This study is designed to determine the estimation methods of water saturation deficit (W. S. D.) as a reliable indicator of water balance in Satsuma orange leaves, and also to determine the effects of soil moisture and fertilizer supply on the W. S. D. and the apparent photosynthetic rate of leaves.
1. The following method could be recommended as a method for simple and accurate determination of W. S. D. of leaves. Leaves is cut out from experimental plants, then put petiols with a whole leaf in a dish containing distilled water for 24 hours for saturation in a moist chamber. Calculation of W. S. D. is as follows:
W. S. D.(%)=Saturated fresh weight-Initial fresh weight/Saturated fresh weight-Oven dry weight×100
This method involves many considerations, namely: leaf age, leaf position on a shoot, and leaf from shoot bearing fruit or not.
2. The soil moisture affects the degrees of W. S. D. in leaves very considerably, the degrees increasing with decreasing soil moistures. The value of W. S. D. at a low moisture level is 2.6 times as high as the value of it at a medium soil moisture level. While an increase in fertilizer supply cause a progressive increase in W. S. D.
3. A reduction in soil moisture and an increase in fertilizer supply results in a decrease in the rate of apparent photosynthesis. When the soil is allow to dry out, as is shown at a low soil moisture level, reduction in the rate of photosynthesis become evident.
There is a highly negative correlation between the W. S. D. and the rate of apparent photosynthesis.

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Stem pitting has been found by the authors in such species of citrus as sweet lime (Citrus limettioides TANAKA), Hassaku (C. hassaku HORT ex TANAKA), Banpeiyu (C. grandis OSBECK), Matopeiyu (C. grandis OSBECK), Tanigawabuntan (C. grandis OSBECK), Matobuntan (C. grandis OSBECK), grapefruit (C. paradisi MACF.), Kotokan (C. kotokan HAYATA), Parson Brown (C. sinensis OSBECK), Wasington Navel orange (C. sinensis OSBECK, var. brasilliensis TANAKA), Funadoko (C. funadoko HORT. ex Y. TANAKA), Kikudaidai (C. canaliculata HORT. ex Y. TANAKA), and Yuzu (C. junos SIEB. ex TANAKA). In these species, stem pititng of Hassaku trees has been known as one of the symptoms of Hassaku dwarf disease, and it is closely associated with stuntiog of tree in the fields. But, stem pitting of other species has not so awared, because of the less cultivation of these species in Japan.
To see whether a certain factor involved in stem pitting initiation of citrus can be transmitted by tissue graft to healthy trees of other citrus or not, the following experiments of transmission of stem pitting were carried out. 1) Budwood from 11 species of citrus (Sweet lime, Banpeiyu, grapefruit, Hassaku, Kotokan and Washington Navel orange) which showed stem pitting in the fields, were inoculated to seedlings of Mexican lime (Citrus aurantifolia SWINGLE) by means of tissue graft. 2) Budwood from Hassaku tree affected by Hassaku dwarf disease, was inoculated to seedlings of sweet lime. 3) Budwood from Hassaku tree affected by Hassaku dwarf disease, was inoculated to two-year old Mediterranean sweet orange trees (Citrus sinensis OSBECK) grafted on Kabusu daidai rootstock (Citrus aurantium LINN.).
The results show that within one or two years after inoculation, stem pitting was formed in Mexican lime (Fig. 3, B, C) and sweet lime seedlings (Fig. 4, B), however, no stem pitting was observed in the wood surface of sweet orange trees. But, in the case of sweet orange trees, abnormal parenchymatous tissue was recongnized in the wood differentiated after inoculations (Fig. 5, B. the arrow).

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Each of four types of“pipe-beds”was established in the open air (Fig. 1, Table 1). After preliminary tests on various structures of beds and fertilizer concentrations, this experiment was made on the effects of structures of beds on the growth of broccoli. Broccoli seedlings were raised in a “ditch-ded”. It was also devised to make water rise by capillarity. Seeds were sown on August 4, 1967. Four seedlings were planted in each bed on August 26. Water was poured into the water-storage pipe continually to fill the capacity of 8 liters as the water level lowered to leave around 2 liters. Liquid fertilizer (20 cc of 10-5-8) was supplied into the pipe once every week.
The results are shown in Table 2 and Fig. 2. It is censidered that the C-type bed is satisfactory for most crops. For root crops the soil underneath the medium should be cultivated.
The studies are on the exploratory stage. Further studies should be made on the spacing of water-conducting pipes, the depth of plastic mulch placed in the central half of the bed, proper ingredients and amounts of fertilizer, and other things.
When these problems are solved, the method of water and fertilizer application is not only effective and efficient for plant growth and for saving labor but also not too expensive for construction and also durable.

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The experiment was carried out to clarify the effects of nitrogen supplied in various growth stages from the transplanting time middle in October to the termination of harvest early in July, on the growth and yield of strawberry (var. Donner) in sand culture outdoors.
The control plants supplied with nitrogen throughout all stages of growth were the highest in the number of flowers and yield of fruits.
In the plants withheld nitrogen supply after late in April or late in February, the growth of tops and roots were inferior to those of the control. Their number of flowers and yield of fruits were also less.
When plants were not supplied with nitrogen during the winter period from late in December to late in February, their number of flowers and yield of fruits were less than those in control plants, however, their yield was the highest among other treatments except the control.
Both the number of flower clusters and of flowers decreased remarkably in the treatments withheld nitrogen supply from the transplanting time till late in December or late in February. When nitrogen was supplied afterward to the plants in these treatments, growth of tops and roots became vigorously, and runner production was also active. Although the fruit yields in these treatments were decreased due to their smaller number of flowers, their fruit set percentages, average fruit weight and soluble solid content of fruits were higher than those in the control.

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In an attempt to eliminate the trouble of hand emasculation from the hybridization work in pepper, possibility of emasculation with a gametocide was examined. Mie Midori, a cultivar of sweet pepper, was used in this experiment. Anther dehiscence was completely suppressed by foliage spray of 250 and 1250 ppm aqueous solutions of sodium 2, 2-dichloropropionate (Dalapon). Suppression of anther dehiscence started about two weeks after treatment. Toxic effects to foliage and to plant growth were not severe while abnormal expansion of ovaries and bending of styles were accompanied with the suppression of anther dehiscence in a considerable number of flowers. The implications of these functional and morphological changes for hybrid seed production are discussed.

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The author investigated the relation between the shape of stigma and the number of pollen grains on the stigma by hand-pollination together with the number of seeds, and on the pollen tube growth and on the hour of fertilization in Cucumis melo L. var. reticulatus NAUD. (Earl′s Favourite) in green house. Two strains, Spring No. 1 and Summer No. 2 were used as the materials for this investigation.
1. In comparison of the exposed portion of stigma between Spring No. 1 and Summer No. 2, it was found that the space of the latter was always wider than that of former.
2. A staminate flower has approximately from 9, 600 to 13, 000 pollen grains. 900-1, 100 grains of them were pollinated by hand-pollinatoin to the stigma of Spring No. 1, and 1, 000-1, 500 were to that of Summer No. 2.
42.6% of these pollen grains were germinated in 20 minutes after pollination, 85.1% of the pollen grains in 30 minutes, and 92% in 60 minutes.
3. About 385 seeds of the melon fruit were obtained in Spring No. 1 after its ripening, and 510 seeds in Summer No. 2. When the castration was carried out, above 560 seeds were produced even with Spring No. 1. It seems to be due to the difference of the flower-type between two strains.
4. The pollen tubes grew to a length of 227μ in 30 minutes after the pollination, 728μ in one hour, 2, 240μ in 2 hours, and the average length of pollen tube growth in the style was 900-1, 000 μ per hour.
5. In 4 hours after pollination, the pollen tube traveled from the stigma to the base of the style (with an average length of 4mm in case of Earl′s Favourite), after the pollen tube entered the ovary.
In 15-18 hours after the pollination, it was found near the surface of placenta, and in 24 hours after pollination a great number of ovules were seen indicating that the fertilization was over.

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1. The main object of the present investigation was to study the effects of combination of temperatures at the stage of seedling on flower bud differentiation, bolting, budding and flowering time in head lettuce.
2. Seedlings with 5 leaves (31 days after sowing) were previously treated with 10°C, 15°C, 20°C and 25°C for 20 days, respectively. The plants treated with 10°C continued vegetative growth by the end of treatment. Those with 15°C were just on turning point from vegetative to reproductive growth. On the other hand, both of the plants treated with 20°C and 25°C differentiated flower buds at their growing points.
3. The plants previously treated as mentioned above were transferred to 10°C, 15°C, 20°C and 25°C, respectevely. As a result, the plants treated with higher post temperature were promoted the flower bud differentiation or its development, regardless of their previous temperature treatments.
4. Degree of seedstalk elongation was classified into I-IV as shown in Fig. 1, and it was highly correlated with flower bud development. As the flower bud development and bolting stage made progress, the degree of seedstalk elongation advanced from I to IV.
5. The earier flower bud differentiation caused by higher temperature treatment accompanied with the greater number of leaves on main seedstalk, and also with slightly increased final number of leaves in the whole plant.
6. The higher the temperature of treatment was, the longer the seedstalk elongation. However, post temperature treatment is more effective on seedstalk elongation than previous temperature treatment.
7. The effect of combination of temperature treatments on bolting and flowering was parallel to that on flower bud differentiation.
8. It may not be concluded, however, that there is a relationship between summation of temperature and flower induction in head lettuce.

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An investigation was made of the anatomical structure of the shoot apex in To-pe-tsai (Brassica chinensis L.). It is found that the young apex has one tunica layer, and the zonation is not evident. The tunica layer increace to the maximum of 4-5 when the apex becomes adult, and when tend to reproductive phase, the layer increase to 5-6, and then decrease rapidly to 3 before the 1st flower primordium is initiated.
1st to 4th leaf primordia are initiated at the 2nd layer of the peripheral zone by periclinal division, whereas 5th to the terminal leaf (bract) are initiated from the 3rd layer, and are also by periclinal division. The floral primordia are initiated from 4th layer constantly.
The upper internods elongation occure before the 1st floral primordium is initiated. The first symptom of the bolting can be observed as a cell elongation at the subapical region.

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In order to make clear the characteristics of water consumption of taro plants under upland field conditions, the authors measured both leaf transpiration and evaporation from the soil surface using the chamber method (the vopor-trnsfer method).
The measurements were carried out at Taketoyo, Aichi in summer of 1963, 1964 and 1966.
1. The amounts of transpiration of taro plants during the growth periods (from late May to early October) were 370mm and 408mm in 1963 and 1964, respectively. For the sameperiod in 1966, the evapotranspiration amount of these plants was 582mm.
2. Transpiration rate of taro plants in the early growth stage was little owing to small leaf area, on the other hand the rate of evaporation from the soil surface was much on account of slight covering the soil surface with the foliage of taro plants.
The rate of transpiration increased gradually with the increase of leaf area and the rise of air temperature. The maximum transpiration observed was 6.8mm/day on September 10, 1964.
About 60% of total amounts of transpiration was transpired for 50 days from July 24 to September 10, 1964. The water requirements were relatively larger (500-800g/g) in the early and late growth stages than the middle growth stage (200-300g/g).
3. The relative transpiration increased gradually with the progress of growth, nemely, the increase of leaf area index. This relationship is approximately expressed with the rectangular hyperbolic equation:
RT=bL/(1+aL)
where RT=relative transpiration, i.e. the value of the rate of transpiration (mm/day) divided by the pan-evaporation (mm/day); L=leaf area index; a and b=constants. The value of inflection point of the hyperbolic curve was about 2.5 of leaf area index, which corresponded to the stage that the soil surface was covered almost thoroughly with the foliage of taro plants.
4. Unit relative transpiration, namely, the rate of transpiration (g dm^-2 12 hrs^-1) divided by the pan-evaporation (mm 12 hrs^-1) or daylight hours mean saturation deficit (mm Hg), decreased exponentially with increasing leaf area index. It was approximetely applicable to the above relation that the exponential eqution was given by
Tp=Tp₀e^-KL
where Tp=transpiration power, i.e. unit relative transpiration; Tp₀=hypothetical transpiration power when leaf area index was zero; e=base of natural logarithm; L=leaf area index; K=constant.
5. The rate of evaporation from the soil surface varied by the covering degrees of the soil surface with the foliage of taro plants.
The ratio of the evaporation from the siol surface to the evapotranspiration was about 30% in the stage of largest leaf area index (4.0).
6. The largest evapotranspiration rate of taro plants was 9.8mm/day in summer. The daily mean evapotranspiration rate of taro plants was within the range of 5-7mm/day in summer, at Taketoyo, which was estimated by relative evpotranspiration was 1.12-1.14.
7. As regards correlations among transpiration, evapotranspiration and various environmental factors, in general transpiration had a positive correlation with leaf area and evapotranspiration had positive correlations with pan-evaporation or solar radiation.

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1. Two observations to analyse the air temperature in the plastic house were carried out. The one is the air temperature in the tunnel in the plastic house, and the other is the air temperature in the curtain in the plastic house. On both cases, a warm wind heater equipped with ducts is utilized.
2. When the air in the duct laid in the tunnel is discharged out of the tunnel, the longer the distance from the heater, the lower the air temperature in the tunnel.
The next notation was set up:
heat transmission rate of the tunnel; h₁kcal/m² h°C
heat transmisson rate of the duct; h₂kcal/m² h°C
heat transmission rate of the soil surface; h₃kcal/ m² h°C
radius of the tunnel; r₁ m
radius of the duct; r₂ m
wind velocity in the duct; v m/h
specific gravity of the air; w kg/m³
specific heat of the air; c_P kcal/kg°C
then, the condition to minimize the air temperature lowering near the tunnel end is
2h₂r₁/r₂vwc_P•(πh₁+2h₃)/(πr₁h₁+2πr₂h₂+2r₁h₃)=1
3. When the air in the duct laid in the tunnel is released into the tunnel (the length of the duct is a little shorter than the tunnel) the air temperature in the tunnel is too high near the end of the duct. The larger the blast amount of the heater, the more uniform the air temperature in the tunnel.
4. On the two cases, that the duct is laid in the tunnel, the data measured in the large vinyl house at Hanyu Shi, Saitama Ken have good fitted the theory.
5. When the tunnel is removed and the duct is laid in the curtain, the analysis of the air temperature in the curtain is similar with the one in the tunnel in which the air in the duct is discharged.
6. On the air temperature in the curtain, by the data measured in the fylon house at the Saitama Ken Horticultural Experimental Station, we have decided the constant of the function which is obtained by the theory.
7. The results calculated the air temperature in the curtain were as follows: 1) To get the even distribution of the air temperature in the curtain, large radius of many ducts and high speed of the air in the duct are effective. 2) A considerable difference in maximum air temperature and a smaller one in minimum air temperature were observed between two heaters which had heating power of 3×10⁴ kcal/h and 2×10⁴ kcal/h respectively.
The air temperature inside the curtain dropped by 3.4°C and 6.6°C, when the air temperature out of the house and the soil surface temperature fell down by 10°C.

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These experiments were carried out to study the porperties of a selective herbicide, solan (CMMP; N-(3-chloro-4-methylphenyl)-2-methylpentanamide).
(1) Many varieties of tomato and Japanese honewort showed highly tolerance to postemergence application of solan.
(2) Only apoplastic movement of solan, in one way direction from root to top, was observed in Kidney bean.
(3) After spraying with solan, chlorophyll content in tolerant plants for solan did not decrease more than 10%, but in susceptible plants it decreased rapidly day by day.
(4) Both of crude enzymes extracted from tolera nt and susceptible plants did not decompose solan. It was assumed that the selective action of solan did not come from the difference in the rate of decomposition of the herbicide.
(5) Solan equally inhibited the Hill reaction in all chloroplasts prepared from many kinds of tolerant and susceptible plants.
When the plants were treated by solan in vivo, Hill reaction of the chloroplasts prepared from tolerant plants on the 15 days after spraying was at the same level as the control.
(6) Disappearance of solan selectivity by combining solan with phenitrothion, dimethoate or carbaryl, was assumed that it would occur in another place than Hill reaction.

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This study was carried out to clarify flower bud differentiation in Aster savatieri Mak. and the development as affected by temperature, photoperiod and some environmental factors in high land.
1. To clarify the flower bud differentiation and the development of two different sizes of suckers, 100 plots which consisted of combinations such as five different temperatures (2°, 5°, 10°, 15° and 20°C), two different daylengths (8 and 24 hours with natural diffused light and artificial light), and five different treatment durations (1, 3, 4, 5 and 6 weeks) were made. And two different sizes of suckers (small size with 4 to 5 leaves and large size with 7 to 8 leaves) were used in this test.
2. The flower bud were differentiated when the suckers had been grown at 10° and 15°C for three weeks, and 5°C for four weeks, however, the suckers grown at 2° and 20°C for 6 weeks showed no flower bud differentiation.
The period for flower bud differentiation of the suckers treated with 10°C was shorter than that with 15°C.
3. The large suckers were more effectively influenced by low temperatures than the small ones.
The sensitivity of the plants for flower bud differentiation varies by sizes of the sucker, photoperiod and especialy, temperature.
4. To clarify the effect of environmental factors in high land on flower bud differentiation and development, an experiment was made, by combining two different altitudes (about 750 and 1, 000 meters), three different planting dates (Aug. 3, 14 and 25, ′65) and three different light intensities (about 36, 60 and 100%).
Flower bud differentiation and the development was accelerated when the suckers were grown at about 1, 000 meters above sea level. Moreover, the flower bud differentiation and the development of suckers planted in the nursery bed of high land on August 3 were more acceleratively influenced than those on Aug. 14 and 25. And the flower bud differentiation and the development were accelerated when the suckers received the light intensities of 36 to 60% of full sunlight, when they were grown at about 1, 000 meters above sea level, however they were not accelerated when grown at about 750 meters above sea level.
5. The result seemed to show that the acceleration of flower bud differentiation and the development of suckers could be attained by using large size suckers with temperature of 10°C for more than 3 weeks from the middle of August to early in September, or by nursing the large size suckers at the altitude of 1, 000 meters or higher above sea level for more than 7 weeks from early August to late September.

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This work was done to make good use of polyethylene wrapping into the packing styles of tomatoes, for the purpose of extending shelf-life of fresh fruit. And a simple method of wrapping tomatoes with polyethylene sheet without sealing was adopted so that tomato growers may easily carry out package of their products when shipping. The gaseous components in this wrapping package, and shelf-life of tomato fruit wrapped by this method were investigated, and transportation test was also carried out.
1. The gaseous componts in this sheet-wrapping package changed by the respiration of tomatoes to the extent of that in hermetically sealed packaging, and it was found to be effective for the inhibition of color development and for extension of shelf-life of fresh fruitt.
2. When this wrapping package of fruit was excessively ventilated (over 2-2.5m/s) by an electric fan, the gaseous components in the package did not change so much. Therefore, the effect of modified atmosphere by this wrapping was not expected.
3. The effect of pre-cooling was observed distinctly as tomatoes were packed in insulated boxes. However, the effect of pre-cooling decreased by the ventilation in consequence of rapidrising of fruit temperature.
4. The concentration of CO₂ in the sheet-wrapping package was 6-7%, and O₂ was 13-14% in this shipping test by railway and the effect of modified atmosphere was also observed.
5. When a freight car was loaded with tomatoes in large quantities, even in a ventilation car, outside temperature had a little influence to fruit. In particular, the temperature of fruit packed with polyethylene sheet and kept at the center of a car did not change for a long time.

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In our previous studies, it was ob served that natsudaidai fruits suffered physiological injury when stored at 1-1.5°C, and respiratory behavior of the fruits was abnormal prior to the appearance of visible symptoms. This paper reports further observations on the physiological changes occurring in natsudaidai fruits stored at low temperatures. Healthy-appearing fruits were measured throughout the experiments.
(1) Respiration of albedo tissue slices was measured at 30°C. Higher respiratory quotient and more active decarboxylation of pyruvate added were found in the slices prepared from 1°C-stored fruits as compared with 6°C-stored fruits.
(2) Organic acids in flavedo part of peel were determined by silica gel chromatographic procedure. Malic and citric acids were found as major acids, and ratio of the former to the latter became much higher in 1°C-stored fruits than 6°C-stored fruits.
(3) When citric acid-¹⁴C was added to flavedo slices and incubated for 60 minutes at 30°C, considerable amount of radioactivity was detected in succinic, fumaric, malic, and two unidentified acid fractions. From succinic acid-¹⁴C fumaric and malic acids were produced, but little conversion to citric acid was found.
(4) Production of carbon dioxide-¹⁴C from glucose-U-¹⁴C, citric acid-1, 5-¹⁴C, and succinic acid -1, 4-¹⁴C in flavedo tissue slices was determined at 30°C. The greatest production was obtained from the succinic acid, and it was more conspicuous in the slices taken from 1°C-stored fruits than 6°C-stored fruits.
(5) Ethylene production in the fruits was remarkably higher at 1°C of storage temperature than at 6°C.
(6) When fruits were treated with ethylene at 6°C which is a safe storage temperature in ordinary environments, a physiological injury developed on the peel, and the symptoms were quite similar to the chilling injury.
(7) The relation between metabolic abnormality and increase of ethylene production in 1°C-stored fruits, and possible role of ethylene in the development of chilling injury were discussed.

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The strawberry cultivars used were Kogyoku and Danner. They were sealed in the polyethylene bags (0.03mm in thickness) and were irradiated with Co 60 gamma rays at 125, 250, 500 and 1000 Krads.
The storage temperatures were at room temperature and 1-5°C. The decay of partially green strawberries (Stage I) tended to be less than that of uniformly red ones (Stage II). The concentration of CO₂ and O₂ in a polyethylene bag during the storage were approximately 4-6% and 6-8% respectively, except for high dose level. The contents of anthocyanins and ascorbic acid decreased with higher doses immediately after irradiation. These compositions in the Irradiated berries increased temporarily at low temperature storage and the subsequent changes showed almost same tendency to decrease as those in unirradiated berries. A degradation of protopetin to soluble pectin evidently occurred in the irradiated berries of Stage I immediately after irradiation. The further decrease of protopectin was less in the irradiated berries than in unirradiated ones. There were no differences between sugar contents in irradiated and unirradiated berries. The titratable acidity in the irradiated Stage I-berries at high dose of radiation apparently decreased during the storage of at room temperature.
The organoleptic evaluation indicated that irradiation over the dose of 500 Krad caused more deterioration of the qualities in both stage berries immediately after irradiation and during the storage, while there were no changes of the qualities in the berries which were irradiated at the dose of 250 Krad or less.

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