effect of the same treatments on shoot growth and cluster development in the following spring was also studied. The treatments consisted of all possible combinations of N, P and K and no fertilization (control).
The results of the present study imply that in the growing of grape vines N, P and K are required to be applied all together in the fall from the standpoint of accelerating the photosynthetic rate and translocation of photosynthates to the roots and also of promoting the shoot growth and cluster development of the following year.
N fertilization increased cluster length, number of clusters per vine, number of flowers per cluster and fruit growth in the following spring. P fertilization increased cluster length and number of clusters, but decreased number of flowers, whereas K fertilization did not affect cluster length and number of clusters, but increased number of flowers. Among the treatments, the combined application of N, P and K was most effective for the growth of clusters and fruits. As to the shoot growth, the treatments including N were promotive, whereas P, K and PK treatments did not exhibit any obvious effects.

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This paper presents an evaluation of the pressure chamber method for estimating leaf water potential (ψ) of Satsuma mandarin (Citrus unshiu MARC.) trees growing in both pots and field. Results obtained are as follows.
1. The rate of pressure increase within the range from 0.2 to 0.6atm/sec did not affect the estimating of ψ. In this study, therefore, the pressure was increased at the rate of 0.35atm/sec.
2. There was very little difference in potential between a leafy shoot and the leaves attached on the same shoot. This result shows that xylem pressure potentials in the shoot and petiole may be at dynamic equilibrium, and that number of replications would be reducible with the same precision by using shoots in place of individual leaves.
3. Main sources of variation in ψ in a tree were attributed to leaf age and to the radiation to which the leaves were exposed. As the radiation decreased by means of shading treatments, ψ increased rapidly. It was deduced that fluctuations of leaf temperature in response to changes in solar radiation must cause changes in ΔC (difference in water vapor concentrations between the leaf surface and the ambient air) which has a very large effect on transpiration rate. Variation of ψ in the day time was very large, as the differences of microclimatic conditions surrounding individual leaves may influence ψ through the effects on transpiration rate. Variance of ψ measured before sunrise was so small, resulted from minimal transpiration rate that the number of samples necessary for a precision of 0.5atm was only about three leaves.
4. When soil matric potential at the 15cm depth was higher than -1atm (less negative), ψ (ψ_max) measured before sunrise was linearly correlated (r=0.977) with soil matric potential. When soil matric potential was less than -1atm (more negative), ψ_max was curvilinearly related to glass-block resistance value. The results of this experiment indicate that ψ at night reflected soil moisture stress. During the daytime, however, ψ and soil water tension were not well correlated, because plant water status in mid-day was influenced by environmental factors.
In conclusion, it is quite clear that for Satsuma mandarin trees, the pressure chamber is a useful tool for measuring ψ rapidly and precisely in the field as well as in the laboratory.

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Diurnal and seasonal fluctuations in osmotic concentration in leaves and shoots of alternate- and annual-bearing satsuma mandarin trees were examined to test whether or not these changes are correlated to the internal moisture status. The following observations were made:
1) Osmotic values of leaves and shoots increased during the day attaining a maximum about 2-4PM and subsequently decreased to a minimum at 6AM. This diurnal pattern did not vary among the different seasons. Analysis of seasonal samples taken once a month at 10AM revealed that the osmotic values were relatively low in mid-summer and high during the months of January and February. The osmotic values increased beyond the degree of the decrease in water contents in winter. It was also confirmed from these data that the change of osmotic values in winter was due not only to that of the water contents but also to that of the solute ratios.
2) Calculations of the solute ratio by the following equation:
Solute ratio=osmotic value (atm)×% moisture content/24.05, the constant 24.05=the osmotic value of a molal solution, disclosed that the values of leaves and shoots closely paralleled the water contents in the organs from spring to summer and corresponded to osmotic concentrations of them from autumn to winter. Changes in solute ratios of leaves and stems occasionally oscillated as much as I mol which was comparable to the maximum amplitude of their diurnal fluctuations found in the organs.
3) The presence of fruits influenced the osmotic values of the sap extracted from leaves and shoots. The osmotic values of leaves and stems in non-bearing 4-year-old trees were respectively higher in almost every season as compared to those of correspondingly aged organs in the bearing trees.
4) As for alternate bearing mature trees in the on-year, osmotic concentration of 1-year-old leaves was relatively low during the period from June to September, increasing markedly after harvest. From autumn to winter, however, two-year-old leaves and shoots of heavily cropped trees did not show an increase in osmotic concentration which comparable organs from trees with a light or no crop manifested at the same period.

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1) Tomatoes, cv.‘Shin-Hogyoku No. 2’were grown under constant temperature regimes of 17, 24, and 30°C, of two light intensities of natural sunshine and shaded with three cloths and at two levels of N, P and K during two growing seasons (1962, 1963) to study the interaction among those factors on flower bud differentiation and its subsequent development. In 1963, the soil at the level 2(NPK) was used as bed soil.
2) The effect of the levels of fertilizer on the plant growth was light at high temperature of 30°C and hard at low temperature of 17°C. Especially, in 2(NPK) plot where bed soil was used at 17°C in 1963, the growth of seedlings was very high and remarkably different from the previous results, but it was very small at the low level of fertilizer (NPK). The difference between bed soils at 2(NPK) and NPK level was very large.
3) The influence of the levels of fertilizer on the time of flower bud differentiation was low at high temperature of 30°C and remarkable at low temperature of 17°C. Especially, the plot of 17°C, using bed soil at 2(NPK) level, in 1963 was flower bud differentiation at the earliest stage, in 19 days from sowing time, but NPK plot was remarkably late. The difference between bed soils at 2(NPK) and NPK level was very large.
4) The influence of light intensities on flower bud differentiation was remarkable in order of 30°C and 24°C. Especially, in 1963, in the shaded plots of those temperatures, the time of flower bud differentiation was late and lacked uniformity, but the shade influence at the low temperature of 17°C was the lowest.
5) The time of flower bud differentiation was the earliest in the bed soil 2(NPK) of 17°C among all plots, but the length of flower bud was rather larger at 24°C than at 17°C.
6) The effect of the levels of fertilizer on the number of flower buds was low at 30°C, but it was remarkable at 17°C. In 1963, the number of flower buds at 17°C in the bed soil at 2(NPK) level was very large, but it was very few at 17°C at NPK level. The difference between bed soils at 2(NPK) and NPK level was very large.
7) The effect of light intensities on the number of flower buds was remarkable at 30°C, but it was lower at 17°C than at all others.

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Pot experiments were carried out to clarify the effect of K fertilizer on the growth of some vegetable crops in the volcanic ash soils with different levels of exchangeable K.
1. On the soil with 94ppm exchangeable K, growth of spinach, lettuce, turnip and cucumber plants not receiving K fertilizer seemed to be inferior to those supplied with K, already from the cotyledon stage. In radish, carrot and snap beans, the increase of growth due to K supply did not become apparent until the mid-stage of growth. Howewer, at the harvest time, K application resulted in a marked increase in yield of all species investigated.
2. On the soil with 255ppm exchangeable K, K application resulted in a noticeable increase in yield of spinach and cucumber. With lettuce and carrot there was a slight increase in yield due to K fertilizer.
3. On the soil with 472ppm exchangeable K, there was no increase in yield due to K supply, with the exception of spinach.
4. These results suggested that the exchangeable K level, below which yield increase due to K application would be expected, might be higher for vegetable crops on volcanic ash soils than that reported by other investigators. It seemed that the critical level of exchangeable K described above might be different by the plant species.

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In the previous paper (6), it was reported that the temperature of 25°C in day and 14°C at night was the most suitable for raising healthy seedlings of cucumber. The purpose of the present study was to examine the effect of night-temperature on the translocation of ¹⁴C-photosynthates after ¹⁴CO₂ feeding by using tracer techniques.
Seeds of cucumber, variety“Natu-Sairaku No. 3”were sown on April 17, 1971, and transplanted into plastic pots of 15cm in diameter on April 21 at the stage of cotyledon expansion. From April 24, the pots were placed in a phytotron programmed by“the gradient temperature control system”(6). The day-temperature was set from 10:00AM to 14:00PM at 25°C and the night-one from 2:00AM to 6:00AM at 14°C. The shift between day- and night-temperatures was made as moderate as possible.
On May 30, uniformly raised seedlings were exposed to ¹⁴CO₂ in an assimilation chamber for 60 minutes under the natural light condition. Then the distribution of ¹⁴C-radioactivities was determined immediately after ¹⁴CO₂ feeding (Exp. A), and two days (Exp. B), and three days (Exp. C) later. The temperature after ¹⁴CO₂ feeding was kept at 25°C in day and at 20°C (high-night; H) or 14°C (low-night; L) at night by the horizontal temperature control system.
Results obtained were summarized as follows:
1. Percentage of dry matter to fresh weight decreased at the high night-temperature after ¹⁴CO₂ feeding, while it remained constant in the low night-temperature. It is considered that the plant exhausted much more photosynthates at the high night-temperature (20°C) than at the low one (14°C) (Fig.3).
2. Specific activity of respective plant part, shown in Table 2 was the highest in the blade of the tenth leaf from the base, and very low in the old- (1st-2nd) and adult-leaves (3rd-7th), when it was determined immediately after ¹⁴CO₂ feeding. After ¹⁴CO₂ feeding, specific activity of the young leaves except stem apex (8th-12th) decreased remarkably, and those of the stem apex (T), the stem, and the root increased, at high night-temperature. In other hand, only a little decrease in specific activity occurred at the low night-temperature (Fig.4).
3. After the dried sample of each plant part was extracted with hot ethyl alcohol, the alcohol extract was fractionated into four fractions by the procedure described in Figure 1. Radioactivities of five fractions including the alcohol insoluble fraction were compared for each plant part. Radioactivity of the alcohol insoluble fraction containing starch, protein and cellulose increased in the low night-temperature lot, but not in the high night-temperature lot (Fig. 11).
4. The translocation of photosynthates was faster and their exhaustion by respiration was higher at the high night-temperature (20°C) than at the low night-one (14°C). Consequently, the final reservation of photosynthates was more at the low night-temperature than at the high night-one.
On the efficient temperature management in the cultivation under growing structures, it is reasonably recommended from the point of reservation of photosynthates that the air temperature should be kept low at night.

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These studies were carried out to obtain some informations on the mode of action of CMMP (solan).
CMMP was compared with the same anilides, DCMP (karsil), DCPA (propanil), and DCMA (dicryl) on the main site of herbicidal action, and the schema on the mode of action was proposed.
(1) The inhibiting action of CMMP on photosynthesis was compared with that of DCPA on intact plants. In consequence, both of CMMP and DCPA inhibited photosynthesis strongly after the treatment.
(2) It is assumed that the recovery of photosynthesis of a CMMP resistant plant, mitsuba (japanese honewort), is different from the antidote such as DCPA which is hydrolysised in rice plant.
(3) Hill reaction of spinach chloroplast was strongly inhibited by CMMP as same as DCMP, DCPA and DCMA. This is suggested that the main site of herbicidal action of their acid amides is an inhibition of photochemical action and the rate of inhibition of Hill reaction has no relation with their substituted radicals.
(4) The inhibition of CMMP to respiration was compared with those of DCMP, DCPA and DCMA by using roots of rice plants and water foxtails. In consequence, all of these compounds showed inhibition at the concentration of 2.5×10^-3M. The descending order is as follows: DCPA>DCMP>CMMP>DCMA. Therefore, it appears that the inhibition of anilide to respiration is related with their side chain.
(5) The combination of CMMP, DCMP, DCPA and DCMA with chlorophyll takes place apparently and this reaction is considered as one of the reactions of herbicidal action.
(6) The herbicidal effect of CMMP, DCMP and DCMA except for DCPA was particularly reduced by spraying chlorophyllin, although all of these acid amides are similarly included in anilides.
(7) From the results obtained, the following schema on the mode of action of CMMP is shown tentatively in Fig. 8.
The process of death of susceptible plants is as follows: the first step is inhibition of biosynthesis of chlorophyll, the second step is inhibition of photosynthesis and photophosphorylation, and the third step is destruction of chloroplast.
In tolerant plants photosynthesis and photophosphorylation are so inhibited as in susceptible plants, but tolerant plants are resistant for inhibition of chlorophyll biosynthesis and destruction of chloroplast. This resistance is considered to be a cause of the survival of tolerant plants.
It is also considered that the reduction of effect of CMMP by spraying of chlorophyllin is caused by relative increase of active chlorophyll in the second step mentioned above.

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A possibility of the application of the pruning techniques for the isolation, fixation and propagation of wholly mutant plant from a small sectorial mutation induced by gamma irradiation on Begonia rex has been investigated.
Among the irradiated Begonia plants, variety‘Winter Queen’, partially changed plants each having a small green chimeric mutation with a number of small silver- white spots on leaf were found and one of these plants was employed throughout the present experiments (Fig. 1).
For extending and fixing the mutation, this plant was subjected to repeated cutting-back, layering and division in order to accelerate the development of axillary or adventitious buds and to grow them up to the shoots having the wider mutated area (Figs. 2-4). After the application of these techniques, the wholly mutated shoot was finally obtained (Fig. 4). This changed shoot was layerd and grown to the wholly changed plant (Fig. 5). The leaf color of new plants was green with a number of small silver-white spots as that of the original small sector (Figs. 6 and 9, and Table 1). The procedures of these experiments are illustrated in Figs. 7 and 8.
From this investigation, it is suggested that the combination of irradiation and various pruning techniques can be useful in the breeding of horticultural crops, which are propagated vegetatively, under ordinary cultural conditions.\

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In the previous paper the present writer reported that the physiological states for corm formation in freesia were induced by the chilling treatment at about 10°C for seed corms or seedlings. This study was carried out from 1970 to 1973 in order to clarify whether dormant corms or cormlets produce pupas by the chilling treatment.
In this experiment, corms and cormlets (cultivar‘Rijnveld′s Golden Yellow’) of various dormant states were treated periodically with the low temperatures of 5°or 9°C for 30 to 45 days and then were stored in the thermostat or pan of moist sand at 20°C.
In the lots of dormant corms or cormlets, the pupa formation, i.e. new corm formation was scarcely ever recognized. After the emergence from dormancy the effect of the chilling on pupa formation tended to increase, and the percentage of pupa-formation and the size of new corm increased. Therefore, it is sure that in the deep dormant corms the physiological state for corm formation was not induced by the chilling treatment, but that was induced in the corms the dormancy of which had become lighter. The aforesaid phenomena in corm formation of freesia resemble to vernalization in flower formation.

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The present investigation dealt with in vitro the growth of the excised ovules just after fertilization in Petunia hybrida.
Most of these ovules were cultured on a medium composed of inorganic salts, vitamins, glycine, sucrose and agar without any growth regulators or plant extracts. They were able to develop into viable seeds only when cultured on the medium containing Fe-EDTA as an iron source. Some of the seeds germinated in situ immediately and developed until flowering. However, ovules cultured on a medium containing ferric citrate failed to develop into viable seeds.
The addition of some growth regulators to the medium containing Fe-EDTA rather inhibited the normal development of ovules. A supply of casamino acids did not also increase the percentage of normal seedlings; however, the number of normal seedlings increased progressively with decreasing the concentration of sucrose.

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In order to examine the effect of low temperature on flower bud formation, bulbs of iris‘Wedgwood’were stored at low temperature of 8°C or 13°C for 35 days from August 12 and then shifted to 15°C, 20°C or 30°C. Flower bud formation was most promoted in the bulbs stored at 13°C followed by 15°C, at 8°C followed by 15°C, at 8°C followed by 20°C and at 13°C followed by 20°C in the succeeding order. Bulbs shifted to 30°C after the low temperature storage did not initiate flower buds, but were in rest. On the other hand, flower bud formation was occurred after long termes of period in the bulbs which were not exposed to the low temperature and kept at continuous 20°C. More leaves were formed before flower bud formation in the bulbs stored at 13°C than in those stored at 8°C. Longer first leaf was obtained at 20°C than 15°C and 13°C than 8°C, whereas leaf elongation was restricted at 30°C.
Flower bud formation was not promoted by pretreatment of high temperature at 30°C or 35°C for 13 days from August 9 to 22, just before the low temperature treatment, but rather delayed compared with no pretreatment.
In the bulbs treated at 10°C for 45 days, flower bud initiation was delayed by the treatment with high temperature at 35°C for the following 16 days, but not delayed by the treatment for 2, 4 or 8 days. In the cese of storage at 10°C for 30 days, it was delayed by the treatment for 8 or 16 days, but not by the treatment for 2 or 4 days. The length of period delayed, however, was nearly the same as the duration of high temperature treatment in both cases.
The conclusion that the low temperature not only induces directly the flower bud initiation, but accelerates afterwards the flowering during forcing period, may be drawn based on the results obtained. The flower bud initiation was delayed by high temperature after low temperature treatment when the latter was incomplete or the former was long enough. The effect of high temperature, however, was not so remarkable.

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Ethrel was sprayed at 2, 000ppm concentration on pinched and unpinched plants of pot chrysanthemum cultivar‘Jack Straw’in early vegetative stage. Results showed a reduced plant height, shortening of internode leading to rosette formation, increased number of new shoots, almost complete prevention of flower bud formation and temporary damage and atrophy of leaves in Ethrel sprayed plants. When applied as soil drench at the above concentration, the responses were almost the same but poorer compared to spray application.

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To clarify the effects of low O₂ level with and without CO₂ in CA storage of apples, Jonathan and Ralls fruits were stored at both 20°C and 4°C for one and two months, respectively. A factorial design of 0, 5, and 10% (Ralls-20%) CO₂, and 3, and 19-21% (Ralls-16-21%) O₂ was used.
At the higher CO₂ levels combined with the high O₂ level, the more slowly the ground color yellowed, and, but for the occurrence of the flesh brownings, the firmer fruits with higher acidity were found. At low O₂ level without CO₂, the ground color yellowed slowly at both temperatures and the softening was reduced at 20°C.
At the low O₂ level, no marked difference was found in the yellowing among CO₂ levels. But for the occurrence of flesh brownings, the firmest fruits with the highest acidity seemed to be obtained in atmosphere with the highest CO₂ and the low O₂ levels.
The effects of increased CO₂ and reduced O₂ levels were additive as regards rate of O₂ absorption at 20°C in Rails.
Jonathan spots were reduced at the low O₂ level. The more flesh brownings were found in atmospheres with the higher CO₂ and the low O₂ level. The browned tissues had low acidity and firmness.
The optimum CO₂ level for CA storage at the low O₂ level seemed to be lower than that at the high O₂ level. Discussions were made about the browning types in relation to fruit maturities.

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