Defoliation and girdling were performed on spurs of different ages of 'Nijisseiki' pears (Pyrus pyrifolia Nakai) 10 days after anthesis, and the effects on fruit growth and quality, carbohydrate levels of leaves and shoots on the spurs were determined. Girdling resulted in the reduction of fruit size and fresh weight on 1-and 3-year-old spurs at harvest, but did not affect fruit growth, final size, and fresh weight on 5- and 7-year-old spurs. Complete spur leaf removal (100% LR) had little effect on fruit development on 1-year-old spurs during the whole growing season, but significantly retarded fruit development and decreased the final size of fruit on spurs over 3 years old. This treatment also increased flesh firmness, soluble solids and pH of fruit on spurs over 3 years old which may be related to the decreased fruit size. Presence of bourse shoot and 50% LR treatment had little effect on the final size of fruit on the spurs of different ages. Our results indicate that spur leaves play a more significant role in fruit growth and development as the spur age increases. The growth and development of fruit on a 1-year-old spur depends to a great extent, on the leaves external to the spur complex ; whereas fruits on 5-year-old spurs or older depend on their own spur leaves under normal conditions. On 3-year-old spurs, the fruit is nourished by its spur leaves and leaves outside the spur. Spur leaves seem to have an important role in the accumulation of carbohydrates in the spur, especially in the older parts of the spur shoot.

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Chlorophyll (chl) derivatives in the peel of green satsuma mandarin (Citrus unshiu Marc. cv Nichinan No.1) fruits were studied to clarify the mechanism of chl degradation. High performance liquid chromatography (HPLC) and high performance thin-layer chromatography (HPTLC) were used to separate chl derivatives in acetone extracts from green satsuma mandarin fruits. Pyropheophorbide (pyrophed) a was present in the green skin but it gradually disappeared with ripening ; it was undetectable in the last harvest. A possible participation of pyrophed a in chl catabolism is discussed.

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Young apple trees were grown for two growing seasons under 100, 52.9, 34.2, 15.8 or 5.0% natural photosynthetic photon flux density (PPED) to assess the difference of growth on dry weight basis. Total dry weight gains of trees decreased with increasing shade, except for trees grown at 5.0% PPFD which showed a net loss at the end of the second growing season ; because dry weight of the root stem, and trunk decreased. Although the growth increment in the root system was negative at 5.0% PPFD, new roots were produced in small amounts in both seasons. Shading neither decreased the photosynthetic light compensation points of leaves nor increased the initial slopes of the light response curves. Specific leaf weight declined significantly with the decrease in light level to 5.0% PPFD. In trees receiving a PPFD level above 15.8%, 42.1 to 49.5% of the total increment of dry weight was partitioned to the old trunk and branches, respectively. A high correlation between total increment and trunk thickness (r=0.983^**) was found, but not in trees under 5.0% PPFD. Therefore, the minimum light condition required to sustain a growth in dry weight increment in succeeding years appeared to be between 5.0 to 15.8% of natural sunlight in the northern part of Japan.

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Accumulation and utilization of storage starch and epidermis-related development in roots of vigorous and non-vigorous satsuma mandarin (Citrus unshiu Marc. cv. Miyagawa Wase) were compared anatomically from early winter to early summer. Only a few starch grains were deposited in the cortex of the pioneer roots of both kinds of trees in December. In vigorous trees, the number of starch grains per cortical cell and the ratio of areas of starch grain to the area of cortex (area-ratio) increased considerably during January and February, attaining a maximum in March. Area-ratio gradually decreased from April to May ; by June, it approached zero as the starch grains almost disappeared. In contrast, the area-ratio in non-vigorous trees was unchanged from January to February and increased slightly in March. The area-ratio reached the highest level in April, followed by rapid reduction in May, as the starch grains disappeared in June. Neither the vigorous nor the non-vigorous trees contained starch grains in July. Fibrous roots on vigorous trees were filled with many starch grains up to April, then the grains disappeared completely in June ; whereas in non-vigorous trees starch grain depletion started in June but the grains persisted until July. The pioneer roots on vigorous trees had but one layer of phellogen cells beneath the epidermis in January. The periderm was distinct with the formation of phellem, phellogen, and phelloderm in March. Periderm formation in non-vigorous trees was initiated in March, and it continued slowly into April. Root hair and epidermal development was faster in roots of vigorous tree.

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A differential nitrogen (N) fertilization trial for a high density planting of satsuma mandarin was conducted for 11 years starting in 1982 on 13-year-old trees. Satsuma mandarin (Citrus unshiu Marc. cv. Sugiyama) trees, which had been grown in a 0.4 ha field with little or no fertilizer, were administered a combination of 2 levels of organic matter application and 3 levels of N triplicated in a factorial arrangement. Levels of organic matter were +OM (rice straw application of 20 t·ha^-1·year^-1) and -OM (sod culture system). Levels of N fertilizers were N-1 : 100, N-2 : 200, and N-3 : 300 kg·ha^-1·year^-1. The total soluble solids-titratable acidity (TSS-TA) ratio of the juice, the 'a' index of peel color, percentage of mesocarp, and specific gravity of fruit in the -OM treatment were slightly higher than those in the +OM treatment. In contrast, TA content in the juice and mean fruit weight were slightly increased by organic matter application. TSS-TA ratio, the color indices of 'L', 'a' and 'b', % of mesocarp, and specific gravity of fruit decreased with increased N application, whereas TA content in the juice increased. The N and K contents in the leaves and leaf color index in the +OM treatment were slightly higher than those in the -OM treatment. Leaf N content and the leaf color index increased, but leaf P and K contents decreased with increased N application. TSS, TSS-TA ratio, the 'L', 'a' and 'b' color indices, % of mesocarp, and specific gravity of fruit were negatively correlated to leaf N content, wherease TA content correlated positively with leaf N.

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Inheritance of high resistance in Japanese pear 'Kinchaku' and Chinese pears 'Hong-li' and 'Mi-li' to pear scab caused by Venturia nashicola was examined, using hybrid seedlings of known parentage. The seedlings were inoculated with conidial suspension, and the resistance to scab was classified into three categories : highly resistant (HR), susceptible (S), or necrotic (N). Most progenies derived from crosses between susceptible cultivars were rated S, whereas progenies of S×'Kinchaku' segregated into 1HR : 1S. Crosses between S×'Hong-li' or 'Mi-li' produced HR, N, and S seedlings, which closely fit a 1HR : 1(N+S) ratio. Progenies derived from crosses between HR cultivars segregated into 3HR : 1(N+S). The results support the hypothesis that HR phenotype in 'Kinchaku', 'Hong-li', and 'Mi-li' is controlled by a single dominant gene. The gene symbol Vn is proposed for the gene controlling HR phenotype.

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Cut 'Bridal Pink' roses, pre-cooled for 2 hr, were subjected to simulated transport for 0, 24, 48 and 72 hr at 20°C or 5°C ; their vase life was then evaluated by placing them in deionized (DI) water at 20°C under a 12-hr photoperiod. The vase life of control (no transport) cut flowers was rated to be 9.2 days. When cut flowers were transported dry in carton boxes for more than 24 hr at 20°C and for more than 48 hr at 5°C, they displayed bent necks during the transport and some buds failed to open, shortening their vase life. Contrarily, when flowers were transported wet with their stem bases in DI water, they maintained their fresh weight, especially at 5°C, thus prolonging vase life, although flower buds opened during the transport at 20°C. Substituting 0.3 mM 8-hydroxyquinoline sulfate and 0.1 M fructose for DI water during the 72-hr transport period at 5°C, the vase life of cut roses was extended more than 2 times that of dry transported ones. A flexible vial (a water-proof plastic wrapper containing hydro-wool and a tie, Flower Mate, CI Kasei Co. Ltd., Tokyo) was used to pack cut flowers wet in carton boxes as substitutes for buckets.

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We cloned and sequenced three cDNA homologs of 1-aminocyclopropane-1-carboxylate (ACC) synthase (pCS-ACS1, pCS-ACS2 and pCS-ACS3) and two of ACC oxidase (pCS-ACO1 and pCS-ACO2) from cucumber (Cucumis sativus L.) fruit using RT-PCR (reverse transcription and polymerase chain reaction) and RACE (rapid amplification of cDNA ends) PCR. Conserved amino acid sequences reported for other plant tissues were found in all the cloned ACC synthase and ACC oxidase cDNAs. Among the ACC synthase and ACC oxidase cDNA clones, pCS-ACS1, pCS-ACS3, and pCS-ACO1 were highly homologous to ACC synthase and ACC oxidase genes cloned from other Cucurbitaceae family at both the nucleotide and the amino acid levels. Northern blot analysis showed that wounding induced the accumulation of CS-ACS1, CS-ACS2, and CS-ACO1 mRNAs, whereas IAA treatment induced expression of all the three ACC synthase genes and CS-ACO1. These expressions paralleled ethylene production in both treatments. Transcripts for CS-ACO2 were constitutively expressed and were not affected by wounding and IAA treatments. From the expression pattern and the sequence similarities of these genes, we conclude that CS-ACS1 could be a wound-inducible gene and that CS-ACS3 is an auxin-inducible one. These results strongly suggest that in cucumber fruit these genes are differentially expressed by wounding and auxin and are involved in the regulation of ethylene biosynthesis at the transcriptional level.

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The development of the abscission zone in potato flower pedicels was compared between two cultivars. Cells of the abscission zone formed at the sepal-developing stage in 'May Queen', and the at petal-developing stage in 'Toyoshiro'. These cells were found initially in the epidermal and cortical regions of the pedicel. With the progress of flower bud development, cell division gradually spread to the vascular bundle region, and finally to the central parenchyma region of the pedicel. These results show that the formation of a protective layer starts earlier in the pedicels of 'May Queen' than it does in 'Toyoshiro'.

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To develop an effective propagation method, a symbiotic culture was attempted in nine species of Japanese terrestrial orchids. Seeds of three species of Goodyera (Goodyera biflora var. macrantha, G. foliosa var. laevis, and G. hachijonesis var. matsumurana), when inoculated non-symbiotically or with fungi from the binucleate Rhizoctonia fungus group among the 20 fungus strains tested germinated with virtually the same TTC activity level as embryos. Those on a symbiotic culture with binucleate Rhizoctonia grew markedly well compared with seeds on a non-symbiotic culture. The low germination rates in six of the species in the TTC test results are attributed to the unsuitability of the test culture conditions. There were numerous effective fungal strains with 5 species other than Cypripedium macranthos var. speciosum, which developed a symbiotic relationship with only one of the fungal isolates tested. Among the 3 species (Aorchis cyclochila, Dactylorhiza aristata, and Gymnadenia camtschatica) the binucleate Rhizoctonia fungal group would be suitable for symbiotic germination and subsequent growth, whereas the 2 species Amitostigma kinoshitae and Ponerorchis graminifolia var. graminifolia. responded better to R. repens

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The apple cv. Hokuto is very susceptible to a new skin-browning disorder called stain during storage. To study the cause of 'Hokuto' stain, young fruits were individually covered with commercial double paper bags from early June to late September. These shaded fruits were harvested in late October and stored at 0°C for up to six months. Incidence of stain between bagged and unbagged (control) fruits during storage at 0°C was recorded and volatiles in their skins were determined by gas chromatography-mass spectrometry and gas chromatography. There was less stain in bagged fruit than in unbagged ones. The same 50 volatiles were identified in the skin of bagged and unbagged fruits during storage. Differences in content of volatile compounds in the skin of bagged fruit were compared to those in unbagged fruit, noting the compositions whose contents were smaller in the skin of bagged fruit than those in unbagged ones. The difference in content of trans-2-hexenal was the greatest among the volatiles, followed by 2-methyl-butan-1-ol, n-hexanal, n-propanol, trans-3-hexenol, n-hexyl propionate and n-amyl acetate, in that order. No difference was found in (E, E)-α-farnesene whose oxidation products are believed to cause superficial scald. Exposure of healthy 'Hokuto' apples to seven volatiles and farnesene (mixed isomers) at 20°C for 20 hours showed that both trans-2-hexenal and n-hexanal induced stain-like injury at the lowest concentration, followed by n-amyl acetate, n-hexyl propionate and 2-methyl-butan-1-ol, in that order. No symptoms of stain appeared on fruits exposed to n-propanol, trans-3-hexenol and farnesene. Comparison in stain-like injury between C₆-aldehydes and its C₆-alcohols i.e. trans-2-hexenal and trans-2-hexenol, n-hexanal and n-hexanol, revealed that the injury was greater in C₆-aldehyde than in its respective C₆-alcohol. Application of linolenic and linoleic acids, respective precursors of trans-2-hexenal and n-hexanal, on 'Hokuto' apple skin at 0°C for four days induced stain-like injury in both unsaturated acids. The injury was greater in linolenic acid than in linoleic acid. However, the degree of the injury decreased remarkably in nitrogen gas. Results suggest that shading of the apples by double paper bags reduces concentration of trans-2-hexenal characteristically and that the shading is related to metabolism of linolenic acid to trans-2-hexenal, which were used in these experiments to induce stain-like injury to 'Hokuto' apples.

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Interspecific crosses between Prunus mume cv. Baigo (seed parent) and P. salicina cv. Sordum (pollen parent) were made in 1984 from which four fertile seeds were obtained. When the seeds were planted in a greenhouse in the following spring, three seedlings were obtained. Eventually, the seedlings flowered and set fruits ; they proved to be interspecific hybrids based on peroxidase and esterase isozyme analyses. Morphological characteristics of these seedlings are as follows. Mature leaf : General shape, tip and base form of the leaf and petiole color of the seedlings are similar to 'Baigo' ; 'Sordum' and the seedlings have reniform glands on their leaf base, but 'Baigo' has none. Flower : The flower size of seedlings was intermediate between 'Baigo' and 'Sordum'. 'Baigo' has one flower per flower bud, whereas 'Sordum' has two or three flowers. The hybrid seedlings bear one or two flowers per flower bud and trichomes on the exocarp like 'Baigo', unlike 'Sordum' which has none. The pollen of the seedlings were fertile. Fruit : The shape of matured fruit of 'Baigo' and 'Sordum' is round ; the latter has a slightly mounded tip. Two seedlings segregated to a round fruit and one into an elliptical shape. Flesh color of 'Baigo' is yellow, whereas that of 'Sordum' is red. One seedlings segregated to a red flesh whereas two inherited a light yellow flesh.

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Cuttings from one-year-old wood of fig cv. Masui-Dauphine were made on Dec.1, and raised for 45 days in a glass house or phytotron under different light intensities. The rooted cuttings were planted on Jan. 15, in a non-circulating closed solution culture, using a capillary absorption system together with a irrigation tube. The effects of nursery treatments on subsequent fruiting, plant growth, and fruit quality were investigated in the current year. Light treatment of 8.5 klx under a 14-hr photoperiod in a phytotron increased total chlorophyll content and color value of the leaf at planting time. The number of fruits below the 5th node increased in trees when the color value of 3rd leaf from the base was above 25 at planting time. But, there was no difference in leaf color value and fruiting between the light treatment of 17 and 8.5 klx. The supplementary lighting of 0.2 klx after sunset to keep 14-hr of sunlight in the glass house had no effect on leaf color value ; it approximated that of the control. Harvest started on May 27 ; by July 10, 85% of the fruit was harvested. In trees raised in the phytotron, vegetative and fruit growth was promoted, contrary to those raised in the glass house. The Brix value was slightly lower in fruits from the phytotron-grown trees in early June. During the rainy season from the middle to the end of June, fruit growth did not decrease and the Brix decreased significantly because of the redused photosynthetic rate, a high transpiration rate, and the large uptake of nutrient solution, irrespective of the treatment. Trees raised in the phytotron had higher photosynthetic rates than did trees raised in the glass house in July, but the fruits from the former had lower Brix values than had fruits from the latter.

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The effects of five methods of girdling and bark inversion on tree growth and fruit quality in 'Megumi' apple (Malus domestica Borkh.) were compared. Bark inversion treatments were : BI-100 (5 cm bark ring was removed from the trunk and replaced in an inverted position), BI-90 (90% of a 5 cm bark ring was removed from the trunk and replaced in an inverted position, leaving a vertical 10% strip of the bark intact), bark exchange ; B-EX (90% of a 5 cm bark ring was removed from the trunk and exchanged with 'Hokuto' bark, leaving a vertical 10% strip of the bark intact), girdling ; G (90% a 5 cm bark ring was removed from the trunk leaving a vertical 10% strip of the bark intact) and G-N (90% a 5 cm bark ring was removed from the trunk, then that bark was reattached in a normal position, leaving a vertical 10% strip of the bark intact). All treatments, except G-N and B-EX significantly reduced the growth of the trunk's girth below the treatments, but had no effects on trunk growth above the treatments. The shoot length was significantly shorter and the spur/shoots ratio was significantly higher in BI-100 than in those of other treatments. Flowering the following spring was significantly increased by all treatments. Chlorophyll concentration in the leaves of BI-100 was lower than that of the control trees at one month after the treatment ; it decreased after three months in all treatments except B-EX. Soluble solids content in the fruit of BI-100 was the highest, followed by G, BI-90, B-EX, and G-N, and the control in decreasing order. Sugars and sorbitol content on a fresh weight basis were significantly higher in BI-100 than in BI-90, G-N and control fruits. But on a dry weight basis, they were lower in the treated fruits than in the control fruit because in the treated fruits had lower water content than the control fruit. Fruit firmness and fruit size were influenced little by the treatments. All treatments reduced calcium concentration in the fruit flesh. Soluble solids content in the fruits of BI-100 and BI-90 in following year was significantly higher than that of other treatments. These results show that girdling and bark inversion improved the eating quality of the fruit by increasing soluble solids content while lowering water and calcium content.

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The role of the endosperm in releasing embryo dormancy was investigated in 'Campbell Early' grape seeds. Embryos, with or without their endosperms, which were excised from seeds of maturing berries were cultured in vitro and their germination rates and growth monitored. Embryos without endosperms germinated best when berries were taken a week before veraison, but the germination percentage thereafter declined abruptly to a deep dormancy level 2 weeks after veraison. On the other hand, embryos with endosperms gradually increased the germination rate to reach a maximum percentage 2 weeks after veraison. After berry harvest, mature seeds were collected and their embryos with endosperms were incubated in vitro for 0, 6, 12, and 24 hours ; the embryos were isolated from endosperms and cultured. Those incubated for 0 or 6-hr neither germination nor rooted, whereas those incubated for 12-hr germinated slightly and some rooted. A 24-hr incubation greatly improved the germination and rooting percentages. Although the removal of endosperm portion surrounding cotyledons and epicotyl did not greatly reduce germination or rooting ; removal of the endosperm surrounding the root tip elicited no response. Microscopic observations revealed that the root tip on embryos with endosperms incubated for 24 hr began to elongate and the endosperm cells adjacent to the root tip became densely stained, indicating that the cells were physiologically active. Therefore, we conclude that the mature endosperm controls the release of embryo dormancy and that endosperm portion linked to the root tip plays an important role in regulating embryo dormancy in grape seeds.

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Root segments derived from cultures of Actinidia kolomikta were cultured in vitro on BW medium (Sugawara et al., 1994). Twelve combinations of 2, 4-dichlorophenoxyacetic acid (2, 4-D) (0, 0.1, 1 and 10μM) and zeatin (0, 1 and 10μM) were tested at 25°C, under a 16-hr photoperiod with a light intensity of 70μmol·m^-2·s^-1. Calli formed from root segments at all concentrations of 2, 4-D and zeatin. Of the adventitious buds which formed from the callus, 92% developed into shoots with a combination of 0.1μM 2, 4-D and 10μM zeatin. Root segments excised from cultures formed the most somatic embryos when cultured with 10μM of 2, 4-D and zeatin. When young leaflets with roots were cultured on the BW medium with zeatin, adventitious buds formed on the root tip. The rate of adventitious bud formation increased with an increase in zeatin concentration. The adventitious buds developed into shoots ; shoots rooted and grew into vigorous plantlets when transferred onto Miller's medium with 1μM 1-naphthaleneacetic acid (NAA).

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The effect of the leaf/fruit ratio and the density of artificial pollination on the berry maturation and qualities in highbush blueberry (Vaccinium corymbosum L.) cv. 'Bluecrop' and 'Northland', pot-grown in a greenhouse, were studied. The results obtained in this study were as follows : 1. The berries on shoots with a leaf/fruit ratio of approximately 5 : 1 were heavier, had higher soluble solid content and an optimum titratable acidity than had fruits on shoots with ratios of 2 : 1 and 1 : 1 ; the berries also matured earlier. 2. The berries pollinated at a day after full bloom (FB) with an applicator had more seeds and were heavier than those pollinated at FB ; berries pollinated ten times with an applicator had much more brown seeds compared with berries pollinated three times at anthesis. Hence, pollen density affects berry development. 3. Data on fruit development and maturation show that berry weight correlated highly with the number of seeds, flowering and harvest dates, and the length of the growth period. Moreover, it was found that shortening of the flowering period also shortened the harvest period.

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The differences in the dry matter production (DM) and the assimilate partitioning in each organ among 'Sansa', 'American Summer Pearmain', 'Golden Delicious', 'Orin', 'Fuji', and 'Ralls Janet' of 6-year-old apple trees on M.9 EMLA rootstock, trained to a central leader were studied. The trunk area was largest in 'Orin' ; it diminished in the order of 'Fuji', 'Golden Delicious', 'Ralls Janet', 'American Summer Pearmain', and 'Sansa'. The leaf area and leaf area index of 'Golden Delicious' are 1.8 time greater than those of 'Sansa'. A significant correlation (r=0.780) between the trunk girth measured early in the growing season and the total leaf area per tree existed in all cultivars. Total DM of the crop was largest in 'Fuji' followed in the order of 'Golden Delicious', 'Orin', 'American Summer Pearmain', 'Ralls Janet', and 'Sansa'. 'Fuji' fruits accumulated 2.7 times more dry weight (F) than did 'American Summer Pearmain'. DM per leaf (L) was largest in 'Fuji', succeeded in the order of 'Orin', 'Ralls Janet', 'Golden Delicious', 'Sansa', 'American Summer Pearmain'. The DM per leaf of 'Fuji' was 1.4 time that of 'American Summer Pearmain'. There are significant correlations between the trunk girth measured early in the growing season and DM (r=0.861), and F (r=0.866), independent at cultivars. There are significant correlations between DM and F (r=0.894), and DM per L and F per L (r=0.911), independent at cultivars. The assimilate partitioning rate to the fruit was 30∿35% in 'Fuji' and 'Orin', but 17% in 'American Summer Pearmain'. The assimilate partitioning to new shoot was higher in 'American Summer Pearmain' and lower in 'Orin' than in the other cultivars. The dry weight in each height increment between 50 cm to 250 cm increased in each cultivars. The leaf area was maximum between 50 cm and 150 cm in 'Sansa', 'American Summer Pearmain' and 'Ralls Janet', but it was largest between 100 cm to 200 cm in 'Golden Delicious' and 'Orin', and from 100 cm to 250 cm in 'Fuji'. In all cultivars, the specific leaf weight (SLW) increased in proportion to the height of tree. The percent instantaneous incident photosynthetic photon flux density from 100 cm to 250 cm of tree was highest in 'Sansa' ; it was higher in 'American Summer Pearmain' and 'Ralls Janet' than the rest of the cultivars.

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Ovule set and growth were investigated on ginkgo as related to open-and hand-pollination as well as the critical pollination period. 1. The ginkgo pollen placed on an agar medium under 25°C took 3 days to germinate. Over 73% of the pollen stored for less than 7 days after anthesis at room temperature germinated but pollen stored much longer at room temperature did not. 2. All ovules which were covered with paper bags during anthesis to be free from pollen contamination abscised for 41 days after leafing. 3. When non-viable, heat-treated pollen were used for hand-pollination, the ovules began to drop 28 days after leafing ; the percentage ovule set decreased from 19 to 47 days after leafing. Thereafter, for 82 days after leafing, fewer ovules dropped ; the final seed set was 7%. These female reproductive organs set parthenocarpically because no embryo formed. The seeds and nuts resulting from hand-pollination were larger than those obtained from open-pollination. 4. Of seeds that set by hand-pollination 16 and 19 days after leafing, 59% and 94%, respectively, remained at harvest and their sizes were significantly larger than those obtained from open-pollination. None of the ovules pollinated 23 days after leafing persisted until harvest.

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Cherry tomato (Lycopersicon esculentum Mill. cv. Piko) plants were drip-irrigated at four soil moisture levels (pF 1.5, pF 2.0, pF 2.5 and pF 2.9) from the 17th day before fruits on the first cluster reached the red ripe stage. Under high water stress (pF 2.9), the total dry weight and water content of the plant decreased, compared to other treatments. However, the proportion of fruit dry weight per plant gradually increased proportionately to the pF, but the proportion of the leaf and root dry weight decreased. The total sugar content of the fruit increased as the pF value rose, but that of sucrose was lower than that of glucose and fructose under all of water conditions. Starch content in the fruit was equal and decreased during its ripening in all treatments. Although the water content of the fruit decreased with higher water stress, the difference in concentration among the four conditions was within 3% so that the sugar concentration was barely affected. Total nitrogen content and the nitrogen content in the water soluble protein under water stress at pF 2.9 were lower than thoes at pF 1.5 which suggests that the low nitrogen content may account for the high sugar content. We conclude that the optimum pF value ranges between pF 2.5 and 2.9, within which is optimum tomato fruit quality without any reduction in yield.

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To study the effects of transplanting depth on yield and uniformity of head size, cabbage seedlings were raised in plug trays and transplanted directly into the field at depths of -2cm, -1cm, 0cm (exposed rootball plots), +1cm, +2cm (soil-coverd rootball plots). At fixed intervals during the experiment, shoot growth, leaf area, rooting capacity, soil moisture content, and shoot water potential were measured ; at harvest, the fresh weights of the heads, and uniformity of head size were recorded. 1. Cabbages in the soil-covered rootball plots were about 1.5 times heavier and more uniform than were those from the exposed rootball plots. 2. Cabbages in the soil-covered rootball plots had better survival rate, larger leaf area and more roots, and grew faster than did cabbages from exposed rootball plots. 3. After transplantation, the moisture content in the exposed rootballs decreased more rapidly than it did in the soil-covered ones. In each plot, the initial moisture contents of the rootballs were higher but eventually became lower than of the ambient soil. 4. The decline of the shoot water potential in plants from the soil-coverd rootball plots was slower than that of shoots in the exposed rootball plots. We conclude from these observations that transplanting rootballs at 1∿2cm depths resulted in a better stand and a higher yield of more uniform-sized cabbages than planting at shallower depths. The benefits of soil-covering are attributed to : 1) better soil moisture retention within the rootball, 2) improved rooting, and 3) a favorable shoot water potential.

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Cabbage seedlings were raised in plug trays and transplanted to the field to test the effects of rootball moisture content at the time of transplanting on their establishment and growth. 1. The establishment of seedlings were hastened by maintaining a high rootball moisture content which accelerated rooting and prevented wilting. 2. Rooting, shoot water potential and primary growth of seedlings after transplanting were improved by making of the rootball uniformly moist. 3. The moisture content of the rootballs was raised and made uniform in the tray by subirrigation. Thus, we conclude that a fast and uniform establishment of cabbage plug seedlings can be obtained by subirrigation before transplantation.

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The problem that night lighting of the street lamp caused bolting of spinach grown under a plastic greenhouse have happened. Therefore, effects of night lighting and critical illuminance (light intensity under which over 80% of the spinach plants are marketable) on the growth and bolting of spinach cultivars grown under a plastic greenhouse were investigated and evaluated. 1. The growth and flower stalk development of plants grown under night lighting differed among cultivars and between sowing dates. 2. The natural photoperiod and the average temperature in greenhouse during the November experiment were about 11-hour, 13°C and during the May experiment were about 15-hour, 23°C. When plants were grown under night lighting of high illuminance, such as 25lx (0.31μmol·m^-2·s^-1), plants height and the number of leaves per plant increased but leaf size remained small. May-sown seedings did not grow as tall as those sown in November. May-sown plants grown under night lighting of 2 (0.02) to 3lx (0.03) had more leaves but of shorter length. 3. In plants exposed to night lighting of 1 (0.01) to 25lx in November, the day to flower stalk development and flowering were promoted at the higher intensities ; the converse was true in the May-sown plants. Thus, in cultivars such as 'Okame' sown in May, flower stalks appeared at relatively low light intensities, whereas November-sown plants bolted under high light intensities. 4. Likewise, the critical illuminance of cultivars, such as 'Parade' sown in November ranged from 3 to 5lx (0.05), whereas in May-sowing plants, 50-99% of the plants at 1 lx bolted. Critical illuminance for 'Okame' and 'Tonick' sown in November, it was 2 to 3lx and 13lx (0.16) respectively.

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Genetic relationships were estimated by RAPD analysis by using 10-mer random primers in individuals of Lilium japonicum Thunb., native to Shimane and other Prefectures. UPGMA clustering analysis indicated that individuals of L. japonicum from various collection sites in Shimane and Ehime Prefectures had no distinct differences from each other and that they belonged to the same cluster at 0.588 level of similarity coefficient. However, they were distinguishable from those native to Nara, Wakayama, and Shizuoka Prefs. Similarity coefficient between L. japonicum native to Shimane, Ehime, Nara, Wakayama Prefs., and that native to Shizuoka Pref. was 0.428, and that between L. japonicum native to the first four prefectures and L. rubellum Baker was 0.429 which suggests that L. rubellum was included in the variation of L. japonicum. Thus, this species displays a large variation depending on its native habitats. These results suggest that when creating new cultivars of L. japonicum in Shimane Pref., the native parents should be cross with L. japonicum from Shizuoka or Wakayama Pref. to instill possible hybrid vigor in the hybrids between genetically remote L. japonicum individuals determined by RAPD analysis.

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Embryogenesis of Cymbidium koran Makino, a terrestrial orchid native to Japan, and the germination ability of its seed in vitro was investigated. 1. Ovaries started to elongate soon after pollination and they reached full size in 140 days after pollination (DAP). 2. The ovule began to differentiate after pollination and formed an 8-nuclei embryo sac between 240 and 250 DAP. Ovule formation occurred 70 days DAP. Double fertilization was observed in the ovules 90 to 100 days DAP, the fertilized polar nuclei divided into four to eight endosperm nuclei. 3. The tetrad proembryo was recognized as C₁ type according to Veyret's classification, and progressed to the compound, modified J type (Polystachya microbambusa type) and F type (Coelogyne parishii type) after the tetrad stage. The main spherical part of the mature embryo was derived from the apical 'ca' cells of proembryos. and the embryonic tube was derived from 'cb' cells. 4. The percentage of seeds which germinated varied depending on the stage of embryo developement. Both seed germination and subsequent rhizome growth are superior when the seeds are cultured at the completion of embryogenesis. The best medium for seed germination is the "T" medium among the four (Hg, HI, MT and T) tested. The Percentage of seed germination in seeds after embryogenesis was completed was markedly reduced in all four media.

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Changes in ascorbate metabolism during maturation of sweet pepper (Capsicum annuum L.) fruit 'Golden Bell' were investigated. The mature fruits were divided into four stages, based on changes in peel color from green to yellow ; Green=100% green, Green/Yellow=10∿20% yellow, Yellow/Green=50∿60% yellow, Yellow=100% yellow. 1. Ascorbate content in sweet pepper fruit increased during maturation, whereas dehydroascorbate content remained at 1% throughout the maturation. 2. L-Galactono-γ-lactone dehydrogenase activity increased during maturation, the highest activity was occurring at Yellow stage. 3. Ascorbate peroxidase activity was highest at Green/Yellow or Yellow/Green stage and lowest at the Yellow stage. 4. Dehydroascorbate reductase activity was almost constant during maturation, whereas monodehydroascorbate reductase activity increased from Green to Yellow stage. From our results we attribute the increase of ascorbate contents during maturation to the increase in L-galactono-γ-lactone dehydrogenase and monodehydroascorbate reductase activities.

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The identity of and the changes in phenolic acids in relation to the browning of freshly prepared bamboo shoots stored at 20°C were made. 1. Using insoluble polyvinyl pyrrolidone (PVP) column chromatography, it was found that the content of crude phenolic compounds on the initial day were 165 mg and 106 mg per 100 g fresh weight, in the apical and basal sections, respectively. The levels decreased rapidly in both sections after 2 days. 2. Tracings of the individual phenolic acid in the crude compounds separated by gas liquid chromatography (GC) and identified by GC-mass spectrometry (MS) revealed 23 peaks initially in the basal section, which increased to 25 peaks after 9 days at 20°C. Among those peaks, 5-dehydroshikimic acid, shikimic acid, p-hydroxyphenylethanol, p-hydroxyphenylpropionic acid and ferulic acid were present. 5-dehydroshikimic acid and shikimic acid, which are intermediated of the shikimic acid pathway, increased more rapidly in the basal than in the apical section during storage at 20°C. 3. Caffeic acid and chlorogenic acid were separated from the shoots by Toyo pearl column chromatography and GC, and identified by GC-MS. Caffeic acid content in both sections increased gradually during storage, whereas chlorogenic acid content in the apical section decreased rapidly ; but in the basal section when browning was initiated, chlorogenic acid increased about six times that of the initial day and then decreased rapidly.

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Two experiments were conducted to test the effects of exposing Japanese persimmon 'Tonewase' fruit harvested at different maturies to varying concentrations of carbon dioxide on firmness, the evolution of ethylene and respiration. In Phase I, the fruits were exposed to ambient air and to 100% carbon dioxide for 24 hr (control) and subsequently stored at 20°C. In Exp. I, Phase I was repeated on immature fruit and the third treatment was added in which the carbon dioxide concentration was decreased from 100% to 0% after 17 hr. In Exp. II, the procedure was similar to that in Exp. I, except that more mature fruits were used and the carbon dioxide concentration was reduced from 100% to 0% after 6, 12 and 20 hr. 1. The fruits of the Japanese persimmon 'Tonewase' exposed to ambient air and those treated continuously with 100% carbon dioxide softened equally fast and ripened within 6 days. 2. Slightly immature fruits exposed to air and 100% carbon dioxide softened as in Phase I, whereas those exposed to 100% carbon dioxide for 17 hr were still firm after 2 weeks in storage. 3. Fruits exposed to air and 100% carbon dioxide softened as did those in Phase I, wheras those exposed to 100% carbon dioxide for 6, 12 and 20 hrs maintained their firmness longer during storage.

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