Responses on various characters of guava trees due to foliar spray of zinc were studied in the field trial. The guava trees were sprayed with 0.0%, 0.2% and 0.4% zinc sulphate solutions during July 1966 and 1967. Significant improvement in growth characters, i.e., elongation of terminal shoot, number of leaves, leaf area per shoot and chlorophyll recovery was observed with zinc spray. The zinc spray also significantly reduced the time for fruit maturity and increased fruit yield significantly. The significant improvement was also recorded on Fruit weight, length, diameter, reducing sugars, Vitamin C, pectic substances and total soluble solids, And significant reduction in acidity.
It has been clarified8, 9) that the abnormal tissue in secondary wood, related to stem pitting in citrus tree, was almostly formed in parenchymatous growth ring, but not in fibrous rings. And it was assumed that the formation of abnormal tissue (stem pitting phenomenon) might be dependent on cambial condition in a given season of a year. So, the following experiments, using phytotron and green-house, were carried out with two year old trees of sweet lime (Citrus limettioides) in order to ascertain the effects of environmental factors on the formation of parenchymatous growth rings; in one, the effect of temperature on the trees grown under the constant high temperature (day and night: 30°C) and the alternate high temperature (day: 25-30°C and night: 15°C) during winter season (from the beginning of October till the end of April). And in another, the effect of day length on the trees grown under long day condition (13-15hr.) during the same winter, were examined. From the observation of the trees grown in natural conditions, it was revealed that the parenchymatous growth ring was formed in winter season while the fibrous growth ring was formed in summer season (from the beginning of May to the end of September). On the other hand, within all cases mentioned above, the formation of the parenchymatous growth rings was similar to that in the trees grown under natural condition in winter season except in the only case of the trees cultivated under the alternate high temperature. Under the alternate high temperature, during winter season, the differentiated secondary tissues were fibrous such as in summer season. These observations provided that the thermoperiodicity was necessary for the differentiation of the fibrous growth rings in citrus tree wood. Adding to the results mentioned above, the following facts were found; the formation of tissues in the secondary wood of two year old Buntan trees (Citrus grandis) which were operated mechanically (wounding to the basal part of main stem or cutting off the top of main stem) was similar to that of the tree grown under natural conditions, but in the case of cutting off all leaves or one part of lateral roots, the traumatic parenchymatous rings (similar to the terminal-type2)) were found in the secondary woods (Fig. 5. A and B, arrow).
Sensitivity of grapevines to injury by sulfur dioxide were studied. One or two-years old plants were exposed to different concentrations of the gas (0.26, 0.13, 0.065, 0ppm) at different season in a green house. The results obtained are summarized as follows: 1. Sulfur dioxide injury emerged on the middle leaves of grapevine at first, however the degree of leaf lesion was remarkable on the lowest leaves. Leaf lesion and early leaf fall increased in proportion to the gas concentrations. 2. Six varieties of grapevine used varied considerably in their sensitivity to the gas. Variety of Fredonia was highly sensitive and Delaware grape was fairly sensitive. Kyoho and Neo muscat grapes were intermediate. Kyogei grape was resistant, Koshu grape was the most resistant and was not suffered from leaf injury through exposure periods. Fredonia grape was absorbed the gas more than Koshu grape. 3. Sensitivity of Fredonia grape varied with season (stage) and increased from spring to autumn. Absorption of the gas also increased. 4. Fredonia and Delaware grapes were exposed to the gas from May 23 to Oct. 29 of 1967 to clarify the effect of preceding year exposure on shoot growth and cluster formation. Degree of leaf lesion of Fredonia grape became remarkable in proportion to the gas concentrations and the extention of exposure duration. Also leaf lesion of Delaware grape formed abundantly at the concentration of 0.26ppm after extension of the exposure duration. After terminating the gas exposure, new shoot growth and cluster formation of Fredonia grape decreased in 1968 with increasing gas concentrations, corresponding the degree of leaf lesion and falling in 1967. Shoot growth of Delaware grape decreased at 0.26ppm and cluster formation also decreased at 0.13ppm and above.
Gynoecious, gynomonoecious and monoecious cucumber varieties of foreign and Japanese origins were treated with gibberellin. Promoting effect of gibberellin upon staminate flower formation was strongest in gynoecious strains, weaker in gynomonoecious varieties and weakest in monoecious plants. As the result, the application of gibberellin diminshed the difference in sex expression between gynoecious and monoecious plants. It was also observed in all the treated varieties that gibberellin promoted the internode elongation of cucumber in low concentration but inhibited it in high concentration. Foreign gynoecious strains which had originally shorter internodes were more strongly offected than Japanese varieties in internode elongation, but no marked difference was found among Japanese varieties.
Twenty potted plants each of Donner variety were transfered from the open to a greenhouse, in which minimum temperature was maintained higher than 10°C, at two weeks intervals from September 28 to February 2. One half of each group was kept under natural day length, while another half was exposed to longday (16 hours), and their subsequent vegetative and flowering behaviors were recorded. Petiole length and leaf area of new leaves and flower cluster length were reduced as the transfer was delayed until November 23, and thereafter, they were increased as it was delayed. This result showed that dormancy in Donner variety was deepest in late November, and was broken gradually by chilling temperature during winter in this experimental condition. Vegetative growth of the plants exposed to long day was better than that of the corresponding plants grown under natural day length (short day). The promoting effect of long day was least in the plants transfered in late November, and was significant in the plants in non-dormant condition. Runner was not formed in the plants transfered earlier than January 18 under natural day length, and earlier than January 4 under long day condition. It seemed that the plants could not form runners until their dormancy was nearly broken. A flowering period of about 60 days was followed by a second flowering period with a short interval of few flowerings in the plants under natural day length. Under long day condition, the second flowering period was observed in the plants exclusively transfered from October 26 to January 4 while it was not found in the plants transfered earlier or later than the above mentioned period. This result suggested that the plants in deep dormancy could form flower buds even under the long day condition which was known to be unfavorable to the flower bud formation. Proper time of covering plants with plastic film was discussed in relation to the forcing of Donner variety.
Wooden frame experiments were carried out to clarify the suitable combination of nitrogenous dertilizer between the basic fertilizer and the side-fressing upon the tuber-formation and tuber-thickening growth in sweet potato. Four types of soil were used. 1. In spite of the differences of soil used, tuber yield at the plot of NH4NO3+(NH4)2SO4 was the highest among the following three treatments, that is, NH4NO3+(NH4)2SO4, NH4NO3+CO(NH2)2, and NH4•NO3+NH4NO3. 2. In the plot of NH4NO3+(NH4)2SO4, it was more unfavourable to tuber-formation than other treatments owing to the considerable elongation of vines during the tuber-formation stage from the middle of July to the middle of August. On the other hand, yield of tubers at the plot of NH4NO3+(NH4)2SO4 was increased, especially that of large tubers, as it was favourable to the accumulation of assimilation nutrients owing to the vigorous vine growth during the tuber-thickening period. 3. From the results of this investigation, it is evident that dry matter content of tubers at the plot of NH4NO3+(NH4)2SO4 was the highest among these treatments in the light soil, that is, sand to loam, with the exception of clayey loam, in which it was rather low.
As previously reported, both MH-induced swelling and long-day-induced bulbing were caused by inhibition of meristematic activity in the buds of onion plants. On the basis of these results, this investigation was undertaken to clarify the relationship between the bulbing or swelling and function of meristematic region of the onion using cultivar‘Kaizuka-wase’, and this paper reported that the swelling of sheath was induced by means of mechanical procedure or removal of meristematic region. 1. Each leaf of onion plants grown under short-day was removed separately from the disc, and was implanted in sterilized sand after curing. Intact plants served as control were kept under the same condition as they were implanted. Twenty days after implanting, the basal leaf- sheaths of the treated plants swelled even in short-day condition, but those of intact plants did not swell. Especially, the 3rd and the 4th leaf-sheath of the treated plants swelled three or four times as thick as the same sheaths of the intact plants, but the inner sheaths less swelled. Both parenchyma cells and inter-cellar spaces of the sheaths of the treated ones enlarged in size, although it was not followed by an increase in sugar content in the leaf-sheath. 2. The leaf-sheaths failed to swell when leaves removed about two-third of blade were implanted under short-day and even when complete leaves were implanted under dark condition. On the basis of this result, it seemed reasonable to assume that cell enlargement will depend on the photosynthesis or on the process of high intensity of light. 3. The onion plants removed apical buds from the lower part of disc (bottom) by means of razer blade were planted in sterilized sand under short-day, and the plants with apical bud served as control. Thirty days after treatment, the leaf-sheaths of the treated plants swelled as thick as those of ‘leaf-culture’. On the contrary, the onion plants with apical bud failed to swell their sheaths. 4. Both onion plants removed apical bud and intact plants were grown under short-and long-day conditions. The plants without apical bud swelled their sheaths either in long-day or in short-day, but failed to elongate their leaves, and plants with apical buds swelled only in long-day. Long-day condition was more effective in swelling than short-day condition.
Several investigations were carried out to elucidate the effects of high salt concentrations and osmotic pressure of rooting medium on the growth, water uptake and osmotic pressure of root sap of cucumber seedlings in water and sand cultures. In addition, the specific difference in ability to stand the high salt concentrations was examined using cucumber, eggplant, tomato and peper plants grown in gravel cultures as test plants. The results obtained may be summarized as follows: Growth of cucumber seedlings was significantly suppressed when grown in rooting media of both KNO3 solutions and balanced nutrient solutions at the osmotic pressure of 2.5 to 3.0atm, and it was severely depressed when the osmotic pressure of both solution was raised to 4.0 to 4.5atm. In an experiment where cucumbers were grown for several days in growth media to which polyethylene glycol added to change its osmotic pressure without any change in nutrient concentrations, depression of growth occurred, and transpiration rate was decreased at the osmotic pressure of higher than 1.8atm. Osmotic pressure of root sap of cucumber plants grown in 2.4atm pressure medium was about 2atm higher than the one of those grown in the standard medium of 0.6atm pressure. In another experiment, adaptation of cucumber plants to high osmotic pressure of growth medium was observed, when it was raised stepwise from 0.6 through 1.8 and 3.0 to 4.2atm at two day intervals with polyethylene glycol and by increasing the concentration of valanced nutrient solutions respectively. This phenomenom was more remarkable when polyethylene glycol was used to increase the osmotic pressure. Cucumbers were the most sensitive to high salt concentrations, followed by tomatoes. Eggplants and peppers showed higher ability to tolerate them.
Anatomical and histochemical studies on phagocytosis were carried out with the juvenile portion (digestion was in an early stage) and the mature portion (digestion was in a late stage) of the wild rhizome of Cymbidium goeringii REICHB. f. Using PAS reaction and ruthenium red method, it was detected that the positive substance with PAS reaction in fungal clot was mainly pectin-like substances. The results with ninhydrin-Schiff′s reaction and azure B method suggested that protein and RNA of fungi were gradually decomposed in the course of content in host- and digestion-cells were indicated by the result with Feulgen method. The significance of phagocytosis in the transference of nitrogenous compounds was discussed in connection with the organogenesis of this orchid.
This study was carried out to ascertain the mechanism and favourable condition of germination of some palms (Livistona chinensis, Phoenix roebelenii and Sabal species) in 1966 through 1969. The results obtained are as follows: 1) The seed of Livistona chinensis is very easy to germinate. The cotyledon elongates to develop outside the seed at a certain distance, but the edge of it attached at seed. The seed of Phoenix roebelenii is the smallest one in the genus of Phoenix and the pattern of germination is close to that of Canary palm dealt with in the previous paper. The seed of Sabal palmetto has a solid endosperm tissue, and shows elongation of the cotyledon in the distant position from seed. 2) The optimum temperature for germination is about 30°C in Livistona chinensis and Phoenix roebelenii, while about 25°C in Sabal palmetto. These palms showed the percentage of germination above 90. 3) The seed of Livistona chinensis germinate very well in vermiculite, while the seed of Phoenixroebelenii germinate well in every soil examined. Sabal palmetto shows poor germination in clayey soil at 35°C. 4) The least days for germination are 12 in Livistona chinensis, 25 in Phoenix roebelenii and 14 in Sabal palmetto respectively. 5) There is no prerequirement for seed germination in Livistona chinensis, Phoenix roebelenii and Sabal palmetto although Sabal minor needs some months for after-ripening. The germinability of seed in Sabal minor lasts about one year in the room storage, although it lengthens about two years and eight months in the refrigerator storage (3-5°C).
Investigations were made for the growth and development of Aphelandra squarrosa cv.‘Dania’ grown under 60%-, 30%-, 16%-, 10%-and 5%-light conditions. 1. The 30%-, 16%-and 10%-light plants were taller than the others. The stem of 5%-light plant was the thinnest of all. Among the others differences in stem thickness were insignificant. 2. For the growth in plant weight 30%-light was the most favourable of all. The total weight of the unshaded plant was not different from that of the 30%-plant in the earlier growth period, but it was considerably small as compared with the latter in the advanced growth period. The most deeply shaded plant did not show the significant increase in dry weight throughout the experimental period. Leaf growth in weight was larger in the 30%-and 16%-light plants than in the others. The largest leaf area per plant was recorded for the 16%-light plant. The ratio of leaf area to leaf weight, or L/F ratio, became larger with the decrease of light intensity. 3. The longevity of leaf was longer in the more deeply shaded plants than in the unshaded. Plasto chron tended to delay with the increase of shading. Leaf shape was independent on light condition. Unshaded leaves were rugous and greenish yellow in color, while the shaded were smoothed and green or deep green. 4. The formation of flower bud was strongly dependent upon light intensity and was not observed under the more deeply shade. 5. The shapes of light-photosynthesis curves differed with the growth conditions. Those of the unshaded leaves were of sun-plant type compared with the shaded. 6. The proportion of various organs in plant body was influenced with light condition. The root of the deeply shaded plant was small in proportion, while the proportion of leaf was small in the unshaded.
This study was carried out upon a means for stably maintaining both O2 and CO2 concentrations within storage atmosphere in closed CA system. In a clrosed CA system, the storage atmosphere is recirculated by an air pump through a scrubber. Exess CO2 in CA chamber is removed by the scrubbing of the storage atmosphere. Level of O2 in CA chamber is controlled by means of the ventilation of fresh air. However, intermitent ventilation of air results in fluctuation in the concentration of O2. Fundamental tests were carried out upon O2 concentration in CA chamber. The strongest correlation was observed between O2 concentrations within modified atmospheres and O2 contents of water under them. It was clear that a part of O2 within water have been discharged into modified atmosphere when water under air was touched low-oxygen atmosphere. In general, a scrubber using water makes possible a means for continuously removing the excess CO2 in storage atmosphere. Authors were found that water became a very usefull method to maintain both O2 and CO2 concentrations in CA chamber of closed system. Such a laboratory apparatus had been designed as a approach Uota′s apparatus and used successfully in controlled atmosphere studies on eggplants. In new closed CA system, N2 gas was introduced into the CA chamber to reduce the O2 concentration at the first. Eggplants, as a result, were reduced the respiration rate. The most of CO2 produced their respiration during the storage was removed by the water in the gas-exchanger. The O2 being consumed with their respiration was supplied from O2 of current water through the gas-exchanger, simultaneously. The scrubbing of atmosphere by a large amount of water would provide uniform levels of O2 and CO2 in CA chamber and the keeping quality of eggplants after three weeks had been well evaluated.
In McIntosh apple fruits, investigations were carried out on the reasonability of application of respiratory climacteric to the determination of the optimum harvest date for storage and the significance of determination of flesh firmness, soluble solids and acid contents for maturity determination. And a new method for maturity determination was devised on the basis of the pattern of the respiration rate variation of a fruit arising from the change of period from picking till measuring. Here, a mention must be made on the terms of RC and rc. The former stands for respiratory climacteric“on the tree”estimated from the respiration rates of fruits picked at different dates, and the latter dose that of at each fruit“off the tree.” 1. Considerable individual variation was observed on the respiration rate on a weight basis in fruits picked at the same time, but this may be neglected by using fruits of uniform appearance. 2. When the respiration rates of each picking for periods of about ten days following harvest were measured, all stages of respiratory climacteric were found at earier pickings but rc-minimum (min.) was not found later and neither rc-min. nor rc-rise at last as fruits were getting ripe. 3. In order to estimate RC, fruits were picked ten times and the respiration rates were measured. In such cases, the longer the time from picking till measuring became, the sooner RC appeard. 4. The usual method for RC estimation requires respiration measurements on the fruits picked several times at successive dates. And an estimation on the time of RC-min. cannot be made before RC-rise appears. Besides, RC pattern varies with the time from picking till measuring. It seems, therefore, that it is not a suitable method for the determination of the best picking date of the fruit for storage. On the contrary, if the difference of the respiration rate between two measurements carried out different hours after picking is applied, RC estimation becomes possible by only one picking. In other words, when the respiration rate measured 24 hours after harvest is smaller than that done after six hours and larger than after 48 or 96 hours it is before RC-min., and in the reverse case it is after RC-min. 5. No index to maturity was found in flesh firmness or acid content. The variation of soluble solids proved to be taken as a reliable index to maturity. But it has no practical use because it does not allow of the determination being repeated on the same fruit and is involved in considerable individual variations.