Tachibana (Citrus tachibana (Mak.) Tanaka) trees growing in the wild and cultivated in Japan were surveyed and analyzed for their isozyme genes. Many trees were observed in south-western areas from Izu Peninsula, Shizuoka Prefecture to Ishinami, Kushima, Miyazaki Prefecture. Although most of them are cultivated, some are suggested to be wild. Isozyme analysis of the tachibana population clearly demonstrated a difference between the tachibana and mandarin cultivars introduced from China. Almost all tachibana trees examined had CC genotype atPx (peroxidase) locus, while most of the Chinese mandarins are reported to have DD at Px. In addition, an allele A at Got (glutamate oxalacetate transaminase)-2 was unique to the tachibana population. A rare allele T at Got-3, which has not been recorded in any other citrus, was found in some individuals of the tachibana population. A heterogeneity for isozyme genes was also observed in the tachibana population. These findings indicate that tachibana has been genetically isolated from other citrus in the Asian Continent, and is native to Japan. Several natural hybrids between tachibana and cultivated Chinese mandarins were found in the tachibana-growing areas.

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Inheritance of resistance to bacterial canker disease caused by Xanthomonas campestris pv. citri in citrus was studied using 4, 523 F₁ seedlings obtained from 61 crosses.
When greenhouse-grown F₁ seedlings were 4 months old, the leaves were inoculated with bacteria in August in a greenhouse. Resistance to bacterial canker of each seedling was evaluated by an early evaluation method developed by the authors (Matsumoto and Okudai, 1988); 100 to 120 days after inoculation the size of the lesion on the leaves was measured and the seedlings were classified as either resistant or susceptible, according to the size of the lesion being smaller or larger than that on nucellar seedlings of Natsudaidai which shows an intermediate degree of resistance.
The F₁ segregation ratios on 61 crosses showed that the resistance was conferred by a single dominant allele. The genotype of Hyuganatsu, ponkan, satsuma and Tosa-buntan was dominant homozygous, that of Yuzu, Sweet Spring, Kiyomi, Hassaku, Natsudaidai, Clementine and Hirado-buntan was heterozygous, and the recessive homozygous cultivars were Fukuhara orange, grapefruit and Clement.
The dominant homozygous and heterozygous cultivars determined by the above-mentioned early evaluation method ranged from highly resistant to moderately susceptible to bacterial canker disease under field conditions. The moderately susceptible cultivars showed a degree of canker resistance similar to that of Natsudaidai, while the recessive homozygous cultivars were more susceptible, and were classified as susceptible to highly susceptible in the field. Thus, the results obtained from the early evaluation method using young seedlings were in good accordance with those from field observation. This confirms the validity of using Natsudaidai to classify the seedlings into R (resistant) and S (susceptible). The possible relationship between this resistance gene and endogeneous resistance-related substances in citrus was discussed.

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Segregation patterns of citrus rind texture were studied in 1944 seedlings derived from 99 cross combinations employing 51 parent cultivars. Rind texture was classfied into five classes: smooth, slightly smooth, medium, slightly coarse and coarse.
Of 51 parent cultivars, 33 belonged to smooth group, 7 to slightly smooth group, 7 to medium group and 4 to slightly coarse group.
Frequency of smooth texture in hybrid seedlings generally increased as the rind texture of the parent materials was smoother. However, no significant difference was observed in segregation patterns of hybrid seedlings between smooth and slightly smooth, and between medium and slightly coarse. Smooth and slightly smooth parents were divided into two groups, A and B, based on segregation patterns of hybrid seedlings. Smooth and slightly smooth parents of A group yielded more hybrids with smooth and slightly smooth rind texture than did those of B group.
These results suggest that the rind texture in citrus is not controlled by a single major gene. The results also suggest that smooth and slightly smooth varieties in A group may be more homozygous than those in B group. Therefore, smooth and slightly smooth varieties in A group appeared to be useful parents for obtaining hybrid seedlings with smooth rind texture.

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In the present experiment, seed development was investigated in self-pollination of 4X Hyuganatsu and several cross combinations between 2X and 4X Hyuganatsu. In addition, possible methods to overcome self-incompatibility of 2X Hyuganatsu were examined, using pollen of 4X Hyuganatsu as a mentor or pioneer pollen. The results are summarized as follows.
1. Pollen of the 4X was not uniform in size and form as observed by scanning electron microscopy. Its in vitro germination was inferior to that of the 2X by 5%. The band patterns of glycoproteins from pollen and pistils of the 4X analyzed by isoelectric focusing electrophoresis were largely different from those of the 2X.
2. In almost all cases one well-developed seed was contained together with many large imperfectly developed seeds in the fruit of the 2X pollinated with the 4X and in the fruit of the self-pollinated 4X, although the fruit set was somewhat different between two pollinations. When the 4X was pollinated with pollen of the 2X, only one fruit was harvested, lacking a well-developed seed. The fruit set of the open-pollinated 4X tree was very low. A few fruits were harvested, containing about 3 well-developed seeds per fruit.
3. Three pollination methods were tried for overcoming the self-incompatibility of the 2X Hyuganatsu. When pollens of the 2X and 4X were pollinated on the left and right sides respectively, of stigmas of 2X Hyuganatsu (differential pollination), the most effective result was obtained on overcoming the self-incompatibility. One hour time-lag double pollination, where pollen of the 2X was used one hour after pollination by the 4X, showed the next best effectiveness. Pollination with mixed pollens of both ploidies was not effective at all.

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The effects of 14 different rootstocks on leaf photosynthesis, distribution of photosynthetic product, and growth of one-year-old trees of satsuma mandarin (Citrus unshiu Marc. var. Sugiyama) were investigated. It was shown that leaves of satsuma mandarin grafted on trifoliate orange strains, such as ′Rubidoux′, ′Pomeroy′, and ′USDA′ showed higher photosynthetic rates than those on common trifoliate orange (Poncirus trifoliata Raf.) rootstock. However, ′Oba′ (Large leaf strain), ′Barnes′, and ′sour orange′ rootstocks had lower rates. Stomatal density and ribulose-1, 5-bisphosphate carboxylase (RuBPCase) activity in leaves seemed to be important factors for photosynthetic capacity. Also, the distribution of photosynthetic product differed among the rootstocks. The greatest value of top-root ratio was measured in ′Rubidoux′ trifoliate orange rootstock. Among the trifoliate oranges, tree size on ′Rubidoux′ rootstock was greatest and resulted in the highest dry matter production. This was mainly the result of total photosynthetic capacity of the trees.

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Ultrastructural changes in cells of developing juice sac primordia at anthesis and 19 days after anthesis in citrus fruits, satsuma mandarin (Citrus unshiu Marc.), were studied by light and transmission electron microscopy, to further explore the question of the pathway for transport of solutes into juice sac. The distribution density of plasmodesmata in the walls of juice sac cells increased markedly during the first 19 days after anthesis. During the same period plasmalemma invaginations developed and multivesicular bodies were seen in the invaginations of the tonoplast membrane protruding into the vacuoles. These developed most commonly in the basal portion of juice sac. Plasmalemmasomes in juice sac cells were also seen. These features of juice sac cells show the possibility of two pathways for translocation of solutes, one via plasmalemma-vesicles to vacuoles, the other through plasmodesmata.

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In order to study the effect of KT-30 (N-(2-chloro-4-pyridyl)-N''-phenylurea) treatment on the fruit growth of ‘Monty’ kiwifruit, the changes in some chemical components of the fruit throughout the growing season were investigated, and cell size and starch distribution were observed histochemically. The treatment was done by dipping the flowers into 10ppm KT-30 solution on the 7th d after pollination.
1. The fruit weight increase of the kiwifruit was accelerated with KT-30 treatment by 35-42 d. Weight of the treated fruit was about 1.4 times that of the control on the 170th d after pollination. Some deformity in shape attributable to KT-30 treatment was observed.
2. In the control and treated fruits, starch granules were observed from the 63rd d after pollination in the pericarp, and from the 105th d in the central core by light microscopy. There was no difference in the number of starch granules between the control and treated fruits. There was no change in cell size with KT-30 treatment. It suggested that fruit enlargement with KT-30 treatment was caused by increase of cell number.
3. The analysis of sugar by high-performance liquid chromatography (HPLC) revealed the presence of fructose, glucose and sucrose, and total sugar content in the fruit increased about 1.2 times by KT-30 treatment compared with the control on the 170th d after pollination. This suggested that KT-30 treatment promoted the growth of kiwifruit.
4. As for free organic acids, more citric and quinic acids were found in the treated fruit than in the control, but almost the same pattern was observed in the changes throughout the growing season.
5. Changes in total pectin contents throughout the growing season were similar in both the control and treated fruits, whereas the content was slightly higher in the control. Total pectin was largely composed of hydrochloric acid soluble pectin (HSP) in both control and treated fruits.
6. The pericarp of the control fruit became deep green throughout the growing season, while that of the treated fruit became pale. Chlorophyll content tended to show a higher value in the treated fruit than in the control up to 35 d after pollination, but thereafter it decreased steadily. In the control fruit, however, chlorophyll content tended to increase throughout the growing period. It was supposed that chlorophyll content in kiwifruit was affected by KT-30 treatment.

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Shoot tip culture was applied to 139 Japanese persimmon cultivars and four Diospyros species, D. japonica, D. lotus, D. oleifera and D. virginiana, and shoot growth in shoot tip culture was investigated in relation to each cultivar′s characteristics, fruit type, tree vigor and earliness of sprouting time. Shoot tips, 1mm in diameter, were excised from dormant axillary buds and cultured in Murashige and Skoog′s medium containing half-strength nitrogen plus 10^-5M zeatin, 3 % sucrose and 0.7% agar. Principal component analysis was performed using four shoot growth characters (shoot length, leaf number, leaf length and callus diameter) after six-week culture. The first principal component scores indicated a size factor, because the shoot, leaf and callus grew better with increases in the score. Eighty-two cultivars and three species, D. lotus, D. japonica and D. virginiana (female plant), had -1.0 or more of the first principal component scores and maintained good shoot growth through three subcultures. Ten cultivars and D. oleifera had -1.0 or more of the score; however, these were not established because of an inadequency of subculture medium. Established explants were obtained from 102 cultivars and three species. The cultivars of three fruit types, pollination constant and non-astringent (PCNA), pollination variant and non-astringent (PVNA) and pollination variant and astringent (PVA), had less shoot elongation. Shoot growth in shoot tip culture had no relation to tree vigor and earliness of sprouting time.

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In order to clarify the relation between embryosac development and night temperature in Japanese persimmon cv. Nishimurawase, seven trees were covered with plastic films and heated at 20°C with oil heaters. Night heating treatment was performed from 6:00p.m. to 6:00a.m. from 27 April to 15 May. The development of ovaries and embryosacs was accelerated by night heating treatment, which hastened anthesis by 10d compared with control. The following abnormal embryosacs were observed; aborted or degenerated embryosacs, embryosacs with nine or more nuclei, and ovules with two or more (multiple) embryosacs. In control, abortion or degeneration occurred in the embryosacs at the stages from 6.5mm to 9.0mm in ovary diameter and the percentage of this abnormality was 21 at anthesis. In the night heating treatment the abnormality occurred only at a stage of 9.0mm in ovary diameter and was observed in 12% of embryos at anthesis. The occurrence of the other abnormalities was not different between control and the heating treatment, increasing gradually with time after observation, and the abnormalities were 10-20% after the stage of 8.0mm in ovary diameter. Frequency of all abnormalities was 38% at anthesis in control and 24% in the night heating treatment.

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This work was carried out to clarify the relationships between parthenocarpy and seed abortion in seedless Japanese persimmon, cv. Hiratanenashi.
1. Incomplete embryo-sacs, oblong or swollen types, were found abundantly in ovules of ‘Hiratanenashi’ at anthesis.
2. Ovules in the parthenocarpic and pollinated fruit continued to develop until 60d after anthesis; however, the size of young seeds in pollinated fruits varied from 3mm to 20mm length.
3. All ovules in parthenocarpic fruit and the majority of young seeds in pollinated fruit at both 30 and 60d after anthesis had a part of embryo-sac cavity filled with densely clustered tissues called “bar tissue”, staining with fuchsine acid, instead of embryos. “Bar tissue” surrounding the micropyle to chalazal region may originate from dividing inner integuments tightly investing the nucellus.
4. Some ovules in pollinated fruit contained complete cellular endosperm even at the beginning of its formation, and most of them were found a little later to contain collapsed endosperm due to the abnormal division of cells. Therefore, it seems likely that the embryo may cease growth as a result of the degeneration of endosperm.
5. “Bar tissue” in the ovules seems to operate instead of embryo for fruit growth at early stages in parthenocarpic ‘Hiratanenashi’.

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The relationship between dry matter production of bearing shoots and physiological fruit drop of Japanese persimmon cv. Fuyu was investigated under non-shading and 50% shading treatments.
Both non-shaded and shaded trees had only 1 peak of fruit abscission at 4 weeks after pollination, and the rate of fruit abscission was higher in shaded trees than in non-shaded trees. However, fruit abscission was not related to the light transmission rate of the bearing shoots.
The abscised fruit increased less in dry weight increment from 1 week before fruit abscission in both non-shading and shading treatments. And the growth of abscised fruit ceased completely at 3 or 4 days before fruit abscission. This indicated that fruit drop had already been induced at 1 week before fruit abscission and that the period of the last 3 or 4 days represented the process of detaching fruit from tree.
As to dry matter accumulation, the main sink organ in the bearing shoots was the vegetative part until 3 weeks after pollination, but thereafter, it changed to the reproductive part.
In bearing shoots whose fruit abscised at 3 or 4 weeks after pollination, dry weight increment of leaf and shoot was significantly higher at 1 week before fruit abscission than in the other bearing shoots. Therefore, it was considered that fruit drop of this type was induced by great sink strength of leaf and shoot.

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A few fundamental experiments were carried out to increase information about the incompatibility of Japanese pear (Pyrus serotina R.). The results obtained are summarized as follows.
1. Flowers of ′Kosui′ at anthesis were self- or cross-pollinated after emasculation, and pollen germination on stigmas at 6h after pollination was observed. Pollen grains in cross-pollination germinated well and their pollen tubes elongated into stigmas by that time. But in self-pollination, the number of pollen grains observed on the stigma surface was very small and few pollen grains stretched their tubes into stigmas. Tube growth of cross-pollen was smooth in styles and some of the pollen tubes penetrated into ovaries 72h after pollination. On the contrary, tube growth of self-pollen was very poor and most of the tube tips stayed around 2mm below the stigma surface at 72h after pollination.
2. Flowers of ′Kosui′ and ′Chojuro′ at anthesis were emasculated, self- or cross-pollinated, fixed at intervals, stored in 70% Ethanol and processed for fluorescent microscopy through a routine procedure, where the number of pollen grains left adhered to the stigma surface was counted. On ′Kosui′, cross-pollination greatly surpassed self-pollination at 3h after pollination. But the difference decreased as time went on and there existed no difference between self- and cross-pollination at 12h after pollination. On ′Chojuro′, cross-pollination was superior to self-pollination from 6 to 12h after pollination.
3. Pistils of ′Kosui′ that were sampled soon after pollination were analyzed for proteins by IEF electrophoresis in combination with a silver nitrate staining procedure. Clear difference was observed between self- and cross-pollination as to the band pattern of buffer-soluble proteins of ovaries as soon as at 3h after pollination.
From these results, it was suggested that the stigma might play some significant role in the function of incompatibility of Japanese pear.

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Relationships between fruit growth on lateral branches of different ages and reserve substances in Japanese pear cv. Nijisseiki were investigated.
1. The fruits on four-year-old lateral branches and five-year-old lateral branches were bigger than on the other lateral branches. On six-year-old lateral branches and seven-year-old lateral branches, fruit weight was related to the number of cluster leaves.
2. When upper and basal parts of two-year-old to five-year-old portions of lateral branches were girdled, clusters and fruit growth on the four-year-old portion and five-year-old portion were greater than on the other portions. Total sugar and total amino acid contents in these clusters on four-year-old portions and five-year-old portions were higher than on the other portions.
3. The later the girdling time in the period from sprouting stage to full bloom, the higher the total sugar and total amino acid contents in clusters.
4. From these results, it was concluded that relationships between the age of lateral branches and fruit growth in Japanese pear are related to the mobilization of reserve substances.

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Net photosynthesis (Pn) and dark respiration (Rd) were determined on detached leaves of pear (Pyrus serotina, cvs. Suishu, Chojuro, Doitsu, Nijisseiki, Pyrus communis cv. Bartlett and Pyrus betulaefolia) infected by Japanese pear rust (Gymnosporangium asiaticum MIYABE et YAMADA).
In the resistant cultivar (Bartlett), very few symptoms in leaves occurred. Pn and Rd were unaffected by infection. However, in susceptible cultivars (Suishu, Chojuro, Doitu) and P. betulaefolia, depression in Pn and stimulation of Rd accompanying an increase in size of lesions on leaves occurred.
In Japanese pear cv. Nijisseiki, no significant differences were found either in Pn and Rd rate or in degree of infection by shading treatment.

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The influence of 2, 4-dichlorophenoxy propionic acid triethanolamine salt (dichlorprop) and 2-methyl 4-chlorophenoxy butyric acid enthylester (MCPB) sprays on preventing preharvest drop of apples was examined. The effects of concentration, number of applications and time of applications were investigated. In addition, the dose response of the cultivars (‘Tsugaru’, ‘Starking Delicious’, ‘Jonagold’ and ‘Oorin’), variability due to year, influence of soil moisture, and fruit quality were studied.
1. Sprays of 30 or 45ppm dichlorprop applied 25 and 15d. before harvest significantly reduced preharvest drop of all cultivars tested. A spray of 15ppm dichlorprop reduced preharvest drop of ‘Starking Delicious’ but not ‘Tsugaru’. Double applications of dichlorprop at 10-day intervals were more effective than a single application for preventing preharvest drop of ‘Tsugaru’ and ‘Starking Delicious’. But with ‘Jonathan’, single and double applications had the same effect.
2. Double applications with 30, 50 or 70ppm MCPB similarly reduced preharvest drop of ‘Tsugaru’. The triple application treatment of 30ppm MCPB was more effective than the double application for ‘Tsugaru’. A double application of 30ppm MCPB reduced preharvest drop of ‘Tsugaru’ and ‘Starking Delicious’ but was not effective for ‘Jonagold’. With ‘Oorin’, preharvest drop was promoted by this treatment.
3. No fruit quality differences were detected between the dichlorprop treatments and the control, but double or triple applications of 30ppm MCPB enhanced fruit color development and seemed to accelerate fruit maturity.
4. The effectiveness of dichlorprop spray for prevention of preharvest drop of ‘Tsugaru’ was clearly demonstrated by the 10 year trial, but effectiveness varied due to annual variation (C.V. of 45ppm double application=78.8). The effectiveness of dichlorprop treatment was reduced in the years with low August rainfall, but was enhanced by irrigation in dry years.
5. The application of dichlorprop in a lanolin paste to the peduncle did not prevent preharvest drop, but application to the bourse, bourse shoot or the zone where abscission occurred reduced it significantly.

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Application of 2-(3, 4-dichlorophenoxy) triethylamine (DCPTA) as a treatment to sugarbeet (Beta vulgaris L. cv. Dihill) seed enhanced leaf and root development and increased taproot sucrose yield, as compared with that of controls. During mid-exponential plant growth, seed treatment with 1ppm DCPTA increased leaf growth and total leaf area development 98% and 75%, respectively, as compared with controls. The increased canopy size of DCPTA-treated plants was caused by delayed senescence of older, mature leaves. After 5 months growth, taproot fresh weight of 10ppm DCPTA-treated plants was increased 28% over that of controls. The sucrose content (%, fresh weight) of these taproots was 15% greater than that of controls, which gave a 47% increase in the sucrose yield per taproot. Taproot in-terring widths between vascular rings two, three, and four of DCPTA-treated plants were generally unchanged relative to controls, suggesting that plant growth regulation by DCPTA does not adversely affect photosynthate partitioning between taproot development and sucrose accumulation. Our results indicate that 10ppm DCPTA seed treatment increased the sucrose yield of ‘Dihill’ sugarbeet.

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This experiment was done to clarify the influence of the absence of the genes responsible for ripening and ethylene production using three types of tomato fruits; cv. Rutgers as ripening type, nor mutant as slight ripening type and rin mutant as non-ripening type. Changes in 1-aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase activity and ethylene forming enzyme (EFE) activity in these tomatoes were measured at several stages. ′Rutgers′ tomato produced ethylene in ripening stage, whereas nor tomato produced ethylene slightly and rin hardly produced it except for production due to decay of fruits. It seems that ethylene production of ′Rutgers′ is attributed to accumulation of ACC and increase in EFE activity during climacteric, and insufficient ethylene production of nor tomato fruit is due to accumulation of ACC only, without increased EFE activity in the tissue. And very little ethylene production of rin is due to the small amount of ACC content without increased EFE activity.

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Studies were carried out to clarify the effects of benzyl adenine on translocation and distribution of ¹⁴C-assimilates in relation to fruit setting and development in cucumber plants.
Fruit setting and early fruit development were accelerated by pollination. Furthermore, parthenocarpic fruit setting was induced by benzyl adenine. Great changes occurred on the RSS (Relative Strength as a Sink) values before and after anthesis.
The RSS value was high before anthesis and it decreased rapidly on the day of anthesis. After pollination or treatment by benzyl adenine the RSS increased rapidly again.
The changes in auxin content by pollination and treatment by benzyl adenine were almostly similar in pattern to the changes of the RSS. Therefore, it seems that the effect of benzyl adenine is related to the inhibition of decrease of auxin content.
¹⁴C-benzyl adenine moved to the acropetal area of fruit and accounted for more than 10 per cent of total amount of ¹⁴C supplied to fruit within 24h.
There were physiological changes in the flower buds before and after anthesis. It is likely that the flower bud acts as a growing point, like a leafy bud, before anthesis. However, from the time of anthesis until fruit setting the flower bud suspends physiological activity and after fruit setting the flower bud probably changes physiological phase and the fruit develops rapidly.

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Effects of vernalization in Raphanus sativus L. cv. Harumaki-Minowase were studied. Early flowering and vigorous growth of the plant were observed in the low temperature treatment at 3°C for 2 or 3 weeks followed by incubation at 15 or 25°C. Days to flowering after low temperature were around 50, irrespective of the different conditions.
Plants incubated at 3°C for 2 weeks were planted in the field during the period of March through November. They flowered and seeded, except the ones treated with low temperature in August and November. Days to flowering after planting were from around 24 days with the May-, June-and July-treatments to 96 days with the October-treatment. On the other hand, the largest number of flowers was obtained with the April-treatment, and flowering dramatically decreased with the October treatment. The number of seeds with the June- and July-treatments was 2-3 per capsule, but it was 5 in other treatments.
Plants pre-incubated at 3°C for 2 weeks followed by planting in the field under summer conditions were not devernalized, but they were devernalized by 35°C after 3°C pre-incubation for 2 weeks. When the 3°C treatment was prolonged for 3 weeks, they were not devernalized. From these results, effective treatment for vernalization of ‘Harumaki-Minowase’ radish was 3°C for 2 or 3 weeks.

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A chromatographic study of methanol-soluble flavonoid compounds in mature leaves was undertaken to analyze the phylogenetic relationships among the cultivars and strains of Camellia vernalis (triploid, tetraploid and pentaploid group), C. japonica, C. sasanqua and Stewartia pseudo-camellia. The majority of experimental materials were collected from Hirado Island, Nagasaki prefecture. The former species have been assumed to be hybrids between the second and third species. The results obtained were summarized as follows.:
Thirty-nine kinds of spots were detected in the chromatograms of the three species of Camellia and S. pseudo-cammelia used in this study and compared with each other in appearance. Since the peculiar spot patterns on the chromatograms occurred only in C. japonica and C. sasanqua, we examined the spot pattern in C. vernalis and compared it with that of C. japonica and C. sasanqua. A close relation was noted within the triploid group of C. vernalis and C. japonica, and within the tetraploid group of C. vernalis and C. sasanqua. On the other hand, no corresponding connection between the above-mentioned groups was noticed except for two cases.
Numerical analyses of the data obtained clearly indicated that the hybrid character of C. vernalis originated from hybridization between C. japonica and C. sasanqua. Also, the affinity values suggested that the triploid group of C. vernalis showed a higher affinity to C. japonica than to its own tetraploid group. On the other hand, numerical treatment of S. pseudo-camellia revealed a heterogenous relation in comparison with the species of Camellia.

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A marked increase in ethylene production occurred in cut carnation flowers (Dianthus caryophyllus L. cv. Izu-Pink) during senescence. The application of ethylene hastened senescence by promoting ethylene production, while the applied 2, 5-norbornadiene (NBD) retarded the progress of senescence of flowers by reducing the rate of ethylene production, such that no initiation of wilting of flowers was observed 8d after harvest when untreated flowers had completely wilted. Most of the ethylene produced by senescing carnation flowers was derived from petals.
The activity of 1-aminocyclopropane-1-carboxylate (ACC) synthase was markedly induced in petals of carnation flowers during senescence, and was accompanied by increases in the level of ACC and the rate of ethylene production. This induction was promoted by ethylene and suppressed by NBD. It is considered that ethylene accelerates ethylene biosynthesis by promoting the induction of ACC synthase, while NBD reduces ethylene biosynthesis by suppressing the induction of ACC synthase, which may result from inhibition of ethylene action by NBD.

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Some unique and interesting characteristics of highly polymeric tannins are well known, such as having a strong ability to bind with proteins, alkaloids, and heavy metals. In a series of experiments designed to determine industrial uses for kaki-tannin, a typical condensed tannin from persimmon fruit, a simple procedure for kaki-tannin purification has been investigated in our laboratory.
This paper describes several properties of tannin in Kakishibu, a special and astringent persimmon juice, that are altered during heat-browning at 80°C. A procedure for purification of the browned tannin from Kakishibu using a High Porous Polymer (HP) resin column was developed.
1. Heating at 80°C caused a remarkable browning of two types of aqueous tannin solutions with ca. 0.6% tannin concentrations, Kakishibu from cv. Tamura and K₂HPO_4-purified tannin from cv. Hiratanenashi immature persimmon fruits. The extent of browning was followed qualitatively by measuring absorbance at 420nm and 480nm.
2. A F/V ratio, being a ratio of optical densities is both Folin-Ciocalteu and sulfuric acid- vanillin methods, of both tannin solutions increased linearly after incubation for 8h at 80°C, accompanied by browning and an increase of absorbance at 420nm and 480nm.
3. Only 55% and 20% of the tannin in the Kakishibu and the K₂HPO_4-purified tannin solutions, respectively, adsorbed to HP resin before heating at 80°C. However, after heating for 8h the percentage of adsorption increased to 96% and 72%, respectively. The majority of adsorbed tannins was eluted with 40% aqueous methanol.
4. In contrast to unheated tannins or those heated for 8h and 24h, tannins heated for 48h or 72h showed a distinctly lower capacity of hemoglobin-precipitation.
5. The browned tannin heated excessively (48h and 72h at 80°C) became less soluble in water after drying with a freeze-drying method.
The present data has shown that moderately heat-browned tannin is purified easily from Kakishibu using HP resin column chromatography. The tannin obtained thus has lost a bad, fermented smell, still has a high capacity of de-proteinizing, became more soluble in water, and therefore, may be more useful in some industrial fields.

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Changes in respiratory rate and ethylene production in ‘Sensyu’ apple fruit, and electrolyte leakage from flesh tissue during storage were investigated in relation to fruit maturity and chilling sensitivity. Fruits were harvested at early maturity (pre-climacteric), standard maturity (climacteric) and late maturity (post-climacteric).
1. During storage, the rates of respiration and ethylene production were greatly reduced at -1°, 0° or 5°C compared to 20°C. After transfer from the chilling temperature (-1° to 5°C) to 20°C, fruits harvested at the same maturity showed nearly the same pattern of changes in respiratory rate and ethylene production.
2. When apple fruits were stored at 20°, 5°, 0° or -1°C, ethylene-forming enzyme (EFE) activity increased rapidly in proportion to the increase in storage temperature, excepting for the early-harvested fruits. In these fruits, the increase of EFE activity of fruits stored at 0°C was faster than in fruits stored at 5°C.
3. During storage at 20°C, fruit softening and rotting were markedly observed in the fruits of standard and late harvest as compared with the early-harvested ones. On the other hand, the development of chilling injury symptoms was severe in the early-harvested fruits, while slight pitting occurred in the fruits of standard and late harvest during storage at 0° or -1°C. It could be suggested that storage temperature at 5°C would be available for the early-harvested fruits, while for the fruits of standard and late harvest it would be -1°C.
4. The rate of electrolyte leakage from flesh tissue on the first inspection of the fruits just harvested was low in the early-maturity fruits, which showed high chilling sensitivity. On the other hand, a marked increase in the rate of electrolyte leakage occurred in the early-harvested fruits during storage at 0° or -1°C, while almost no change was observed in the fruits of standard and late harvest.

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Changes in leaf and stem tissues and cells of water convolvulus (Ipomoea aquatica Forsk.) were studied in relation to chilling injury and browning of young leaves and stem tips. Microscopic observations were made using materials stored at 1 and 20°C for 5 days. While partial browning occurred in the leaves stored at 1°C, samples were prepared from green parts. In the epidermis cells of 1°C-stored leaves many particles stained with azureII-methylene blue and basic fuchsine were found, but no significant change was found in other tissues under light microscopy. In the stems, no influence of low temperature was found.
Under electron microscopy, well developed thylakoids, grana stacks and envelopes were clearly found in the chloroplasts of leaves at harvest. Leaves stored at 20°C showed little change of subcellular components compared with those at harvest. In the 1°C-stored leaves, the chloroplsts were sensitive to chilling temperature. They were swollen and the number of thylakoids and grana stacks decreased. The mitochondrial cristae became somewhat unclear, and a part of the tonoplasts were invaginated into the vacuoles and became unclear. These subcellular changes could play a role in bringing about chilling injury.

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