Rind yellow spot, a physiological disorder of Naruto (Citrus medioglobosa Hort. ex TANAKA), usually appears at late January, increases rapidly from February to mid-March, and symptoms do not develop after late March. Thus, the period of occurrence seems to be associated with low temperatures during the winter. Affected fruits produced a much higher amount of ethylene compared to healthy fruits when picked before late March, while those picked after that did not. However, when the latter were subjected to a temperature of 5°C and transferred to 20°C, there was an increase in the rate of ethylene production in response to the low temperatures. Peak rates were repeated upon transfer from 5°C to 20°C. These results suggest that low temperatures, possibly along with diurnal changes of temperature in winter, are involved in the development of the disorder.
1. Little is known about the conditions which cause the shedding of flowers and fruits of satsuma mandarin trees. 2. Six 15-year-old satsuma mandarin trees, growing in Fujieda, one of citrus regions in Shizuoka prefecture, were selected for uniformity in size and generaln conditions. Each flower was tagged to secure detailed informations with respect to its performance. 3. Smaller flowers were found more on the horizontal framework branches than on the vertical ones. 4. The development of flowers on the leafless shoot was inferior to that on the leafy shoot in size and weight. 5. Fruits with the larger ovaries on June 8 showed less drop throughout the season, whereas most of those with smaller ovaries ceased growth and abscised earlier in the season. 6. On the vertical framework branches 21.2 per cent of fruits reached maturity, whereas, 14.4 per cent of fruits on the horizontal branches reached maturity. 7. Flowers or fruits on leafless shoots, being inferior in nutritional competition, abscised earlier in the first period of dropping. Earlier in the season, flowers or fruits abscised at the abscission zone of the pedicel base. 8. Later in the season (the second period of dropping), fruits abscised at the abscission zone of the fruit base. Dropping of fruits on leafy shoots, being superior in nutritional competition, did not occur until the end of June. 9. The ratios of leaves/flowers or leaves/fruits decreased as the season proceeded and were larger on vertical framework branches than the horizontal ones. 14-15 leaves per fruit (on the basis of the number of leaves at full bloom) may be an appropriate criterion for reasonable fruit production of satsuma mandarin oranges.
1. Topping before bloom with removal of lateral shoots produced a slightly longer clusters in the first crop compared with those not treated, and augmented the number of seeded or seedless berries per cluster, resulting in a marked increase in cluster weight. On the other hand, the crop included some clusters which did not color, and showed a decreased refractometer index of the fruit juice, when the second crop was left on the second lateral shoot. Topping after bloom with removal of the lateral shoots showed few or no effects on berry weight, seeded berry set, cluster length and cluster weight. 2. Treatment of clusters in the first crop with gibberellin after bloom promoted the enlargement of both seeded and seedless berries, improving the weight and shape of the cluster. Especially, seedless berries treated with gibberellin showed a value about 2.5 times, 10.9g, that of those untreated, on control shoots. The weight of clusters treated with gibberellin on the shoots was on the average about twice as much as that of the untreated clusters, 196g. The refractometer index and acidity in both seeded and seedless berries decreased with the treatment of gibberellin. 3. Topping at node-order 10 with removal of lateral shoots promoted the development of second lateral shoots arising from axillary buds on the bearing shoots, causing them to bear the second crop. In those treated before bloom toward the end of May, the lateral shoots and the berries of the second crop grew most vigorously compared with those treated at other topping times, though the bearing rate of the clusters per shoot and the activity of their development were a little low. The bearing rate of clusters, the development of rachises and their number showed the utmost value in those treated by topping after bloom in the middle of June. The same result with regard to the age of bearing shoots topped after harvest was obtained by topping at the green part. Clusters produced from this topping contained more nitrogen and carbohydrates than those from topping at the tip of the bearing shoots which were not so well differentiated and had fewer rachises. If the topping time was delayed or if the topping was performed at a mature part of the bearing shoots, the second lateral shoots became weaker in growth and bore clusters with aborted rachises. 4. Berries of the second crop grew less vigorously than those of the first crop. Berry weight of the second crop produced by topping on May 31 revealed a maximum of 8.8g at harvest and that from July 13, 6.4g. The number of berries per cluster in the second crop born by topping toward the end of May through late June was about 2 or 3 times more than that of the first crop. The cluster weight was also superior to that of the first crop. 5. The second crop showed a higher refractometer index and acidity than the first crop. And as the topping was late, there was also a tendency for the refractometer index to lower, but the acids to increase. However, the quality of the second crop was improved by delaying the harvest time or by covering the plants with plastic film in September, producing an increase in soluble solids and a decrease in acidity.
A long-term preservation of germplasm of fruit trees is becoming important. This study was designed to develop a routine method for long-term preservation of hardy deciduous fruit buds in liquid nitrogen. Dormant shoots of apple (Akane, Red Gold, Jonathan, Fuji, Starking Delicious, Golden Delicious), pear and Japanese pear (Chojuro, Hokusei, Mishirazu, Bartlett, Flemish Beauty), currant (London Market), raspberry (Latham), blueberry (Harbert), gooseberry (Oregon Champion) were collected in early January and were subjected to an artificial hardening regime which consisted of holding samples at -5°C for 14 days, -10°C for 3 days to induce maximum hardiness. After hardening the twigs enclosed in polyethylene bags were cooled at 5°C increments each day to -30°C, and then to -70°C in 10°C increment at two hours intervals. Twigs frozen to selected test temperatures were thawed in air at 0°C. Twigs prefrozen to -40°C or -50°C were immersed in liquid nitrogen for 2 hours, and were then rewarmed slowly in air at 0°C. In the twigs of apple (Akane, Red Gold, Jonathan, Fuji, Starking Delicious, Golden Delicious), pear (Mishirazu, Hokusei, Flemish Beauty) currant (London Market), gooseberry (Oregon Champion), little or no injury were observed in the leaf buds and cortex, when immersed in liquid nitrogen after prefreezing to -40° or -50°C. Thus, this prefreezing method is applicable to the longterm cryopreservation of leaf buds of these hardy deciduous fruit trees in liquid nitrogen.
To clarify the role of nitrogen applied in the previous autumn and stored in the tissues which would be utilized in the development of organs or tissues in the following spring, calcium nitrate containing 11.4g N labelled with 9.64 excess % of 15N was added to the soil in each pot carrying an eleven-year-old satsuma mandarin tree on Nov. 18, 1974 (as an autumn nitrogen), or Mar. 1, 1975 (as a spring nitrogen). The results obtained were as follows: 1. The proportion of autumn nitrogen supplied 21 days before harvest to the total nitrogen were 11, 5, 11.3, 2.6 and 3.3% in the leaves on bearing shoots and non-bearing shoots, peel, and pulp, respectively. The results indicated that the amount of autumn nitrogen incorporated into fruits was far lower than that into leaves. 2. The utilization rate of nitrogen supplied in autumn and spring during the period from the time of labelled nitrogen application until the sampling time of mid-June were 41.4 and 25.1%, respectively. 3. Breaking up the tree, the total nitrogen in the newly developed tissues such as spring leaves, spring shoots and young fruits was 28% originated in autumn nitrogen, and 17% in spring nitrogen. 4. The amount of nitrogen in one-year-old leaves decreased through the stage before spring flush and through the period of spring shoot formation was corresponding to about 30% of total nitrogen in spring flush organs. 5. It was concluded that the increase of the 15N level in one-year-old leaves from Feb. 26 to May 15 resulted from the outflow of nitrogen from stems, roots and others to spring flush organs via one-year-old leaves, because the total nitrogen in one-year-old leaves did not increase. This amount corresponded to about 25% of total nitrogen content in the developing spring flush.
In this paper an account is given of fungi found in and out of the hairy root tissues of the wild species of Juglans, J. subcordiformis DODE and J. Sieboldiana MAXIM. The following results were obtained. 1. Finely branched and rod-form roots were observed at the end of root system. They seemed to be mycorrhiza of the sample tree. 2. The fungal sheath of M. maximus HONGO covered the hairy root of J. subcordiformis as same as in ectotrophic mycorrhiza, but hyha found in the cortex cells could not be identified whether it was the same fungus or not as the above fungus. 3. The septal hyphae sticked to the epidermis of the hairy roots near the place where Pezizales species grown, and bore the characteristic of Ascomycetes. But in the cortex cells were observed the hyphae without septa and clamp-connection. 4. The fungi without septa and clamp-connection were seen always in the cortex cells through all researches. However, any sign of disease was not recognizable and the phagocytic reaction of the cortex cells coincided with growth of the host. The hairy roots, therefore, were presumed to be an endotropic mycorrhiza caused by the fungus. 5. The allied but uncertain fungi were also observed in the cortex cells of J. Sieboldiana.
A chromatographic study of methanol-soluble leaf extracts was undertaken to analize the phylogenetic relationships between a number of species, vavieties and cultivars in Brassica and its allied genera. Raphanus sativus (genome constitution; RR), 9 out of 18 detected spots in this species being quite specific, was remarkably different in its characteristic spot pattern from three diploid species of Brassica and Sinapis arvensis. Accordingly, it was clearly indicated in the chromatogram on the occurrence of two genome-specific spot groups originating from both parental species that Raphano-brassica was composed of R. sativus and B. oleracea. B. campestris (AA), B. nigra (BB), B. oleracea(CC) and S. arvensis (SS) could be determined from each other by their genome-specific spot patterns, though many kinds of spots detected usually occur throughout those species. Because of the similarities of spot constitution in the diploid Brassica species, the spot patterns of three amphidiploids Brassica species (AABB, AACC and BBCC), natural or artificial, could not be revealed as a complete complementation of the spot groups of the diploid ancestral species. Based on peculiar spot patterns on the chromatograms, cultivars examined within B. campestris or B. oleracea could be distinguished from each other in some minor points, but the intraspecific variations of spot patterns did not correlate with taxonomic rank. Good numerical information of the phylogenetic affinities between and among the taxa analized could be obtained by the application of the concepts of paired affinity and grouped affinity (Ellison et al., 1962) to the results of the present study. Referring to the affinity values it will be noted that : R. sativus generally shows the lowest affinity to all other species used. S. arvensis is closer to B. nigra than to the other species used. The highest degree of affinity is obtained between B. campestris and B. oleracea, and B. nigra shows a higher affinity to B. campestris than to B. oleracea.
In order to explore the possibility of application of isozyme analysis to melon breeding, several enzymes of melon seedlings were studied using the polyacrylamide gel isoelectrofocusing technique. The plants examined included 10 cultivars of 3 botanical varieties and 3 F1 hybrids between them. As to the zymograms of glutamate dehydrogenase, malate dehydrogenase, and esterase, there was no significant difference among cultivars. In the peroxidase isozymes there was a slight difference in zymograms between powdery mildew resistant cultivars and susceptible ones : that is, the former had 22 bands and the latter 21 bands. In the acid phosphatase isozymes remarkable differences in banding patterns expressed by optical density were shown not only among varieties, but also within a variety, that is, between the American type and the British one in var. reticulatus. It is concluded that acid phosphatase isozymes seem useful for the discrimination of varietal differences among plants, and accordingly it may be applied to the selection in melon breeding.
Effects of fertilization and foliar spray treatment on the ascorbic acid content of lettuce and garland chrysanthemums were investigated. 1. The growth of garland chrysanthemums was not affected by the treatment of different compositions in nutrient solution, but that of lettuce was greatly influenced and dry weight decreased in 1/2N, 1/2P, 1/2K, 1/2Ca, and 1/2Mg regimes. The ascorbic acid content of both vegetables were inclined to decrease in 3/2N, 3/2K, and 1/2Mg regimes and to increase in 3/2P, 1/2Ca, and 3/2Mg regimes of nutrient solutions. Urea foliar spray treatment largely increased the ascorbic acid content. 2. The fresh weight of lettuce grown in 1/4 fold of standard nutrient solution was decreased 27-46% as compared with that of 1/2 fold or more concentrations, but the ascorbic acid content was singularly increased at that time. There are positive correlations between the ascorbic acid and sugar content, and these relationships were discussed. A total of four or five foliar spray treatments of 0.5% of urea solution every 5 days was expected to increase the ascorbic acid content. 3. The treatment of very low concentration of s-triazine herbicide did not increase the growth of lettuce. But foliar spray treatment of 2.5% simazine solution increased the ascorbic acid and sugar content, and decreased the NO3-N content.
Possibility of flower bud differentiation in spring was studied for the purpose of regulation of flowering in Hydrangea macrophylla and it was intended to clarify effects of high temperature and day-length during the vegetative stage on flowering. 1. Besides the natural flower bud differentiation in autumn, normal flower bud differentiation was induced in spring when cutting was done by using new shoot in February. High temperature and day-length during the vegetative stage had no effect on flower bud differentiation. 2. Velocity of flower bud development was suppressed when Hydrangea macrophylla were treated with high temperature during the vegetative stage. Day-length treatments after high temperature treatment affected on flower bud development seriously. Most of the plants flowered under short-days but did not so under long-days due to necrosis of the clusters. 3. Hydrangea plants entered dormancy after flower bud differentiation when they were treated with high temperature during the vegetative stage under long-days. Their dormancy was broken by chilling treatment and they flowered normally. However, when hydrangea plants were not treated with high temperature during the vegetative stage, they did not enter dormancy after flower bud differentiation and flowered normally. It is suggested that high temperature and long-days during the vegetative stage are responsible for entering the onset of dormancy in Hydrangea macrophylla.
Rooted cuttings of carnation, cultivar ‘Yosooi’, were planted 12 times a year at the intervals of about a month from Jan. 26, 1969. They were grown in a greenhouse. Two to three weeks after planting the plants were pinched, and three lateral shoots were allowed to grow on each of the plants. Water was applied to them by subirrigation method. The amount and feature of consumptive water use of the carnation plants, thus cultured, were studied. The duration from pinching to flowering time, the fresh weight and leaf area of a shoot at the flowering time changed with the cultivation season, having drawn wavelike curves. They were the smallest when the plants were pinched in May, and were the greatest when pinched in October. The total amount of transpiration during the period from pinching to flowering changed seasonally. and that of water consumption (transpiration plus soil evaporation) changed also seasonally. The curves of their seasonal changes had two peaks and two bottom levels. When the plants were pinched in June and October, the total amount of transpiration and that of water consumption showed the upper extremes. They became the lowest when the plants were pinched in August and January. The plants pinched in June showed the greatest amount of water consumption of 523mm, and those pinched in January showed the smallest one, 375mm. The amount of transpiration per day increased as the plants grew, and it was greatly affected by weather conditions. Therefore, the amount of transpiration changed in parallel with that of pan evaporation. The amount of transpiration per leaf area in the plants which were at the middle stage of growth, budding stage, showed seasonal change in parallel with that of pan evaporation. The maximum amount of transpiration per leaf area was observed in mid August. The amount of transpiration per day in that time was 2.24mm. The minimum one, 0.35mm per day, was observed in mid December. The ratio of transpiration per leaf area to pan evaporation (transpiration ratio) of the plants at the middle stage of growth was smaller in spring, and it was 0.30-0.35cm3/cm2•cm. In summer, the transpiration ratio was 0.40 to 0.45cm3/ cm2•cm. In autumn and winter it was the greatest in the year, and was 0.50cm3/ cm2•cm. On the basis of the transpiration ratio, daily amount of water consumption of greenhouse carnations in various seasons were calculated.
To study the ripening phenomena in Golden Delicious, Starking Delicious and Fuji apples, fruit samples were taken at 7-14 day intervals with a total of 2 to 6 harvests during the period of maturation and ripening. The physicochemical components and quality were measured at harvest or after holding at 15°or 20°C, and the internal C2H4 concentration was also measured 1 day after harvest. 1. As harvest was delayed, there were increases in fruit weight, soluble solids and non-reducing sugars, and decreases in firmness, titratable acidity, alcohol insoluble solids (AIS), starch and total pectin. 2. During the 7-day period after harvest, soluble solids, non-reducing sugars and reducing sugars increased, except that in late harvested Fuji apples nonreducing sugars decreased, and titratable acidity, AIS and starch decreased, and softening also occurred except in Fuji apples. The amount of AIS decreasing was nearly equal to that of starch decreasing, which was nearly equal to the amount of total sugars increasing except in Fuji apples. In Starking Delicious apples, the higher the internal concentration of C2H4, the smaller the increase in non-reducing sugars during the 6-day period after harvest, while the increasing rate of reducing sugars was almost constant. 3. In Starking Delicious apples, firmness was correlated with fruit weight and starch, and multiple regression analyses showed stronger relationships of firmness at 1 day after harvest with fruit weight and of firmness at 7 days after harvest with starch, respectively. There was also a strong relationship between firmness at 7 days after harvest and internal C2H4 concentration. Non-reducing sugars and starch were significantly related to internal C2H4 concentration, and these relationships were little influenced by fruit weight. 4. When the decreases in titratable acidity and starch, and the increases in fruit weight and non-reducing sugars, proceeded in fruits on the tree, a rapid increase in internal C2H4 concentration occurred and then an acceptable quality was developed. Starking Delicious apples having a high internal concentration of C2H4 became overripe 7 days after harvest, as a result of a great loss in firmness. 5. These data suggest the following : When an increase in non-reducing sugars with a concomitant decrease in starch, and a decrease in firmness resulting in part from an increase in fruit size, and other ripening phenomena such as fruit coloring proceed with advancing maturity in fruits on the tree, a rapid increase of C2H4 production in fruit begins and subsequently the fruits reach a full maturity. During the 7-day period after harvest, the fruits having a low internal concentration of C2H4 at harvest do not develop an acceptable quality, despite gains in sugars and losses in acidity and starch. On the contrary the fruits having a high internal concentration of C2H4 become overripe with poor quality.
In the previous paper, it was reported that the chilling injury in a cultivar of mume (Japanese apricot) fruits, unlike many other commodities, develop much sooner at 5°-60°C than at 1°C. This paper reports 4 years′ investigation on the aspects of chilling injury in mume fruits in relation to such factors as cultivars, maturity, and storage temperature, as well as polyethylene packaging as preventive measure. A study was also conducted to test van der Plank and Davies′shypothesis that the occurrence of maximum chilling injury at an intermediate temperature which they observed in plums, peaches, and grapefruits grown in South Africa would be a consequence of the interaction of the opposing two-equilibrium and kinetic-factors. Nine cultivars of mume fruits were picked at the ordinary mature-green stage unless otherwise indicated, and stored at 0°-20°C. While the primary symptom of chilling injury was pitting on the peel in most cases, but sometimes peel browning appeared first. Development of chilling injury was generally more rapid at 5°C than at 0°C. At 10°C, the injury was not found in 11 out of 24 cases, but sometimes it occurred to a serious degree. At 15°C, no injury was found. Among cultivars used, Gyokuei was a very susceptible one showing rapid development and higher extent of the injury, while Bungo and Yasawa exhibited less sensitivity. Late-harvested fruits tended to be less susceptible than early-harvested ones even though the appearance at harvest was still in a mature-green stage. The extent of the injury also varied markedly with harvest years. Packaging with polyethylene film (0.03mm thickness) bag completely prevented the occurrence of the pitting injury of the fruits stored at low temperatures. The incidence of rotting, however, was comparatively sooner in the bags at 5°C, holding at 0°C was needed for long term storage. Prior to the storage at 5°C, a part of the fruits had been held at 0°C for several days. This treatment delayed the occurrence of the injury, as compared with the fruits of steady-5°C-storage, by an extent that exceeds the duration of 0°C-holding. This seems to be in opposition to van der Plank and Davies′ assumption, since, in addition to kinetic factor, the disposition towards injury (equilibrium factor) was considered more marked at 5°C.
Changes in respiratory rate of the cucumber fruits and in electrolyte leakage from the discs of tissues were investigated at various temperatures in the range between 0°-25°C with the purpose of research on the mechanism of chilling injury. 1. The respiratory rate of intact fruits continued to increase gradually at 0° and 5°C during storage, and the occurrence of pitting which was one of the typical symptoms of chilling injury was observed on the fruit surface at those temperatures after 5 days of storage. However, there was no symptom of chilling injury observed in the fruits stored at 10° and 20°C throughout storage period. 2. While, changes in the rate of leakage of potassium ion and of total ions into the incubation medium from the discs of fruits stored at 10° and 20°C showed a principally constant level during storage. The rate of leakage from the discs of fruits stored at 0° and 5°C started to increase rapidly on the seventh day after storage and reached to approximately twice rate compared with those from 10° and 20°C after 12 days of storage. 3. The rate of potassium leakage from the discs of the tissues was represented according to the Arrhenius equation in the range between 0° and 25°C. A breaking point was obtained in the figure of Arrhenius plots at the temperatures arround 7°C which corresponded with the critical temperatures for chilling injury. This breaking point in Arrhenius plots of rate of potassium leakage from the tissues of fruits that had been stored at 5°C for 9 days or longer became obscure. The rate of potassium leakage from the fruits tissues increased remarkably after suffering chilling injury. 4. To confirm the above mentioned results, the Arrhenius plots of rate of potassium leakage from the tissues of chilling sensitive plant, bell pepper, and from the chilling insensitive plant, potato tuber, were compared each other. There was a breaking point in the Arrhenius plots of rate of potassium leakage from the tissues of bell pepper as same as the case of cucumber fruits, but the figure of Arrhenius plots of rate of leakage from potato tuber tissues showed a linear line in the range of temperature between 0°and 25°C. From the results mentioned above, it may be reasonable to consider that the phase transition in the membrane of tissues of chilling sensitive plants occure at low temperatures and that disintegration of the membranes, e.g. plasmalemma, tonoplast, take place in the cells of the sensitive plants suffered from chilling injury.
This papper reports the changes of K ion leakage from sliced tissues and contents of phospholipid in eggplant fruits during storage. Effects of addition of phenolic compounds on K ion leakage, phospholipid contents, and ultrastructural changes of eggplant fruit sections were studied. K ion leakage of eggplant fruits stored at 20°C did not change during storage. In contrast K ion leakage of eggplant fruits stored at 1°C increased according to occurrence of chilling injury. Major phospholipids in eggplant fruits were phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Contents of PE and PC in unripe eggplant fruits decreased apparantly, but overripe eggplant fruits showed slight decrease of PE and PC contents during storage at 1°C. Eggplant fruits at harvesting stage showed decrease of PE and PC contents during storage at 1°C and 20°C. The rate of K ion leakage of eggplant fruit sections was increased by the addition of p-coumaric acid and chlorogenic acid. Pattern of K ion leakage induced by chlorogenic acid was similar to that induced by 2, 4-dinitrophenol. Addition of ascorbic acid depressed the increase of K ion leakage induced by chlorogenic acid at 1°C. Contents of PE and PC in eggplant fruit sections were decreased by the addition of chlorogenic acid at 1°C. Ultrastructural changes of eggplant fruit sections, for example swelling of mitochondria and partial disappearance of tonoplast, were accelerated by the addition of chlorogenic acid at 1°C.
The changes of L-ascorbic acid (ASA) content during storage in fruits and vegetables depends on interaction between ascorbate oxidase (E.C. 220.127.116.11) and peroxidase (E.C. 18.104.22.168) which oxidize ASA and oxidized ascorbate reductase (E.C. 22.214.171.124) which reduces oxidized ascorbate. The object of this experiment is to determine characteristics of oxidized ascorbate reductase and differences of this enzyme's activities in several fruits and vegetables. We also investigated the changes of the activities during development of chilling injury (browning) and yellowing that a decrease of ASA content was remarkable. The results obtained were as follows: 1. This enzyme catalyzed the reduction of L-monodehydroascorbic acid (MDHA) by means of NADH as a coenzyme and showed high activity in tris-HCl buffer. 2. The optimum pH and temperature of this enzyme were about 7.5-8.0 and 35 °C, respectively. 3. This enzyme was extremely sensitive to SH reagents such as p-hydroxy mercuribenzoate (PHMB), 5, 5'-dithio-bis-(2-nitrobenzoic acid) (DTNB), and monoiodoacetic acid and inhibited by chlorogenic acid. It was also inhibited by AgNO3 (1×10-3M, 1×10-4M) and FeCl2 (1×10-3M), but other metal ions didn't actually exert on its activity. 4. The activities of this enzyme were high in pumpkin, cucumber, and carrot in which ascorbate oxidase activities were high, while in leaf vegetables, potatoes, and sweet potatoes its activities were low. 5. This enzyme's activities during development of chilling injury in sweet pepper seeds and sweet potatoes in which ASA content decreased remarkably increased temporarily before occurrence of chilling injury and then declined with the advance of chilling injury. 6. The activity of this enzyme in spinach leaves lowered with the decrease of ASA content with yellowing.