A census of the weed population by species and their coverage and heights was made periodically over the summer in fruit trees and grapevines to characterize the vegetation of winter annual weeds in sunny orchards (Exp. 1). The timing of herbicide applications on the reduction of competition between winter annuals and the growth of 1-yr-old 'Hikawahakuho' peach (Prunus persica Batsch. var. vulgaris Maxim.) trees was studied (Exp. 2). The competition between those weeds and 4- and 6-yr-old 'Hikawahakuho' peach trees was also examined incorporating various vegetation management practices (Exp. 3). When weed management allowed winter annual weeds to grow freely in young sunny orchards, Vicia angustifolia L. became dominant from March to June, followed by Stellaria media (L.) Villars, and Lamium amplexicaule L. Those winter weeds reduced the overall growth of 1-yr-old peach trees when they were not controlled by May. Growth inhibition of newly developing shoots and fine roots by winter weeds was not as strong as that by summer weeds. Shoot length was reduced significantly in 4-yr-old peach trees but not in 6-yr-old ones. The results indicate that winter weeds need to be controlled by early May to minimize inhibition of peach tree growth.

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Crosses between satsuma mandarins and tetraploid ponkan were made to produce triploid hybrid cultivars.
Triploid embryos were obtained from the crosses using three seed parents, 'Ootsu No. 4', 'Aoshima' and 'Imamura', which produced comparatively small numbers of embryo per seed. Of the three, the frequency of triploid embryo production per fruit was highest in 'Aoshima'. The frequency of triploid embryo production per seed in undeveloped seeds was higher than that in fully developed seeds. By the embryo rescue technique, triploid plants were obtained efficiently from the embryos of undeveloped seeds. Tetraploid plants were also obtained from fully developed seed of 'Ootsu No. 4' and 'Aoshima'.
RAPD analysis showed that all the triploid plants were hybrids and the tetraploid plants were also hybrids or natural auto-tetraploids. Two hybrid embryos in one seed with identical banding RAPD patterns on agarose gels, indicate that the embryos are derived from the same single egg cell.

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The effects of chitosan coating on respiration, ethylene production, and storage of peach (Prunus persica Batsch. var. vulgaris Maxim cv. Hakuho), Japanese pear (Pyrus pyrifolia Nakai cv. Shinko and Housui), and kiwifruit (Actinidia deliciosa L. cv. Hayward) during storage were investigated. Acetic acid was found to be a suitable solvent of chitosan for coating fresh fruits. Chitosan coating significantly reduced the respiration rate of peach and 'Shinko' pear in storage and of kiwifruit after storage. Coating reduced the ethylene production of the peach markedly, increased the internal CO₂, and decreased the internal O₂ levels of 'Shinko' pear. Chitosan significantly inhibited the growth of Botrytis cinerea and fungi isolated from decaying 'Housui' pear. This resulted in a decrease of post-harvested spoilage of peach, 'Housui' pear, and kiwifruit. Chitosan-coated peach and 'Shinko' pear were markedly firmer and less mature at the end of storage, indicating that the treatment could be an alternative means of preserving fresh fruits.

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We measured ethylene evolution, ACC content, ethylene forming enzyme (EFE) activity, and respiration in highbush blueberry (Vaccinium corymbosum L.) from flowering to harvest to assess the role of ethylene in the processes. Cultivars used were 'Collins' (early maturing), 'Berkeley' (mid-season), and 'Dixi' (late maturing). Ethylene evolution increased at both petal-fall and maturation stages, and was higher in the early stage than in the late stage. Ethylene at petal fall was produced by the calyx and ovary parts, but not the corolla. This indicates that ethylene evolution in flowering is correlated with pollination or fertilization or both. Ethylene evolution rate in the maturation stage was high between the blue pink (BP) peel color in 'Collins', and mature green (MG) stage in 'Berkeley', and green pink (GP) stage in 'Dixi'. Ethylene evolution was higher for 'Collins' than for the others in both years and higher in 1995 than in 1994. The pattern of EFE activity was not similar to that of ethylene evolution except in 'Collins'. Therefore, the correlation between ethylene evolution and EFE activity in the maturation stage was different with each cultivar. Berry ACC content was high at GP stage in three cultivars before ethylene evolution increased.

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Vegetative winter buds of pear (Pyrus communis L. cv. Beurre d'Amanlis) were successfully cryopreserved at -150 °C after pre-freezing to -30 °C. Meristems were excised from the buds and cultured on medium (WPM) containing 1.0 mg-liter^-1 6-benzylamino-purine (BA), 25 g-liter^-1 sucrose and 0.8% (w/v) agar. Partial dehydration at 25 °C prior to pre-freezing at - 30 °C improved the subsequent shoot formation rate. The optimal water content of the dehydrated buds was about 41%. Pre-freezing with a daily decrease at 5 °C increments to -30 °C followed by slowly thawing in air at 0 °C was effective for producing the highest rate of shoot formation. Micrografting of the cryopreserved vegetative buds on young seedlings also induced normal shoot growth. This procedure was successfully applied to twelve other cultivars of pear. Thus, this protocol of using vegetative buds is a simple, reliable method for cryopreserving pear germplasm.

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The relationship between planting density and fruit yield of 'Starking Delicious' apple (Malus domestica Borkh.) grafted on dwarfing (M. 9 and M. 26) and semidwarfing (M. 7 and MM. 106) rootstocks was studied.
1. On all four rootstocks, the yield per tree decreased with increasing density, the decreasing rate becoming significant at a certain density. As the trees aged, the density at which the yield per tree decreases abruptly shifting to the lower density plots. This relationship between the density (ρ) and the yield per tree (X) could be represented by the following reciprocal equation,
1/X=Axρ+Bx- (1)
where Ax and Bx depend on the tree age and rootstocks.
2. In regard to the yield per hectare, the existence of the optimum planting density (ρopt) was recognized on all four rootstocks. The ρopt shifed to lower density with the progression of tree age.
3. Regardless of the differences in tree age and rootstock, the relationship between the yield per tree (X) and the trunk cross-sectional area (θ) could be prescribed by the following equation,
X=Hθ^h. - (4)
4. From Eqs. (3), (4) and (5), the relationship between the density (ρ) and the yield per hectare (Y) can be expressed by the following equation,
Y=Hρ/ (Aρ+B) ^h- (6)
where A, B, H and h depend on the tree age and rootstocks.
On all rootstocks, theoretical curves given by Eq. (6) fit well with curves derived from the experimental data, indicating that Eq. (6) can satisfactorily explain the density effect on fruit yield.
5. The ρopt is given by the following equation, ρopt=B/A (h-1). - (7)
The ρopt decreased exponentially with the progression of tree age and this decrease rate was accelerated in trees on M. 26, M. 7 and MM. 106, compared with trees on M. 9. The slopes of the time trend of the decrease changed abruptly at age 10 regardless of the rootstocks.
6. On all rootstocks, the cumulative yield per hectare from age 6 to age 11 calculated from Eq. (6) was higher in the planting system of ρopt than in the non-thinned planting system. However, the increase rates were only 925 %. In both the planting systems of ρopt and non-thinning, the cumulative yield in trees on dwarfing rootstocks was higher than that in trees on semidwarfing rootstocks.

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Factors related to variations of leaf photosynthetic activities in many pear cultivars were studied by using a rapid measuring system for leaf characteristics, leaf diffusive resistances, leaf apparent photosynthetic rates (P_n), and the respiratory factors.
1. Vegetative shoots were sampled in early summer, dipped in water and light-saturated under an artificial source. The P_n values and diffusive resistance factors of the leaves attached to the middle of a shoot were measured by a portable measuring apparatus (Li-Cor Model 6200 and its modefication) for photosynthesis, transpiration, and the dark respiratin (R_d) and photorespiration rates (R₁). Furthermore, the leaf area, leaf width, leaf specific weight, facial density of leaf chlorophyll, chromatic value of leaf surface, leaf optical properties, percent of leaf vein area and the 3 phases (liquid, solid, and gas) of leaf tissue, were measured rapidly by several portable apparatus which we bought or built.
2. Higher coefficients of variation were found in chromatic values (a^* and b^*) of leaf adaxial face, transmittance and reflectance of PPFD of leaf tissue and leaf area, whereas lower coefficients were found in relative values of facial density of leaf chlorophyll (SPAD), leaf width, and percent of liquid phase in leaf tissue within the 94 cultivars. The principal component analysis using the 60 cultivars suggested that leaf color or amount of substance absorbing PPFD in leaf tissue, physical properties of leaf tissue, reflectance of adaxial face and leaf moisture was I, II, III and IV principal component, respectively.
3. Coefficients of regression of the P_n values from multiple regression analysis using the 18 cultivars was about 90% when the diffusive resistance in the mesophyll (R_m) is included as one of the variables and about 60% when excluded.
4. Our simple correlations, the results from the analysis using polynominal fitted lines for P_n using a simple variable and the results from the multiple regression analysis indicated that a higher activity of leaf photosynthesis appears in leaves with a dull somewhat rugose surface, a dark green color and watery tissue.

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The relationship between the occurrence of cracking and morphological characteristics of 'Fujiminori' grape berries was studied in comparison with other tetraploid cultivars; 'Kyoho', 'Pione' and 'Takasumi'.
The frequency of occurrence of berry cracking was markedly higher in 'Fujiminori' than in other cultivars. In 'Fujiminori' berries, the crackings were observed in the skin around the pedicel and stylar end. At the early ripening stage, crackings occurred predominantly around the pedicel.
The reduction in the firmness of skin after veraison was much faster and greater in 'Fujiminori' than in other cultivars. In 'Fujiminori', several fractures occurred on the cork layer developed on the skin surface adjacent to the pedicel; then they penetrated into the flesh. Contrarily, in 'Pione', the fractures were healed by the development of the newly emerged cork tissue. The thickness of the cork layer was thinner in 'Fujiminori' than in the other cultivars. In 'Fujiminori', the depression of skin elongating longitudinally from pedicel to equator existed; subsequently the fleshy tissue beneath the depression collapsed.
The skin around the stylar scar of 'Fujiminori' berry, exhibited small ring fractures one week after veraison; they gradually expanded until harvest. Only small fractures were observed in 'Pione' 6 weeks after veraison.

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Adult trees of satsuma mandarin 'Okitsu wase' grown in the open with a leaf: fruit ratio of 15: 1 were drenched in July with an aqueous solution of IAA. Meanwhile, young trees of 'Nichinan ichigo' grown in a plastic-house were pruned in late July and drenched in September with an aqueous solution of IAA, BA or Paclobutrazol. The treated trees initiated more fibrous roots and flower buds than did the untreated control trees. In late fall, carbohydrate content was higher in the new shoots but lower in the fibrous roots in the soil-drenched trees compared to their respective control parts. Thus, the C-N ratio in the stem of the new shoot was larger and that of the fibrous roots lower in the treated trees relative to those of the control. Another trial to 'Nichinan ichigo' was a soil-drenching treatment with L-proline solution in September. It promoted shallow fibrous root growth and flower bud differentiation significantly. The physiological basis for the enhanced flower bud differentiation of satsuma mandarin by soil-drenching with phytohormones and amino-acids and its possible use are discussed.

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Differences in fruit characters between caprifig and other fig types, and first and second crops among fig (Ficus carica L.) hybrid seedlings, fruit weight (FW), and soluble solids content (SSC) in the juice of the hybrids from 9 cross combinations were investigated. The family means of the groups namely, caprifig-type first crop, fig-type first crop, and fig-type second crop were searched for and the three family means compared within the family in each group. Correlation coefficients between the groups of the three family-means and the mid-parental values in 9 families were caluculated.
1. For size, the caprifig-type first crop weighed the least in 8 families; the fig-type first crop was heaviest in 7 families. The family means of FW in 5 families became progressively larger in the order of: caprifig-type first crop, fig-type second crop, and fig-type first crop.
2. The family means of SSC in all families became larger in the order of: caprifig-type first crop, fig-type first crop, and fig-type second crop.
3. There are positive correlations between the FW of the three groups and mid-parent and between the SSC of fig-type first and second crop, and mid-parent.
4. There are negative correlations between the FW of caprifig-type and fig-type first crop and the SSC of mid-parent and between the SSC of fig-type second crop and the FW of the mid-parent.

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Osanijisseiki', a self-compatible, spontaneous bud sport of the Japanease pear 'Nijisseiki' is an excellent cultivar with a smooth skin. However, this cultivar is susceptible to Japnaese pear black spot disease caused by Alternaria alternata Japanese pear pathotype. To obtain resistants mutants from 'Osanijisseiki', nursery plants of 'Osanijisseiki' have been irradiated chronically with gamma-rays in the Gamma Field of the Institute of Radiation Breeding, NIAR, MAFF, since 1986. Screening tests using AK toxin, a host-specific toxin produced by A. alternata Japanese pear phathotype, were performed from 1988 to 1993.
Four branches of young trees planted at a distance of 40 m from the ⁶⁰Co source were selected as being resistant mutants in 1991 (IRB 502-13T and IRB 502-14T) and 1993 (IRB 502-17T and IRB 502-18T). Sensitivity of the four resistant mutants to AK-toxin and susceptibility to the pathogen were compared with other of susceptible and resistant cultivars. The results showed that these four mutants possessed intermediate resistance. Furthermore, a mutant, IRB 502-13T, had the same characteristics as the original 'Osanijisseiki', except for the difference in toxin sensitivity. The characteristics of the other mutants, IRB 502-14T, IRB 502-17T, and IRB 502-18T, care beiing examined.

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The effects of applications of 6-benzylaminopurine (BAP), gibberellic acid (GA₃), and abscisic acid (ABA) on the root formation of grapevine hardwood cuttings were investigated. BAP suppressed rooting of grapevine cuttings completely, whereas GA₃ and ABA inhibited it temporarily. Endogenous indoleacetic acid (IAA) in cuttings treated with BAP increased linearly to 12.6 and 19.4 times per cutting and per g fresh weight, respectively, over the control for 30 days after planting. In cuttings treated with GA₃, the level of diffusible IAA was higher than that of control cuttings through the experimental period; the fluctuation pattern of extractable IAA was similar to that of the control. In cuttings treated with ABA, the extractable IAA content was significantly lower than that in control cuttings 10 days after planting. The fluctuation pattern of endogenous IAA in BAP treatment was different from that in GA₃ and ABA treatments. Cuttings treated with BAP presumably failed to root because the level of endogenous IAA was unbalanced. GA₃ may inhibit root formation directly whereas ABA may cause inhibition of rooting by depressing the bud activity.

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To differentiate tobacco mosaic virus (TMV) strains in southcentral China, strain identification of TMV isolates collected from fields of sweet peppers or chillies in the cities of Shanghai (30°N), Wuhan (30°N), Chengdu (30°N), Lhasa (30°N), and Dali (25°N) was performed by using the series of TMV-resistant Capsicum spp. carrying the genes of L⁺, L¹, L², L³, and L⁴, respectively. As anticipated, no isolates were identified as P₀ strain, because all of the TMV isolates were collected from cultivars with a L¹ resistance gene. On the other hand, it was found that the P₁ and P_{1, 2} strains which can infect cultivars with the L¹ resistance gene were widespread in southerncentral China. In addition, the P_{1, 2, 3} strains which can break down the resistance of cultivars with L³ resistance gene was also detected in Shanghai. No isolates were capable of infecting C. chacoense Jacq. harbouring the L⁴ resistance gene. Based on the study of the variability of TMV strains in China, methods for the breeding of sweet pepper for TMV-resistance were evaluated.

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The effect of wind on the transpiration rate of tomato scions was studied.
1. Under high relative humidity, winds decreased the transpiration rates with increasing light intensity. Under low relative humidity, winds increased the transpiration rates.
2. Under light and high relative humidity, leaf, temperature was always higher than air temperature. The difference between leaf and air temperatures decreased with air movement.
3. Irradiation with thermal rays raised leaf temperature and reversed the wind effect, thus, suppressing the transpiration rate.
4. Under light conditions, at low-VPD of air, VPD of the boundary layer was higher than VPD of air; conversely, at high-VPD of air, VPD in the boundary layer was lower. The difference of VPD between air and the boundary layer tended to be large with increasing light intensity.
5. We conclude that under high relative humidity and calm condition, the rise of leaf temperature with light increases the VPD in the boundary layer of the leaf, followed by an increase in transpiration rate. Wind, however, lowers the leaf temperature and decreases VPD in the boundary layer of the leaf, causing a decrease in the ranspiration rate.
6. This result is applicable to the healing process of grafted vegetable seedlings. Under high light intensity and relative humidity, air movement hastened the healing of the grafted union, allowing the plants to grow without wilting.

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Bulblets of Lilium rubellum Baker were cultured for 16 weeks in a 20-, 30- or 40-ml liquid medium renewed 0, 1, or 3 times. The bulblets were assessed for growth and rot infection.
1. Bulblets with fresh weight of more than 600 mg were obtained by using a 20- or 30-ml medium with 3 renewals, or 40 ml with one renewal.
2. Bulblets frequently turned brown when they were cultured in a 30- or 40-ml medium with 3 renewals; they frequently rotted both during a cold treatment and after transplantation.
3. Bulblets cultured in a 20-ml medium did not rot after a cold treatment irrespective of the number of medium renewals; they grew well after transplantation to the greenhouse.
4. Bulblets cultured in a 20-ml medium with 3 renewals most frequently developed into plantlets with elongated axes 15 weeks after transplantation.
These results indicate that the 20-ml medium with 3 renewals appears to be most suitable for bulblet culture of L. rubellum in a liquid medium.

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Delphinium seeds were sown early each month throughout the year and the seedlings were transplanted to an unheated greenhouse to study the seasonal change on the flowering behaviour of delphinium. The formation of flower buds was observed microscopically, whereas the effect of temperature on bolting and flowering was macroscopically studied in a phytotron. Furthermore, the bolting characteristics of several cultivars in a heated house under natural day-length were also studied.
1. Flower bud differentiation occurred under a wide range of temperatures almost year-round. When seedlings were planted in warm and hot seasons, the period from sowing to flower bud differentiation was shortened, whereas, when they were planted during the cool or cold seasons, the period was prolonged. Therefore, the flower bud differentiation process is hastened by high temperatures.
2. Delphinium seedlings react sensitively to the higher temperature; when the temperatures were kept constant at or higher than 20 °C, seedlings bolted after the plants developed 5 or more leaves. However, plants kept at 15 °C remained in the juvenile phase for an extremely prolonged period and about half assumed the rosette form.
3. When the seeds were sown in March-July and the seedlings were transplanted in summer, the plants differentiated flower buds at a lower node and produced poor spikes with few florets. Plants derived from seeds sown in August-February developed many leaves below the first floret, produced spikes of higher quality with more florets. Thus, the greater the ratio of leaves to floret, the more florets per spike were formed.
4. Low temperature did not act as vernalization inducing in the flower bud initiation, but caused the rosette to break or expanded the temperature range the plant could grow to lower side. Thus, low temperature acted to make growth activity higher.
5. Flower bud differentiation was always accompanied with bolting even under un-heated conditions, so that the time of flower bud differentiation could be estimated easily.Therefore, early bolting plants resulting in a low cut flower quality can be eliminated atan earlier stage before transplanting.
6. When delphinium were grown in a heated house under natural day-length, many cul-tivars formed rosettes. Plants, which formed rosettes, were slow to bolt and producedmalformed spikes.

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The growth periodicity of Zephyranthes candida grown outdoors and the effect of temperature on the initiation and development of flower buds were investigated.
A bulb has a sympodial branching system; each unit of the sympodial branch is com-.posed of 2 foliage leaves with a circular base and 1 foliage leaf with semi-circular base in 1/2 alternate arrangement from the base upwards and terminates in an inflorescence with 1 floret. During the growing period, extending from spring to autumn, repeated sympodial branching results in 3-4 inflorescences.
In October, after the flowering season, 2 inflorescence primordia remain in each bulb. The first inflorescence is at carpel initiation stage and the pollen mother cell is at the tetrad stage; the pollen grains mature and become functional between June and August of the following year. Anthesis occurs from July to September.
When plants with inflorescences at carpel differention stage were moved to a growth chamber kept at 10°, 15°, 23° or 30 °C, plants transferred to 23 °C chamber developed flower buds most rapidly and reached the pollen formation stage 4 months later and bloomed after 20 days. Plants kept at the other temperature regimes had fewer inflorescences and flowered later.
In plants kept continuously at 23 °C from October, the first inflorescence flowered in March of the following year. During the growing period for about 13 months, these plants produced 4.7 flowering inflorescences and initiated 5.1 inflorescences by repeated sympodial branching.
In a commercial forcing trial, plants kept at a min. 20 °C from early March flowered in May, 2 months earlier than the natural flowering time.

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The effects of N, P, K and Mg on the growth and flowering of Phalaenopsis were investigated.
1. When no nitrogen was supplied, the number and size of fully developed leaves was reduced and defoliation increased, resulting in considerable reduction of total leaf area. The concentration of chlorophyll decreased but no decrease in the number of flower stalks occurred. Roots showed no visible changes, but the total plant dry weight was lighter compared with plants supplied nitrogen.
2. In -P plants, defoliation increased and the production of new ones was curtailed. Phosphorus deficiency induced purple and red coloration of the older leaves, leaf distortion and curling of the leaf apices. Yellowing of an incividual leaf began from its apex and gradually spreaded basipetally to the entire leaf, ending in defoliation. The deficiency symptoms spread upward from the basal leaves of a plant. The area of newly developed leaves was reduced and plant growth was stunted. The dry weight of the plants was also reduced and new roots were not produced. The production of flower stalks was almost completely inhibited.
3. No significant difference in new leaf formation or defoliation was observed among plants supplied or denied potassium. However, the surface area of fully developed leaves tended to become smaller in plants lacking potassium. The production of flower stalks was not affected, but flower stalks tended to develop rather early. Leaves and roots showed no noticeable symptoms of potassium deficiency.
4. Calcium deficiency produced no noticeable change in plant growth and/or production of flower stalks.
5. No noticeable symptoms of magnesium deficiency were observed, but the development of flower stalks was delayed slightly in comparison to the control.

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To develop a new method of fertigation in cut flower production of roses, the relationships between plant growth and its nutrient and water uptake and the ratio of cut flower to plant growth were investigated. Two-year-old rose plants, cv. Sonia and Carl Red, grafted on Rosa multiflora Thunb. were grown hydroponically for about a year. The overall plant growth was determined by weighing separately cut flowers, prunings, defoliated leaves, roots, trunks, and old leaves.
The growth rate decreased immediately after harvesting cut flowers and pruning. On a long term basis, however, the growth rate was slower in summer than in other seasons. Growth in 'Sonia' plants was faster than that in 'Carl Red' plants. After flower production had become stable, the ratio of cut flowers to plant growth on a fresh weight (FW) basis was always about 40%in both cultivars.
The amounts of nutrients absorbed per 100 g increments of plant FW in both cultivars were about N: 0.70 g, P: 0.10 g, K: 0.40 g, Ca: 0.17 g, and Mg: 0.04 g. The amountof nutrients absorbed per 100 g cut flowers were 2.5 times greater than those on per plant FW basis.
'Sonia' plants absorbed 2-3 liters of water in winter, 4-5 liters in spring and fall, and 8-9 liters in summer per 100 g FW. 'Carl Red' plants absorbed more water than 'Sonia' plants.
The concentration of nutrient absorbed by the plant (nutrient/water) was lower in summer than in winter, and that of 'Carl Red' was nearly 80% of 'Sonia'. The amount of nitrogen absorbed by 'Sonia' plant was about 230 ppm in winter, 145 ppm in spring and fall, and 110 ppm in summer. The amounts of P, K, Ca, and Mg uptake by plants were on the average 14, 60, 24, and 6 percent of N, respectively.

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The present experiments were carried out to determine the relationship between depth of dormancy and sleeper occurrence after chilling, and also to know factors involved in sleeper occurrence, using 'Hinomoto'. Bulbs, 19 to 22 cm in circumference were planted at different times of the season and sprouted at 10, 15, 20, and 25 °C to determine the depth of dormancy. To determine sleeper occurrence, bulbs were vernalized at 9 °C for 6 weeks at different intervals after harvest and allowed to sprout at prevailing summer temperatures (20 to 30 °C) or at 25 °C.
Bulbs which were planted later in the season sprouted at a higher percentage frequency and quicker at 15 °C and 20 °C. This sprouting pattern indicated that the depth of dormancy decreased with increasing storage period at room temperature after harvest.A high percentage of bulbs sprouted if chilled immediately after harvest. The sprouting percentage decreased markedly when bulbs were chilled after dry storage at room temperature for 1 to 3 weeks. When the chilling was delayed, the sprouting percentage improved.
Most bulbs that were stored dry at 20 to 30 °C for 2 weeks and then chilled, did not sprout and became sleeper; bulbs vernalized without dry storage had a high sprouting percentage.
Soaking bulbs in 47-48 °C water for 1 hour immediately after harvest accerelated sprouting at 20 °C; dry stored, chilled bulbs also had a high sprouting percentage following the hot water treatment.
These results indicate that there is no relationship between depth of dormancy and sleeper occurrence and that dry storage of bulbs at 20 to 30 °C for 1 to 3 weeks after harvest in June induced occurrence of sleepers after subjecting to chilling

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The effects of increasing ambient CO₂ levels on the growth of developing Doritaenopsis plants in a greenhouse were studied for 840 days. Leaf area, dry weight, and content of total carbon and total nitrogen in dry matter were measured every three months, and the time course of the relative growth rate (RGR) was investigated. Leaf area and dry weight increased with increasing CO₂ concentration from 438 ppm to 946 ppm in the atmosphere. In an initial grwoth stage when plants were transplanted from flasks to pots, RGR increased as the CO₂ level increased. RGR during a later vegetative growth stage was not affected by the CO₂ concentration, and its value was 0.006/day. The value of RGR was less than that of the other C₃, C₄, and CAM plants.

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The effect of CO₂ enrichment on Phalaenopsis cut flower production was examined for 30 months throughout five flowering cycles. The plant was cultured in three greenhouses with different CO₂ levels of (A) : control, daily mean of ambient air=438 ppm; (B) : 700 ppm; and (C) : 1000 ppm.
1. The fresh weight of cut flowers, the numbers of inflorescence and flowers per 20 plants varied, depending on the CO₂ concentration for each flowering cycle.
2. The preservability (vase life) of cut flowers always improved under higher CO₂ levels. Organic acid contents of plants were also higher under higher CO₂ levels. The malic acid content in the flowers was higher than in the younger leaf and flower stalk at 1:00 PM and 10:00 PM; and it was also higher in the younger leaf than in the flower stalk at 10:00 PM, but lower at 1:00 PM.
The pH value of plants was always lower at higher ambient CO₂ levels, and lower in the younger leaf and flower stalk at 1:00 PM than at 10:00 PM, wheras at those same times the sugar content at the higher ambient CO₂ levels reached its maximum.

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The effects of wound stress by slicing sweet pepper fruits 'Golden Bell' on ascorbic acid metabolism were invesetiged.
1. The ascorbic acid contents in sliced tissue of mature green and ripe yellow pepper fruits stored at 20 °C were not changed by wounding; although the dehydroascorbic acid contents increased after wounding, that level was maintained constant during the subsequent storage period.
2. The level of hydrogen peroxide in sliced tissues stored at 20 °C was slightly lower than that of whole fruit; thereafter the hydrogen peroxide content in sliced tissues increased to the equal that in whole fruit within 24 hours of storage.
3. In both mature green fruit and ripe yellow fruit, the activities of ascorbate peroxidase were not influenced by wounding. The activities of monodehydroascorbate reductase in sliced yellow ripe fruit tissues stored at 20 °C increased during 12 hours after wounding, thereafter they decreased. On the other hand, the activities of monodehydroascorbate reductase in sliced mature green fruit tissues stored at 20 °C were not influenced by wounding. The activites of dehydroascorbate reductase in sliced tissue prepared from mature green fruit and ripe yellow fruit increased during 12 hours after cutting, and then decreased during the subsequent storage period.
4. The activities of catalase, glutathione reductase, and L-galactono-γ-lactone dehydrogenase in sliced tissues prepared from mature green fruit and ripe yellow fruit increased after cutting, and then decreased during subsequent storage period.
Our results suggest that wound stress by cutting activates the biosynthesis of ascorbic acid and reductases on ascorbic acid metabolism, so that the level of ascorbic acid in sweet pepper fruits remains high.

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The average diameter of the cortical cells of 'Fuji' apple did not significantly differ for fruits ranging in weight from 172 to 390 g. This indicates that the fruit size of this cultivar is mainly determined by the number of cells per fruit. But the average cell diameter fluctuated from season to season indicating that the difference in fruit size depends on cell size and cell population. For 'American Summer Pearmain', 'Tsugaru' and 'Senshu' which mature early, the larger fruit tended to have larger cell diameters. In 'Jonagold', which matures in late October, the cell diameter remained nearly constant in fruits weighing between 215 and 387 g. Thus, the difference in the sizes of 'Jonagold' fruit is a function of cell number rather than cell diameter, similar to that of 'Fuji'.

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PCR-RFLP analysis was applied to classify nine Lilium species, L. japonicum, L. rubellum, L. nobilissimum, L. speciosum, L. auratum, L. auratum var. platyphyllum, L. henryi, L. concolor var. pulchellum and L. leichtlinii var. maximowiczii, and one interspecific hybrid, L. x formolangi.
When PCR products amplified in specific regions of ribulose-1, 5-bisphosphate carboxylase large subunit (rbcL) gene in chloroplast and nuclear ribosomal RNA (rRNA) gene were digested by 20 restriction enzymes, some polymorphisms were observed.
The examined plants were classified into six groups based on the combined results in rbcL and rRNA gene. The tested species in Archelirion and Sinomartagon were classified into different groups. Furthermore six species in Archelirion were classified into three groups. Thus our study suggested that PCR-RFLP analysis could be used for classification of lilies.

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