Showing papers in "Journal of The Japanese Society for Horticultural Science in 1973"

Studies on the Translocation of Photosynthates in Satsuma Mandarin

Abstract: Effects of water stress and H-ion concentration on the rate of translocation of 14C-labeled photosynthates in Satsuma mandarin trees were studied.When the root growth was suppressed, translocation to the remaining plant parts (growing areas) was decreased and more 14C was accumulated in the leaves.In the plot of pH 3.0 a little decrease in the rate of translocation to fruits was observed, while in the plot of water stress the accumulation of 14C in the juice was heavily decreased.Water stress caused an increase in total sugar concentration of the juice. It seems likely that this was partly a result of the concentration effect arisen from water stress. However, in this case other factors such as polisacharide metabolism may also play an important role in the process of sugar accumulation in the juice.

Fruit Development of Peach and Japanese Pear as Affected by Destruction of the Embryo and Application of Gibberellins

Abstract: The effect of gibberellins on the setting and subsequent growth of peach and Japanese pear fruits has been studied after the embryos were destroyed or the seeds were removed mechanically at different stages of fruit development.1. In the peach, 14-year-old ′Okubo′ trees were used. Among the growth regulators tested, GA3 was only effective on the fruit set and development following destruction of the embryos.2. In young stages of fruit development, that is 5 and 9 weeks after bloom, the application of GA3 to embryo-killed peach fruit resulted in 8 and 6 per cent set of the mature seedless fruit, respectively. In advanced stages, however, embryo destruction 13 weeks after bloom, with or without application of GA3, resulted in 93 and 85 per cent set of the seedless fruit at maturity.3. Injury to the fleshy pericarp without destruction of the embryo had little effect on the rate of fruit set when treated 5 and 9 weeks after bloom.4. Seed removal and gibberellin application to the cut surface of the Japanese pear fruit, cv. ′Shinseiki′ were done at five different stages of fruit development. Only GA4+7, applied as a lanolin paste to the cut surface of seed-removed fruit, was effective in sustaining further growth of the fruit when treated 3 and 5 weeks after bloom.5. At the stage of 7 weeks after bloom, however, not only GA4+7, but also GA3 application began to work effectively to sustain the treated fruit. In late stages subsequent to 9 weeks after bloom, GA3 in lanolin was more effective than G GA4+7 on maintaining the seedless fruit.6. It was also found that a large number of treated fruit were infected with rot and fruit splitting in late stages of fruit development and they abscised before ripening.

Inhibitors Concerned in the Dormancy of the Gladiolus Corm

Abstract: 1) The methanol extract of gladioli corms was purified with ethyl acetate and sodium bicarbonate. The final acidic fraction was paper and column chromatographed, then three crude inhibitors were separated.2) Inhibiting activities of inhibitors I and III were examined by the dripping of the solution on corms and by soaking cormlets in it. The inhibiting activity of inhibitor III was slightly higher than that of inhibitor I.3) Inhibitor II was identified as abscisic acid based on its UV absorption on the paper chromatogram, the Avena coleoptile assay and its O.R.D, measurements. Abscisic acid inhibited sprouting of the bud in gladiolus cormlets at a dosage of 10-4 M.4) Purification and identification of inhibitors I and III are being carried out. Synergistic action of inhibitors with abscisic acid is also discussed.

Studies on the Mechanism of Ethylene Action for Fruit Ripening

Abstract: This study examines the role of glycolysis in respiration of banana fruits stimulated by ethylene.Monoiodoacetate inhibited the respiration of banana peel sections in the absence of ethylene, and the inhibitory effect was strengthened in the presence of the gas (100μl/l). The experiment of incorporation of glucose-1-14C, and glucose-6-14C to carbon dioxide showed a conversion of the pathway from HMP to EMP with the advance of age in peel sections. But the period of alternation of the pathway did not coincide with that of the respiratory increase. However the incorporation rate of each penetrated glucose-14C to carbon dioxide changed with the increase of the respiration rate of peel sections.While the content of reducing sugar increased continuously in pulp and peel, the levels of glycolytic intermediates such as G-1-P, G-6-P, F-6-P, F-1, 6-diP, dihydroxyacetone P and pyruvate corresponded to respiratory changes of climacteric in pulp tissue. Especially, the change of F-1, 6-diP content was remarkable among the intermediates. Although the respiration of peel sections decreased after removal of ethylene, the levels of G-6-P and F-6-P were higher in this tissue than in the tissue in which the respiration was continuously enhanced with ethylene. On the contrary, this tendency was reversed for F-1, 6-diP, dihydroxyacetone P and pyruvate.These results suggest that the respiration climacteric with ethylene may be related to the enhancement of glycolysis and the step between the F-6-P and F-1, 6-diP may be concerned with a regulation of this pathway in pulp and peel of banana fruits.An alternation of temperature caused a change of respiration in green banana fruits. While the respiration was stimulated at 30°C, the levels of G-6-P and F-6-P decreased and other intermediates (F-1, 6-diP, dihydroxyacetone P, phosphoenol-pyruvate, and pyruvate) had no change. This data indicates a difference of metabolism of glycolysis between the respiration climacteric and activated respiration by temperature alternation.

Studies on Clonal Propagation of Cattleya through Tissue Culture Method

Abstract: 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.

Effects of Micro-meteorological Elements and Positions in the Tree Crown on the Development of Shoots, Leaves and Fruits of Satsuma Mandarin

Abstract: 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.

Fundamental Research on the Suna Saibai (a type of sand culture)

Abstract: It is generally accepted that the population of subterranean micro-organisms having a direct concern with the nitrogen metabolism of plants grown in the sand is rather scarce as compared with those in ordinary farm soil, and the ammonification as well as the nitrification processes in sand, in consequence, has been considered to be generally small. For raising of plants in sand, therefore, it is quite necessary to make clear the nitrification processes which take place in the sand, and also to get more advanced knowledge concerning the fertilizing method of nitrogen in the Suna Saibai (a type of sand culture). In this connection, the author carried out studies on the nitrogen metabolism in the Suna Saibai, e.g., the influence of water content in the sand, of the concentration of nitrogen in the sand, and the effect of applying clay (bentonite) to the sand under 30°C constant temperature condition.1. The ammonification and the nitrification in the sand took place quite sufficieutly. The nitrification of urea was detected 4 days after application.2. The effect of the water content of the sand upon the ammonification was relatively small, and when the concentration of applied nitrogen was 125 or 333ppm, the ammonification at the 4th day attained ca. 65 to 85% of total nitrogen.3. When the concentration of applied nitrogen was 125ppm, the nitrification was not influenced at all by the water content of the medium. The rate of nitrification per the total nitrogen attained ca. 95 to 100% at the 20th day. When it was 333 ppm the effect of the water content became detectable only after 12 days. The nitrification occurred earliest in the plot with a water content of 30ml per 150g of the sand, next in the plot of 20ml, and finally those of both 10 and 40ml. Namely, in the plots of 10, 20, 30 and 40ml water content, the nitrification attained to 35, 60, 70 or 40% on the 12th day and 60, 90, 95 or 60% of total nitrogen, respectively on the 20th day.4. When the water content was the most favorable (30ml of water per 150g of sand, i.e., ca. 60% of the maximum water holding capacity), the ammonification and the nitrification were remarkably influenced by the concentration of applied nitrogen, and the higher the concentration, the later these occurred. The rates of ammonification at each level of nitrogen concentration (125, 250, 500 and 1, 000ppm) were 80, 65, 50 and 35% on the 4th day, and the nitrification on the 16th day was 100, 95, 70 and 50% respectively.5. The added bentonite was refinitely effective in each of three different kinds of nitrogen levels, (250, 500 and 1, 000ppm), inducing good effect on the ammonification and the nitrification. In the case of 250ppm of nitrogen and 30ml water per 150g of sand, the effect of supplying bentonite at four different levels (0, 0.5, 1.5 and 4.5g) could be noticed on the 12th day after application when the population of soil organisms was considered to become sufficiently large. The nitrification rates on the 16th day were 45, 80 and 100%, respective to the increased application of bentonite upon pH was as follows: When 4.5g was added, pH was 7.2 at about 60% nitrification (on the 16th day). On the other hand, when the bentonite was not added at all, the pH value remained very low, being 4.6 at about 45% nitrification (on the 16th day). Thus the effect upon the ammonification, the nitrification and upon pH caused by the addition of bentonite was quite evident.

Influence of Iron, Boron, and Sugars on Viable Seed Production in Excised Ovule Culture in Petunia hybrida

Abstract: The present investigation deals with in vitro growth of ovules on a half of the placenta of Petunia hybrida, W166H×K146BH (each clone is self-incompatible), with special reference to the influence of iron, boric acid, and sugars. The culture medium of NITSCH (1951), modified by the addition of 500mg/l KNO3 and 80mg/l NH4NO3, was used as a basal medium.The optimal initial hydrogen-ion concentration was at pH of 4.5-5.0 in the basal medium and at pH of 6.0 in the basal medium with Fe-EDTA at an iron concentration of ca. 2.5ppm instead of ferric citrate.The number of viable seeds per ovary increased with an increasing concentration of ferric citrate from 10 to 40mg/l in the basal medium. Iron complex Fe-EDTA composed of 50mg/l FeSO4•7H2O and 40mg/l disodium ethylenediaminetetraacetate, dihydrate (Na2-EDTA) was also an effective compound and was favorable for the viable seed production.10mg/l or above boric acid should be added to the basal medium containing either ferric citrate or Fe-EDTA. Medium containing 50mg/l boric acid was superior for the viable seed production to those with any other concentration. The efficancy of boron was influenced by the organic forms of iron. The medium with Fe-EDTA at an iron concentration of ca. 2.5ppm was superior to that with 10mg/l ferric citrate.Basal medium containing 7.5 per cent sucrose or 5 per cent fructose produced the maximal viable seeds and that containing a mixture of sucrose and fructose or sucrose and glucose was inferior to the basal medium.From these results, experiments were conducted to clarify the interaction among three components, iron, boric acid, and sugars. About 5-6 normal seedlings with two cotyledons and roots per ovary were obtained in the medium containing ca. 10 ppm Fe as Fe-EDTA, 25mg/l boric acid, and 7.5 per cent sucrose. This was about six times as the number of seedlings produced in the basal medium.In the basal medium containing fructose instead of sucrose, however, the higher concentrations of boric acid and/or iron failed to bring about the noticeable effect.

Histochemical Changes in the Apical. Meristem of Bulb of Lilium longiflorum THUNB. during the Storage

Abstract: 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.

Effects of Leaf Age and Defoliation on Tree Growth, Flowering and Fruit Set of Satsuma Mandarin

Abstract: 1. To observe the effects of spring leaves (spring cycle leaves of the current year) or old leaves on flowering and fruit set, experiments were conducted with secondary scaffold branches of Satsuma mandarin (Citrus unshiu MARC.) trees grown under field conditions. Treatments were as follows; (1) all spring and old leaves were removed from the shoot (no-leaf plot); (2) all old leaves were removed and enlarging spring leaves were retained (new-leaf plot); (3) developing spring leaves were removed and old leaves were retained (old-leaf plot); (4) both spring and old leaves were kept intact (control plot).When the above treatments were applied from early spring to the end of July, old-leaf plot gave the best development of floral organs at full bloom. These development of floral parts was reduced in the following order, no-leaf, control and new-leaf plot. Fruit set and fruit growth for the first month after blooming were also greatest in old-leaf plot. The ranking for these criteria was: control>no-leaf> new-leaf plots. Not only was the development of floral organs in new-leaf plot the poorest among the four plots, most of the fruits abscised in this plot immediately after bloom. In the remaining three treatments marked fruit drop was observed in early July, particularly, in old-leaf plot. This observation suggests that old leaves play an important role for fruit set and growth during the first month after blooming, but that new leaves are required for sustained fruit growth.When treatments were started two weeks after bloom, fruit set was best in control plot followed in order by new-leaf and old-leaf plots; almost all fruits were shed in the no-leaf plot. Fruit growth in control and new-leaf plots was superior than that in old-leaf and no-leaf plots.When treatments were made in August, fruits remaining on the trees in no-leaf and old-leaf plots decreased to 48.9% and 63.6%, respectively, but fruit sets in both new-leaf and control plots remained unchanged (100%). Treatments initiated during September resulted in no fruit abscission in any plots.2. With 3-year-old Satsuma mandarin trees grown in the pots, the effects of leaf age, temperature and light intensity on the development of floral organs were investigated. Leaf removal was done as described in the above experiments, while the temperature was kept at 23°C and 30°C in the conditioned growth chamber and the light intensity was varied from 10 to 100% of full sunlight. Flowering was accelerated at 30°C, but floral organs developed better at 23°C. At both temperatures, fresh weight of floral organs in the first inflorescence was smallest in new-leaf plot compared to the other treatments. Light intensity was no significant effect on the development of floral organs. At three light intensities, fresh weight of floral organs was smallest in new-leaf plot compared to the other treatments. Tree growth was suppressed proportionately with decreasing light intensity in all treatments. As the light intensities decreased from 100% to 10%, the percentage of old leaves abscised increased; that of the control plot being greater than in the old-leaf plot.

Studies on the Flower Formation in Tomatoes and Eggplants

Abstract: Tomatoes1) Tomatoes, cv.‘Shin-Hogyoku No. 2’were grown under constant temperature regimes of 17, 15 and 13°C and at two levels of N, P and K in 1964 to study the interaction of those factors on the differentiation and subsequent development of flower buds.2) The plant growth both in bed soil at 2(NPK) (high level of fertilizer) and in volcanic loam at NPK (low level of fertilizer) was promoted at 17°C and restricted in the lower temperature ranges of 15 to 13°C. The seedlings in the 2(NPK) plot grown under the same temperature were larger than those in the NPK plot. The growth was found to be most remarkable at 17°C in the high level of fertilizer as in the previous report (7).3) The differentiation and its subsequent development of flower buds both in bed soil at 2(NPK) and in NPK plots were accelerated at 17°C and retarded in the lower temperature ranges of 15 to 13°C.4) The differentiation and its subsequent development of flower buds in bed soil at 2 (NPK) plot were earlier than those at NPK plot. The most favorable conditions for them were combination of temperature range of 17°C and high level fertilizer (bed soil at 2(NPK)).5) The number of flower buds per plant was increased at 17°C in high level of fertilizer (the bed soil at 2(NPK)) plot, and decreased at the lower temperature of 15 to 13°C. At the lower level of fertilizer (NPK) plot, it was fewer and there was no difference among the temperature ranges of 17, 15 and 13°C.6) From the results in 1963 and 1964 of tomatoes, it was found that effect of high level of fertilizer on the growth, the differentiation and development of flower buds were most marked at 17°C in the temperature ranges from 30 to 13°C (30, 24, 17, 15 and 13°C).Eggplants1) Eggplants, cv.‘Kisshin No. 2’were grown under constant temperature regimes of 30, 24, and 17°C and two levels of N, P and K in 1965 to study the interaction of those factors on flower bud differentiation and their subsequent development.2) The plant growth both in bed soil at 2(NPK) and in volcanic loam at NPK was promoted most remarkably at 30°C and restricted in the temperature ranges of 24 to 17°C. The seedlings in the 2(NPK) plot were larger than those in the NPK plot.3) The differentiation and its subsequent development of flower buds both in bed soil at 2(NPK) and NPK plot were promoted at 30°C and retarded in the temperature ranges of 24 to 17°C.4) The differentiation and its subsequent development of flower buds in the 2(N PK) plot were earlier than those in the NPK plot. The morphological differentiation of flower buds was not found at the temperature of 17°C in low level of fertilizer (NPK) in this experiment.5) The number of flower buds both in bed soil at 2(NPK) and in NPK was greatest at 30°C and fewer at 24 and 17°C. The 2(NPK) plot had much more flower buds than the NPK plot.6) In case of eggplants, the effect of high level of fertilizer on growth and the differentiation, development and number of flower buds was small under the low temperature of 17°C, but it was very great under the high temperature of 30°C.

Studies on Growth of Japanese Pear Fruits

Abstract: 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.

Effect of Temperature on the Translocation of Photosynthates in Cucumber Plants

Abstract: The purpose of the present study was to know diurnal changes of air temperature favourable for the raising of cucumber seedlings. Activities of assimilation and distribution of photosynthates in plant parts were measured by a G.M. counter using tracer techniques.Seeds of cucumber, variety “Natsu-Sairaku No.3” were sown on Jan. 16, 1971, and transplanted into plastic pots, 12cm in diameter, on Jan. 28 at the stage of cotyledon expansion. Then the pots were placed in the phytotron which day and night temperatures were programmed with consideration of the diurnal change of natural temperature. The day temperature was set from 10:00AM to 2:00PM and the night one from 2:00AM to 6:00AM. The shift between day and night temperatures were made as moderate as possible. This temperature regulating system was called “the gradient temperature control system”.To clarify the effect of day or night temperature, temperatures were maintained at 28°C for the day temperature and 14°C for the night temperature (abbr. 28°-14°), 25°-14°, 20°-14°, 15°-14°, and 25°-18°, 25°-14°, 25°-10° (Fig.1). Seedlings raised under the condition of 25°-14° were taken as control.On Feb. 25, whole plants were exposed to 14CO2 for 60 minutes in the artificial light, 18, 000lux at the plant level, and the distribution of 14C-radioactivities in the plant is determined immediately after 14CO2 feeding (Exp. A) or after being kept for one night at the corresponding night temperature (Exp. B). The experiments of A and B were done separately.When the plants were raised at 14°C for the night temperature, the effect of day temperature on growth was as follows; the growth shown in dry weight at 28°-14° was almost the same as that of control (25°-14°), but at 20°-14° and 15°-14°, those were 80 and 70% of control, respectively (Table 2). Senescence of lower leaves of plants grown at 28°C during the day and 14°C at night was accelerated in comparison with control (Fig. 2).When the plants were raised at 25°C for the day temperature, the effect of night temperature was as follows; at 25°-18°, plants grew heavier and broader in the leaf area (Table 2), and higher (Table 1) than control (25°-14°), and senescence of lower leaves was accelerated (Fig.2). Their photosynthetic activity (14C-radioactivity per dry weight) was lower than control, and dry weight per unit leaf area (cm2) was the lowest (Fig.3). The translocation of photosynthates in the plants grown at 28°-14°, 25°-14°, and 20°-14° was greater than in those grown at 15°-14°. The translocation of photosynthates in the plants grown at 25°-18°, 25°-14° was greater than in those grown at 25°-10°. However, the acceleration of respiration rates in plants grown at 25°-18° resulted in a release of CO2 from 14C-photosynthates outside of the plant.In so far as seedlings were raisen under the gradient temperature control system, the best possible growth of seedlings from the view point of 14CO2-assimilation and translocation of photosynthates was given when they were grown at 20°-28°C for day- and 14°C for night-temperature. Among them, when seedlings raised at 28°C day temperature, the senescence of lower leaves was promoted and at 20°C day temperature, the production of dry matter was lower than at 25°C or 28°C day temperature. Therefore, the alternation of temperature at 25°C for the day temperature and 14°C for the night temperature was most suitable for the healthful growth of seedlings.

Fruit Growth of Satsuma Orange under Controlled Conditions

Abstract: The experiment was conducted with young trees of Satsuma Orange (Citrus unshiu MARC.) under artificially controlled climates (Phytotron). Though the average day temperature common to all 3 treatments was 18°C, the amplitudes of diurnal fluctuations in temperature were 0°C (daytime 18°C-nighttime 18°C), 10°C (23-13) and 20°C (28-8) respectively (Table 1).1. The difference of the fruit enlargement between 0°C (18-18) and 10°C (23-13) treatments was not recognized. On the contrary, under 20°C (28-8) the depression in fruit enlargement was found significantly in the former half of Stage 3 of fruit growth, but in the latter half of Stage 3 the fruit continued to grow without color development and developed the greatest fruit diameter at the end of the experiment. Greater amplitudes of diurnal fluctuation in temperature did not accelerate the fruit growth rate at all time of Stage 3 (Fig. 1, Table 2).2. Color development in the fruit rind was influenced by diurnal fluctuation in temperature. The earliest and brightest color development was observed under 0°C (18-18) and then 10°C (23-13). The palest color was found under 20°C (28-8) Color development in the fruit rind was affected not only by low night temperature, but also by high daytime temperature (Fig. 2, Tables 3, 4). The temperature 18°C at the daytime and at night seemed to be favorable for the decomposition of chlorophylls and production of carotenoids. Greater diurnal fluctuation in temperature was not necessary for the promotion of rind color development.3. Free acid concentration in the juice was influenced by diurnal fluctuation in temperature. Less diurnal fluctuation tended to produced lower acid fruit. However, acid concentration was influenced strongly by the night temperature rather than by diurnal fluctuation, that is, higher night temperature produced lower acid fruit (Fig. 4).High sugar concentration in the juice resulted from 0°C (18-18) and 10°C (23-13) treatments, but under 20°C (28-8) it was very low. Greater diurnal fluctuation in temperature did not promote the accumulation of sugar in the fruit (Fig. 4).The total soluble solids-acid ratio was the highest under 0°C (18-18). Less diurnal fluctuation in temperature produced earlier and better marketing quality (Fig. 5). Diurnal fluctuation in air temperature was not necessary for the production of better quality fruit of Satsuma orange.

Studies of the Manganese Excess of Carnation

Abstract: An investigation was made to determine the effects of nitrogen forms, and pH in soils having low and high levels of Mn on the growth and flowering of carnation cv.‘Yosooi’. Treatments were arranged factorially involving Iwata and Kawazu soils, NH4-N from (NH4)2SO4, and NO3-N from NaNO3, at high and low pH levels. The number of flowering plants, plant height, and top fresh weight decreased in the Kawazu soil having a high level of Mn. The time of flowering was markedly promoted by NH4-N. The number of flowering plants, and the top fresh weight decreased at the low pH. In the later stage of growth tip burn symptoms were found on leaves of plants grown in the Kawazu soil at the low pH. The Mn in the various parts of plants grown in the Kawazu soil was markedly increased at the low pH, but was not affected by the N forms. The content of N, P and K, and the Fe/Mn in the leaves were slightly higher in the Iwata soil, while the Mg and Al were high in the Kawazu soil. At the low pH the Al in the leaves increased, while the P, K and Ca, and the Fe/Mn decreased. At the termination of the experiment the water soluble, exchangeable and easily reducible Mn increased in the Kawazu soil. The available Mn increased at the low pH, while the easily reducible Mn decreased. The various forms of Mn in the soil were not affected by the N forms. The Na, Ca, Mg and Al increased in the Kawazu soil at the termination of the experiment, while the P decreased. The NH4-N increased in the NH4-N treatment, while the NO3-N and Na decreased. The K and Al, and the value of EC increased at the low pH, while the NO3-N, P, Na and Ca decreased. From these results, the growth retardation and tip burn symptoms of carnation seemed to be highly correlated with the Mn in the plants and soils, and disassociated with the P, K, Mg and Al in the leaves, and the NH4-N, NO3-N, Na, Mg, P and Al in the soils.

Effect of Foliar Spray with Nitrogen, Phosphorus and Potassium on Flowering and Fruiting Behaviour of Kagzilime (Citrus aurantifolia SWINGLE) Grown in Dry Farming Areas of India

Abstract: The experiment was conducted in the Horticultural Garden, Faculty of Agriculture, Banaras Hindu University, during the years 1968, 1969 and 1970. N, P, and K in the form of urea, double superphosphate and potassium chloride at 1 and 2 per cent oncentrations were sprayed singly and in combinations. Urea spray had significant effects in increasing the duration of flowering and fruiting, and percent fruit set and fruit drop, and also in decreasing the percentage of fruit retention and period of maturity in both the spring and summer flushes except the percent fruit drop and fruit retention which were affected significantly by 2 per cent urea spray in spring flush only. Double superphosphate spray at 1 and 2 per cent concentrations significantly increased the duration of fruiting in both the flushes, duration of flowering and per cent fruit set in summer flush and duration of flowering and percentage of fruit set under 2 per cent in spring flush only. Potassium chloride spray at 1 and 2 per cent concentrations significantly increased the duration of flowering and fruiting and percentage of fruit set in summer flush, and also duration of fruiting and period of maturity under 2 per cent spray in spring season. Combinations of N×P, N×K, and P×K also showed significant effects on duration of fruiting and percentage of fruit set.

Studies on the Utilization of Reserve Substances by Vegetative and Reproductive Organs of the Grape, Vitis spp.

Abstract: The degree of competition for stored reserve substances and their utilization during flowering and berry setting periods in one-year-old grape vines were examined. The uppermost bud on each cutting was allowed to remain and others were cut off. Each experimental plant bore a single inflorescence on a woody cane. Plants were grown in a glasshouse in full sunlight during spring.1 To assess the relative effectiveness of leaves, their position and time of defoliation on berry set, experiments were conducted with Campbell Early grape cuttings whose original weight was 15g. To assess the time of leaf removal on set, leaves were removed at three intervals: at bud break, 15 to 10 days before bloom, and full bloom. The manner in which leaf removal was accomplished was:(1) several leaves basal to a single flower cluster were left while the distal ones were removed (basal lot), (2) all leaves basal to flower cluster were removed and the distal leaves left intact (distal lot), (3) all leaves were removed (complete defoliation lot), and (4) all leaves were left intact (control lot). The average percent of fruited plants per treatment three weeks after full bloom was highest in the basal lot (42.2%). The effectiveness decreased in the following order: complete defoliated lot (24.5%), control lot (5.6%) and distal lot (2.2%). The presence of leaves is evidently not a prerequisite for berry set, although all berries in complete defoliated lot were shed before harvest time. This behavior suggests that the presence of leaves is evidently important for berry enlargement. Furthermore, the effects of leaf number and leaf position to flower cluster on berry set were examined. The presence of only 1 or 2 leaves basal to flower cluster was sufficient to obtain 40-60% of fruited plants. With increased number of leaves distal to flower cluster, the number of fruited vines decreased, which suggests that the competition for reserve substances and photosynthates during the critical period after anthesis may be an important factor for the fruit set and subsequent development.These experiments emphasize the interaction between vegetative growth and development of reproductive organs on utilization of the reserve substances in grape. The poor fruit set in cuttings in which expanding immature leaves were left above flower cluster is probably attributable to the diversion of reserve substances and photosynthates neccessary for setting and subsequent development.2 In experiments with the cv. Delaware whose original cutting weight was 15g, the effects of defoliation and pinching of shoot and pruning of the tip of young inflorescences on subsequent flower and ovary development were investigated. Defoliation resulted in good flowering response and development of ovary while pinching and tip pruning of inflorescences had none. Ovary development for one week after bloom was enhanced by leaf removal as compared to the control vines in which ovary growth was reduced by the presence of immature leaves. Although the fruitlets on cuttings from which all leaves were removed was twice that of intact cuttings, they abscised prematurely. When 1 or 2 leaves were left at a node below the flower cluster, 20-30% of the treated plants fruited.

Effects of Nutrition before Blooming on the Flower Cluster Development and Berry Set of Grape Vine

Abstract: 1 Effects of different application time of nitrogen from January to April on the vine growth and the flower cluster development were studied with 3-year-old Delaware grape vines grown in soils in relation to the nitrogen absorption, assimilation and translocation2 Well developed flower clusters were found to be fewer on the March or later applied vines than on the January or February applied vines, though no marked difference of berry set existed among treatments Shoot growth of the late applied vines was very slow in its beginning and at the stage of flower development, but became rapid toward the blooming time as compared with that of the early applied vines3 The early applied nitrogen was absorbed soon by rootlets even when the soil temperature was still under 5°C and stored there mainly as protein It was then, transported up to the buds with the commencement of the bleeding period namely nearly 20 days before bud burst Thus in the early applied vines the nitrogen content of rootlets began to decrease rapidly, while it increased even after the bud burst in the late applied vines4 When the sap which was bled out at the cut end of the basal part of the shoot was analyzed, it contained more inorganic nitrogen in the late applied vines than in the early applied vinesMoreover, it held less amide, more glutamic acid and less bases of nucleic acid related substances in the former than the latter

On the Rest and Budding of Bulbous Iris cv. Wedgwood

Abstract: The rest period of iris bulbs (cv. ‘Wedgwood’) and the effect of temperature on breaking of the rest were studied.Leaf formation at apical region suspended from mid June to mid August, and bulb weight increased until mid July continuously under the natural condition at Ina district.Bulbs harvested in Kyoto on June 6 and stored at 20°C on and after July 6 did not increased the number of new leaves until August 3, and increased thereafter. Bulbs which were shifted from 20°C to 15 or 10°C on August 3, as well as those shifted to 10°C and returned to 20°C after 28 days, on August 31, also formed new leaves thereafter. Bulbs shifted to 30°C, however, did not produce new leaves until August 31. The first leaves of bulbs stored at 20°C did not grow until August 3, and then began to elongate excepting those of bulbs shifted to 30°C. The latter bulbs began to elongate the first leaves on and after August 31.Bulbs stored at 20°C were planted in wet sand at 20°C on July 6, August 3 and 31, September. 28 and October 26. They began to sprout on September 10, 9, 16, October 8 and 31, respectively. The bulbs planted on August 3 at 10, 15, 20, 25 and 30°C required 37.6, 26.6, 36.6, 73.6 and 65.0 days from planting to 100% sprouting. On the other hand, those planted on September 28 took 12.4, 9.2, 9.8, 9.8 and 8.6 days, respectively.The results mentioned above, might indicate that the rest of ‘Wedgwood’ bulbs stored at 20°Cwas broken in late August. The bulbs seemed to be in the late phase of rest sprouted soon at about 15°C and very late at 25 and 30°C. After the rest had terminated, the bulbs sprouted in a short period at any temperature from 10 to 30°C.

Physiological Studies on the Extension of Shelf-life of Tomato Fruits

Abstract: 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.

Studies on the Mechanism of Gall Formation with Root-knot Nematode

Abstract: (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.