Change of oxalate contents in green-fleshed 'Hayward' and 'Bruno' and in yellow-fleshed 'Golden King' and 'Yellow Queen' kiwifruit, and related species were analyzed during their development and storage. Calcium oxalate crystals in kiwifruit are observed in the form of raphide showing long and needle-shape in the green-fleshed cultivars but short in the yellow-fleshed ones ; the raphide crystals in A. arguta and A. rufa were likewise short. The oxalate contents, which was determined by enzymatic analysis, attained maximum in fruit sampled in July during their early development period. The level gradually decreased with the increase in size until harvest in late October ; it continued to decrease during cold storage. The oxalate content decreased slightly faster in the yellow-fleshed fruits than it did in the green-fleshed ones. The oxalate content in A. arguta was lower than that in A. deliciosa, whereas that in A. rufa was slightly higher.

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Callus cells induced from leaf primordia were used for a rapid and efficient determination of genome size and ploidy level of several Diospyros spp. including D. kaki. Nuclear DNA contents of nine Japanese persimmon (Diospyros kaki Thunb.) cultivars and other 12 Diospyros species were estimated by flow cytometry. Compared to the known nuclear DNA contents of chicken red blood cells and tobacco leaf cells, genome sizes of hexaploid cultivars (2n=6x, x=15) of D. kaki were estimated to be 5.00-5.24 pg/2C and those of nonaploid (2n=9x) to be 7.51-8.12 pg/2C. Nuclear DNA content of another hexaploid species, D. virginiana, was 5.12 pg/2C and that of a tetraploid, D. rhombifolia, was 3.76 pg/2C. Nuclear DNA contents of all the diploid species tested, except for D. montana, fell in the range of 1.57-2.31 pg/2C. Although D. montana is a diploid, its genome size was 3.48 pg/2C and about the same size as that of a tetraploid, D. rhombifolia. There was a strong positive linear correlation between the ploidy levels and the genome sizes of Diospyros spp. tested, except for D. montana. In this study, chromosome number was also counted, using callus cells to determine if ploidy levels can be deduced from flow cytometry. D. kaki cv. Miyazakitanenashi was nonaploid with chromosome number of 2n=135, D. kaki cv. Jiro and D. virginiana were hexaploid with 2n=90, and D. rhombifolia was tetraploid with 2n=60, and the other species tested, including four species whose ploidy levels had been unknown, were determined to be diploid. The results agreed with the deduced ploidy levels from flow cytometry except for D. montana.

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The influence of spur age on ¹³C partitioning of spur complex in 'Nijisseiki' pear (Pyrus pyrifolia Nakai) was investigated under field conditions. Leaves on 1-, 3-, 5-, and 7-year-old fruiting spurs were exposed to ¹³CO₂ at 6, 12, 18, and 21 weeks after anthesis (WAA). At each treatment time, half the spurs of the same age were girdled at the base of the spurs to measure the total amount of ¹³C absorbed. Six WAA, spurs of all ages exported ¹³C-assimilates ; the amount exported increased with increasing spur age. Twelve WAA, only spurs over 3 years old exported labeled photosynthates, but the rate was half that at six WAA. At 18 and 21 WAA, no ¹³C-labelled substance was exported from any spurs. At 18 WAA, about 60% of the ¹³C was partitioned to the fruit on spurs of all ages within 72 hr of labeling. However, the absolute amount of ¹³C translocated to fruit was largest in 5-year-old spurs. The partitioning rate of ¹³C to shoots differed significantly among spurs of different ages, ranging from about 2% in 1-year-old spurs to more than 8% in 7-year-old spurs.

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Eighteen endogenous gibberellins (GAs) which belong to the early 13-hydroxylation pathway and the early non-hydroxylation pathway of GA-biosynthesis were identified by combined gas chromatography/mass spectrometry (GC/MS) in shoots of a cold-requiring plant, Raphanus sativus L. Contents of GA₁ and GA₄, the probable endogenous biologically-active GAs, increased in the stem during a long-day condition (LD) both with or without a prior cold treatment (CT); however, the increase was greater with CT than without it. In contrast to the contents of 3β-hydroxylated GAs (i.e. GA₁ and GA₄), that of GA₃₄, a 2β-hydroxylated GA, was decreased significantly by CT and LD, indicating that CT and LD activated the 3β-hydroxylation and inactivated the 2β-hydroxylation during the course of GA-biosynthesis. GA₁ and GA₄ contents in the leaf decreased during LD subsequent to CT, whereas they increased with LD alone. The increase in GA₁ and GA₄ contents in the stem probably promoted the cold-induced stem elongation and flowering of R. sativus.

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The effect of exogenous applications of several gibberellins (GAs) native to a cold-requiring plant Raphanus sativus L. was investigated to uncover the role of the GAs in cold-induced stem elongation and flowering of the plant. GA₁ and GA₄ promoted the stem elongation and flowering, whereas GA₉ and GA₂₀, which are thought to be precursors of GA₄ and GA₁, respectively, were less active. Prohexadione calcium, which inhibits hydroxylation of GAs including 2β- and 3β-hydroxylation, reduced the effects of GA₉ and GA₂₀ ; in contrast, it enhanced the effects of GA₁ and GA₄. These results strongly indicate that GA₁ and GA₄ are the endogenous biologically-active GAs in cold-induced stem elongation and flowering of R. sativus. We found no difference between GA₁ and GA₄ in their relative activity to stem elongation vs. flowering ; thus, we suggest that they have the same role in the promotion of stem elongation and flowering. Thus, it will be necessary to reduce GA₁ and GA₄ concentrations to control undesired stem elongation and flowering.

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Tomato plants (Lycopersicon esculentum Mill. cv. Momotaro) were cultured hydroponically. The effects, under different weather conditions, of leaf position and sampling time of day on the concentration of nutrient elements in the petiole sap from leaves under the fruit truss at two growth stages were investigated. At the flowering stage of the second truss, the NO₃-N, P, and K concentrations in the petiole sap did not differ among the three leaves under the first truss. At the fruit growth stage of the second truss, no difference in the P and K concentrations existed among the three leaves under the second truss. The concentration of NO₃-N in the petiole sap collected from the leaf just below the second truss, however, was clearly lower than those of the other two adjacent leaves. At both growth stages, the higher the leaf position among the three leaves under the fruit truss, the lower were the Ca and Mg concentrations in the petiole sap. Variations in the concentrations of nutrient elements in the petiole sap were minimal at different times of day and under differing weather conditions.

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Effects of the red (R) to far-red (FR) photon ratio on bulb development in Allium wakegi were investigated. Field experiments were carried out in spring and summer, in which plants were covered with three kinds of acrylic resins : a normal clear one with a piece of white cheesecloth (control), one with low transmittance in a R region, and another with low transmittance in a FR region. The R/FR (660±5 nm/730±5 nm) photon flux density ratios in the control, R-intercepted, and FR-intercepted devices under natural light were 1.00, 0.53, and 1.73, respectively. In both experiments the FR-intercepted treatment inhibited an increase in bulb fresh weight, bulb dry matter percentage, and bulbing index (maximum diameter/neck diameter of a bulb). In the summer experiment, the plants in the FR-intercepted device did not initiate scaly leaves which were formed by all plants in the other treatments. These results show that bulb development of A. wakegi was inhibited under the high R/FR photon ratio. This effect was more obvious in the summer than in the spring experiments. Plants under low R/FR photon ratio produced bulbs similar to the control.

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Commercial preparations of agar, agarose, cellulose, gellan gum, pectin, sodium alginate, and starch were immersed in water and assayed for root growth-promoting activity. Agar greatly stimulated root growth of cucumber (Cucumis sativus L.), Japanese radish (Raphanus sativus L.), lettuce (Lactuca sativa L.), rice (Oryza sativa L.), spinach (Spinacia oleracea L.), tomato (Lycopersicon esculentum Mill.), and Welsh onion (Allium fistulosum L.). Cellulose, gellan gum, and starch also stimulated root growth to a lesser degree. The most consistent results were obtained with lettuce ; thus it was chosen for further experimentations. Water extract of agar stimulated root growth of lettuce whereas an inorganic ion solution whose composition was equivalent to the agar extract was less stimulating. Thus, the stimulating activity of the agar extract is not attributable to inorganic ions in the extract. To examine properties of root growth-stimulating substances in the agar extract, the extract was fractionated on columns of Sephadex G-25, Bio-Gel P-2 and Shodex C18. Activities were found in several low molecular weight fractions isolated with Bio-Gel P-2. When the active fractions separated by Bio-Gel P-2 were subjected to Shodex C18, an active fraction was concentrated in a single major peak, which eluted faster than glucose. These results indicate that commercial preparations of agar contain several root growth-stimulating, highly hydrophilic substances of low molecular weight.

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Capitulum initiation and floret development of seven Dendranthema species (D. boreale, D. indicum, D. japonicum, D. occidentali-japonense var. ashizuriense, D. ornatum, D. pacificum and D. yoshinaganthum) were investigated by scanning electron microscope (SEM). The sequence of events in these seven species was similar. Nine developmental stages were identified : vegetative stage, doming stage, earyly and late stages of involucre and floret formations and early, mid- and late stages of corolla formation. The time of capitulum initiation, its developmental rate and the time of anthesis differed, depending on species. Two types of disc floret development, i.e. petal closed before or after stamen primordia initiation, were observed.

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PCR-RFLP analysis was applied to some interspecific hybrid cultivars of lily to verify their probable parentage. Six Lilium species, L. auratum var. platyphyllum, L. japonicum, L. speciosum, L. nobilissimum, L. auratum and L. rubellum, were analyzed with four pairs of primers and 22 restriction enzymes ; among them PCR-RFLP markers, characteristic to each species, were detected. L.×formolongi, L. speciosum and their artificial hybrids derived by embryo culture confirmed that the PCR-RFLP markers in a chloroplast gene of the female parent were inherited by all hybrids, whereas the markers in a nuclear rRNA gene of the hybrids possessed a combined band pattern of the female and pollen parents. Hence, we utilized PCR-RFLP analysis for tracing the parents of interspecific hybrid cultivars. PCR-RFLP gel patterns were analyzed to trace parents of six lily hybrid cultivars called Oriental hybrids, 'Star Gazer', 'Le reve', 'Casa Blanca', 'Summer Dress', 'Pink Pearl', and 'Marco Polo'. The data indicate that the cytoplasm of 'Casa Blanca', 'Summer Dress', and 'Pink Pearl' was transmitted from L. speciosum, whereas that of 'Star Gazer', 'Le reve', and 'Marco Polo', was inherited from L. auratum var. platyphyllum or L. japonicum. The pollen parents of these hybrids were not completely identified because genetic segregation may have occurred at gametogenesis if pollen parents were interspecific hybrids.

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Polyphenols and polyphenol oxidase (PPO) activity in the fruits of loquat (cv. Mogi) during development and storage were studied in relation to browning of the pulp. The concentration of total phenolics decreased sharply during fruit growth and then increased significantly during maturation and ripening. But, it varied slightly during the two months of cold storage. Chlorogenic acid increased rapidly during fruit maturation and ripening and became a predominant compound in ripe fruits. Chlorogenic acid decreased slightly while the fruit was stored at 5°C. PPO activity declined concurrent to fruit growth and ripening. In cold storage, PPO activity decreased gradually, but from 68.8 to 92.2% of the browning in the reaction mixture prepared from pulp juice occurred within the first hour. Chlorogenic acid oxidation proceeded quickly and played an important role in browning of ripe fruit. Total phenolics was highly related to the degree of browning.

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Changes in chlorophyll, carotenoid, ascorbic acid, and glutathione levels were determined during broccoli storage in 9 controlled atmospheres ranging from 0 to 10% O₂ and 2 to 20% CO₂ concentrations. In low O₂ concentration, the level of glutathione decreased, whereas in high O₂ and low CO₂ concentrations, the level of chlorophyll and ascorbic acid decreased significantly. A mixture of 2% O₂ and 4 to 10% CO₂ was found to be optimum for simultaneous maintenance of pigments, ascorbic acid, and glutathione. Respiration models were developed as functions of storage time and O₂ and CO₂ concentrations using a multiple regression analysis based on these gas compositions. When the modified atmosphere gas environment inside a broccoli package was simulated, an optimum gas condition of 2% O₂ and 5% CO₂ was derived using a film having a 1, 000 ml/day/atm O₂ transmission rate. Simulation result agreed well with experimental data.

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Two different types of partial sequence of homeobox genes, named APHB1 and APHB2, were isolated from apple. From the alignment of amino acid sequences of KNOTTED1-like homeobox genes and apple PCR fragments, APHB1 was considered to be a member of class I type genes because of their similarities. APHB1 expressed itself only in shoot apical tissues, stems, and flowers, but not in mature leaves and developing fruits which is, again, very similar to class I type genes. Likewise, APHB2 is considered to be a member of class II type genes because of their homologies. APHB2 is expressed in all organs involving mature leaves and developing fruits, which is characteristic of class II type homeobox genes. These findings reveal that at least two different types of homeobox genes exist in apple. They probably bind to different genes and play different roles in controlling the developmental switches in apple.

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Changes in contents and molecular distribution of polyuronides were determined on Japanese pear 'Chojuro' (Pyrus serotina Rehd. var. culta) and Chinese pear 'Yali'(P. ussuriensis Maxim. var. sinensis Kikuchi) fruits. The ratios of water-soluble (F1) fraction to total polyuronides increased and that of acid-soluble (F4) fraction decreased as firmness decreased with ripening in both cultivars. However, 'Chojuro' contained polyuronides of predominantly lower molecular weight than did 'Yali' in the F4 fraction.

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Effects of extracts from filter paper on the shoot regeneration of tomato (Lycopersicon esculentum Mill.) were examined. Cotyledon segments of tomato were cultured on supporting material made of polyester supplemented with Murashige and Skoog liquid medium, containing 0.1 mg·liter^-1 indole-acetic acid, 1.0 mg·liter^-1 zeatin and 3% sucrose. Soluble components were extracted from filter paper with hot water and added to the medium. Phenotypically normal shoot regeneration was stimulated by the extracts of filter paper ; the highest percentage of shoot regeneration was obtained by an extract equivalent to 1 g filter paper per ml. When filter paper extracts were fractionated on Sephadex G-25 gel column, the shoot regeneration stimulating activity was found in a low molecular weight fraction. These results suggest that filter paper contains thermostable substances low molecular weight which induce shoot regeneration.

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Effects of defoliation and fruit thinning on the occurrence of watercore fruit in Japanese pear (Pyrus pyrifolia Nakai)'Hosui' were examined. 1. Defoliation significantly reduced the occurrence of watercore fruit. However, at harvest, the fruit were small and had a green ground color. Furthermore, they had a lower specific gravity and soluble solids concentration, and firmer flesh than those of the control. 2. Trees which were thinned excessively, leaving only 2, 4 and 8 fruits per m² canopy, had a higher incidence of watercore fruit. The fruit at harvest were larger than those of the control, which had 12 fruits per m² canopy, but they had lower specific gravity and greener ground color. Watercore occurred especially around the stalk cavity and below the skin ; these symptoms are similar to those of fruit produced under abnormal climate conditions such as a cool summer. Thus, watercore of Japanese pear 'Hosui' is considered to be caused by higher source-sink ratio of the tree.

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The fig trees, propagated by cuttings of different diameters, were cultured in a non-circulating closed culture system supplied by a Hoagland II nutrient solution. The nutrient solutions were adjusted to electrical conductivity (EC) of 1.2, 1.8, and 2.4 dS/m and the trees exposed to a 10-or 14-hr photoperiod. 1. The amount of nutrient solution absorbed per plant in the EC 1.2 dS/m plot became larger than that in the EC 1.8 dS/m plot in mid-May, and the amount was about 1.8 liters/day at the end of July. 2. Storage of cuttings at 0.5°C for 21 days decreased the percentage of transplantable cuttings, but of those which were usuable, shoot growth and the first node at which fruit set were unaffected. 3. Cuttings with thicker diameters fruited at the more basal nodes than did those with thinner diameters. 4. Trees in the EC 2.4 dS/m plot during the raising period through the growing season bore most fruit at the second node, whereas most fruits in the EC 1.2 dS/m plot were borne on the third node. 5. The 10- or 14-hr photoperiod during the raising period had no influence on the percentage fruit set at the lowest node.

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Hardwood cuttings of fig cv. Masui Dauphine were grown in nutrient solutions having electrical conductivities of 1.8, 2.4 or one in which the EC was reduced from 2.4 to 0.6 dS/m in mid-season. The non-circulating closed culture system was supplied with a capillary action of rockwool and irrigation ; the experiment was designed for double cropping per year. For the first planting, cuttings were made on Jan. 10 and the rooted cuttings were transplanted on Feb. 24. The EC of the 1.8 and 2.4 dS/m solutions increased gradually to 9.5 and 10.1 dS/m, respectively, until Jun. 30 when the first crop was harvested. 1. In the EC 2.4 dS/m plot, the amount of solution absorbed by the plant was less than that absorbed by plant in the 1.8 dS/m plot. When the EC was decreased from 2.4 to 0.6 dS/m, the amount of solution absorbed increased from May to harvest. 2. The leaf area of plants which absorbed the least amount of solution in the three plots was smallest. At harvest the early fruit from the EC 1.8 and 0.6 dS/m plots was larger but Brix of the juice was lower, compared to fruits from the 2.4 dS/m plot. When the bearing shoots were cut back on Jun. 30, shoot growth was renewed after 12 days. The number of fruits set for the second crop was smaller, below the 10th node, compared to the first crop. Harvest of the second crop started on Nov. 16 and continued until Dec. 28. 3. The leaf area at the highest node, fruit size and Brix of the juice were smaller than that in the first crop. Many fruits cracked in the plot where EC was decreased from 2.4 dS/m to 0.3 dS/m from September to December.

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Fresh weight of strawberry fruit is known to be greater when plants are grown under relatively cool temperature because the enlargement of receptacle is partly influenced by temperature. However, fruit weight also depends on the number of achenes per fruit. Therefore, the effect of temperature during the period of flower bud formation on the number of achenes was investigated. 1. Strawberry plants 'Nyoho' grown under controlled conditions, were subjected to 32/27°C, 28/23°C, 24/19°C, 20/15°C and 16/11°C (day/night) under a 12-h photoperiod after stamens differentiation of apical flowers. The number of achenes per fruit increased proportionately as the temperature was lowered. 2. When 'Nyoho' and 'Toyonoka' plants were subjected to the same treatments as above but during the flower bud differentiation, respectively, the number of days from anthesis to ripening and the fresh weight/achene ratio did not differ among the treatments. The number of achenes correlated negatively with temperature as in Exp. 1. Consequently, fruit fresh weight also correlated negatively with temperature. 3. When 'Nyoho' plants were subjected to the same treatments as in Exp. 1, but during the pistil differentiation period, the number of achenes per fruit decreased because the plants were exposed to 5 days of high temperature early.

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The soluble sugar content and composition in four strawberry cultivars grown in the open field and under forcing culture and sampled at various maturation stages in different harvest seasons were compared. 1. Sucrose, fructose, and glucose are the major sugars, and inositol and sorbitol are the minor ones in the sugar compostion of strawberry fruit. Content and compostiion of souluble sugars differed among cultivars, fructose and glucose being higher in 'Toyonoka' and 'Hokowase' than in 'Nyoho' and 'Reiko' fruits. 2. The percentage of fructose or glucose to total sugar content was large in 'Toyonoka' and 'Hokowase' as compared to 'Reiko' and 'Nyoho' during the early maturation stages ; the percentage decreased in 'Reiko' and 'Nyoho', while it increased in 'Toyonoka' and 'Hokowase' as the fruits ripened. 3. In 'Reiko' and 'Toyonoka', the variation of total sugar content in the fruits grown by open culture was larger than that of fruits grown under forcing culture.'Toyonoka' fruit had large amounts of sugars with small variations during the harvest as compared to 'Reiko'. 4. The amount of sugars in strawberry fruit varied among cultivars, harvest years, cropping types and developmental stages of fruit, but the ratio of each sugars to total sugar content was nearly constant. The sugar composition of each cultivars seems to be a heritable characteristic, unaffected by the environment.

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Fresh strawberry fruits from 9 wild strains and 41 cultivars were anlayzed for sugar composition and evaluated by the principal component analysis. 1. Sucrose, fructose, and glucose are the major sugar components of strawberry fruits. The differences in content and compostion of sugars among strawberries were examined. Forty-one cultivars were classified into 4 groups by the principal component analysis. Cultivars, such as 'Toyonoka' in Group 1 contain a high percentage of fructose and glucose and high content of total sugar ; such as Group 2 included 'Kogyoku', which possesses a high percentage of sucrose ; Group 3 amplified by 'Nyoho' is intermediate between Group 1 and 2 ; whereas Group 4 cultivars, such as 'Kaho' has a high percentage of fructose and glocose, but low total sugar. In wild strawberries, Fragaria vesca with the exception of 'White' and F. Chiloensis is characterized by a sugar compostion with nearly equal percentages of sucrose, fructose and glucose. F. Virginiana is characterized by a small amount of total sugar and a low percentage of sucrose. 2. Sugar content and vegetative characteristics in 41 cultivars revealed that total sugar content correlates positively with plant height, leaf area and soluble solid content. Fructose or glucose content correlates negatively with the number of days from flowering to harvest. Consequently, we conclude that sugar content is an important factor in breeding high quality, sweet strawberry cultivars.

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Methods of preparing materials for sap analysis of petioles of tomato and leaflets of rose were studied ; the proposed standard is as follows ; 1. Plant samples should be cut into small pieces and mixed with distilled water in the ratio less than 1 : 5. Then the sample is homogenized for 30 seconds together with a small amount of activated carbon. 2. The homogenate is filtered through a filter paper and the filtrate is analyzed. For macroelement analysis, fresh extract should be analyzed as it is, whereas for microelement analysis, the extracts are acidified with 0.1 N HCl to ensure that the microelements in the extracts are completely dissolved. 3. For the concentration of minerals in the sap, analytical data should be corrected according to the plant sample : water ratio used for the extraction and the dilution factor.

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Tomato plants were pruned and trained to a single-truss cropping system and grown hydroponically in a greenhouse kept at minimum air temperatures of 5°C, 10°C, 15°C, and 20°C. The yield and fruit quality were studied. When flower buds attained the size of rice garains, tomato seedlings were transplanted, and treatment began. Higher minimum air temperatures advanced maturity, considerably shortened the length of cultivation, but decreased the average weight of the fruit. Minimum air temperature had a greater affect on reducing the cultivation period than it had on decreasing fruit yield. Fruit growth rate was not increaesd significantly at higher minimum air temperature. We postulate that at higher air temperatures, the fruit became mature before sufficient fruit growth occurred. Hence, the fruits were smaller at harvest. The Brix of fruit was affected little by minimum air temperature, but the titratable acidity of the fruit juice was significantly increased by high minimum air temperatures.

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To evaluate mechanisms of the growth of Asteraceae plants by osmoregulation under saline conditions, ions uptake, accumulation of compatible solutes, and osmotic potential were measured in leaves of glycophytes safflower (Carthamus tinctorius L.'Roundish Leaf', salt sensitive), Chrysanthemum paludosum Poir. 'North Pole'(moderate tolerance), and a halophyte sea aster (Aster tripolium L., high tolerance) grown under hydroponics including NaCl. Salt stress was imposed for 16 days by adding 12.5, 25, or 50 mM NaCl into nutrient solutions for safflower and C. paludosum, and 75, 150, or 300 mM NaCl for sea aster. Leaf osmotic potentials decreased and the uptakes of Na⁺ and Cl^- increased with increases in NaCl for all species. In C. paludosum and sea aster, Na⁺ concentration in the shoot was significantly higher than that in the root, showing that much Na⁺ was translocated from root to shoot. K⁺ content was unchanged in C. paludosum and sea aster under saline conditions, but in safflower its uptake was inhibited by NaCl stress. Proline and sucrose contents of safflower and sea aster significantly increased by intensifying NaCl stress, furthermore in sea aster, glycinebetaine content significantly increased. Major contributions to decrease leaf osmotic potential by osmoregulation under NaCl stress were the accumulations of the compatible solutes (sucrose, proline, and glycinebetaine) in safflower. In C. paludosum and sea aster, an increase in ion concentrations (Na⁺ and Cl^-) largely contributed to a decrease in leaf osmotic potential. This adaptation mechanism allows plants to keep a positive cell turgor by continuing water uptake so that seedlings can grow under salt stress.

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A disease of large-flowered chrysanthemum plants with characteristic stunting symptoms was observed in Niigata Prefecture in 1988. Chrysanthemum stunt viroid (CSVd) was transmitted from those plants by grafting onto 'Mistletoe', and it was confirmed by electrophoretic analysis of nucleic acid. Although it has been reported that CSVd-infected spray-type chrysanthemum flowered up to 2 weeks earlier than the non-infected, CSVd-infected chrysanthemum cultivars used in this study flowered 1 to 2 weeks later with bearing anemone-type abnormal shaped flowers. In the cultivar 'Senryoumusume', CSVd was not detected from the winter rosette sucker of infected plants in 50 to 61% of plants tested. Subsequent assays indicated that by vegetative propagation during a period of low temperature, CSVd could be eliminated. We found that sap transmission rate was different among varieties tested and that CSVd was not transmissible to healthy plants from infested soil. After RT-PCR amplification of CSVd, a 354 nucleotide sequence was determined which is comparable with that of the English and Australian types.

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Stock (Matthiola incana R. Br. cv. Asanami) was examined for ontogenic changes in leaf area, leaf weight, total nitrogen, nitrate nitrogen and phosphorus in individual leaves at successive growth stages. The final leaf number was 51 and the maximum leaf area at the 15∿20th positions was different from the maximum leaf dry weight at the 33∿36th positions. The dry weights of the lower leaves decreased little with aging although nitrogen and phosphorus were translocated from the lower leaves to the upper leaves on other parts up to the 30th position. The total nitrogen remained almost constant at 4.5 to 5.0% in actively developing leaves, but it decreased with age. The phosphorus concentration was higher in young leaves than in the older ones until the day before anthesis, when it decreased about above the 25th position to less than 0.35%. The translocated quotients (%) of both elements decreased with increasing leaf position from the 8th to 30th position. Nitrate nitrogen concentration in leaves above the 5th position decreased with increased node height ; the peak translocated quotient occurred at the 18th position. From these changes in dry weight, N and P contents in individual leaves during growth, we classified the leaves into three groups, lower leaves (1st∿7th position), middle leaves (8th∿30th position), and upper leaves (above 31th position). Lower leaves which developed slowly had higher translocated quotients of N or P. Middle leaves were finishing their development and N and P were retranslocated without any decrease in leaf dry matter contents ; flower buds became visible. Upper leaves continued to develop ; no export of N or P was apparent.

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Quality and storability of spinach cultivars grown on solution culture method known as Nutrient Film Technique (NFT) during the summer and winter months were studied. The temperature of the nutrient solution was kept constant or non-controlled. 1. Cultivars grown in winter weighed more than those grown in summer. Some cultivars were grown fully in summer, and the growth was improved by cooling the solution of the culture. 2. There were not much difference on ascorbic acid and chlorophyll contents at harvest time between summer- and winter-grown spinach. 3. Quality, based on freshness of spinach, declined equally during storage of both summer and winter spinach ; Shelf life was estimated to be around 12 days at 8°C. Ascorbic acid content was decreased gradually, corresponding to the decrease in quality and chlorophyll content in winter spinach, whereas in summer spinach, ascorbic acid content was almost disappeared within 5 days of storage although the quality and chlorophyll content remained high.

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To remove limonin, the bitter compound in products, the in vitro synthesis of limonin glucoside, a non-bitter compound, in pummelo fruit (Citrus grandis Osbeck) was studied. We discovered that a crude enzyme extract prepared from the albedo of the pummelo, in sodium chloride solution, can catalyze the synthesis of limonin glucoside from limonin and uridine 5'-diphosphoglucose disodium salt (UDPG-2Na). This reaction has a wide active pH range from 3.0 to 10.0, at an optimum temperature of 37°C. Within this range, a major peak of activity is noted at pH 5.5 and a minor one at pH 8.5.

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The development of root systems of cabbage seedlings raised in a conventional soil bed (control) was compared to plug-grown ones after transplanting. Plug-grown seedlings developed horizontally oriented roots from the side of the root ball ; therefore, they had a shallower root system than those of conventionally raised transplants. The drag resistance of plug-grown plants was significantly smaller than that of the control ; thus, the plug-grown cabbages were less stable, compared to the deeprooted, conventionally raised ones.

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