Effects of four nitrogen doses, i. e. 0, 500, 1000 and 1500g/tree and zinc sprays (0.6% ZnSO4) viz. water spray, spray in February, spray in April and spray in February and April on fruit yield, quality and leaf composition of‘Hamlin’sweet orange were investigated. Growth parameters in terms of girth, height and spread were not affected significantly by N, Zn or their combinations. Significant increase in the yield of fruits by N and Zn treatments was recorded. Fruit weight and diameter were significantly decreased by N application, whereas they were improved by zinc spray. Percentages of juice and T. S. S. were significantly increased by N application alone. The percentage of acidity, reducing sugars and T.S.S./acid ratio were not significantly affected by N, Zn and their combinations. Significant increase in N content and reduction in Zn content of leaves due to N application were observed. Spray of zinc in April or in February and April increased foliar zinc content. No significant variation of P and K contents of leaves was observed due to N, Zn or their combinations.
The purpose of our investigation is to clarify the development of apple fruit in the early stages of its growth. Tukey (22, 23) observed that early fruit development was stimulated by high night temperatures. This observation suggested that night heating treatment would be a useful means for our purpose. Therefore, the effect of heating on fruit development, elongation and division of cells and development of seed and embryo were investigated. Eight-year-old ′Spartan′ trees were covered with plastic films and heated with oil heaters for 30 days beginnirg on the 7th day after full bloom. Night temperatures in night-heating treatment and day- and night-heating treatment were regulated at 23°C, and the day temperature in day-and night-heating treatment was kept 4°C higher than outdoor temperature. Under these conditions, the developments of fruit and seed were histologically investigated. 1. Little difference between night-heating and day-and night-heating treatments was recognized in the development of fruit. 2. Increase of diameter and weight of fruit was enhanced by heating, and the differences between control and heating were seen at their maxima 19 days afterfull bloom. However, no difference was recognized 35 days after full bloom and the size of fruit in heating was almost the same as in control. 3. Changes of cell diameter of fruit flesh in heating were similar to those in diameter and weight of fruit. In other words, the difference of these values between heating and control was at its maximum 19 days after full bloom but it became smaller with time and finally disappeared. 4. Cell division of fruit flesh was stimulated by heating. It ceased 40 days after full bloom in control while 10 days earlier in heating. 5. The development of seeds in fruit in heating showed a tendency to correspond to the increase in number of cell layers of fruit flesh. The seed in heating developed rapidly unitl the 30th day after full bloom, and ceased to develop thereafter. The seed development in control, however, continued unitl the 40th day after full bloom. 6. The development of embryos was stimulated by heating. The embryo in heating reached the spindle type stage ten days earlier than in control. However, the difference in embryo development between heating and control reached its maximum on the 30th to 40th days after full bloom. As described above, the development of fruit was stimulated by heating, and that was due to the enhanced cell enlargement and division of fruit flesh. In addition, a close relation was observed between the developments of fruit and seeds. However, it seems that the embryo has hardly any effect on the development of fruit. Therefore, it is surmised that the endosperm may be related to the development of fruit.
The close relationships between plant water stress and deficient water supply has long been recognized, but no work has been done on the water absorption linked to transpiration in pear trees which often suffer from water stress, for instance ′leaf burn′. In the present study, water balances (transpiration versus absorption) were investigated by employing a technique of auto-irrigator, the method by Impens et al. measuring transpiration and a heat pulse method, using Bartlett and Red Bartlett (Pyrus communis Rehder) on Pyrus serotina rootstocks and Nijisseiki (Pyrus serotina Rehder) on the same rootstock grown in a glass house. 1. The rates of daily water absorption (A) and transpiration (E) were greatest in Red Bartlett among 3 cultivars throughout the season. The seasonal changes in the ratio of (E) to (A) differed little with the cultivars. The value of the ratio exceeded 1 when daily mean VPD (vapor pressure deficit) was above about 9 mmHg or when total solar radiation was over about 400 cal cm-2 day-1. The critical rates of daily transpiration above which it exceeded daily water absorption were about 12g dm-2 day-1 in Bartlett, about 13.5g dm-2 day-1 in Red Bartlett and about 10.5g dm-2 day-1 in Nijisseiki. 2. From the sunrise to the noon, the rates of leaf transpiration exceeded those of water absorption, especially on fine days after the rainy season. From the afternoon to the night, the latter exceeded the former, resulting in the decrease in the extent of water stress. The ratios of the rate of water absorption to that of transpiration were larger late in August than early in July and early in August. The absorption lag in midday was greatest in Bartlett. The diurnal changes in the heat pulse velocities were rather more closely related to those of the transpiration, although they were intermediate between those of the transpiration and water absorption. 3. From these results, it is clear that a severe water stress in midday in pear trees, especially in Bartlett, is caused by the innate, inefficient water absorption, although a causal relation between the water absorption and the transpiration has not yet been clear. Further, some field conditions, especially, soil water deficiency, shallow rooting and root rot will promote the water stress on hot summer days.
Muskmelons were cultivated in a KUNTAN cultural system using rice hull charcoal, in which we can easily control the nutrient uptake of plants by lowering the concentrations of nutrient, and the effects of controlling the nutrient uptake on the plant growth and the fruit qualities were investigated. The effects of controlling the nutrient uptake varied with the seasons; remarkable effects were observed on the net formation and its callus development on the fruit surface in autumn, and on the growth of upper leaves in spring, although the weight and size of fruit were not affected. The net appearance was irregular and the callus developed vigorously when the nutrient uptake was not controlled, while the net appearance was uniform and the callus developed moderately when the nutrient uptake was depressed. The excessive growth of upper leaves was reduced by depressing the nutrient uptake. The content of soluble solid seemed to be increased by keeping the nutrient uptake at low level before harvesting. From these experiments, it is surmised that in order to obtain good quality fruit it will be better to depress the nutrient uptake in fruit enlargement and net initiation stages, to release the depression in net callusing stage and then to remove nutrient elements from culture solution for about 10 days before harvesting in the cultivation of muskmelon in hydroponics.
Relationship between organ growth and nitrogen accumulation was examined using “kuntan” (rice hull charcoal) culture. The growth rate of the fresh weight of the fruit rose markedly immediately after pollination and dropped near 30 days after pollination. Growth rate of fruit even at harvest time was about a half of maximum growth rate. It is suggested that the fruit has an ability of good enlargement throughout all growth stages. Increase in nitrogen content and dry weight in stems and leaves ceased within 30 days after pollination, while that in the fruit did not stop even at the harvesting stage. From these results, it is considered that nitrogen absorbed from the 30th day after pollination to harvest time is mainly incorporated into the fruit, and that photosynthate is actively transported to the fruit. Increase in fresh weight and dry weight of the fruit had no relation to nitrogen uptake. It is surmised, by considering the physiological aspects of the fruit growth, that the nitrogen uptake during the first 10 days after pollination affect the enlargement of the fruit, and that it is desirable to depress the nitrogen uptake past 35 days after pollination for the production of fruit with delicate flesh and high content of soluble solid.
Green soybeans (Glycine max Merr.) were grown to maturity in sand to determine relationships between salt tolerance of the plants and CaSO4 applications, using diluted sea water. Dry weight of the whole plant, fresh weight of pods and seeds, and number of pods and root nodules were greatest at 0 ppm Cl and decreased with increasing sea water concentrations. Growth at 0 and 250ppm Cl tended to be greater at 1mM CaSO4 than at 12mM CaSO4. There was no effect of CaSO4 treatments on the growth at 500, 1, 000 and 2, 000ppm Cl. Na and Cl in leaves and sand solution, and EC values of sand solution increased with increasing sea water concentrations. CaSO4 applications scarcely affected Na and Cl in leaves and sand solution, and EC values of sand solution at each sea water concentration. Ca in leaves, and Ca and SO44 in sand solution tended to be higher at 4, 8 and 12mM CaSO4 than 1mM CaSO4. In the current experiment, salt tolerance of green soybeans in sand culture was not enhanced by the application of CaSO4, indicating that the role of Ca to salt tolerance may differ with crops.
The morphologically unusual blind phenomenon which is found exclusively in Chrysanthemum morifolium Ramat. cv. Tenryu-no-asa widely grown for cut flowers, was shown to occur depending mainly on light intensity and duration of the vegetative growth phase. With decrease of light intensity below 60% of full day light, almost all of the flower buds stopped their growth and become blind. These results were peculiar to ‘Tenryu-no-asa’, and was not found in other cultivars tested.
This work was designed to study the effect of scale planting depth and fertilizer application on growth responses of parent scale and newly formed plantlet during scale propagation in the Easter lily under outdoor conditions. The dry weight to fresh weight ratio (D/F ratio) of the apical part of parent scale decreased more rapidly than that of the basal part. This tendency was more prominent on the light exposed scales or those fertilized than on those buried 3cm below the soil surface or those not fertilized, respectively. A little after the decrease of parent scale D/F ratio, the foliated scale bulblet ratio and the dead scale ratio increased simultaneously on the light exposed scales, whereas on the buried scales the dead scale ratio increased very slowly as compared with the increase of foliated scale bulblet ratio. No effect of fertilizer application was observed on the number of scale bulblets or the type of leaf development (plant type). Stem roots developed more rapidly and the number of stem roots was greater when scales were buried than when they were light exposed. Regardless of scale planting depth, number of foliage leaves on the shoots was greater on those fertilized than on those not fertilized. The size of scale bulblet was a little greater on the light exposed scales than on the buried scales at the earlier stage of the plantlet growth. In May, however, it was greater on buried than on the light exposed scales. No difference was observed between the D/F ratio of scale bulblet in bolted plantlets and those not bolted. The scale bulblet D/F ratio became greater as the scale bulblet grew. It was generally greater on those not fertilized than on those fertilized. The increase of scale bulblet D/F ratio during December to May was greatest on buried-fertilized scales. Thus, the fertilizer application on the buried scales is thought to be desirable for the promotion of scale bulblet growth, for it produces much more foliage leaves and stem roots which are essential for bulblet growth.
Pollen-tube growths of L.×elegans and L. regale in the style of L. longiflorum were examined as the representative case of ′half-growth interspecific incompatibility′ and ′short-growth interspecific incompatibility′, respectively. The pollen-tube growth of L.×elegans: The pollen-tube growth suddenly slowed down half-way down the lower portion of the style of L. longiflorum between three and four days after pollnation. By comparing with the tube growth in grafted styles, it was suggested that the pollen-tube itself rather than an interaction with the lower portion of the style, was responsible for the growth cessation, because the pollen- tube seemel to hene a critical period of time to grow. The pollen-tube growth of L. regale: From the facts that the pollen-tube in the style of L. longiflorum showed abnormal growth in contrast with that on stigma-exudate from L. longiflorum and that the growth was restored by injection of the exudate into stylar canal, it was indicated that the tube growth might be inhibited by an interaction between the pollen-tube and the canal tissue rather than by the contents of exudate.
Some experiments were carried out in order to promote sprouting of ‘Valeria’ cormels which are difficult to sprout when planted in early spring. Sprouting was promoted by storing the cormels in alternate dry (in the air) and wet (in moist sphagnum) conditions. If the dry and wet conditions were alter nated weekly, 3 cycles of wetting and drying before planting were sufficient to stimulate sprouting. Sprouting of the cormels was also hastened by presoaking them in a solution of 3% hydrogen peroxide for 3-24 hours just before planting. Similar results were obtained with other cultivars. These treatments had the same, beneficial effects on sprouting of cormels as artificial cracking of their shells, perhaps by causing some physical changes to the shells.
The degree of peeling easiness, i.e. easiness to remove the pellicle from the kernel in roasted nuts, was numerized using"peeling score". Peeling score was obtained by grading the peeling easiness of roasted nuts into four grades, based on the peeling time, the time required to peel off the pellicle from kernel with a knife without damaging embryo. The peeling score correlated to the peeling time of raw nuts (r=0.78**), and also to the strength of adhesive force between the pellicle and embryo of raw nuts evaluated by a rheometer (r=0.81**). The peeling score seemed to be useful to evaluate briefly the easiness of peeling off the pellicle in chestnuts, and to improve the efficiency of selection in chestnut breeding. The pellicle of Japanese chestnut was completely stripped by incubating the nut in sodium chlorite solution, which was known to solubilize phenolic compounds, without visibe damage to the surface tissues and pleats of the embryo. This fact suggested that the phenolic compounds of the pellicle played an important role in the adhesion between the pellicle and embryo. Free and polymerized phenolic compounds in the pellicle were determined separately by precipitaing the latter with gelatin. In Japanese chestnuts, which are difficult to peel off their pellicles, the amount of total phenolic compounds in pellicles increased rapidly with their maturation, and the increments were mainly composed of polymerized ones. The change in the amount of phenolic compounds with developmental stages of nuts corresponded to that of the peeling time of the pellicle from kernels, and the positive correlation of 0.89** was obtained between the amount of phenolic compounds and the peeling time in raw nuts. In Chinese chestnuts, whose pellicles are easily removed from kernels, the amount of total phenolic compounds contained in the pellicles of matured nuts was less than 50% of that of matured Japanese chestnuts. The increase of polymerized phenolic compounds with nut maturation was also less than that of Japanese chestnuts. These results suggested that the rapid increase of phenolic compounds, especially polymerized ones, with nut maturation might be involved in the relative easiness of peeling off the pellicles of chestnuts.
The effect of Ag+, applied in aqueous solution as AgNO3, on respiration, ethylene evolution and softening (three of ripening parameters) of Japanese persimmon (Diospyros kaki Thunb. cv. Fuyu) at various stages of development was studied at 25°C. Immediately after the calyx portion was cut away from the fruit, various concentrations of Ag+ was vacuum-infiltrated through the scar of the fruit. The results were summarized as follows. In stage I fruits (harvested July 20), at 0.1mM Ag+ inhibition was almost complete on all of three ripening parameters. At higher concentrations (0.5mM and 2.5mM), however, inhibition was far less on respiration and ethylene evolution than at 0.1mM. On the contrary, fruit softening was accelerated at higher concentrations. In stage II fruits (harvested August 16), the inhibitory effect of 0.1mM Ag+ on these three parameters decreased. In stage III fruits (harvested October 23 and November 13), 0.02mM Ag+ was effective on all of three parameters. On the other hand, 0.1mM and 0.5mM Ag+ accelerated the respiration, ethylene evolution and softening of the fruit.
Both acid phosphatase and ribonuclease activities increased markedly in close relation with the climacteric and the subsequent senescence in the pulp tissue of banana (Musa AAA group, Cavendish subgroup cv. Giant Cavendish). fruit The activity of acid phosphatase increased in both supernatant and precipitate obtained by centrifugation at low speed, e.g. 2, 000×g. At an earlier stage of ripening, however, the activity in the precipitate was much higher than that in the supernatant fraction. In the case of ribonuclease, the greater activity was found in the supernatant fraction throughout the period of ripening. Polyacrylamide gel electrophoresis separated acid phosphatase into 9 bands. There were essentially no qualitative differences in isozymes between supernatant and precipitate fractions, nor between unripe and ripe fruis, although some isozymes appeared to increase in activity during ripening. There was a gradual decline in the rate of 14C-leucine incorporation into protein of the pulp tissue of banana fruit during ripening, while there was a sharp increase in ribonuclease and acid phosphatase activities.
The differences in volatile components of grapes among 11 wine grape cultivars, grown in Japan were investigated. Grape musts were distilled with reduced pressure, extracted by dichloromethane, concentrated under vacuo and analyzed by gas chromatography. Comparatively larger amounts of volatiles were found in ‘Riesling’and ‘Chardonnay’ among white wine cultivars and predominantly in ‘Cabernet Sauvignon’ among red wine cultivars. The above cultivars contained abundantly volatile esters, alcohols and C6-compounds compared with other European and Japanese native cultivars. The volatiles found abundantly in all of cultivars were iso-butanol, iso-pentanol, 2-phenylethanol and C6-compounds, although methyl anthranilate was not detected in all of the cultivars examined.
To evaluate th edifference in flavor between ‘Koshu’ and ‘Riesling’, the formation of C6-compounds in grape berries of different maturity and in the musts obtained by crushing berries under various conditions was investigated. 1. In ‘Riesling’ berries, the amouts of trans-2-hexenal and 1-hexanal reached the maximum value when sugar content reached the maximum with maturity, and decreased thereafter. While, 1-hexanol and trans-2-hexenol which were found only in small amounts, increased with time throughout ripening. 2. In ‘Riesling’ must, trans-2-hexenal and 1-hexanal increased rapidly until 60 minutes after crushing and then decreased, while, 1-hexanol and trans-2-hexenol showed a steady increase with time, although their amounts were small. The pressence of 100ppm SO2 in the must remarkably depressed the formation of C6-compounds, at least, during 120 minutes after crushing except trans-2-hexenal, which was less depressed in its formation and increased with time. 3. The effects of SO2 concentration on the formation of C6-compounds in the must were somewhat different between ‘Koshu’ and ‘Riesling’. In ‘Koshu’, almost no C6-compounds except trans-2-hexenal, which was found at about 250μg/l, were formed in the presence of 200 to 1, 000ppm SO2. In ‘Riesling’, however, 1-hexanol and trans-2-hexenol were formed, though slightly, in the presence of 200 to 1, 000ppm SO2 in addition to trans-2-hexenal. 4. Heat treatment of berries at 65°C for 10 to 15 minutes depressed completely the formation of C6-compounds in both cultivars, except that in ‘Riesling’, little 1-hexanol and trans-2-hexenol were formed even by the treatment over 65°C for 15 minutes. 5. The berries were crushed in different solvents out of contact with air. C6-compounds were formed in large amounts when crushed in distilled water, in less amounts in the presence of 200ppm SO2 and in the least amounts in dichloromethane. In distilled water, ‘Riesling’ formed more C6-compounds than ‘Koshu’ irrespective of the addition of SO2. The amount of C6-compounds in dichloromethane might be supposed to be the original content in fresh berries. Thus, in fresh berries, C6-aldehydes were higher in ‘Koshu’ than ‘Riesling’, while, there was no difference in C6-alcohols between two cultivars.
To clarify the flavor characteristics of ′Koshu′ grape, volatile components from the must were identified by gas chromatography and coupled gas chromatographymas spectrometry. Relation between volatiles, especially terpenic constituents, of the must and wine were discussed in comparison with other grape cultivars. Twenty six compounds were identified in the flavor fraction of ′Koshu′ grape must removed the acidic volatile components. Pyridine and 2 phenols, 2, 6-di-tert-butyl-4-methylphenol and tert-butyl-2-methoxyphenol, were newly found in the must as flavor components of grape. A large amount of terpinen-4-ol and a trace of linalool were also found in Koshu grape as main terpenic components. Terpinen-4-ol was detected more abundantly in ′Koshu′ grape than in other grape cultivars. Furthermore, the odor unit of the compound was close to 1 in the must and wine of ′Koshu′ grape. Based on the above results, it was concluded that terpinen-4-ol is one of the characteristic compounds in flavor components of ′Koshu′ grape.