Carbon-14C dioxide was administered to a bearing tree (an unsprayed control) and a non-bearing tree (fruit bud fromation inhibited by application of a gibberellic acid spray) during the bud formation stage (April 14-15), when the photosynthetic activity in old leaves resumed in early spring. Samples were taken from various parts of the experimental trees one week (April 21) and 4 weeks (May 12, full bloom stage) after the 14CO2 was supplied, and the distribution of radioactivity in the harvested trees was examined. 1. The newly emerging growth organs (floral-, and new shoot-organs) of the bearing tree contained 18.9% of the total 14C activity one week after application, and 35.4% four weeks after; those of the non-bearing tree contained 5.4%, increasing to 43.8%. The percentage of 14C in the floral varied little, from 16-17% at week 1 to 15% at week 4, but in the new shoots it increased greatly, from 2-3% a tweek 1 to 20-43.8% at week 4. 2. The decrease in the amount of 14C in the available carbohydrate fraction of old leaves in the non-bearing tree from the first week to the fourth week was much larger than that of the bearing tree. It was concluded that reserved carbohydrate is applied principally to development of the floral organ, and that carbohydrate produced by old leaves in spring is applied principally to the development of new shoots during the period from the sprouting stage (April 21) to the full bloom stage (May 12).
Changes in volume and composition of exudates from cuts made on grapevines (Vitis vinifera L. cv. Muscat of Alexandria) from mid-Feb, to May, 1978, were determined. The amount of exudate reached a maximum of 525ml/vine on Apr. 11. The pH of the exudate became lower as the volume increased, while the sugar concentration changed proportionally with volume, indicating a dilution effect. The amount of exudate fluctuated diurnally, being greater at night than during the day. The pH of the exudate declined quickly at the end of the day.
Action of CCC [(2-chloroethyl) trimethyl ammonium chloride] for berry development of the first crops and induction of the second crops of ‘Kyoho’ grapes under open culture in the temperate areas like Japan was studied. Develpment of the first crops bearing on the primary shoots, i.e., maturation of the crops, was delayed by CCC. The delay was discussed in relation to the lower respiratory activities, the lower contents of sugar (refraction levels) and the lower values of pH compared with the control plants. The harvest of the first crops of the primary shoot treated by CCC was carried out in ca. 40 days after harvest of the control crops. As CCC inhibited flower shatters and berry drops of the first crops, the berry numbers per cluster increased and the berries showed small shapes compared with the control. CCC also elicited hardening of the berry flesh. Only the lateral shoots emergd on the primary shoots by CCC application and by treatment of shoot topping laded the second crops which matued (refraction; ca. 16° Brix) in 3 weeks after harvest of the first crops treated with CCC. It was indicated that CCC application under open culture will be possible to produce the crops of ‘Kyoho’ grapes twice a year.
1) The effect of one of the naphthoquinone derivatives, 2-benzimidoyl-3-hydroxy-1, 4-naphthoquinone (bendroquinone) on the flower thinning of Nijisseiki pear (Pyrus serotina) was investigated. 2) Spraying the clusters with 10ppm bendroquinone from before flowering to full bloom induced hard flower abscission, but after fruit setting, more than 100ppm was required to induce the flower abscission. The flower thinning with bendroquinone was related closely to the developmental stage of each flower in the cluster. The flowers at the stages before and after flowering responsed significantly to bendroquinone, namely spraying the cluster with 5 to 10ppm bendroquinone at the flowering of secondary to fifth flower induced adequate flower thinning. 3) Concerning the clusters at a similar stage of flowering, flower thinning with bendroquinone was not affected by their position on the branch. Bendroquinone sprays applied to the clusters on or on clusters with eight leaves tended to induce stronger flower thinning than on long bearing shoots oron clusters with seven leaves. 4) At flowering, 200ng of bendroquinone retained on the surfaces of pedicels and receptacles induced stable flower abscission and 5 days after flowering, more than 300ng was required to induce them. 5) In a growth chamber, flower thinning with bendroquinone was induced markedly under a low temperature (10°C) after treatment compared with mid-range (17.5°C) and high (25°C) temperatures. This agrees with the relation between yearly variation of flower thinning and daily mean temperature after spraying during five years in Aburahi and in Tottori. 6) For other varieties of Japanese pear, in Hakko, Kikusui, Nijisseiki×Yahri and Seiryu, bendroquinone sprays significantly induced flower thinning. On the other hand, in Shinsui, Shinsetsu, Gion, Syusui and Yakumo×Kohgetsu, flower thinning was barely induced. 7) As for the quality of the fruit at harvest, there was no difference between the sprayed fruit and the unsprayed fruit upon examination of fruit weight, fruit width, fruit height, seed number, soluble solid and acids.
The changes of the activity of growth inhibitors in the latter half of the development of strawberry fruits and the interaction of cytokinin and growth inhibitors on fruit development were investigated. 1. Fruits grown at day/night temperature of 30°C/25°C matured earlier than those at 20°C/17°C. The activity of growth inhibitors in the fruits increased with their maturing, and inhibitor activity in the fruits grown at high temperature appeared earlier than that at low temperature. In chromatography of inhibitors on a Sephadex column, peak of inhibitory activity in a bioassay using rice seedling was found in fractions 5 and 6 corresponding with those of authentic ABA. 2. Number of days to maturity of fruits in vitro decreased as the concentration of ABA increased in the medium. Number of days to maturity was definitely affected by the concentration of ABA independently of BA concentration when fruits were cultured on the medium with BA and ABA. Fruit maturing was suppressed and inhibitor activity in them decreased when fruits were cultured on the medium with BA. Based on these results, following conclusion can be induced. In the latter half of the development of strawberry fruits, ABA synthesized actively owing to lowering of cytokinin activity in fruits promotes fruit maturing.
Effects of daylength, temperature, and soil moisture on bulb formation in Alliumwakegi Araki were investigated. Bulb formation in A. wakegi was induced by long daylength and high temperature conditions, as is also the case with onions. A low temperature period preceding the long daylength and high temperature phase served to fasten bulb formation. Low temperature requirements differed between two ecotypes, the “Japanese” and the “Southern” types, the former having a lower temperature requirement for such treatment. Low soil moisture under long daylength conditions also enhanced bulb formation; under these conditions, endogenous abscisic acid in whole plants increased steadily, and auxin in the leaf blade increased at an early stage (only 5 days after water stress treatment). An increase in both abscisic acid (a growth inhibitor) and auxin (a growth promoter) seemed to be necessary for the induction of bulb formation. Further, the “Southern” type responded more quickly than the “Japanese” type to the low soil moisture conditions.
In order to clarify the effect of light on the anthocyanin content of seedlings of benitade (Polygonum hydropiper L.), coverings were made under natural light condition for 5-7 days from their emergences or a few days later, with cheesecloths and various plastic films as described below. Also, seedlings were irradiated with artificial lights for 11-12 hours per day during 5 days. The temperatures were regulated in most experiments. In the experiments which changed the levels of transmitted light intensities by shading with cheesecloths, anthocyanin content of seedlings increased with the increment of light intensities to about 200cal/cm2 day, however did not increase between about 200 and 350cal/cm2 day. In the experiment of white light irradiation from a xenon short-arc lamp, anthocyanin content increased steeply with the increment of light intensities to 37klx, but did not increase above 37klx. Anthocyanin content was significantly affected neither by covering the seedlings with the transparent plastic films not transmitting near-ultraviolet region of sunlight, nor by irradiation with near-ultraviolet light in combination with white light from fluorescent tubes. In covering-experiments with colored plastic films, anthocyanin content was higher under yellow and red films that transmitted much of the red and far-red region of sunlight, than under blue and green films. When colored lights were applied to seedlings with respective fluorescent tubes at about the same intensity (9.3-10.8×103erg/cm2 sec), anthocyanin content was the highest in red light, and became lower in the following order, yellow=blue>green >far-red. When seedlings were continuously irradiated with supplemental white or red light from respective fluorescent tubes at about the same intensity (7.7-8.0×103erg/cm2 sec) during 3 days under the natural light condition, anthocyanin content was higher in the seedlings irradiated with red light than in those with white light. It seemed that anthocyanin synthesis in Polygonum seedlings was affected by light intensity and promoted by red light region.
This work was carried out to clarify the effect of temperature on the bulb formation of onion plant of which the 4-5th leaf had emerged during winter season. The onion plants were grown under short-day condition until the start of treatments. Plants of onion cultivars ‘Kaizuka-wase’ and ‘Sapporo-ki’ were previolsly exposed to 24hr day-length (LD) for 14 days, and then transferred to short-day (SD). During the exposure to LD and SD the temperatures of greenhouse were controlled at 20°C or 10°C. When both cultivars were grown at 20°C under LD, the bulbing of ‘Kaizuka-wase’ were accelerated at 10°C as well as 20°C under SD, but that of ‘Sapporo-ki’ depressed at 10°C under SD. ‘Kaizuka-wase’ grown at 10°C under LD formed their bulb regardless of temperatures under SD, but ‘Sapporo-ki’ did not. When the plants of ‘Kaizuka-wase’ previously exposed to LD at high temperature for 10 days were tranferred to SD at low temperature (below 10°C) for 10 days, the bulbing was depressed even though the low temperature was followed by high temperature. During the periods of LD and the following SD, top and root of ‘Kaizuka-wase’ plants were maintained with high (20°C) or low temperatures respectively. When the top received high temperature under LD, the bulb was formed under SD regardless of to paned root temperatures, even though if the root temperatures under LD was low. When the pot received low temperature under LD, however, the balb was not formed at all. The plants of ‘Kaizuka-wase’ and ‘OX’ were daily exposed to 8hr light of high intensity (main light period), 8hr light of low intensity (supplementary light period) and the 8hr dark. During each period plants were grown at high or low temperature, the plants grown at high temperature during main light period accelerated thier bulbing compared to those grown at low temperature. The effect of temperatures at the supplementary light or the dark periods on the bulbing was less than that at the main light.
Cabbage plants were grown in nutrient solutions containing 3 levels of nitrogen (as NaNO3; 10, 100, 500ppm N) combined with 3 levels of sulfur (as Na2SO4; 1, 10, 50ppm S), and the effects of the nitrogen and sulfur supply on the growth and the chemical composition of the plants were studied. Total plant dry weight increased with an increase in the S supply when the N supply was 100 or 500ppm, but was always small when the N supply was 10ppm, irrespective of the S supply. The highest cabbage-head yield was obtained at 100ppm N and 10ppm S, while little cabbage-head yield was obtained at 10ppm N or 1ppm S. The total N content in each organ increased greatly with an increase in the N supply and decreased slightly with an increase in the S supply. The total S content incresased greatly with an increase in the S supply and decreased slightly with an increase in the N supply. A total N content below 2% and a total S content below 0.1% on a dry basis in the outer leaves was found to be insufficient for cabbage-head formation. Cabbage-head development was most efficiently when the total N/S content ratio was between 10 and 20, although the ratio fluctuated widely, from 4 to 235. N-deficient plants contained less sugars and more starch as compared with the N- and S-sufficient plants. S-deficient plants contained less sugars and 80% ethanol -insoluble protein N and more 80% ethanol-soluble non-protein N.
The aspect of pollen degeneration of the new genic male sterile line of pepper (Capsicum annuum L.), which we had reported in our previous paper, was clarified by the microscopic observation of anthers using paraffin sections. In the anthers of male sterile plants, the development of archesporial cells and tapeta, meiosis of pollen mother cells and formation of pollen tetrads progressed normally. However, pollen tetrads, which were somewhat larger than those of normal plants, did not release microspores, and gradually collapsed and disappeared. Just before anthesis, the anther loculi became empty and nothing was detected except for dead remains of collapsed tissues.
Pot experiments were carried out in naturally lighted rooms of phytotron to ascertain whether the erratic growth responses of vegetable seedlings to K fertilizer in different seasons could be attributed to the differences of temperature or not. Radish and spinach seedlings were grown on the three soils with different exchangeable K, with and without K application (1g of K2SO4 per pot) under two temperature regimes. Temperatures were kept at 25°C during the day (6:00-18:00) and at 20°C at night in one room, and at 18°C day/13°C night in the other. In the preliminary experiment of radish, temperature was kept at 20°C or 30°C all day long. All pots received 1g of ammonium sulfate and 5g of superphosphate. In the experiment of spinach, 3g of slaked lime was applied. Six and eight germinated seeds were sown in plastic pots (15cm in diameter) filled with 1.6kg of soil (oven dry basis) in the experiment of radish and of spinach, respectively. Seedlings grown at both temperature regimes were harvested between 10:00 and 14:00 on the same day, when the first true leaf began to emerge at 18/13°C. K concentration of plant tops was expressed as % in dry matter or as % in sap, which was derived as follows. K as % in sap=K as % in dry matter×percentage of dry matter/percentage of moisture 1. In the experiment of radish, K application increased the fresh and the dry weight of seedlings, both at 18/13°C and at 25/20°C, on the soils containing 96ppm and 135ppm exchangeable K. On the soil containing 182ppm exchangeable K, K application increased significantly the weight of seedlings only at 18/13°C. In the preliminary experiment, however, K application did not increase the weight of seedlings on this soil, either at 20°C or at 30°C. 2. In the experiment of spinach, K application increased the fresh and the dry weight of seedlings under both temperature regimes, on the soils containing 217ppm and 253ppm exchangeable K. On the soil containing 273ppm exchangeable K, however, K application increased significantly the weight of seedlings only at 18/13°C. 3. As compared with seedlings of both crops grown at 25/20°C, those grown at 18/13°C had higher percentage of dry matter and lower percentage of K in dry matter or in sap. 4. The above results coincided with those of previous experiment (5), in which the growth responses of vegetable seedlings to K fertilizer were obtained only in cool seasons, on the soil with critical K level.
Two experiments were carried out in order to clarify the relationships between the growth responses to K fertilizer and K+Na concentration of the largest leaves in radish, cabbage and snap bean. In the first experiment, cabbage and snap bean were grown under combinations of 3 levels of Na (0, 4 and 40g of Na2SO4) and 6 levels of K (0 to 8g of K2SO4) by soil culture. Seeds of both crops were sown in plastic pots (25cm in diameter) filled with 6.5kg of soil (oven dry basis). This soil contained 91ppm exchangeable K and 47ppm exchangeable Na. After establishment, seedlings of cabbage and snap bean were thinned to three and two per pot, respectively. In the second experiment, effects of five K:Na ratios in the nutrient solutions on the growth and K+Na concentration of the largest leaves were examined by sand culture. Total amount of K+Na in a liter of each nutrient solution was 4me. Two plants (three plants in radish) were grown in each plastic pot (15cm in diameter) and fed twice a day with the nutrient solutions shown in Table 2. 1. In soil culture experiments of cabbage and snap bean, 1g of K2SO4 was sufficient for the maximum growth of tops, regardless of Na levels. 2. In soil culture experiment of snap bean, K-sufficient and K-insufficient plants were distinguished mutually by K concentration of their largest leaves (ca. 50me), regardless of Na levels. Both groups of plants were also distinguished by K+Na concentration of their largest leaves (ca. 50me), because K+Na concentration was approximate to K concentration in this crop. 3. In soil culture experiment of cabbage, K-sufficient and K-insufficient plants were distinguished neither by K concentration, nor by K+Na concentration of their largest leaves. 4. In sand culture experiments of radish, cabbage and snap bean, sufficient amounts of K in the nutrient solutions for their maximum growth were 0.5me, 1 me and 1me, respectively. 5. Results of sand culture experiments suggested that 25me and 45me of K concentration in their largest leaves were required for the maximum growth of radish and cabbage, respectively, regardless of K-Na concentration. In snap bean, however, K concentration required for the maximum growth could not be determined, independently of K+Na concentration. 6. In soil culture experiment of cabbage, K-sufficient and K-insufficient plants were distinguished mutually by K+Na concentration of their largest leaves (ca. 85 me), only in case of K concentration being higher than 45me (Table 3, Table 4).
An experiment was conducted to determine the effect of various concentrations of base nutrient solution (Bs) on the growth and keeping quality of chrysanthemums (Chrysanthemum morifolium Ramat. cv. Seikonohana). Thirty-three day old cuttings were planted in a wooden container (40×40×12cm) filled with sand or soil, and grown in the greenhouse under normal photoperiodic conditions. Treatments consisted of 5 concentrations of Bs-0.5 times (half strength Bs, 0.5S), Bs (1S), 2 times (2S), 3 times (3S) and 4 times (4S) were used for both sand culture (SaC) and soil culture (SoC). Treatments were continued from July 15 to flowering. The plant height, fresh weight of cut flowers, and root dry weight were greatest at 1S in SaC and SoC, and decreased with increasing the concentrations of Bs. The flowering was not affected by treatments. The keeping quality of cut flowers was improved at 0.5S in SaC and SoC, and deteriorated with increasing concentrations of Bs. The keeping quality of cut flowers decreased by 8 to 9 days at 3S and 4S in SaC and at 4S in SoC as compared to 0.5S. Marginal burns on the leaves appeared at 3S and 4S in SaC and at 4S in SoC about 45 days after the beginning of treatments. The injury first appeared on the lower leaves and progressed upward. Generally the injury was more severe in SaC than in SoC, and became more severe with increasing concentrations of Bs. The content of total-N, P, K, Mg and Na in the leaves was significantly increased as the concentrations were raised from 0.5S to 4S, while Ca in the leaves was significantly decreased. At the end of the experiment the content of NO3-N, P, exchangeable K, Ca, Mg and Na, and the EC values of the sand and soil increased with increasing concentrations of Bs.
In Japan, gladiolus cormels are usually harvested during autumn and stored dry at room temperature until planting time in the following early-spring. Natural low temperature from autumn to late winter while in store is known to cause the breaking of dormancy of cormels. It is of importance for the proper handling of cormels to know at which time of the winter the dormancy disappears and how varied each cultivar is for their response to low temperature. The present studies are attempted to clarify the problems. After harvest cormels of 5-6mm in diameter were stored in a dry condition at room temperature till planting. The stored cormels were planted at different times in petri dishes containing growing media of about 0.6% agar alone or in clay pots filled with a mixture of three parts sand and one part perlite. Cormels did not sprout when planted just after harvest. As cormels were planted later-namely when cormels passed through a longer term of natural low temperature- they showed a higher sprouting percentage and sprouted more quickly. Bare cormels (shell removed) began to sprout and attained a high level of sprouting beforecracked ones (shell cracked), which in turn preceded intact ones (shell adherent). The course of sprouting mentioned above suggested the following process of disappearance of dormancy. Cormels were in a state of true dormancy 2-4 months after harvest, depending on cultivars, during which time they could not be induced to sprout even when their outer shells were removed and they were placed at an optimal temperature. They gradually turned to post dormancy in which they were able to sprout by removing their outer shell. And they reached a state of out of dormancy or quiescence in which they showed a high level of sprouting irrespective of the existence of an outer shell. In the March planting, cormels of most cultivars attained to a state of quiescence, excepting those of ‘Professor Goudriaan’ and ‘Valeria’ which were still in a state of post dormancy. Sprouting of cormels was influenced by the date of harvest; the earlier they were harvested, the earlier the dormancy was broken. In the April planting, many cormels harvested at the end of the previous October were still in a state of post dormancy.
The effect of packaging with perforated PE/PP film on keeping quality of green soybeans was investigated. The results were as follows: 1. The quality of soybeans was kept good by packaging in perforated film with hole density: 0.5 hole (0.9mmφ)/cm2. Smaller density than that seemed to hasten fermentation. It seems to be brought by the suppression of transpiration, the increase of CO2 and the extreme decrease of O2. The marketable quality was able to be kept for 6 days at 30°C and for 14 days at 5°C by the adequate package. 2. About 30% of sugar content in soybeans at harvest time decreased after a day and 7 days after harvest respectively at 30°C and 5°C. 3. Storages in water-proof corrugated fiberboard boxes had the same effect as the packaging with perforated film. 4. There was a high correlation between the surface color and the ascorbic acid content of soybeans.
The mechanism of chilling injury in Cucurbitaceae fruits including cucumber, oriental pickling melon, marrow, squash, balsam pear, white gourd and chayote was investigated by using an Arrhenius equation for the rate of potassium ion leakage from the tissue slices at 0-30°C. 1. The symptoms of chilling injury were pitting, surface pitting and watery breakdown following the decay by the secondary infection of microorganisms. There was observed to be a significant deviation among chilling tolerance of cucurbits fruits at 0-5°C. The fruit of balsam pear showed the most sensitive to chilling and Cucurbita fruit was observed to be the most chilling tolerant species. In general, chilling sensitivity might depend on fruit maturity, and fruit harvested commercially at mature stage showed much more tolerant to chilling than the fruit that was harvested at immature stage. 2. In all species, there were break points at ranging 5-12°C in the Arrhenius plot of rate of potassium ion leakage from the tissues. A higher rate of potassium ion leakage was observed at the lower temperatures below the break points. These breaks corresponded nearly with the critical temperatures for chilling injury of these fruits. 3. The break points were observed in the Arrhenius plot for the tissues of cucumber fruit stored at 20°C (safe temperature) throughout storage period. On the other hand, the break points became obscure during storage at 5°C (chilling temperature) and became hard to distinguish after storage for 15 days. The abrupt breaks at the critical temperatures observed in the Arrhenius plots may suggest that the occurrence of phase change of membrane lipid in the fruit tissues might be primary event of chilling injury of the Cucurbitaceae fruit.
Chilling injury of cucumber fruit (Cucumis sativus L.) of several kinds of cultivars and different stages of maturity, oriental pickling melon (Cucumis melo L. conomon Makino) and winter squash fruit (Cucurbita maxima Duch.) was investi gated to elucidate the relationship between the changes in membrane permeability and the occurrence of chilling injury at low temperature. 1. There were considerable deviations in chilling sensitivity among different cultivars of cucumber fruit. In general, the cucumbers of western cultivars showed less sensitivity to chilling than oriental species. Chilling symptom of surface pittings began to appear after storage for five days in the fruit of sensitive cultivars and fifteen days in the fruit of less sensitive cultivars at 5°C. 2. Considerable deviations were observed in the chilling sensitivity of different stages of maturity of cucumber fruit cv. Horai, especially, chilling injured pittings occurred only after long term storage period at 0°C in the case of full mature fruit. 3. There was a sudden rise of electrolyte leakage from the tissue slices of cucumber, oriental pickling melon and winter squash fruits into deionized water or 0.4 M aqueous solution of mannitol just after the occurrence of chilling injury at 0°C, while electrolyte leakage from the tissue slices of the cucurbits fruits showed no obvious rise throughout storage period at 20°C which was safe temperature. Above-mentioned results suggested that the changes in membrane permeability of the cucurbits fruit tissues during chilling may play an important role in the mechanism of the occurrence of chilling injury of fruits.