The effects of high temperature (30°C-35°C) before and after flowering on the development of flower and young fruit in Citrus unshiu Marc. were investigated, and the occurrence of fruit of abnormal shape in plastic greenhouses was histologically studied.
1. Following high temperature before flowering, the development of petal, filament and pistil was repressed in size and weight, and the shape of ovary became markedly slender. Such ovaries showed a marked development of the wall of their pedicel end owing to a greater number of cell layers and larger cell size.
2. The reaction of the ovary wall to high temperature was most sensitive in the pedicel end, less in the stylar end, and least in the equatorial part of the ovaries. Occurrence of the abnormal fruit was promoted by high temperature at the stage of vigorous growts of the pedicel end.
3. Relative growth rate of the ovary wall was higher in the pedicel and stylar ends before flowering. For a while after flowering, however, it was higher in the equatorial part and later in the equatorial part and the stylar end.

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Early fruit growth was studied in realtion to the final fruit quality in satsuma mandarin (Citrus unshiu Marc.). Flowers were classified into two groups of leafy and leafless ones, and flowers of each group were further classified into early and late ones and inside and outside ones according to their flowering date and position in the canopy, respectively. Microscopic observations on the development of the juice sacs in the locules was also conducted.
1. The percentage of physiological fruit drop was 80-90 percent for the fruit from leafless flowers and about 40 percent for the fruit from leafy flowers. Among the leafless fruit, fruit drop was about 10 percent higher for the fruit from early flowers than from late flowers. Among the leafy fruit, however, there was little difference due to the flowering date.
2. The transverse diameter of fruit was always larger and its increasing rate was also larger for the fruit from leafy flowers than for the fruit from leafless flowers. The fruit from late flowers were smaller in the transverse diameter than the fruit from early flowers at the early stage of their growth but the difference gradually disappeared later. While the increasing rate of transverse diameter was higher for late-flowered fruit until 40 dates after anthesis.
3. Juice sac primordia appeared on the inner wall of the locules at anthesis, that is, May 10 for the early flowers and May 20 for the late flowers. The locules of both early- and late-flowered fruit were filled with juice sacs on June 19, which was 40 and 30 days after anthesis for early- and late-flowered fruit, respectively.
4. Leafy fruit, early-flowered fruit and outside fruit were larger, showed more advanced coloration, higher in Brix and lower in acid content as compared with leafless fruit, late-flowered fruit and inside fruit, respectively.
5. From these results, it would appear that the percentage of high quality fruit can be increased by thinning of small fruit from early July to early August which would be otherwise harvested as low quality fruit.

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Effects of flooding on the growth and some other physiological changes were examined with 8 apple rootstocks (M27, M9, M26, M7, MM106, M11, M16 and Malus prunifolia; weeping type).
1-year-old pot grown rootstocks (propagated by either root cutting or layering) were flooded by immersing the pots in water to several centimeters above the soil surface for 30 days in a plastic greenhouse at the growing season in 1980 and 1981.
Flooding reduced stem growth of all rootstocks, but the degree varied greatly among rootstocks. M9, the least tolerant to flooding, ceased growth and showed leaf symptoms of injury after about 10 days of flooding, while the growth of M. prunifolia, the most tolerant, was somewhat decreased, but no leaf symptoms of injury were observed throughout the flooding period. Leaf injury due to flooding was slight with M27, M7 and M16, but considerable with M26, MM106 and M11. Root activity judged from TTC redution was greatly reduced by flooding with M9, MM106 and M26, but unaffected with M. prunifolia. Total phenol content was also decreased greatly for M9 but only slightly for M. prunifolia. Roots of M9 accumulated large amounts of ethanol after 10 to 20 days of flooding. Flooding increased leaf diffusion resistance, especially with M9, M26 and MM106. Leaf contents of N, P, K, Ca and Mg were significantly reduced in all rootstocks by flooding.
In conclusion, flooding tolerance of the rootstocks tested can be ranked in the descending order as follows: M. prunifolia>M16, M7>M27>M11>MM106> M26>M9.

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1. Effects of severity (heavy, medium and light) of renovation pruning on improving the yield and the quality (size) of the nut in low-yield or senescent chestnut trees were examined.
2. Heavy pruning resulted in causing vigorous top growth, which was maintained for a longer period of time. Light pruning could increase tree vigour for only a short period of time, but its effect disappeared in the third year. In this case, however, the tree vigour was recovered by trying it again in the fourth and fifth year.
3. Removal of most of the primary or secondary scaffold branches stimulated the growth of shoots on the remaining scaffold branches in the same tree, as compared with that of a few of them.
4. The heavy pruning resulted in greater ‘leaf-area index’ and ‘leaf-area density’, and also much greater ‘leaf-wood’ and ‘leaf-sapwood’ ratios than the medium or light pruning.
5. The yield per tree was reduced by the pruning in the first year, but it increased markedly in propotion to the severity of pruning after the third year. Therefore, the cumulative yields per tree in five years were in the following order: heavy>medium>light pruning. Yearly changes of the yield per ground area occupied by a tree showed almost identical trends with those of the yield per tree.
6. Nut size increased with the severity of pruning. This effect did not disappear for five years in the heavily-pruned tree. Whereas, it disappeared in the third year in the lightly-pruned tree. In this case, the nut size increased again by another renovation prunings in the fourth and fifth year.
7. To improve the nut yield and quality in low-yield or senescent chestnut trees, therefore all their scaffold branches should be renovated at the same time or over the consecutive several years.

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As an approach to the analysis of components associated with the production of high quality fruit of Muscat of Alexandria grapes (Vitis vinifera L.), seasonal changes in the growth rate, dry matter accumulation, and CO₂ evolution from clusters, and the apparent rate of photosynthesis in leaves were investigated throughout the growing season.
1. The increment of cluster volume exhibited a typical double sigmoid curve. The ratios of cluster volume increase were 37% in the stage I, 19% in the stage II, and 44% in the stage III, respectively, of mature clusters. Dry matter accumulation followed a simple sigmoid curve, the ratios being 11%, 17%, and 72% in stages I, II, and III, respectively. The accumulation in stage III was most significant.
2. Percentage of dry matter in clusters decreased rapidly from the stage of full bloom, became minimum at the end of stage I, and then increased linearly thereafter.
3. CO₂ evolution from clusters on fresh weight basis increased linearly for the first 6 days from the full bloom and decreased drastically thereafter. CO₂ evolution per cluster, on the other hand, showed 2 peaks, one at the transition point from stage I to stage II, and another at the early phase of stage III.
4. The ratios of amounts of dry matter translocated into clusters, the sum of accumulated dry matter and glucose equivalent dry matter calculated from CO₂ evolved, were estimated to be 13%, 20%, and 67% in stages I, II, and III, respectively.
5. The apparent rate of photosynthesis in leaves increased gradually and reached a maximum at about 1 month from the leaf expansion, about at blooming stage, and decreased thereafter due to low light intensity during the rainy season. It increased again for some time during the stage II, and then decreased gradually until leaf fall.
6. The seasonal pattern of apparent photosynthesis was different from that of dry matter accumulation. The translocation of photosynthate into clusters became maximum in stage III, while photosynthetic ability of leaves was in the process of gradual decrease. Based on these results, it was inferred that overloading of fruits in this stage result in an inhibited growth, delay of maturation, and low sugar content in mature berries.

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The xylem sap in cucumbers (Cucumis sativus L.) which were or were not grafted onto figleaf gourd (Cucurbita ficifolia Bouché) was collected after decapitation from the cut end of the stems hourly. The exudation rate was highest in the first one hour collection regardless of grafting, and then decreased rapidly with time. However, there was a diurnal change in the exudation rate with the maxima occurring at 1:00 to 3:00 PM and the minima at 7:00 to 8:00 AM, irrespective of decapitation time. The grafted cucumbers were smaller in amplitude than the non-grafted ones.
The rate of xylem exudation and the concentrations of NO₃-N, P, Ca and Mg in the first one hour exudate were higher in the grafted cucumbers than in the non-grafted ones. Only the K concentration was higher in the non-grafted cucumbers. The mineral concentration in the exudate changed remarkably with time after decapitation; the NO₃-N, K and Ca concentrations decreased and the P concentration increased rapidly for the first several hours. The Mg concentration scarcely changed. Thereafter, the NO₃-N and K concentrations of the exudate in the grafted cucumbers fell below the NO₃-N and K concentrations in the nutrient solution, while in the non-grafted cucumbers the former was kept always above the latter.
From these results, the grafted cucumbers were considered to be superior to the non-grafted ones, in water uptake and nutrient absorption except for K and also to depend more intensely in NO₃-N and K absorptions on some metabolities from the upper parts of the plants.

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Young plants of cucumber (Cucumis sativus L.) cultivars, ‘Suyô’and ‘Kurumeochiai H’, widely used as summer and spring crops respectively, figleaf gound (Cucurbita ficifolia Bouché) and ‘Suyô’ grafted on figleaf gourd were grown for 10 days in a third strength Hoagland No.1 solution kept at 12, 14, 17, 20, 25 and 30°C. Growth of ‘Suyô’ was severely suppressed at 12 and 14°C, while that of ‘Kurumeochiai H’ was suppressed at 12°C. Figleaf gourd showed a high ability to toleratelow root temperatures. Growth of ‘Suyô’ at lower root temperatures was significantly improved when grafted on figleaf gourd. The difference in growth response between cucumber and figleaf gourd was most remarkable in the roots. Thus, at lower root temperatures, the root growth was suppressed greatly in both cucumber cultivars, whereas it was promoted in figleaf gourd. Leaf water content decreased at lower root temperatures, and the decrease was most marked in ‘Suyô’. Chlorosis occurred at lower root temperatures on the leaves which expanded after the beginning of root temperature treatment, and most pronounced in ‘Suyô’ at 12°C, where the plant growth was severely depressed. Low root temperature reduced nutrient concentrations of leaves, and it was particularly true for P and Mn. When the 4 crops were included, highly significant correlations were observed between the degrees of growth suppression and decrease in the nutrient concentrations of leaves, particularly in N, P and K.

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Using water culture, a study was made on the effect of K and Ca levels in the nutrient solution on ammonium toxicity in vegetable crops. Materials used were sweet corn, cucumber, kidney bean, lettuce, cabbage, Chinese cabbage, and spinach. Nitrogen was supplied as NO₃, NH₄, or NO₃+NH₄(1:1) at N levels of 12me/l, which was combined with K or Ca levels of 2, 6 and 18me/l, respectively. The pH of the solution was adjusted to 6.0. Plants were grown in the different treatments for about 3 weeks. In another experiment, lettuce and spinach were grown in order to compare the effect of chlorides, carbonates, sulphates, and silicates of K and Ca in the solution on ammonium toxicity.
1. Regardless of the kind of vegetables, the growth of plants fertilized with NO₃ +NH₄ was almost equal to, or better than that of NO₃ fertilized plants. When plants were cultured with NO₃ or NO₃+NH₄, the level of K or Ca in the solution had a great influence on the concentrations of these elements in leaves but had almost no influence on the growth of plants.
As compared to NO₃, NH₄ nutrition decreased the growth of all vegetables except sweet corn, and lowered the concentrations of K and Ca in leaves of all vegetables. The concentrations of K and Ca in leaves increased with increasing K and Ca levels in the solution, respectively. Under NH₄ nutrition, increasing K level in the solution alleviated the growth reduction only in tomato and kidney bean. Increasing Ca level in the solution also alleviated the growth reduction only sweet corn, cucumber, lettuce, and cabbage. In both cases, however, the alleviation was so small that the growth of NH₄-treated plants was much inferior to that of NO₃-treated ones except sweet corn.
2. Even under NH₄ nutrition, the pH of the nutrient solution was kept rather high for a long period after the application of carbonates or silicates of K and Ca. This effect was especially remarkable for CaCO₃. In all cases, however, NH₃ toxicity in lettuce and spinach was hardly reduced.

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We investigated whether a spring planting culture in garlic, a new cropping type, could be commercially made in a cool district of Japan.
1. The spring planting culture using seed bulbs produced in spring by a forcing culture, was considered to be non-commercial, because the corm yield was very much lower than that of any autumn planting culture. As against this, another spring planting culture using seed bulbs produced last summer by an autumn planting culture could be commercially made, on condition that keeping the optimum methods given in the following.
2. Seed bulbs produced last summer needed to be stored at low temperatures till planting times of the following spring. The optimum storage temperature was-2°C.
3. Whether seed bulbs were dormant or were awakened from dormancy at the beginning of cold storage, it affected growth and bulbing of garlic after planted. The seed bulbs awakened from dormancy produced higher percent of normal bulb formation and higher corm yield than the dormant seed bulbs.
4. As seed bulbs were planted earlier after melting of continuous snow cover, the percent of normal bulb formation and the corm yield became higher.
5. Among ten cultivars tested, the local cultivars in cool temperate regions of Japan were better than the local cultivars in warm temperate regions of Japan, in respect of both percent of nomal bulb formation and corm yield. Among the cool temperate cultivars, the late cultivars developing long bolting-stalks with numerous bulblets and florets were better than the late or medium cultivars developing short bolting-stalks with a few bulblets, in respect of percent of normal bulb formation. The percent of normal bulb formation of the former late cultivars reached 100% when the other conditions were proper.
6. As average weight of seed bulbs increased, both the percent of normal bulb formation and the corm yield increased.
7. When the spring planting culture was made keeping the optimum conditions given in the above items 1-6, the percent of normal bulb formation became 100% and the corm yield reached about 80% of that of the autumn planting culture. The harvesting time of the spring planting culture was a few days later than that of the autumn planting culture. The garlic of the spring planting culture matured in four months after planted.

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The process of leaf development in relation to temperature was investigated morphogenetically to clarify the mechanism of the “small head” formation in Chinese cabbage. Seedlings of ‘Nozaki-Kohai No.3’ were grown in a phytotron kept at day-night temperatures of 30-25°C (high), 23-18°C (medium), and 15-10°C (low). For histological observations, leaves and shoot apices collected at intervals of 7 days were fixed and sectioned by the paraffin microtechnique.
In leaf 5 (numbered from the base) the thickness of the midrib was greatest at the medium temperature and smallest at the high temperature. The number of rows of parenchymatous cells along the dorsiventral axis in the midrib (hereafter referred to simply as “the number of parenchymatous cells”) was greater at lower temperatures. The proportion of the number of parenchymatous cells on the adaxial side to that on the abaxial side of the midrib was also greater at lower temperatures. The length of the parenchymatous cells was greater at higher temperatures. The thickness of the midrib vein was greater at lower temperatures. The thickness of the lamina was greater at lower temperatures.
Increase in the width of successive leaf primordia in plastochrones was more rapid at higher temperatures, whereas in a certain number of days after the initiation of leaf primordia, it differed little between the medium and high temperatures.
At the lower nodes, leaf primordia grew upright, but at progressively higher nodes, hyponastic curvature was observed first at the tip, next in the upper half, and finally in the whole of leaf primordium. Consequently, the leaf primordia folded over the shoot apex, forming the “small head”. This process progressed faster at lower temperatures.
The increase in the number of parenchymatous cells in successive leaf primordia was more rapid at higher temperatures. It differed little between the abaxial and adaxial sides at the lower nodes, whereas, at the higher nodes, it was greater on the adaxial side. In addition, it ceased earlier at the high temperature, so that the difference in cell number between the abaxial and adaxial sides was smaller than at medium and low temperatures.
There appears to be a correlation between the hyponastic curvature of leaf primordia becoming more pronounced and the difference in the rate of increase in the number of parenchymatous cells becoming greater as the plants grew. This correlation was also evident in relation to temperature. Therefore, the hyponastic curvature of leaf primordia (future midribs) is thought to be caused by the relative retardation of cell elongation on the adaxial side in the state where the rate of increase in the number of parenchymatous cells was greater on the adaxial side.
Hyponasty of the lamina was also found in its young stage, and this hyponastic growth was necessary in the formation of the folded leaves. The mechanism of lamina hyponasty was not clarified in this report, but it is possible that the difference in duration of cell division in the various tissues of the lamina, which is seen in many dicotyledonous plants, causes the hyponasty of the lamina in Brassica plants.

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This study was conducted to clarify the ascorbic acid content of tomato fruits varing with cultivation methods, growing seasons and cultivars with special reference to the effect of light conditions.
Long term harvest cultures (sown in August and harvested up to the 11th and 15th clusters) were performed by soil and water culture. In both cultures the ascorbic acid content in fruits was low in lower clusters and remarkably high in the uppermost 4 clusters. There were little differences in the fruit constituents between soil and water culture, but the ascorbic acid content of fruits in low clusters was lower than that of soil grown plants. This was considered to be due to the fact that the larger stem and leaves in water culture easily shaded the lawer cluster fruits.
Seeds were sown monthly on the 20th day throughout the year to study the influence of growing season on the ascorbic acid content of fruits. Plants were grown by water culture and detopped above the third cluster. Ascorbic acid content was lowest in the fruits of August-sown crop, then it gradually increased and become highest in the fruits of the next April-sown crop.
Comparisons were made between European cultivars (‘Best of All’, ‘Money Maker’: red-orange and small fruit type) and Japanese cultivar (‘FTVNR-3’: pink and large fruit type). Plants were grown twice a year (in summer and winter) by water culture using two concentrations of nutrient solution. In winter crop the ascorbic acid content of ‘FTVNR-3’ went down to about 1/2 of summer crop, but the fruits of European cultivars kept about the same level as in summer crop.
From the results obtained, the relations between light condition and ascorbic acid content of tomato fruits were discussed.

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In Lilium rubellum Baker, segments excised from stems and floral parts were found to form bulblets on the modified Murashige and Skoog medium supplemented with 1 mg/l naphthalenacetic acid and 0.1mg/l 6-benzylaminopurine (9). It was especially true for stem- and tepal-segments, which were comparable to scale segments in their ability of bulblet formation.
The bulblet formation, however, was found to vary with the age of parent plants at excision. Thus, tepal- and stem-segments formed many bulblets when excised from the plants 4 to 2 weeks before flowering but did scarcely when excised at flowering. Filament segments formed bulblets when excised from the plants 2 weeks before and at flowering, whereas style segments did only when excised at flowering. None of stem segments formed any bulblets when excised at flowering.
The bulblet formation also varied with the position of segments on each plant parts. The proximal segments of floral parts formed more bulblets than the distal ones, whereas the reverse was true in the stem segments.
Stem segments were divided into the nodal- and internodal-ones. Nodal segments formed more bulblets than internodal ones. Further, both segments, especially the nodal ones, formed bulblets in higher percentage when excised from the distal 5cm of the young stem 10 to 15 days after sprouting.
It could be concluded from the results that the segments excised from tepals and stems 4 to 2 weeks before flowering were as useful as scale segments to effectively produce bulblets in the in vitro propagation of L. rubellum Baker.

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Sudachi (Citrus sudachi hort. ex Shirai) is a small-fruited, 20 to 35g, acid citrus traditionally grown in Tokushima Prefecture, Japan. The fruit served as cut-halves makes unique garnishes and the juice is an excellent flavor enhancer.
Sudachi is harvested only in the green stage, for the characteristic fragrance vanishes as the fruit turns to yellow. Thus, the harvest season of outdoor-grown Sudachi has been limited to less than 2 months starting from mid-August until the fruit degreens early in October. The objective of this study was to develop a long-term storage method for green immature Sudachi.
1. Storage temperature was the most important factor in prolonging the storage life of green Sudachi and 1-2°C was the best when compared to 5°, 10°, 15°, 20°, and 25°C.
2. Seal packaging with plastic bags was effective in reducing weight loss due to transpiration and in keeping green peel color and the characteristic fragrance. At 1°C, 0.02 to 0.03mm thick low-density polyethylene film was the best because thicker film caused storage injury.
3. Curing at ambient conditions for 2 to 4 days before storage decreased decay and the storage injury. The optimum degree of curing was not established, however it seemed to be dependent upon the time of harvest in a given season.
4. Low temperature, film packaging and curing treatment combinations made it possible to store green Sudachi for up to 4 to 6 months and to ship all year round in conjunction with heated plastic house culture.

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1. In order to alleviate chilling injury of cucumber fruits during the storage at 5°C, the effects of intermittent warming on the respiratory rate (CO₂ production) and the appearance of chilling injury of the fruits were investigated in relation to the time, duration and temperature of warming.
2. Warming treatment at 18°C for 7h after 3 days in storage reduced considerably the respiratory rates and markedly the chilling injury as compared with the control. These effects were reduced as the time of warming was delayed. Repeated warming at 2-days intervals was much more effective than a single warming.
3. The longer the duration of warming at 18°C applied after 4 days in storage, the greater the reduction of subsequent respiratory rate at 5°C and the delay of the appearance of chilling injury. The pronounced effects were obtained by warming for more than 24h.
4. When warming treatments above 18°C for 24h were performed after 4 days in storage for the fruits harvested in April, the respiratory rates decreased and the appearance of chilling injury was delayed gretatly with increase in the warming temperature. Chilling injury was evaluated 3 days after transfer of the fruits to room temperature at the end of 13 days in storage at 5°C. The fruits which had been warmed at 18 to 30°C showed only a slight injury and those at 36 to 40°C retained good eating quality although 60-90% of the control fruits decayed. However, warming at 42°C slightly caused a high temperature injury on the fruits. Essentially the same effects of warming were obtained for the fruits harvested in July, although on the control fruits chilling injury was found severe as compared with those harvested in April.

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Histological observations were made on the taro (Colocasia esculenta Schott cv. Dotare) tuber during development of internal browning due to chilling injury at 4°C. An attempt was also performed histochemically to detect phenolic substances and polyphenol oxidase associated with internal browning.
It was found that tannin cells were scattered in the epidermal and vascular tissues, and also in the inner parenchyma tissues. The shape of tannin cells was generally elliptical, but those in the vascular tissues was rectangular.
Before appearing of internal browning, slight browning occurred already in some tannin cells and surrounding parenchyma cells in each tissues. With progress of internal browning, numbers of browned tannin cells with granulation increased, and also the degree of browning of surrounding parenchyma cells augmented.
Further, in parenchyma cells, nuclei swelled, and leucoplasts and amyloplasts assembled around nuclei before appearance of internal browning. In the stage internal browning progressed, nuclei shrank with plasmolyses and collapsed accompanying with destruction of leucoplasts and amyloplasts.
Although phenolic substances of taro tuber were detected mainly in tannin cells, some of them were also found in secretory canals. Polyphenol oxidase was detected in the parenchyma cells, in addition to tannin cells and secretory canals.
As internal browning progressed, normal color reactions became indiscernible to the reagents for phenolic substances, while some reaction remained to the reagent for polyphenol oxidase.

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