1. The optimum day and night temperatures for a long-term growth of Delaware grapes were observed, by keeping young vines at the various controlled temperatures of the growth chamber (day) and thermostat (night). In the combinations of day (15°, 20° and 30°C) and night (12°, 18°, 24° and 30°C) temperatures, the shoot, root and total growths of April 26 to May 28 were most superior at the 20°C day and 24° or 18°C (average 21°C) night treatment. 2. Apparent photosynthesis of leaves was measured on fine days of the growing season by the Ganong′s punch method with Delaware grapes grown both in pots and in a field. As the results, the most suitable mean temperatures during the measurements were 20°C and 24°C (av. 22°C) within the range of 19° to 36°C. 3. Thus, it may be concluded that so long as the day temperature is optimum for the apparent photosynthesis of Delaware and its growth, the greatest growth can be expected when the night temperature is nearly the same with the day temperature. 4. From the practical point of view, such a place must be most suitable for Delaware growing where the daily or monthly mean temperature of 21°-22°C continues as long as possible to satisfy the temperatures needed for the berry maturation.
1. The morphology of berry growth of Delaware grapes from pre-bloom to maturity was studied. 2. Three distinct growth periods (I, II and III) were identified, after berry set. During period I, rapid berry enlargement occurred for 33 days. During period II, a striking decrease in growth rate occurred, and the duration of period II was very short, only about three days. During period III, the berry growth again tended to accelerate, especially in the fresh weight of berries, for 40 days. 3. The increase of the inner wall tissue in the pericarp was more rapid than that of the other tissues, and was closely related to berry development. 4. Inner wall tissue is constituted by cells of nearly uniform size and shape, which enlarged similarly during the growth of the berry. Outer wall tissue consists of various shapes and sizes of cells. Approximately seven layers in the external portion of the outer wall tissue become sclerenchymatous cells. Placental tissue also consists of cells of irregular shapes and sizes. The development of the placental tissue depends on the number of seeds which iarls contained in each berry. 5. The last cell division in the placenta and inner wall occurred 10 days after bloom. The mean transverse berry diameter at the time of the last cell division was 3.3mm. Cell division radially in the outer wall ceased two days after the last division of the inner wall. However, the cell division in a single row in midcircumference of the outer wall continued for 19 days after full bloom. Likewise, cell division in the peripheral layer of the outer wall, the hypodermis, continued for 33 days after bloom. This means that cell division in the outer wall during the latter half of the cell division period continued only in the tangential direction and ceased earlier in the inner than outer layers. The cell division in the epidermal layer continued for 33 days after full bloom; this was as long as in the hypodermal layer. At that time the transverse diameter of the berry was 12.2mm. This was the day of period I in the berry growth curve.
Both sap inoculation and graft tests were conducted with Nijisseiki pears (Pyrus serotina REHD.) to trace the communication of abnormal leaf disease (so-called Ijoyo) which develops only in a certain training system as stated already. 1. When the sap of abnormal leaves was inoculated to normal leaves, none of abnormal symptoms appeared on the treated leaves. 2. When the scions taken from abnormal shoots were grafted on normal shoots (stocks), newly sprouted shoots from the scions were all abnormal, but those from the stocks were all normal. On the other hand, when the scions taken from normal shoots were grafted on abnormal shoots (stocks), newly sprouted shoots from the scions were all normal, but those from the stocks were all abnormal. 3. The tips of main branches which had grown vigorously for 2 years and were expected to develop abnormal shoots in the following year, were removed in winter, and grafted on normal stocks in spring. At that time, most of newly sprouted shoots. from the scions were abnormal. When the tips were removed in autumn and grafted immediately on normal stocks, some half of newly sprouted shoots from the scions were abnormal. 4. When abnormal scions were grafted on normal stocks, all of newly sprouted shoots from the scions. were abnormal for 2 or 3 years. However, thereafter normal shoots sprouted occasionally from the old parts of the scions.
1. Vine growth, nutrient absorption and respiratory activity of fibrous roots as affected by both different nitrogen sources and controlled soil atmosphere were observed with two-year-old, non bearing Delaware grapes. Oxygen concentration in the soil atmosphere was controlled at six levels of 20 (air alone), 15, 10, 5, 2 and 0 (nitrogen gas alone) per cent respectively by mixing air with nitrogen gas. Sodium nitrate (NO3-N) and ammonium sulfate (NH4-N) were employed as nitrogen source and their effects on growth were compared in relation to the soil oxygen level. 2. Regardless of the soil oxygen concentration, average shoot length and total fresh weight of vines were always superior in the NH4-N than in the NO3-N treatment. The growth rate, however, was more depressed in the former than in the latter as the soil oxygen level decreased. 3. The total N concentration of leaves in the NO3-N treatment was nearly the same throughout the different soil oxygen levels, while that in the NH4-N treatment was lowered markedly as the soil oxygen level decreased less than 2 per cent. The P, K and Mg concentrations of leaves were depressed in the both treatments with decreasing soil oxygen level, though the trend with P and K was rather slight. 4. Respiratory activity of fibrous roots was measured with a Warburg′s manometer by soaking them in 0.1M solution of either sodium nitrate or ammonium sulfate. In general, the respiration rate was higher in the NO3-N than in the NH4-N treatment. When the oxygen concentration in the respiration chamber was changed from 20 to 0 per cent, the oxygen uptake and carbon dioxide evolution declined noticeably in both treatments. Particularly, the tendency was more marked in the NH4-N treatment, showing the higher R.Q. value than in the NO3-N treatment.
This study was designed to clarify the relations of germination and emergence of several kinds of seeds to moisture content of soils, with special reference to their moisture constants and moisture supplying capacities. Seeds were planted in the soils having different moisture contents in the depth of one cm from the surface, and numbers of emerged seeds were counted daily. After the final count, seeds remaining in the soil were exposed and number of germinated seeds were counted. Physical properties of soils used were shown in Table 1. 1. Minimum moisture content allowing germination of radish, rape, and sunflower seeds was close to P. W. P. (permanent wilting percentage) in the fine sandy clay loam (alluvial soil) and the fine sandy loam (volcanic ash soil), but was higher than P. W. P. in the coarse sand (river sand). Minimum moisture content allowing emergence of these seeds was a little higher than that for germination (Fig. 1). Critical moisture levels for carrot seed were higher than those for other seeds (Fig. 1). This may be due to the lower moisture absorbing power of carrot seed than that of other seeds (Table 3). 2. Average number of days required for emergence of each seed was found to be almost the same in the range down to a certain critical moisture content of the soil, below which number of days increased with the decrease of moisture content. This critical point was close to the minimum capillary moisture content in each soil (Fig. 4, Table 5). 3. Pre-soaking treatment decreased minimum moisture content allowing germination and emergence of pea seed, but had little effect to tomato seed, which was much smaller in size than pea seed (Fig. 5). 4. Basing on the above mentioned results, it may be concluded that minimum moisture content allowing germination or emergence of seeds are determined primarily by the moisture tension of the soil, but, at the same time, it is affected by the moisture absorbing power of seed, amount of moisture which should be absorbed by the seed for its germination or emergence, and moisture holding capacity or moisture supplying power of soil.
The present investigation was undertaken in an attempt to elucidate the physiological basis of pollen degeneration caused by low temperature in some vegetable crops, such as green pepper, tomato, eggplant, melon and strawberry. The vegetables were grown in an unheated glasshouse during winter season, and green pepper and eggplant were grown also in a growth cabinet maintained at 20°C (Table 1). Temperature in the unheated glasshouse during the period of study was shown in Table 2. Just prior to anther dehiscence, one anther was taken from each flower for the determination of pollen fertility, and the remaining ones were used for chromatographic analyses of free amino acids. The analyses were repeated several times during the period of growing. 1. Pollen fertility, estimated by percentage of apparently viable pollen grains stainable with acetocarmine, decreased with the fall of temperature in vegetables grown in the unheated glasshouse, as shown in Table 4. The anthers of flowers blooming in the period from December or January to March was reduced in weight and contained only empty pollen grains or degenerating sporogenous tissue as well as in the case of hereditary male sterile plants reported in the previous paper (Fig.2 and 3; Table 3 and 4). In April, however, the apparently viable pollen grains increased in number according to the rise of temperature, and the pollen fertility reached more than eighty per cent. On the other hand, the anthers of vegetables grown in the growth cabinet of 20°C contained sufficient pollen grains of viable appearance, even in the severe cold season (Table 4). 2. Thirteen to fifteen ninhidrin-positive spots were detected in the chromatograms from fertile anthers of the vegetables grown in the growth cabinet of 20°C or in optimum temperature season (Fig. 1). Chromatographic differences were detected visually in the composition of some free amino acids between the fertile anthers and sterile ones caused by low temperature in the unheated glasshouse. 3. In every vegetable tested, correlation was found between pollen fertility and content of proline (Table 4). The chromatograms of fertile anthers had a amazingly large spot of proline, which was either lacking or very faint in the chromatograms of sterile anthers (Fig. 1). The result was in general agreement with that of the previous paper refering to the quantitative difference of proline recognized between fertile and hereditary male sterile anthers. 4. In addition, sterile anthers had smaller spot of alanine than fertile ones in tomato, and a larger spot of asparagine in green pepper (Fig. 1; Table 4-1 and 4-2). Such relations between the pollen fertility and content of alanine or asparagine were not recognized in the other vegetable crops tested. 5. In conclusion, it may be assumed that the low content of proline in mature anthers is related with the pollen degeneration, and amino acids play an important role for development of pollen grains in the vegetable crops tested in the present study.
1. To elucidate possible relationship between branch development and elongation of related stem internodes, length of each internode of the main stem and length of branches were measured at regular intervals. 2. In general, each internode of the main stem except some basal ones continued its elongation for 6-8 days at higher temperatures and for 15-20 days at low temperatures. Before the termination of growth of an internode, the next new internode began to grow out. The internode elongation was more active in upper internodes than in lower ones. 3. In shaded plants and in plants treated with GA, elongation of upper internodes was very remarkable, but that of two or three basal internodes was only slightly affected by the treatment. In these plants, development of lower branches was poor and their subsequent elongation was considerably arrested, in particular, after initiation of enhanced elogation in upper internodes. 4. In plants treated with TIBA, the stem internode elongation was perfectly arrested for 2-3 days. Then, despite the subsequent restoration of internode growth, a remarkable elongation of lower branches was observed after this period of stem growth retardation. 5. It may be concluded from the data presented in this report that there is no morphological correlation between development off lower branches and elongation of relevant stem internodes. On the other hand, a marked influence of upper internode elongation on branch formation was confirmed. Plants with active elongation in upper intenodes had poor branches at lower nodes and vigorous branches at upper nodes, whereas plants whose upper internode elongation was in some way suppressed had active development of lower branches and restricted production of upper branches. 6. It was revealed that, notwithstanding the almost perfect similarity in the pattern of internode growth between the control and TIBA-treated plants, elongation of branches was far more active in the latter. This means explicitly that some physiological processes are operating here other than simple morphological growth correlation.
This experiment was carried out to elucidate the roles of leaves and roots in the bulb formation and development of onion plants, using the methods of defoliation and root-cutting with potted Senshu-Ki variety. (1) In the experiment on the continuous removal of leaf blade tips, it was shown that a rapid increase in plant height followed by a remarkable bulb thickening under long photoperiod was not always required as an essential process of bulbing. The bulb formation was retarded by continous severe removal of leaf blades, but not by slight one, and the bulb development was inhibited by the removal of leaf blades in proportion to leaf area of removed leaves. (2) Defoliation of alternate expanded leaves prior to bulb formation induced the retardation of scale leaf formation, and that during the bulb development inhibited the thickening of bulbs, The effect of defoliation was severer in the early stage than in the later stage, and the more the leaves were defoliated, the less the bulb enlarged. It was noticed that the defoliation of all leaf blades or leaves except the lower half part of bulb induced the emergency of foliage leaves instead of scale leaves even under long photoperiod. Thus, it was clearly suggested that the foliage leaves were developed with the nutrition supplied from roots (3) Removal of about half number of roots just below the crown before bulb initiation induced the promotion of scale leaf formation, and the same treatment during the bulb develoment resulted in the inhibition of bulb thickening. It was observed that the uniform fall over of tops was significantly promoted by root cutting (4) The promotive effects of root-cutting on the initial thickening of bulb and on the fall over of tops were affected by soil moisture. In other words, the former effect was strengthened in wet soil and the latter one in dry soil. These tendency were also ascertained in the subexperiment with the combination of root-cutting and soil moisture content.
1. Small seeded varieties of Spanish and Valencia types showed only shallow dormancy just after harvest, but large seeded varieties of Virginia type showed deep dormancy continuing during rather long period. 2. Differences of nature of dormancy due to difference of growing areas between Japan and Israel could hardly been observed. 3. Preheating for two to three days at 60°C or seven to 14 days at 45°C was most effective for breaking dormancy of peanut seeds. This treatment is usable for routine works. 4. Entire or partial decoating is much effective for breaking dormancy. Presoaking also induces rather high germination. Accordingly, the cause of dormancy of peanut seeds seems to be due to germination inhibitors contained in the seeds. These inhibitors are thought to be contained in both seed coat and embryo during some period after harvest, but to become soon contained only in seed coat.
In this experiment, five varieties of determinate type tomato, Heinz 1350, Heinz 1370, Heinz 1409, E. S. 24, E. S. 58 introduced from Heinz Co., and one determinate variety, Roma, and one indeterminate variety, Taiho, from Kagome Co. were tested. These varieties were compared with one another on the yields of trimmed fruits for processing, and of juice or puree in 1963 and 1964. The results obtained may be summarized as follows. 1. Roma was the highest and Taiho was the lowest, and the other varieties lay between them in yield rate of trimmed fruit for processing. In yield rate of juice, the similar result was obtained also. And Heinz 1370 was much alike to Roma. 2. Heinz 1409 was the highest and Taiho was the lowest, and the other varieties lay between them in yield of puree. But Heinz 1370 and Roma were much alike to Heinz 1409. 3. Heinz 1370 and Roma were both excellent in juice and puree yields per unit area, and Taiho and Heinz 1350 were also fairly excellent in both yields. Heinz 1409 was the lowest grade in both yields. As mentioned above, it was recognized that, for juice and puree yields, two determinate type tomato varieties, Heine 1370 and Roma, were excellent in the varities used in this experiment.