The effect of fruit temperatures on the growth and compositon of satsuma mandarin fruits was investigated during maturation stage, by enclosing fruits on the tree grown under natural conditions in transparent acrylic cylinders whose inside temperatures were regulated at 15°C, 23°C and 30°C, respectively.
Both a whole fruit and peel weights were greatest at 23°C and least at 30°C. But specific gravity of a whole fruit was much less at 15°C and 23°C then 30°C. Free acid content in the juice decreased more rapidly with an increase in fruit temperature. Total soluble solid and sugar content in the juice was highest at 23°C, followed by 30°C and 15°C in this order. In the peel, the lower the fruit temperature, the earlier the chlorophyll degradation and carotenoid accumulation occurred. However, chlorophyll degradation was inhibited and little carotenoid pigments developted at 30°C. ABA levels in the peel, also, began to rise at lower fruit temperatures and were lowest at 30°C. Coincident patterns of free ABA level and carotenoid content at respective treatments, particularly, indicate that ABA level in the peel may be involved in carotenoid synthesis which is affected by fruit temperatures. On the other hand, GA-like activities were not affected by fruit temperatures. These results suggest that temperature has influence on the maturation of satsuma mandarin fruits partly through its direct effect on fruits per se.

View full abstract

In order to clarify the relationship between water conditions and the occurrence of hard end disorder in ‘Bartlett’ pear fruit, it is necessary to know when the disorder begins to develop. In the present study, fruit characters seemed to be related to the occurrence of this disorder were investigated in relation to fruit growth and after ripening in comparison of a tree having every year a high percentage of hard end (affected tree) and normal, healthy tress (growing in the same orchard).
1. Between after-ripened fruits from normal and affected trees, significant differences were found in mean fruit weight, fruit length, degree of flatness of calyx end, and peel and flesh firmness. They were also found in the densities of pectic substance and tannin but not corky substance and starch determined by histochemical observations. However, it was pectic substance alone that showed a close correlation to flesh firmness in their distributions on the vertical section of each fruit.
2. Fruits from the affected tree were smaller in weight and size, and lower in Mg and higher in total polyphenol contents in calyx end than those from the normal trees throughout fruit growth. While, their cell size, Ca content and Ca/K ratio became inferior and K and HCl-soluble pectin contents became superior at calyx end to those of normal trees from 40 to 50 days after full-bloom. Further, from 55 to 60 days after full-bloom, peel firmness and contents of alcohol insoluble solids and holocellulose at calyx end of fruit, and from 60 to 65 days after full-bloom, the degree of flatness of fruit and flesh firmness, and α-cellulose content, at calyx end of fruit, became higher in the affected tree than normal trees.
3. At the time of ripening (about 120 days after full-bloom), there were found great differences only in peel and flesh firmness, contents of HCl-soluble and water-soluble pectins in calyx end of fruit between normal and affected trees.
4. From these results, it is concluded that hard end disorder begins to develop as early as 40 to 65 days after full-bloom, although, externally, it is characteristic of this disorder that the calyx end of fruit is kept hard even at after ripening stage perhaps due to insufficient degradation of pectic substances.

View full abstract

Seasonal and diurnal changes in pH level and organic acid content in exudate from a cut end made on grapevine Muscat of Alexandria were determined from late February to May 8, 1980. The exudate pH became lower until budbreak with increases of malic and tartaric acids. But the diurnal change in pH did not coincide completely with that in malic acid content.
The content of malic acid in exudate rapidly increased following the treatment of calcium cyanamide just after sunset on March 16, but the exudate pH was unchanged. On the other hand, the content of malic acid in exudate was not increased by spraying canes with ethrel just after sunset or covering them with aluminum foil during the day, although the exudate pH declined immediately after those treatments.
Diurnal behavior of malic acid content was observed to have the same tendency as CAM plants until budbreak.

View full abstract

Just before the coloring of loquat (Eriobotrya japonica Lindl.) fruits, each fruit on the tree was covered for 2 to 3 days with a polyethylene bag containing Ethylene Sieve, which evolved ethylene by moisture. Sugar content per fruit at this stage was less than 10% of that in the fully mature fruit. The content in the treated fruit increased more rapidly than that in the control. Ethylene sharply decreased the titratable acid content in the treated fruit, while that in control still increased or remained little changed. Activities of sorbitol-6-phosphate dehydrogenase and NADP-malic enzyme were enhanced during natural ripening of loquat. In the treated fruit, these enzyme activities bagan to rise earlier than in control. Change in rind color became already visible 2 to 3 days after covering the fruit, and chlorophyll content rapidly fell. The treated fruit reached maturity 4 to 11 days earlier than the control. The results were discussed in reference to ethylene effect on sugar accumulation in fruit tissues.

View full abstract

The seedlings of benitade (Polygonum hydropiper L.) were monthly grown in pots for 8-14 days from April to October to clarify the effect of different growing seasons on their anthocyanin content.
The anthocyanin contents per plant and per mg fresh weight increased rapidly at earlier than later stages of seedlings in all growing seasons. In some months, the increase of anthocyanin content per mg fresh weight was not found in later stages. In comparison among different months, the anthocyanin contents per plant and per mg fresh weight tended to be always higher in April and particularly in May, and lower in July, August and September.
The anthocyanin contents per plant and per rng fresh weight at the emergence of the first true leaf, at the commercial harvesting stage, were also higher in April and May, lower in July, August and September, being less than 60% of the former, and medium in June and October.
Until eight days after the unfolding of cotyledons, with few exceptions, the anthocyanin contents per plant and per mg fresh weight were significantly correlated negatively with mean daily temperature, independently of daily solar radiation, and positively with daily solar radiation, independently of mean daily temperature. At the emergence of the first true leaf, the partial correlation coefficients between anthocyanin content per mg fresh weight and mean daily temperature, daily solar radiation, or number of days after the unfolding of cotyledons were -0.667 (P< 0.01), 0.504 (P<0.05) or -0.019 (P>0.50), respectively.
In addition, cotyledons were higher in anthocyanin content than hypocotyl until the emergence of the first true that more anthocyanin could be synthesized leaf.
From the above results, it is presumed that more anthocyanin could be synthesized in Polygonum seedlings in the seasons with lower temperature or higher solar radiation.

View full abstract

While standard-type cucumbers usually bear a single pistillate flower (SP) on each pistillate node, there are variants that bear double pistillate flowers (DP) and multiple pistillate flowers (MP) per node. Genetical analysis of SP, DP and MP was carried out by examining the sex expression of F₁, F₂ and of the BC lines obtained from crossing these plants.
Our results showed that this flowering character was controlled by multiple alleles and that less pistillate flowering was dominant or incompletely dominant over more pistillate flowering. The locus controlling this character was named pf, and the genes for SP, DP and MP were named pf⁺, pf^d and pf^m, respectively.

View full abstract

Edible chrysanthemums (Shokuyo-giku) are cultivated as a flower vegetable in northern Japan and are gradually becoming more popular in other regions. Garnish chrysanthemums (Tsuma-giku) are commonly used as a garnish served with raw fish. Cultivars used in this investigation were collected mainly from Tohoku district and Niigata and Aichi prefectures. Morphological and ecological characters and petal qualities of 136 cultivars of edible and garnish chrysanthemums were investigated. One hundred and eighteen edible cultivars were collected and arranged into 52 cultivars, and 18 garnish cultivars were arranged into 15 cultivars based on our investigation. These cultivars were classified in some characters as follows.
1. The flower of edible cultivars was grouped into 5 color categories, yellow, pink, red, purple and white. The majority of edible cultivars were yellow and pink. However, all garnish cultivars were yellow.
2. The shape of the petal of edible cultivers was classified into 3 different types: flat, spoon and tube. These 3 types sometimes occurred separately or 2 types (flat and spoon, or spoon and tube) were mixed in various ratios on each cultivar. All garnish cultivars were flat-type with the exception of one which was spoon type.
3. Most edible and garnish cultivars had a pleasant flower odor, but a few do not.
4. In general, summer and late summer flowering cultivars were inferior to autumn flowering ones in petal taste according to the test of bitterness and savor. Furthermore, most edible cultivars which had been diverted from ornamentals in recent years were inferior in taste.
5. There were variant clones with useful characters in some popular edible cultivars.

View full abstract

The objective of this study was to know the effects of ambient temperature and light conditions on adventitious bud formation of lettuce hypocotyl tissues cultured in vitro.
Excised tissues of lettuce hypocotyl were cultured first on a Murashige-Skoog medium supplemented with 2, 4-dichlorophenoxyacetic acid (2, 4-D) and kinetin (the initial medium), and subsequently transferred to the medium with kinetin alone (the transfer medium). The results were summarized as follows:
1. The excised hypocotyl tissues cultured at either 15°C or 20°C throughout their culturing period failed to form any bud adventitiously, unless the initial medium was enriched with kinetin. An addition of kinetin at 0.5mg/l improved most effectively the bud formation. The increased kinetin concentrations in the transfer medium, however, decreased the bud formation.
2. When the tissues were cultured at different temperature and light conditions (20, 25 and 30°C×light and dark) for the first 3 and the latter 3 days on the initial medium, the bud formation was increased by low temperature followed by high temperature, while it was decreased by constant low temperature and by high temperature regardless of the following temperatures.
The fluorescent light decreased more or less the bud induction regardless of temperature.
3. Temperatures as low as 10 to 15°C were shown to be also effective in the bud formation when given for less than 3 days and followed by 30°C for less than 4 days on the initial medium.
4. When the tissues were subject to 30°C continuously for 3 to 4 days on the initial medium just before being removed to the transfer medium, 65 to 93 per cent of them formed buds, although number of buds per tissue was not so large as in the case when they were subject to low temperature prior to 30°C.
5. Low temperature (15°C) following high temperature (30°C) on the initial medium decreased the bud formation depending on its duration.
6. Increased bud formation by low temperature followed by high temperaure was nullified by a further exposure to low temperature. Further, such nullification by low temperature was not upset by further exposure to high temperature.
7. On the buds at the initiation stage on the transfer medium the light exerted a detrimental effect regardless of temperature. On the buds at the developing stage on the transfer medium, neither temperature nor light produced marked effect, except that the light increased the bud formation at higher temperatures.
8. From those results it appeared that, in the lettuce hypocotyl tissue culture, the induction of bud formation was markedly stimulated by low temperature followed by high temperature on the initial medium supplemented with auxin and cytokinin, and subsequently on the transfer medium with cytokinin alone the buds were initiated and developed further.

View full abstract

The present paper reports storage of fruits of ‘Fuyu’ and ‘Fukurogosho’ (Diospyros Kaki Thunb.), pollination constant non-astringent cultivars, using ethylene absorbent and the most desirable gas conditions for storage.
1. Fruit softening was most greatly affected by ethylene and next by CO₂ in the inside and outside of fruits. In order to delay fruit softening, it is necessary firstly to reduce ethylene concentration, and secondly to increase CO₂ concentration, but not so high as to induce browning of fruit apex.
2. The use of 0.04mm polyethylene bags containing ethylene absorbent delayed softening of ‘Fuyu’ and ‘Fukurogosho’ fruits.

View full abstract

The effects of 10ppm ethylene treatment on the respiratory rate, ethylene evolution and ripening of Japanese persimmon (Diospiros kaki Thunb. cv. Fuyu) fruits harvested at different stages of development during from June to November were investigated at 25°C.
1. The ethylene treatment was applied continuously for 1, 2 and 3 days begining 1 day after harvest at each stage.
All treatments stimulated respiration, and induced ethylene production and softening of fruits regardless of their stages.
The treatment was more effective for the fruits at stage I than at stage III.
It seemed that the sensitivity of fruit to ethylene decreased as the fruit matured.
The rate of ethylene evolution at the climacteric (or climacteric-like) peak induced by ethylene treatment declined rapidly as the fruit matured.
The fruit treated with ethylene softened more rapidly than the untreated fruit.
2. When 1-day treatments with ethylene were repeated every other day on the fruit harvested at stage III, the fruit showed some response to the first 2 to 3 treatments, but responded little to the subsequent treatments.
3. In view of its characteristics mentioned above, Japanese persimmon fruit was considered to be a type of fruit which differed from both climacteric and non-climacteric fruits.

View full abstract

Vibrating reed method and acoustic impulse response method were applied to ‘Starking Delicious’ apples stored at 0°C and room temperature.
Vibrating reed method measures resonance curve of thin apple flesh beam in bending mode of small amplitude and gives dynamic Young′s modulus (E') and loss modulus (E''). The calculation formulae for E' and E'' are derived from resonance frequency and peak width at which the amplitude is any times of its maximum value. E' and E'' were in the order of 10⁷dyne/cm² and 10⁶dyne/cm², respectively.
Dynamic Young′s modulus and acoustic indices of apples differed significantly between two storage temperatures. Dynamic Young′s modulus measured by vibrating reed method was appropriate for objective evaluation of flesh firmness. The usefulness of acoustic impulse response method for nondestructive evaluation of internal textural quality of apples were confirmed.

View full abstract

Deterioration of aroma of strawberry sometimes occurs immediately following freezing and develops during subsequent frozen storage. This paper reports the feature of this phenomena using 2 cultivars of ‘Donner’ and ‘Hoko-wase’. The berries were frozen and stored at -20°C. The off-odor was detected after 1 day of frozen storage by taste panel and strongest after 1 month storage in ‘Donner’, while ‘Hoko-wase’, the off-odor was not so notable as in ‘Donner’, showing the highest score after 1 week of frozen storage. Longer storage reduced both the off-odor and natural fragrance. Volatiles emanated from fresh and frozen-thawed strawberries were trapped and determined. Esters, dominant compounds in fresh berries, were hardly detected in frozen-thawed berries, while carbonyl compound(s) kept the same level with fresh berries. Fatty acid composition of neutral lipids and polar lipids extracted from frozen strawberries was quite similer to that of fresh berries. Evidence of lipid degradation causing an increase of free fatty acid was not obtained on thin layer chromatogram.
It is thus supposed that the off-odor in frozen strawberry may be a consequence of unbalance of volatiles revealing undesirable odor which is masked in fresh berries.

View full abstract

Green soybeans, immature seeds of Glycine max Merr., are widely used in Japan as vegetable and snack etc. Their quality, however, rapidly deteriorates after harvest. We suggested previously that the polyethylene packaging of whole plants with pods, leaves and roots, unlike such conventional shipping styles as packaging of pods with mesh bag or non-packaged bunch of plants without leaves, effectively prevents the deterioration of taste of beans and also external appearance of pods even at room temperature. In the present study, the effect of whole plant packaging (WPP) was confirmed and the various factors affecting the effect were investigated.
Whole plants of ‘Shirayama-dadachamame’ cultivar were packaged in low-density polyethylene bags of 0.03mm in thickness and held at 20°C as standard WPP. As control materials, pods were packaged in perforated polyethylene bags. The changes in sugar content and free amino acid index (optical density of ninhydrin positive 80 %-ethanol extracts) were used as the criteria of taste changes of beans.
WPP was very effective in keeping the external quality of pods. Although control pods discolored in 4-5 days at 20°C and became unsalable, those in WPP kept green more than a week. Packaging with bags of 0.04mm in thickness was comparable in its effect to the standard packaging with 0.03mm bags, but the effect of 0.06mm bags was slightly inferior. Pinholes were made on 0.06mm bags on the purpose to avoid possible excessive accumulation of CO₂ and/or depletion of O₂ resulting from using thick film. The effect of WPP with the pinholed bags decreased considerably in comparison with that of tight packaging, although it was evidently superior to the control. At 25°C, the effect of WPP on the external appearance was also obvious including liner packaging for bulk materials.
Contents of sugar and free amino acid in beans rapidly decreased within 1-2 days in control materials at 20°C, but the decrease was markedly retarded by WPP. Packag ing of whole plants with perforated bags also retarded the decrease, but the effect was generally inferior to that with sealed bags. Sealing of whole plants from which the roots were cut off, or of branches with pods and leaves, showed somewhat uncertain effect as compared with sealing of complete whole plants. When all leaf blades were cut off from the plants, the effect was markedly reduced, and cutting of distal halves of every leaf blades proportionally reduced the effect. When the plants with wilted leaves were packaged, the effect of WPP was also markedly reduced. Packaging of whole plants with pinholed bags showed the effect to a certain extent, but was inferior to tight packaging in its effect on retarding the decrease of sugar and amino acid contents.
WPP also exhibited an effect on retarding the hardening of beans.
Atmospheres inside the bags of WPP were determined. They showed approximate levels of 12% O₂ and 5% CO₂. Even inside the bags of 0.06mm in thickness, almost similar levels were maintained throughout the holding period at 20°C. This mild CA condition might prevent the occurrence of gas injury, which had been previously found in the packaging of pods with 0.03mm polyethylene bags.

View full abstract

Histological changes were observed during development of external symptoms of chilling injury in cucumber fruirs (cv. Tokiwa Shin No. 2) stored at 4°C.
Main external symptoms of chilling injury of cucumber fruits were pitting and whitish leakage on their surfaces. Pitting tended to appear at the lower relative humidity of 80-95% in cold storage, while leakage was inclined to occur at the higher relative humidity above 95%.
Before appearing of pitting, cell flattening following plasmolysis originated from the parenchyma cells adjacent to substomatal chamber. Flattened cells increased in parallel with the epidermis and to the inner cell layers. Epidermal cells also flattened, after flattening of parenchyma cells progressed to the depth of 8-10th layers under the epidermis. At this stage depression occurred around stoma and pittings were observed externally. At more advanced stage of pitting, the areas of cell flattening around respective stoma extended and joined mutually, and also reached to the depth of 15-20th layars under the epidermis.
Before oozing of whitish leakage, parenchma cells adjacent to substomatal chamber collapsed with their call walls. However, no plasmolysis and cell flattening were observed unlike pitting. At more advanced stage, epidermal cells collapsed with more than 7-8 layers of parenchyma cells under epidermis, and whitish leakage derived from cellular collapses oozed to the fruit surface through stomata and also to intercellular spaces.
At the incipient stage of pitting, nuclei of cells shrank, and then collapsed in the epidermis and immediately underlying parenchyma around stoma. On the other hand, nuclei in the above tissues apart from stoma, and those of parenchyma cells in the internal fleshy tissue shrank accompanying with plasmolysis, after temporary swelling immediately before appearing of the external symptoms.

View full abstract

Histological changes were observed during development of external symptoms, such as pitting or browning caused by chilling injury, in the eggplant fruits (cv. Kokko Shin No. 2) stored at 4C. An attempt was also made histochemically to detect phenolic substances and polyphenoloxidase in the fruit tissues.
Before appearing of pitting, plasmolyses occurred in some parenchyma cells of the 3rd-10th cell layer under the epidermis. Thereafter, cell flattening originated from the plasmolyzed parenchyma cells of 2-3 layers in the 8th-10th cell layer under the epidermis. With pitting development, flattened cells extended gradually with browning, outside to the epidermal cells and inside to the 15th-20th cell layer, and also to the parallel directions with the epidermis.
In appearing of browning without pitting on the fruit surface also, plasmolyses and browning of the affected cells occurred, however, no cell flattening. In the browned cells, yellowish brown granular products were observed, especially near to the epidermis.
Although some nuclei swelled temporarily in parenchyma cells of fleshy tissues before appearing of internal browning, they shrank afterwards with plasmolyses of parenchyma cells.
By histochemical tests, chlorogenic acid was presumed to be the major phenolic substance in the internal parenchyma tissues, vascular tissues and seeds. In the epidermal tissues, the presence of phenolic substances other than chlorogenic acid was presumed, in addition to anthocyan. Polyphenol oxidase was found in the same tissues as the phenolic substanes were distributed.
When browning occurred in cold storage, color reactions of the tissues to the histochemical reagents became indiscernible, while some activity of polyphenol oxidase was detected.

View full abstract