Leaf shape was compared among leaf positions on the spur and the vegetative shoot, between trees of different ages and in different sampling seasons. For optimum leaf sampling, young trees should be avoided, leaves should be sampled from the middle of the vegetative shoots, and shoots should be selected from trees of the same age and in the same season. More than 20 leaves are necessary to classify a plant significantly.

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A simple and numerical expression of leaf shape in pears was developed using a photocopy and eight characters (leaf blade length / width ratio, petiole length / leaf blade length ratio, the widest part of leaf blade, longitudinal curve ratio of leaf blade, wave of leaf blade margin, tip shape of leaf blade, roundness of leaf blade top, roundness of leaf blade base).

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Interspecific hybrids of Hydrangea macrophylla and H. quercifolia were obtained through ovule culture. H. macrophylla ‘Blue Diamond’, ‘Haruna’ and H. quercifolia ‘Snow Queen’ were used. No viable hybrid seeds were obtained by conventional hybridzation. To circumvent the reproductive barrier, ovules were cultured on halflength MS medium containing 3% sucrose. Putative hybrid plantlets were recovered from crosses of H. macrophylla ‘Blue Diamond’ and H. quercifolia, but not H. macrophylla ‘Haruna’ and H. quercifolia. The plantlets showed an intermediate-type morphology of leaf serration and veins. The importance of ovule culture techniques in Hydrangea breeding is discussed.

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Bacterial wilt (Burkholderia caryophylli) is one of the most serious and damaging diseases of carnations (Dianthus caryophyllus) in Japan. It causes serious crop losses in carnations grown in the warm districts. Therefore, the National Institute of Floricultural Science (NIFS), initiated a breeding program for resistance to bacterial wilt (B. caryophylli) in 1988.
‘Carnation Nou No.1’ is a carnation breeding line resistant to bacterial wilt and was derived from interspecific cross between carnation cultivar, ‘Super Gold’ and the highly resistant wild species, D. capitatus. ‘Carnation Nou No.1’ has a perpetual flowering habit. In addition, the yield (number of cut flowers / plant) of this line is very high; the mean yield was 11.5 cut flowers / plant, which was higher than that of ‘Super Gold’, ‘Scania’ and ‘Coral’. It has been shown that ‘Carnation Nou No.1’ is available for a breeding material of carnation and Dianthus cultivars with resistance. The comparative nuclear DNA amount of ‘Carnation Nou No.1’ was estimated to be between D. capitatus and ‘Super Gold’ by flow cytometry.

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The factors causing distorted segregation of primin secretion phenotypes in Primula obconica were studied.
1. In reciprocal crossing between F₁ (primin-free×primin-secreting) plants and primin-free cultivars, distorted segregation occurred only when the F₁ plants were used as the male parent. The results indicated that the distorted segregation observed in primin secretion phenotypes was caused by selective fertilization.
2. In crossing between some primin-free female parents and common F₁ male parent, the segregation ratio differed according to female cultivars. In crossing between common female parents and certain F₁ male parents, the segregation ratio differed according to the male F₁ parent. Thus, selective fertilization was influenced by the genotypes of both male parents and female parents.
3. There were some cases in which the difference in the female genotypes affected the segregation ratio even in the same F₂ progenies, indicating that the primin-secretion gene linked two or more gametophytic genes.
4. Furthermore, it is better to use the heterozygote plants as the male parent in BC₁ seed production for breeding primin-free Primula obconica.

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To establish a new grafting system for the propagation of citrus relatives, tests were conducted on the method of grafting, age of rootstocks and scions, adaptation of grafted plants, etc. Peeling the seeds and keeping them at 25°C in an incubator made uniform their germination and growth. Cut-grafting and fixation of the graft with cellophane tape were effective for the propagation. For calli to form and the grafted plants to survive, it was neccessary to keep them in high humidity by placing them in vinyl bags. On the mutual grafting of trifoliate orange (Poncirus trifoliata Raf.) and its crooked strain ‘Flying Dragon’, the percentage of plants that survived was high when scions at 3 to 4 weeks of age were grafted onto seedling 2 to 3 weeks old. Young citrus shoot scions picked from seedlings were grafted onto young seedling rootstocks of trifoliate orange, and the rate of success was more than 90%. While, when the scions were picked from twigs, the rate of success varied from 0% to 100% depending on the variety. Using this new grafting system, we will be able to propagate citrus relatives rapidly, and clarify the influence of interstocks on the growth and physiology of the plants.

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Lettuce seedlings were grown in 3.8, 8.2 or 45mL cell trays with sufficient spacing, and were planted 24 days after sowing. The growth of shoots and roots was retarded from 19 and 24 days after sowing at a cell volume of 3.8 and 8.2mL, respectively. The growth retardation was greater in roots than shoots, without planting. The shoot (S), root (R) and total (T) relative growth rates (RGR) after planting were highest at 3.8mL. All RGR increased with decreasing cell volume, RRGR was larger than SRGR, and increased markedly with decreasing cell volume. Reducing and non-reducing sugar concentrations at planting increased with decreased cell volume. Root respiration declined with decreasing cell volume. After planting, the respiration recovered more rapidly in smaller cells. It is suggested that reduction in cell volume retards the growth of lettuce plugs, but this dose not affect rooting after planting.

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The effect of leaf removal (removing 2 to 3 immature young leaves from the shoot tips) and Benzyladenin (BA) was examined on branch development from new shoots of two-year-old ‘Fuji’ apple nursery trees which were grown by heading back and disbudding one-year-old whip trees in the spring. BA was effective in inducing the formation of longer branches when applied to shoots 20 to 30 cm long. It was clear that leaf removal was effective in producing branches from axillary buds of new sgoots. Furthermore, 2 to 3 times of repeated leaf removal was more effective. A synergistic effect was observed when BA was combined with leaf removal.

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Effects of the concentration of phosphoric acid in the liquid MS medium on the germination of immature seeds and the bulb formation of Lilium japonicum Thunb. were investigated.
1. Germination rate of immature seeds increased with the addition of phosphate to the culture medium. Scarification treatment with NaOH or NaClO resulted in a decrease in the bulb formation rate of germinated seeds but in an increase in the germination rate. The addition of phosphate raised the bulb formation rate of germinated seeds.
2. The greatest bulb growth during culture was observed in the light and at the phosphoric acid concentration of 2.5 mM.
3. Emergence rate of bulbs after planting in soil was high when bulbs had been cultured at a phosphoric acid concentration of 3.75mM. Bulbs cultured in the light showed a higher emergence rate than those cultured in the dark. When the phosphoric acid concentration in the medium was 3.75mM, emergence rate of bulbs cultured in the dark increased to almost the same degree as that cultured in the light.
4. Bulb enlargement after planting tended to be promoted when bulbs were cultured in the dark, and the greatest bulb enlargement was observed when the medium contained 3.75mM phosphoric acid.

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To develop suitable methods of raising seedlings at cool temperature for Elatum hybrids of Delphinium, effects of raising temperature of seedlings and stage of seedlings at planting and short photoperiod during cool raising on prevention of early bolting and number of florets were investigated. Early bolting was almost completely prevented when seedlings of ‘Blue Springs’ were raised at cool temperatures of 20°C (day, 12 hrs) and 10°C (night). Marketable spikes with more than 30 florets were harvested even at planting in the hot season of August when seedlings of ‘Blue Springs’ were grown at cool temperatures till the stage with 6-7 developed leaves. Short photoperiod (8 hrs) during cool raising increased the number of florets of ‘Magic Fountains Lavender’, but did not change the number in ‘Blue Springs’. Cooling during night (16 hrs) only decreased the number of floret markedly in ‘Magic Fountains Lavender’ and slightly in ‘Blue Springs’.

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This experiment was carried out in order to clarify the amount of decreased nitrogen flowing from bedding plant soil to which zeolite or crushed charcoal had been added. Nitric acid leaching was observed from the 7th to 28th day after transplanting. It became clear that nitric acid leaching from soil can be reduced without suppressing growth of Catharanthus roseus by adding a 10% mixture of zeolite or crushed charcoal. However growth of Catharanthus roseus was found to be suppressed when a mixture of 20% or higher was added. Nitric acid leaching was stopped due to the high cation exchange capacity of zeolite. In the case of charcoal, it was found that nitric acid ion leaching from soil was decreased, because both ions of ammonium and nitric acid were adsorbed on the surface of charcoal.

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The ralation between a temperature rise in the head leaves due to solar radiation and deacclimation was studied in a field using winter cultivated cabbages on 24 February 1997. The day was clear and the temperature of the head leaves was higher than the air temperature throughout the day. The leaf temperature reached as high as 22°C and a deacclimation of the cabbage was induced. The freezing tolerance of the head leaves decreased from 9:00 to 16:00 and short-term deacclimation occurred. Regression coefficients between mean leaf temperature (9:00-16:00) and electrolyte leakage for the freezing torelance test of cabbage leaves revealed an almost positive correlation. The rise in leaf temperature caused by solar radiation may reduce the freezing tolerance of cabbages grown in the field during winter.

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To find peach scion cultivars that are productive and compatible with Prunus tomentosa rootstocks, yield, dry matter distribution and trunk cross sectional area were examined using 15 cultivars of seven-year-old trees. The annual average yield per tree was high in ‘Chikuma Hakuho’, ‘Akatsuki’, ‘Yoshihime’ and ‘Kawanakajima Hakuto’, and low in ‘Takei Hakuho’, ‘Yawata Hakuho’, ‘Yamanashi Hakuho’ and ‘Setouchi Hakuto’. The cultivars with a high yield also showed a large overall distribution of dry matter in each tree. The cultivars with a low yield such as ‘Yawata Hakuho’, ‘Yamanashi Hakuho’ and ‘Ryuho’ accumulated little dry matter indicating a low net production. However in ‘Takei Hakuho’ and ‘Setouchi Hakuho’, much dry matter was distributed to the trunk and shoots although the yield overall was low. Thier total dry matter production was similar to that of high-yielding cultivars. A high bark/trunk cross-sectional area was associated with a low dry matter distribution in the above-ground parts. ‘Kawanakajima Hakuto’ had an especially high fruit/leaf dry matter ratio, indicating that an excess of dry matter was distributed to the fruit, which leads to a shortage of dry matter in the other parts of the tree. This may explain the cause of decline in this cultivar grafted on P. tomentosa.

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In 1993, trees of ‘Seirin-spur’ and ‘Nagafu-2’ on M.9Nagano/Marubakaido were planted in Nagano, Japan to evaluate growth characteristics, yield efficiency and fruit quality under high density planting. Eight-year-old trees of ‘Seirin-spur’ had compact canopies that were less than the half size of those of ‘Nagafu-2’. Trees of ‘Nagafu-2’ grew so vigorously that they had to be thinned every second trees in the rows of 2 × 4 m until the 6th year after planting. Trees of ‘Seirin-spur’ were more yield efficient than those of ‘Nagafu-2’. Despite defects in fruit quality, the compact growth habit of ‘Seirin-spur’ makes it worth using in high density orchards.

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The antioxidant activity, phenolic concentration, and ascorbic acid concentration during fruit development were investigated in four types of Citrus fruit (Citrus spp.); Satsuma mandarin (Citrus unshiu Marc. cvs. ‘Ishiji‘ and ‘Nankan 20’), ‘Shiranuhi‘ [(Citrus unshiu Marc. × Citrus unshiu Osbeck) × Citrus reticulata Blanco], and ‘Lisbon’ lemon (Citrus limon Burm. f.). In general, the superoxide (O₂⁻) radical scavenging activity remained high throughout the development in the skin of all four types. The activities in the pulp decreased with maturation expect for ‘Shiranuhi’ and ‘Lisbon’ lemon. The changes in scavenging activity for the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical differed from those for O₂⁻. DPPH radical scavenging activity in the skin decreased with days after full bloom (DAFB) in the four types of fruit, but increased again at harvest. The activity in pulp decreased with DAFB except in ‘Shiranuhi’ and ‘Lisbon’ lemon. The total phenolic and total ascorbic acid concentrations were higher in the skin than pulp. The ascorbic acid concentrations in the pulp were high at the beginning of fruit development, but decreased toward maturation except in ‘Shiranuhi’ and ‘Lisbon’ lemon. These results suggest that ascorbic acid concentrations influence free radical scavenging activity in the pulp of Citrus fruit.

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Effects of STS, 1-methylcyclopropene (1-MCP) and sucrose on the vase life of cut Oxypetalum caeruleum flowers were investigated. Pulse treatment with 5 or 10% sucrose extended the vase life of cut flowers, but the treatment caused visible damage to the leaves. When the cut flowers were treated with 5% sucrose, STS or a combination of the two, the vase life was extended further by combined treatment than by sucrose alone or STS alone. Pulse treatment with STS in combination with 3% sucrose extended the vase life without causing any visible damage to the leaves. On the contrary, 1-MCP had no effect in extending the vase life. When cut flowers were treated with STS and 3% sucrose at 9°C in darkness, the vase life was improved.

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A questionaire survey was conducted among employees to assess the effects of plants in the workplace on their attitudes and overall mood, and to determine the effective use of interior plants in the office environment. Attitudes of employees regarding foliage plants were favorable, and they agreed that foliage plants in the office made it a more comfortable, satisfactory and desirable place to work. There was no significant difference in their attitude toward the workplace when half of the live foliage plants were replaced with artificial plants. About half of the employees agreed that they felt that the presence of foliage plants had a beneficial effects on their work. Flowering potted plants in the office had more positive impact on human emotions than foliage plants, but there was no significant difference in the beneficial effect on their work.

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