Experiments were carried out to clarify the combined effects of various water regimes and fertilizer rates on the growth and fruiting of young Satsuma orange trees during two months, from July to August in 1969. Four and five year old plants grown in the Wagner′s pots (1/2000 are), filled with a loam soil, were used as materials. At regular intervals, watering were done to maintain the appropriate levels of soil moisture by determining the water content in each plot at the depth of 10cm according to the volumetric method. The water suctions were calculated to express this force on the energy scale, pF and bar using soil moisture constants as shown in Table 2. To make the plots with different osmotic suctions in the soil, the mixed fertilizers on various levels were supplied. Thereafter, separate fertilizers were done by determining the electrolytic conductivity of salts solution prepared from the saturated soil in each plot at regular intervals to maintain the definite osmotic suction. The osmotic suctions (P) in bar were estimated by the calculation from the values of the electrolytic conductivity (EC) of saturation extracts in mmhos/cm according to the following equation. P=0.36×EC Total suction in the soil solution can be obtained as the sum of water suction and osmotic suction. The ranges of total, water and osmotic suction in the soil solution under different treatments are shown in Table 1. Results obtained are as follows: 1. The trees reached their full growth when the total suction in soil solution did not exceed 2.5 bar as the sum of water suction of 0.5 bar and osmotic suction of 2.0 bar. Above its critical pressures, the trees showed a tendency to inhibit their growth. In this case it appeared that the water suction was more important than the osmotic one. 2. The suction in soil solution had the same effect on the fruit growth as described above. Index of fruit shape was also affected by the soil water suction, showing the tendency of increasing the ratio of vertical diameter to cross diameter with increasing the water suction. The full development of fruit color was shown in the plots with lower total suctions, especially the lowest osmotic suction, while incomplete coloring in plots of higher water suctions. Percent of fruit rind was high in the treatments with higher total suctions. 3. Soluble solids in fruit juice were higher in plots with total suctions below 3 bar than the ones in the other plots. On the contrary, citric acid was high in content in plots with higher total suctions and therefore tastes due to lowered sugaracid ratio showed bad quality. 4. Both water saturation deficit and diffusion pressure deficit as measures of internal water status in leaves showed the tendency of increasing their values with increasing water and osmotic suctions in soil solutions. Leaves exposured at higher values of water suctions accompanied by increased solute suctions in soils showed a marked drop in both photosynthesis and transpiration. The suctions in such conditions had the same effect on the viability of fine roots, which were going to rot in very bad conditions. 5. The content of nitrogen, phosphorous and potassium in leaves was high at higher osmotic suctions, while the case with calcium was the reverse. In conclusion, to give the best possible growth and fruiting of Satsuma orange trees, it is important to keep the water suctions below 0.5 bar and the osmotic suctions below 2.0, in other word total suctions below 2.5 bar in the soil solution by adjusting watering and fertilizer rate during the summer. The upper critical range of 2.5-3.0 bar as the total suction in the soil solution may be shown from our experiments.
1. In order to clarify the effects of drought and moist soil condition on the acid change of Satsuma orange fruits from mid-summer (after 3 months from blooming) until the harvest, pot experiment carried out with 4- and 5-years-old early Satsuma orange trees. 2. In experiment used much bearing trees, growth of fruits was greatly inhibited under drought soil condition during 20 or 30 days in August and September, and water content in flesh (flavedo) remarkably decreased. Soil drought resulted in higher acid concentration (g as free citric acid per 100ml. of juice), but in lower acid content in flesh (g as free citric acid per fruit) as compared to no drought. When irrigated water was sufficiently supplied during 5 days followed from the end of each drought periods, water content in flesh increased rapidly, and simultaneously acid concentration decreased remarkably, in while acid content of flesh increased. Aboved changes of acid due to soil drought and irrigation, were more conspicuous in the case of drought treatment from early August to early September than in that in middle or late September. 3. Acid concentration in middle August was already in decreasing process, and peak concentration appears to be at late July or early August, depending on the year. Decrease of acid concentration during the period from middle August to middle or late September which enlargement of fruits is most great, was rapid, and gradual after late September. On the other hand, peak content of acid in flesh was found during the period middle to late September. Therefore, change of acid was apparently differentiated into two process as follows; accumulation before middle or late September and decrease (or disappearance) after this time. Disappearance of acid after this time was actual decrease in total amount caused by a change in nutritional metaboliom of fruits. Great difference depending on the time of drought treatment on the decrease of acid concentration and increase of acid content which were occurred by the irrigation followed from the end of drought period, appeared to be associated with accumulation and decrease in process of acid change. 4. In experiment of soil moisture variation during 2 months of September and October usea less bearing trees, fruits grew larger in moist condition than in drought condition, and had lower acid concentration. Compared of acid change in fruits between moist and drought condition during about one month before the harvest, November 5, actual decrease was greater under drought condition. Fruits grown under drought condition had the qualities such as thin peel, deep coloring and high soluble solids concentration. 5. In conclusion, acid concentration of Satsuma orange fruits was affected greatly by the variation of soil moisture in late summer and autumn, especially after middle or late September. Poor fruit quality, watery taste, occurring frequently under rainy condition or excessive irrigation in late summer and autumn, appeared to be closely related with dilution caused by the increase of flesh water.
Growth substances extracted from the larvae of chestnut gall wasps and the tissues of their proto-plasmic galls were separated into petroleum ether, ether, ethanol and water soluble fractions. From these fractions, detections of indole compounds by Avena straight growth test, chlorophyll retention test for kinins and ability of gall formation were studied. 1. Tryptophane being the precursor of IAA was detected in larvae of chestnut gall wasps and also in gall tissues. This compound showed the activity of Avena straight growth, and this activity was a little greater in larvae fractions than in gall tissue ones. IAA was not detected in both tissues. 2. Kinins delaying the degradation of chlorophyll in the first leaf sections of barley existed in each tissue. 3. Gall formation substance was found in larvae′s tissues. This substance did not cause cecidogenesis with regard to the resistant variety. Considering that kinetin was able to form the galls, it may be kinin-like substance. In gall tissues, such substance did not exist.
Changes in acidities of fruits during their development have been studied by many investigators. In almost all cases, however, their concern was in the ripening stage and not in the younger stage of fruits. So this study was made to determine the changes in acidities of fruits from bloom to ripening stage except grapes which were not sampled until one week after bloom, and to compare the patterns among several different kinds of fruits. Used fruits were Satsuma orange‘Owari-kei Futsu Unshu, ’early Satsuma orange‘Miyagawa Wase Unshu, ’grapes‘Delaware’and‘Campbell′s Early, ’ Japanese pear‘Kikusui, ’and peach‘Hakuho.’ Titratable, total, and combined acidities were determined on the water extract of whole fruits except hardened stone or seeds and were expressed by numbers of milligram-equivalent on 100g fresh weight or per fruit. The results showed that all the kinds of fruits except Japanese pear were alike in the pattern of changes of acidities on 100g fresh weight. The titratable acidity was low at bloom. But soon it began to increase and reached a peak about in the middle stage of growth, then decreased afterwards. Total acidity, comparatively high at bloom, decreased for a certain period and then increased rapidly on grapes and oranges, gradually on peach. It began to decrease after it had a peak about in the middle or later stage of growth. Combined acidity was the highest at bloom and decreased rapidly at the start and gradually later. Ratio of total acidity to combined acidity, increased sharply after a certain period of low value. It reached the highest value about in the middle stage and decreased afterwards. On Japanese pear, however, titratable, total, and combined acidities were the highest at bloom and continued to decrease over the entire growth period. It was suggested from above results that on Satsuma oranges, grapes, and peach, the growth period can be divided into three in respect of changes of acidities, as previously reported on tomato fruits. Patterns of changes in acididies per fruit were different among fruits. Titratable, total, and combined acidities of peach and Japanese pear fruits continued to increase from bloom to harvest. On Satsuma orages the titratable and total acidities. increased until about the middle stage of growth and afterwards the former decreased slowly and the latter showed no distinct change. The combined acidity continued to increase from the start of growth to harvest. On grapes titratable and total acidities increased sharply until the peak in the middle stage, and then decreased rapidly. Combined acidity continued to increase over the entire growth period.
In order to elucidate the influence of tree age on the thinning effect of Peach-thin, experiments had been conducted on three groups of peach trees (cultivar Hakuho); Group one 12-16 years old (1961-65), Group two 4-7 years old (1962-65), and Group three 4-6 years old (1967-69). In every season, 200ppm solution of Peach-thin was sprayed two or three days after full bloom. In addition, twice spraying of 200ppm solution two and four days after full bloom and 400ppm spray two days after full bloom, were applied in some cases. Thinning effect of Peach-thin was evaluated by comparing percentages of fruit setting of sprayed branches with that of corresponding unsprayed branches about 25 days after full bloom. On four years old trees, percentages of fruit setting were very low and variable, and thinning effect of Peach-thin was severe, too. On five or more years old trees, percentages of fruit setting were generally high and stable, and effect of Peach-thin was mild. A high correlation was obtained between the fruit setting percentages of control branches and those of treated branches with 200ppm solution (η=0.519). In the case of mature trees only (12-16 years old), a higher correlation was obtained (r=+0.781). Influence of tree age on thinning effect of twice 200ppm spray and 400ppm spray were not so clear owing to the lack of data on four or five years old trees. A high correlation was obtained between the fruit setting percentages of control branches and those of sprayed branches (twice 200ppm spray r=+0.644, 400ppm spray r=+0.515). Correlations in individual years were higher than that throughout the experimental period (twice 200ppm spray 1962 r=+0.996, 1963 r=+0.748, 1969 r=+0.951; 400ppm spray 1962 r=+0.988, 1964 r=+0.868, 1965 r=+0.651).
The guava trees were sprayed with 0.0%, 0.2% and 0.4% iron sulphate in July 1966 and 1967. It was observed that iron spray in 0.2% and 0.4% concentrations was highly capable to cause significant increase in various characters. The maximum increase in extension of terminal shoots, number of leaves, leaf area per shoot, chlorophyll recovery and yield was observed under 0.4% spray. Maximum increase in fruit weight, length and diametre was noted under 0.2%. Maximum effect of acidity, non reducing sugars and Vit. C was exhibited under 0.4% while reducing sugars and T.S.S. were affected with 0.2% spray.
The effect of light-break on the sex differentiation in cucumber has been investigated using the variety “Higan-fushinari.” Red light induced more female flower nodes than either one of white, green, blue and far-red lights did. The light-breaks with red light of very low intensity could induce more female flower nodes in plants as compared with the control which has grown up without interruption of the dark period. The higher the intensity became, the more the female flower nodes occurred. One minute interruption with red light induced more female flower nodes than the not interrupted. The number of female flower nodes increased with prolonging the duration of light-break. The female increasing effect with red light was reversed by the subsequent far-red light. This effect was quite reversible, alternatively. The divided light-break induced much more female flower nodes than a single continuous one, having the same total energy, did. These results will safely show that the sex differentiation in cucumbers may be controlled by the mechanism concerning the phytochrome.
To elucidate the mechanisms of cross-incompatibility in interspecific hybridization in the genus Cucumis, pollen tube growth, fertilization and embryogenesis in the earlier stage of post-fertilization, were studied in the incompatible crossings, C. dipsaceus (_??_)×C. figarei (_??_) and C. dipsaceus (_??_) ×C. melo (_??_). 1. In both the incompatible crossings, the rate of pollen tube growth in the style was slower and the occurence of the entrance of pollen tube into ovules was less frequent than in selfing of maternal plant. 2. When the parental species were selfed, fertilization took place during 24-48 hours after pollination and the primary nuclear division of endosperm occurred immediately after fertilization. The cell division of the zygotes began after 84 hours or later of pollination when endosperms had already grown including 8-16 nuclei. In the most advanced ovule sampled six days after pollination, the embryo which was surrounded with the well developed endosperm became already globular. No specific differnce was found in the process of embryogenesis as mentioned above. 3. In both incompatible crossings fertilization took place in a part of ovules and the endosperms slightly developed in such fertilized ovules. However, the cell division of the zygotes never occurred even after few days following pollination and the endo sperms could not continue their growth and aborted later. Fertilization and division of the endosperm nucleus did not occur in some of the ovules into which pollen tubes entered. It is assumed that fertilization rarely occurred owing to the abnormal behaviors of pollen tubes.
Yield and viability of seeds taken from Dalapontreated pepper plants were investigated in this report. Miemidori, a cultivar of sweet pepper was used. The plants were sprayed with 30 milliliters of aqueous solution per plant containing 200, 400, 600, 800, 1, 000, 1, 200 and 1, 400 milligrams of Dalapon per liter. Very little influence on fruit setting was observed while seed setting was strongly affected by the treatment, and the number of seeds per cross decreased with the use of high concentrations. After 1, 000 or 1, 200ppm applications the number of seeds per cross was approximately one third in comparison with non-treated. The decrease of seed number seems to result from both the decreased number of ovules and other physiological disorders. Seeds produced after the use of higher concentrations were larger than those of control or lower concentrations. On the other hand, the germination rate of harvested seeds decreased with the use of high concentrations.
Several varieties of different ecotypes were used as materials. The seeds of each varieties were sown in pot on February 15, May 18, July 20, September 15 and December 2 in 1968. The effect of sowing time, temperature, humidity and light intensity on internode elongation was observed. The elongation of hypocotyl, epicotyl and other internode was observed at leaf stages 2, 4, 6, 8 and 10. The results were as follows: The internode elongation was accelerated by high temperature, and low light intensity. Humidity has no effect on elongation of internode. Internode elongation was also affected by genetic factor. In this report, especially, genetic factor is emphasized. The distinct difference was recognized in different genome varieties at early stage. Namely, in A-genome varieties, hypocotyl was elongated by several environmental factors, but epicotyl and other internodes did not elongate except after vernalization. In B-genome varieties, epicotyl and other internodes elongated every sowing time. In C-genome varieties, 4 or 5 internodes were elongated before the 8th leaf stage, and afterwards the plants appeared rosettes. But, when the period of vegetative growth was prolonged, distinct elongation of the lower part of the stem occurred. Takana and Karashina groups were used as AB-genome varieties. Internode elongation of Karashina group is similar to B-genome varieties and Takana group resemble A-genome varieties. AC-genome varieties were constituted several types, some of which are similar to A-genome type and the others (for example, Rutabaga) resemble C-genome type. The other types of AC-genome varieties were distributed between the above two groups concerning the internode elongation. It was also recognized that if the vegetative growth was prolonged, the lower part of the stem was elongated. It resembled the C-geneme varieties. Although the elongation of the lower part of the stem was observed in C- and AC-genome varieties, the length in AC-genome varieties was shorter than in C-genome varieties. As the elongation phenomenon of lower part of stem was not observed in A-genome varieties, it was considered that AC-genome varieties had the intermediate character of A- and C-genome varieties as regards the length of lower part of stem. The distinct difference was also recognized in scape elongation at low temperature. At 5 to 15°C, scape elongation of A-genome varieties was inhibited completely. Scape elongation of C-genome varieties, on the contrary, was formed normal.
The seeds of“Mizuna, ”Brassica japonica SIEB., usually have dormancy during two months after harvest, but, when they are stored in the desiccator, the dormancy continues for as long as more than three years. The dormancy of such desiccated seeds is partial or incomplete, and their percentage germination shows a considerable fluctuation during the period of prolonged dormancy. When desiccated, not only mature seeds but also immature ones show prolongation of dormancy, and the former seems to be less dormant than the latter. When dormant seeds are taken out from the desiccator, their dormancy is completely removed in four weeks, but non-dormant seeds do not enter dormant state even if they are put into the desiccator. In germination, desiccated seeds are more sensitive to temperature than air-dry seeds. Following methods are partially useful for breaking dormancy, i.e., low-temperature, slitting or removing of the seed coat, and soaking in running water.
This study was carried out for three years from the viewpoint of structure of maleic hydrazide (MH) to clarify the mechanism of both retardation of sprouting and occurrence of functional disorders in onion bulbs treated with MH. As known that MH has some specific structure of quinone ring, keton groups, conjugatd double bond and hydrazine or hydrazide base and further is an antagonistic substance of uracil, the following chemicals were examined in relation to those phenomena mentioned above, Malefic acid, p-Quinone, Hydrazine dihydrochloride, Phenylhydrazine, Semicarbazide, Isonicotinic acid hydrazide, Thiouracil and MH. 1. The results of storage test with bulbs applied with each chemicals respectively before harvest showed that the most effective substance comparable to the inhibiting effect of MH on the sprouting of bulbs is Isonicotinic acid hydrazide, more or less effective ones Hydrazine and Semicarbazide, and less effective ones Maleic acid, p-Quinone, Phenylhydrazine and on the other side more severe substances than MH on the occurrence of decay and functional disorders are Thiouracil, Hydrazine, and Semicarbazide. Consequently it appears that the structure of MH effective for the inhibition of sprouting consist in the form of >C=C-C(=O)-NH-NH- and also that for the occurrence of functional disorders and decay is due to both an analogue of nucleic acid and hydrazine or hydrazide base. 2. From the results that both Isonicotinic acid hydra zide and MH antagonized Pyridoxine respectively against the growth of avena coleoptile section it was considered that the inhibiting effect of MH on the sprouting of onion bulbs depends upon the cessation of growth of leaf primordia due to the lowering protein synthesis accompanied by the inhibition of transaminase activity by MH. 3. With increase in concentration of each chemical solution the respiration of stem disk slice in onion bulbs was inhibited. Among them Thiouracil gave the most severe effect followed by MH, Isonicotinic acid hydrazide and Hydrazine in the descending order. Consequently it is considered that the occurrence of functional disorders in onion bulbs by MH depends upon respiratory stress due to an analogue of nucleic acid.
CO2 concentrations in vegetable growing were measured by means of an infra-red gas analyser in order to discuss the CO2 depletion, being considered as one of serious problems for sufficient photosynthesis. Sampling gas was taken occasionally with suction pump controlled by automatic setting box at the rate of 0.3 litre per minute through the plastic tube distributed within and above the plants. In the open field, minimum CO2 concentrations within the canopy measured on a clear day with and without wind were 275-285ppm and 205-250 ppm. This depletion was caused by mean wind speed below 1.5m/sec. over the plants and by dense plant community. In the atmosphere under the glass- and plastic-houses, CO2 shortage was more remarkable than that outside. High CO2 accumulated by leaf and soil respiration was avaiable for photosynthesis in the early morning. Very soon, however, the content fell below ambient. Thus, critical light intensity for increasing dC/dt could be assumed to be 3-5 klux on the plant top. Finally, CO2 concentration fell to 80-85ppm provided the vents remained closed. Measurements of the CO2 profile at the time when plants were well grown in a plastic-house on a sunny day, showed that CO2 depletion was observed twice a day, before and after ventilation. In the first depletion CO2 level dropped to nearly 105ppm and the height of minimum concentration (Zm) was found at the middle part of plant height. When ridge ventilator was opened toa maximum of 25cm, the second depletion was slightly decreased and the concentration remained at 140ppm. On the other hand, a ventilating fan prevented greatly CO2 depletion and Zm was observed over a wide range of plant height. To prevent the CO2 depletion in the particular part within the canopy, air circulating fan was operated in the morning when the vents were keeping closed. The resulting profile 8m away from the fan, showed that it had no effect on CO2 homogenization in and above the plant. CO2 depletion was also greatly affected by leaf area density. The concentration in the air of nursery bed covered with vinyl film was depleted to 65-70ppm. High leaf area density lengthened the time course of equilibrium until ventilated. All of these observations indicate that the ventilation speed and leaf area density are the predominant factors for the CO2 depletion under covered conditions on a sunny day. It may be argued that by keeping the ventilators open CO2 depletion would be avoided. The curves of N. A. R. against the ventilation rate, however, would suggest the air changes of 20-30 times for house volume per hour often occurred in commercial glass-and plastic-houses are not enough CO2 supply within the plant canopy for sufficient photosynthesis. Beneficial effect of CO2 enrichment during the first CO2 depletion was discussed from practical point of view.
These studies were carried out to obtain some informations on the mode of action of a selective herbicide, CMMP (solan) for tomato, carrot and japanese honewort. 1. It was appeared that both of chlorophyll and light are necessary for exhibiting herbicidal activity of CMMP. And in such a case of either chlorophyll or light was excepted, the herbicidal activity did not recognized quitely. 2. Inhibition for biosynthesis of chlorophyll and anthacyan was remarkable for the CMMP susceptible plant, but no influence was gaved for the CMMP resistant plant. 3. The selective inhibition for the above biosynthesis was investigated whether has relation with the difference of penetration in plants. In consequence, both of CMMP susceptible and resistant plants, penetrating CMMP increased day by day regardless of kinds of plant. 4. The reaction of CMMP with chloroplast was recognized apparently on all of CMMP susceptible and resistant plants. And the reaction CM MP with chloroplast increased as adding chloroplast in reaction solution increased. 5. The reaction of CMMP with chloroplast proceeded immediately after added those in reaction solution.
The cytokinin activity of ethanol extracts from the protocorms of Cymbidium insigne ROLFE, C. pumilum ROLFE and C. goeringii REICHB. F. was examined by tobacco callus assay. The previous works with the tissue cultures of these three species have shown that the difference in organogenesis, especially in the kinetin-requirement for shoot formation, exists between the former two and the latter. The extract of C. insigne or C. pumilum showed, at 100 gram fresh weight equivalent per litre, approximately the same activity as that of 10μg/l kinetin. The cytokinin activity of C. goeringii was considerably lower than those of above two species. It is assumed that low cytokinin activity is responsible for difficulty in shoot formation in the aseptic culture of C. goeringgi.