Asparagine was the predominant constituent of the free amino acids in young fruit of Citrus unshiu Marc. In early August, asparagine increased exponentially with total N in the fruit peel, suggesting that it can be used as an indicator of the nitrogen status of young fruit. 15N data showed that the primary assimilation of ammonium was catalyzed by glutamine synthetase, and asparagine was also actively formed in the early stages of nitrogen assimilation. Nitrate assimilation occurred to a lesser extent than ammonium assimilation in the hour-order experiment using excised fruit. In the day-order experiment, however, nitrate taken up via the roots was assimilated in greater amounts than ammonium. 14C-asparagine was rapidly metabolized to different compounds, such as aspartate, acidic and neutral compounds, and alcohol-insoluble compounds. However, considerably less CO2 was formed from asparagine than from aspartate. Our data show that asparagine is not a dead-end-product but plays an important role in the supply of both N and C for the synthesis of other amino acids and protein in young fruit.
Water tolerance was compared among apple trees grafted on several rootstocks. 1. Pot-grown one-year-old ‘Fuji’ trees grafted on 6 different rootstocks were flooded for 21 days from July 14, 1981. Judging from the overall injury symptoms, trees on M9, MM106 and M7 were sensitive to flooding, while those on Malus prunifolia (weeping type), M11 and M27 were tolerant. 2. A similar flooding experiment was repeated in 1982 using one-year-old ‘Fuji’ trees on 9 different rootstocks (M4, M16 and M26 were added to the 6 rootstocks used in 1981) for a period of 30 days. After flooding treatment, the water was drained off and the recovery from injuries was observed for another 30 days. During flooding, trees on M9 and M4 showed the least tolerance and those on M. prunifolia and M16 showed the greatest. Trees on M. prunifolia and M16 recovered almost completely from flooding injury after water drainage and those on M 11, M7 and M27 did to a lesser extent. Trees on the other rootstocks exhibited no recovery, and especially those on M9 and M26 were totally killed within 1-2 weeks after drainage. 3. To investigate the effect of rootstock-scion interaction on water tolerance, factorial combinations were made between 5 scion cultivars (‘Fuji’, ‘Tsugaru’, ‘Golden Delicious’, ‘Starking Delicious’ and ‘Jonathan’) and 5 rootstocks (M27, M9, M26, MM106 and M. prunifolia). The grafted trees were flooded for 30 days in the growing season of 1982. No significant interaction was observed between rootstockscion combinations. Amongs scion cultivers, ‘Jonathan’ exhibited the greatest tolerance regardless of rootstock cultivars, while ‘Starking Delicious’ generally showed the least tolerance. ‘Tsugaru’, ‘Golden Delicious’ and ‘Fuji’ showed intermediate tolerance. On the other hand, among rootstock cultivars, M. prunifolia was most tolerant and M9 and M26 were least regardless of scion cultivars. Recovery after water drainage was prominent in all scion cultivars on M. prunifolia, whereas injury proceeded became intensified with all scion cultivars on M9 and M26.
In order to clarify the water relationships of the occurrence of hard end disorder in ‘Bartlett’ pear, the water potentials of leaves, fruits and stems and water influx into the fruit at the initial time of development of the disorder were investigated. 1. The stem water potentials were almost constant during the fruit growing season. The leaf water potentials fell after the end of July, but it showed large fluctuations before mid-July. The fruit water potentials fell gradually after the end of July, but it seldom fell greatly at the initial time of development of the disorder. In addition, there was no difference in water potentials between the normal trees and the tree affected by hard end. 2. The ratios of the water influx into the fruit per day to the fruit weight or the daily increase of fruit weight were evidently low at the initial time of development of the disorder (from mid-June to the beginning of July). However, there was no difference in the ratios between the normal trees and the affected tree, and the stronger the leaf water stress, the greater the drop in the ratios. 3. From these results, it seemed that the low ratios of the water influx into the fruit to the daily increase of fruit weight during the period from mid-June to the beginning of July tend to result in Ca deficiency of the fruit and the hard end disorder develop at this period in some trees grown in poor conditions which permit only insufficient Ca absorption.
Three-hour light break with a light intensity of 55 lux from 60-watt incandscent lamps increased the leaf growth of strawberry plants grown under natural short days of about 11 hours, and it was especially true when the light break was applied in the middle of the dark period. The major gibberellin(GA)-like substance in the acidic ethyl acetate fraction extracted from strawberry leaves and crown was confirmed to be GA19 or a GA-like substance strikingly similar to GA19, by using thin-layer chromatography and dwarf rice bioassay. The GA19-like substance level in plants treated with light break became higher than that in plants grown under natural short days after 9 days of treatment. But differences in the GA19-like substance level were not so clear among plants treated with light breaks at different times during the dark period. The possibility of GA turnover from the GA19-like substance to other GAs induced by light break was discussed.
In order to clarify the optimum day and night temperatures for anthocyanin synthesis of Benitade (Polygonum hydropiper L.), seedlings were grown for 10-14 days after the unfolding of cotyledons in the 4 outdoor plastic chambers regulated at different temperatures. In the two experiments with constant temperatures through day and night, at the range of 5-20°C and 20-35°C with 5°C interval, the anthocyanin content per plant was higher at 15-20°C. However, the anthocyanin concentration per fresh weight was higher at 10°C. In the 4 experiments with the respective night temperatures kept at 5, 10, 15 and 20°C, the effects of different day temperatures, 5-20°C, 10-25°C, 15-30°C and 20-35°C, were investigated. In the experiments with night temperatures of 10-20°C, the anthocyanin content was the highest at the day temperatures equal to, or at most, 5°C higher than the night temperatures, respectively. However, in case of the night temperature of 5°C, the anthocyanin content was higher at the day temperatures of 10-20°C, and the lowest at 5°C. As for the anthocyanin concentration in case of night temperature of 10-20°C also, it tended to become highest at the relatively lower day temperatures equal to the night temperatures. However, in case of the night temperature of 5°C, the anthocyanin concentration was highest at the day temperature of 10°C, and the lowest at 5°C and 20°C. In the 3 experiments with respective day temperatures kept at 10, 20 and 30°C, the effects of different night temperatures, 5-10°C, 5-20°C and 5-30°C, were investigated. Irrespective of day temperature treatments, the lower the night temperature, the higher the anthocyanin content and concentration, being highest at 5°C. From the above results, the optimum temperature for anthocyanin synthesis in Polygonum seedlings seemed to be 10°C for daytime and 5°C for night.
The effect of low light intensity on the growth and endogenous components (Cytokinin, auxin and sugar) of radish (Raphanus sativusL. radicula group) was investigated. In addition, Kinetin and naphthaleneacetic acid (NAA) was directly supplied to the intact hypocotyl to examine whether the inhibition of thickening growth of hypocotyl under a low light intensity could be overcome by them. Under a low light intensity, abnormal hypocotyl elongation was observed and the thickening of hypocotyl was markedly inhibited, so the T/R ratio became high. The cytokinin, auxin and sugar content of the hypocotyl rapidly increased with the thickneing growth under a high light intensity, but did not increase under a low light intensity. When intact hypocotyl was treated with kinetin or NAA under a low light intensity, NAA did not affect the thickening growth, but kinetin significantly increased the hypocotyl diameter. At the same time, hypocotyl elongation was inhibited by kinetin treatment. These results suggested that a decrease in cytokinin activity is one of the main factors inhibiting thickning growth of hypocotyl under a low light intensity and the inhibited growth can be overcome by a direct application of cytokinin to the intact hypocotyl.
Muskmelons (Cucumis melo L.) were grown in sand to determine the salt tolerance as affected by salinization of sea water, NaCl, Na2SO4 and MgCl2 in Experiment I, and MgSO4 in Experiment II at osmotic potentials of -0.95 (MgSO4 only), -1.20, -1.70 and -2.70 bars as compared to a control of -0.70 bars of base nutrient solution. Fruit fresh weight and whole plant dry weight were greatest in the control and decreased in each salinity with decreasing osmotic potentials of treatment solutions. At -2.70 bars fruit fresh weight in the control was 37.3, 31.4, 11.8, 24.8 and 17.0% in the sea water, NaCl, Na2SO4, MgCl2 and MgSO4 series, respectively. No plant died in the sea water and NaCl series. A few plants at -2.70 bars in the MgCl2 series withered by harvest. All plants died within 60 days after transplanting at -2.70 bars in the Na2SO4 series and at -1.70 and -2.70 bars in the MgSO4 series. The growth in decreasing order was control>sea water_??_NaCl>MgCl2> Na2SO4_??_MgSO4. The addition of single salts or sea water to the base nutrient solution increased the content of the respective added ions in leaves and soil solutions (SSa) and EC of SSa, and decreased osmotic potentials of SSa. Ca in leaves decreased in the Na2SO4, MgCl2 and MgSO4 series with decreasing osmotic potentials of treatment solutions. The result seemed to suggest specific effects of Mg and SO4 ions on muskmelons.
This study was conducted to clarify the rooting ability of 6 willow species, and the relationship between seasonal changes in the rooting ability of cuttings and the content of endogenous factors in comparison of easy- and difficult-to-root willows. Among easy-to-root willows there were Salix koriyanagi, S. gilgiana, S. babylonica and S. alba, and among difficult-to-root willows there were S. bakko and S. vulpina. Cuttings of S. koriyanagi, an easy-to-root willow, rooted readily throughout the year irrespective of NAA treatment. Cuttings of S. bakko, a difficult-to-root one, rooted poorly without NAA treatment. With NAA treatment, however, they rooted well from July to October, but did poorly thereafter. No differences in the activity of extracted auxin, nor in the content of total phenols were found between the easy- and difficult-to-root willows. The root promoting activity of water extract was always higher in the easy- than difficult-to-root willows, but it did not seem to participate in the seasonal changes in rooting ability in both the easy- and difficult-to-root willows, because of the lack of the correlation between them. In S. koriyanagi with and without NAA treatment and S. bakko without NAA treatment, there were no significant correlations between seasonal changes in the rooting ability and in the activity or content of endogenous factors. Only in S. bakko with NAA treatment, however, a significant correlation was recognized between the rooting ability and the activity of extracted auxin.
Seasonal changes in shoot development and in organ formation activities of shoot apex explants in vegetative phase were examined throughout the year in Cymbidium. Protocorm-like bodies (PLB) formation of shoot apices excised with two leaf primordia was morphologically observed under light microscope. The activities of shoot elongation, leaf differentiation, and PLB formation changed parallel with each other throughout the year. The activities remarkably increased in April and reached maxima in June. The activities decreased slightly in August and thereafter remained unchanged until the next March. Then, they decreased remarkably in August and disappeared in September. Definitely from the axillary region and adventitiously from the basal region, PLBs were formed. In the former case they were called “definite PLBs” and in the latter case “adventitious PLBs”.
In gladiolus, about 10 contractile roots developed from the stem between the leaf sheath base and mother corm at the beginning of the 3-leaf stage, while in oxalis (Oxalis bowieana Lodd.), only 1 contractile root, together with absorbing roots, developed from the base plate of mother bulb after planting. In both species, the dry weight of contractile root(s) reached a maximum simultaneously with the number of leaves, then it decreased with the contraction of the contractile root(s) showing the highest rate at the beginning of contraction. In gladiolus, the leaf sheath base thickened to form a daughter corm, while in oxalis, axillary buds of mother bulb and underground stem developed into daughter bulbs. The increase in the dry weight of daughter corm or bulbs began at the early period of contraction of contractile root(s), when the decreasing rate in their dry weight was greatest. The content of carbohydrates and nitrogenous compounds in plant parts changed with time almost in parallel with that of dry matter. In both species, the major carbohydrates were polysacchrides in leaves and mother- and daughter-corms and bulbs. Especially in oxalis, starch amounted to 70-80% of polysaccharides in mother and daughter bulbs. In the contractile root(s), however, soluble sugars amounted to 70-90% of carbohydrates before their maximal growth, and thereafter the total carbohydrates decreased rapidly toghther with soluble sugars with the contraction of contractile root(s). Most of the nitrogenous compounds were insoluble in all plant parts. The contribution rate of the contractile root(s) to the thickening growth of the daughter corm or bulbs was estimated at 22.4 and 64.7% in gladiolus and oxalis, respectively, at the early days of contraction of the contractile root(s), on the assumption that 100% of the decrement in the dry weight of contractile root(s) was contributed to the increment in the dry weight of daughter corm or bulbs.
1. Day/night temperatures of 30/24°C markedly promoted the growth of aboveground parts in both gladiolus and oxalis (Oxalis bowieana Lodd.), and especially in oxalis, continued unfolding of leaves and development of axillary inflorescences were without formation of daughter bulbs. Low temperatures of 17/12°C, however, depressed the growth of aboveground parts, and especially in oxalis, there occurred no increase in the number of leaves and leaf area and no development of inflorescences. While at 24/17°C, the growth was much favoured in both of the aboveground parts and the underground parts. Moreover, when root temperature was controlled independent of air temperature in gladiolus, the growth of aboveground parts was better at lower root temperatures, and such effect of root temperature was greater at the medium than high air temperatures. 2. In both gladiolus and oxalis, the number of contractile roots was not affected by air and root temperatures. The elongation and thickening growth of contractile roots, however, were promoted at lower temperatures. The maximal weight of contractile roots and its decrease following contraction were greater in order of low, medium, and high temperatures. Especially in oxalis, there occurred no thickening growth and in gladiolus, not a few contractile roots deteriorated, at the high temperatures of 30/24°C. The formation and thickening growth of daughter corm or bulbs were depressed at higher temperatures, and in oxalis no daughter bulbs were produced. The above-mentioned effects of temperature seemed to be mostly due to the root temperature, at least in gladiolus, according to the experiment in which air and root temperatures were controlled separately. 3. The contribution rates of contractile root(s) to the thickining growth of daughter corm or bulbs were calculated as in the previous report (2). In oxalis, the values as high as 56-59% were obtained and they did not vary with growing temperatures. While in gladiolus, they were markedly low and differed with growing temperatures, being comparatively higher at lower temperatures.
Statice (Limonium sinuatumi Mill. =Statice sinuata L.) is one of perennials, and has a low temperature requirement for bolting and flowering. It is generally stated that in perennials and biennials the low temperature requirement is satisfied when growing plants are chilled in winter, but not when germinating seeds are chilled. In this study, the effect of chilling of germinating seeds on bolting and flowering of statice was investigated. Three cultivars, ‘Early Blue’ (early flowering), ‘Midnight Blue’ (medium flowering), and ‘Super Blue’ (late flowering) were used. 1. The statice plants sown in autumn developed flower stalks and formed flower buds in the following spring only when they experienced a certain amount of low temperature in winter. 2. The plants from seeds vernalized by chilling at 2-3°C for 30 days flowered earlier with a smaller number of foliage leaves than those from non-vernalized seeds. The vernalized plants produced a greater number of cut flowers in early crop season, that is, until the following March. Although L. sinuatum is perennial, it proves to be a plant of seed vernalization type. 3. The most effective temperature for seed vernalization was 2°C. The temperature of 5°C had less effect. Early and medium flowering cultivars were vernalized sufficiently by 2°C for 20 days, while late flowering cultivar for 40 days. 4. When the vernalized seedlings were transferred directly to high temperature conditions (constant temperature of 30°C), and grown there for 5 days or more, the vernalization effect was nullified completely. Under field conditions, daily mean temperatures higher than 25°C caused the devernalization.
Ripening changes in chemical composition of the 4 winegrape cultivars were investigated during 3 years from 1979 to 1981. The cultivars tested were ‘Riesling’, ‘Chardonnay’, ‘Koshu’ and ‘Riesling Lion’, cultivated on the experimental vineyard of Yamanashi University. The results are summarized as follows: 1. The berry weights of ‘Riesling’, ‘Chardonnay’ and ‘Riesling Lion’ reached the maxima in mid-September, and were 1.6g, 1.9g, and 3.4g, respectively. The berry weight of ‘Koshu’, however, reached the maximum of 4.0g in mid-October. The berries of ‘Koshu’ and ‘Riesling Lion’ were heavier than those of ‘Riesling’ and ‘Chardonnay’. 2. The 4 cultivars showed respective changes in pH of the musts during ripening. At full maturity, the pH of ‘Riesling’ and ‘Chardonnay’ musts were 3.5, that of ‘Riesling Lion’ must 3.3, and ‘Koshu’ must 3.2. 3. In ‘Riesling’, ‘Chardonnay’ and ‘Riesling Lion’, the °Brix was 15% in early September and 18 to 19% in late September. In ‘Koshu’, a late cultivar, the °Brix was 15% in late September and 17% in mid-October. 4. The highest titratable acidity was observed in late July in ‘Riesling’ and ‘Chardonnay’, while in early August in ‘Koshu’ and ‘Riesling Lion’. At the harvest time, the value was more than 0.70g/100ml in ‘Chardonnay’, ‘Koshu’ and ‘Riesling Lion’, and 0.60g/100ml in ‘Riesling’. 5. The °Brix-acid ratios of the 4 cultivars at full maturity were more than 20 in the Kofu Area. The time to give full maturity, the °Brix, titratable acidity (g/ 100ml), and the ratio were mid-September, 17.3, 0.76, and 22.8 for ‘Riesling’; mid-September, 17.7, 0.88, and 20.1 for ‘Chardonnay’; early October, 17.6, 0.84, and 20.2 for ‘Koshu’; late September, 18.4, 0.81, and 22.7 for ‘Riesling Lion’, respectively. 6. At full maturity, the tartaric-malic acid ratios and the glucose-fructose ratios were 1.5 and 0.9 for ‘Riesling’, 2.0 and 0.9 for ‘Koshu’, 1.1 and 1.0 for ‘Chardonnay’, and 1.6 and 1.0 for ‘Riesling Lion’, respectively. 7. Several viticultural characteristics of the 4 cultivars were as follows. ‘Riesling’ suffered from white rot and ripe rot frequently, and the grapes were closely clustered and easily cracked. The whole ripening period was short and the heat accumulation for the optimum maturity was low, so it is a cultivar adapted to cultivation in cool areas. ‘Chardonnay’ seldom suffered from any disease and was a good producer. So this cultivar was easy to cultivate and can be adapted in cool areas. Both ‘Koshu’ and ‘Riesling Lion’ were easy to cultivate, although sometimes suffered from downy mildew. ‘Riesling Lion’ needed regulation of cropload. 8. The sensory impressions of the aftertastes of the wines made from the grapes of 4 cultivars were as follows. The ‘Riesling’ wine lacked vinous aroma and body. The ‘Chardonnay’ wine was fruity and harmonious with body and the best among the 4 wines. The ‘Koshu’ wine had a fresh and fruity aroma. The ‘Riesling Lion’ wine had a neutral flavor, and was slightly watery in taste.
The limonoid content in the component parts of Hassaku (Citrus hassaku hort. ex Tanaka) and pummelo(Citrus grandis Osbeck) fruits was investigated at monthly intervals. 1. The major limonoid in Hassaku fruit was limonin, showing a maximal concentration of 50ppm in the flesh in September. The nomilin concentrations in the flesh and segment membrane reached maxima of 20 and 500ppm, respectively, in August and then decreased rapidly. In the seeds, nomilin and limonin showed maximal concentrations in October and November, respectively. 2. All the parts of pummelo fruit except flavedo contained a large amount of nomilin, and it was particulary true in albedo and segment membrane. The deoxylimonin content in the segment membrane was similar to the limonin content in the segment membrane during fruit maturation. The limonin concentration in the seeds showed a maximum in December and it was far higher in the kernel than in the seed coat. 3. In pummelo fruit, the total limonoid content reached a maximum of 200mg per fruit. The total limonoid content in the seeds was less than that in albedo or segment membrane in spite of a high concentration of limonoids in the seeds. It became clear that in both Hassaku and pummelo fruits the limonin concentration reached a maximum one month later than the nomilin concentration in all the component parts.
Activities of lipoxygenase (LOX) and linoleic acid (LA) hydroperoxide (LAHPO) cleavage enzyme in flavedo tissues of Naruto (Citrus medioglobosa hort. ex TANAKA) fruit were investigated as related to aging of the rind. Activities of LOX and LAHPO cleavage enzyme were determined by measuring n-hexanal formed from LA and LAHPO, respectively. LOX activity was high in summer when the fruits were immature-green, low in winter, and again, considerably high in April when the fruits were matureorange. Subsequently, however, the activity decreased as the fruits regreened. The activity of LAHPO cleavage enzyme seasonally varied in parallel with LOX activity, although it was 20-100 times higher than the latter. Fruits harvested at different stages were held at 1 to 25°C, and LOX activities were determined. The higher the storage temperature, the faster the rise in LOX activity. However, as the fruits aged, the temperature which resulted in the highest LOX activity shifted downward (to 15°C). The optimum temperature for the development of color similarly shifted downward, being 25°C for immature-green fruits and 15°C for mature-yellow fruits. Gibberellin (GA, 100ppm) and high temperature (350°C, 48h) treatments of detached fruits not only delayed degreening but also reduced LOX activity, while ethephon (500ppm) treatment increased LOX activity.