Growth, flowering and fruiting of own-rooted persimmon trees (Diospyros kaki Thunb. cv, Nishimurawase) propagated by cuttings (C trees) during the initial five years after field establishment ware compared with those of trees grafted on seedings stocks (G trees) and those of own-rooted and micropropagated trees (M trees). M trees grew most vigorously, followed in order by C trees and G trees, as indicated by changes in trunk girth, tree height, total shoot length, and shoot number. C and D trees bore some male flowers, while M trees scarcely bore male flowers. Among the tree types, there was no significant difference in total yield for three harvest years and fruit quality. The yield efficiency increased in the order, M trees, C trees, G trees, but the difference was not significant. These results suggested that different propagation methods produced own-rooted trees differing in growth and flowering.
Winter buds taken from mature trees of Japanese Apricot (Prunus mume Sieb. et Zucc.) were successfully established in culture on woody plant (WP) agar medium supplemented with 4.4 μM benzyladenine (BA) and 3% glucose. The efficiencies of development of the bud into normal shoots are 50 to 100%. The efficiencies were improved by treating the buds with antioxidants, ascorbic acid, reduced glutathione, ferulic acid, and caffeic acid. Shoot proliferation in subcultures was also best in WP agar medium containing 4.4 mM BA and 3% glucose. Root formation was induced when shoots were transferred into WP agar medium containing 0.54 μM naphthaleneacetic acid. Rooted plantlets were incubated on autoclaved vermiculite containing fertilizer, and growing plantlets were then transferred to soil and successfully acclimated.
The suitability of media and root-zone volume in a soil-less culture system using a combination of subirrigation and circulation of nutrient solution were investigated in the ‘Muscat of Alexandria’ grapevine. The grapevines were planted in three types of containers differing in volume, 70, 100, 200 liter, and filled with either perlite or porous charcoal. The planting containers were individually placed in larger trays, and the water level was maintained at a constant level and sub-irrigated. The canopy area of each grapevine was restricted within 5 m2. The shoot growth, leaf area and LAI of grapevines in perlite were significantly larger than those of grapevines in charcoal medium. Grapevines grown in perlite showed a slightly lower berry set percentage but higher yield than grapevines grown in charcoal medium because of the high incidence of berry sunscald on fruit grown in charcoal. The shoot length was measured periodically and the total leaf-area of each shoot and LAI measured at full bloom and veraison were the largest among grapevines grown in 200 liters of media and smallest in those grown in 70 liters of media. Grapevines grown in 200 liters of media showed a higher berry set percentage and yield but lower incidence of berry sunscald than did grapevines grown in 70 liters of media. Although the shoot growth did not different between the two methods of nutrient solution supply, with or without periodic circulation, grapevines grown without circulation of nutrient solution developed leaf sunscald probably due to water stress in the summer and then growth declined during the next season. The yield and fruit quality of the grapevines growth in 200 liters of perlite with sub-irrigation and circulation of nutrient solution satisfied the cultivation standards of ‘Muscat of Alexandria’ grape in Okayama Prefecture.
Relationship between high temperature–induced rosetting and increased daytime leaf–temperature as affected by drought treatment was investigated in Eustoma grandiflorum cv. Tsukushinoyuki. At high temperature (27–33°C), the rosetting rate was higher than 70% in stressed plants that were irrigated only when the water concentration of the medium decreased below 25% for 9 weeks. Contrastingly, the rate was 0% in the unstressed control in which the water concentration of the medium was maintained over 40% throughout the experiment. A follow up experiment proved that drought treatment for one week was sufficient to stimulate rosetting at high temperature (29–35°C). In the daytime, when the air temperature was recorded as 30°C, leaf temperature of stressed plants increased to 45°C, while that of control plants remained similar to the air temperature. These results suggest that drought-induced stress stimulates rosetting at high temperature due to increased temperature of the leaf and/or other parts of the plants receiving high solar radiation.
Eight-year-old ‘Pione’ vines were grown in plastic containers under forced conditions. Twelve vines, that were trained to cordon with spur pruning, were used for the experiment. Bark was peeled by high-pressure water two weeks after forcing. After that, 10% 15N-urea solution was applied to the trunk or spurs. In the control vines, tap water was applied to all trunks and spurs. There was no difference in the date of bud-break among the three treatments. At the second leaf-expansion stage, total nitrogen and 15N contents of shoots were higher receiving in vines application to the trunk than in vines receiving application to spurs or in controls. When the trunk of vines was treated with 15N-urea, shoot growth was the most vigorous. The chlorophyll contents in the leaves at the third and fifth node in vines receiving application to the trunk were higher than in those vines receiving application to the spurs or in controls. These results show that nitrogen absorbed throughthe surface of the trunk is effective for growth immediately after bud-break.
We investigated the effects of plant growth regulators on shoot growth of a columnar type apple tree. The shoot growth of ‘Trajan’ differed from that of normal type trees and it's growth stopped in June, but then continued until early October. The shoot growth was inhibited in ‘Trajan’ when treated with NAA and MH, but promoted with BA, BA + MH and BA + GA3. However, the number of shoots was greater when treated with BA than with NAA, and the response to BA alone was greater at 600 ppm than at 300 ppm. In addition, the effects of applying BA plus MH or GA3 had an interactive effect on ‘Trajan’. It is evident from the above results that cytokinins, auxin, and gibberellins affect shoot growth of the columnar type.
This study was investigated to clarify the effect of flower-bud stage and root pruning at the onset of chilling on the flowering of a forced and retarded tree peony. The flowering percentage of ‘Shin Shima no Kagayaki’ was increased by advancing the stage of flower bud in forcing and retardation culture, even if the rootstocks of tree peony plants were pruned at the beginning of chilling. However, the flowering rate of ‘Shin Ka Jishi’ was low, regardless of the flower-bud stage. When plants with advanced flower-bud stage were forced after the chilling plants in pots without root pruning, the flowering percentage increased (80%) and cut flower quality was superior. Therefore, chilling the plant in a pot without root pruning is an effective method for improving the flowering rate of the cultivar, which is low in a forcing and retardation culture.
To study characteristic of ornamental plants used for landscaping, 16 annuals and 24 perennials were sown on Sep. 19, 1996 and grown under reduced maintenance for 5 years. Species studied can be divided into 10 groups according to flowering times, longevity and development of growth areas. The flowering of groups I~V began the first year after sowing. Species classified in Group I contained 1 annual and 8 perennials, which flowered continuously for 5 years and expanded their growth areas. Group II contained 5 perennials, which were maintained in their initial growth areas. Group III contained 3 annuals, in which the growth areas were decreased slowly. Group IV contained 9 annuals and 1 perennial, which flowered 2 or 3 years before disappearing. Group V contained 2 annuals, which flowered only 1 year. The flowering of group VII~IX started in the second year after sowing. Group VII contained 6 perennials, which were maintained in a confident area. Group VIII contained 2 perennials, in which the growth areas decreased slowly. Group IX contained 1 perennial, which flowered for 3 years before disappearing.
The effects of the variety and cropping type under different planting densities on the uniformity of cabbage head weight were investigated. High uniformity of cabbage head weight was obtained using a small-spreading and early ripening variety despite high density planting because of the shorter period of competition between plants and a higher H (head-weight)/T (total top weight) ratio. A high uniformity of cabbage head weight in winter sown-early summer harvesting cropping type (cropping type for rising temperatures) was successfuly maintained despite the high density cultivating condition compared with summer sown-winter harvesting cropping type (cropping type for decreasing temperatures) because of suppressed spreading of the initial growth. We conclude from these observations that the once over harvest of cabbage crops can easily be introduced using the cropping type for rising temperatures. In the cropping type for decreasing temperatures, it is effective to maintain sufficient uniformity of cabbage head weight by planting an early ripening variety.
Forcing cultures were investigated in three hybrid lily cultivars, ‘Morino-otome’, ‘Morino-sei’ and ‘Morino-roman’, developed by crossing Lilium × formolongi with L. rubellum. When these cultivars were grown in an unheated plastic house, they bloomed on May or June. When the chilled daughter bulbs were grown in a greenhouse from November 1 or March 1, ‘Morino-otome’, ‘Morino-sei’ and ‘Morino-roman’ bloomed on February 24, March 14 and April 1, respectively. When the daughter bulbs were stored at 5°C or 13°C for 4~8 weeks from September 3, and grown in greenhouse, ‘Morino-otome’, ‘Morino-sei’ and ‘Morino-roman’ bloomed on December 23, January 11 and January 25, respectively. When the immature daughter bulbs were stored at 5°C or 13°C for 6 weeks from July 8 or January 28, and grown in greenhouse, ‘Morino-otome’, ‘Morino-sei’ and ‘Morino-roman’ bloomed on October 16, October 17 and November 5, respectively.
To examine the effects of timing and severity of summer pruning on flower bud formation rate, 5-year-old ‘Satonishiki’ sweet cherry trees were pruned on May 7, 17, 28, June 4, 17, 25, or July 6 with heading cuts at 4, 5, or 6 buds from the base of the current shoot. The influences on flower bud formation rate on the current shoots varied depending on the timing or severity of summer pruning. Summer pruning leaving the 5 or 6 buds during June was the most useful for increasing the rate of flower bud formation which ranged from 71 to 82 percent on the current shoots. The terminal buds on the shoots also developed leaf buds, ranging from 80 to 100 percent under the summer pruning conditions described above.
Effects of fertilizer application levels on peach fruit growth and pit spilitting were investigated using ‘Hakuho’ trees supplied with complete liquid fertilizers containing 80 ppm (normal fertilization) and 160 ppm (higher fertilization) of nitrogen twice a week. Cleavages at the inner endocarp, an early type of the pit splitting, were found 3 weeks after blooming regardless of fertilizer application levels. Anatomical investigation demonstrated that the cleavage might be the result of physical pressure by seed outgrowth. A higher rate of undeveloped fruit was observed in the highly fertilized trees 6 weeks after blooming. In those fruit, the ventral suture had been incompletely united and seed vascular bundles and the seed coat had turned brown. The incomplete union of the ventral suture, producing a crevice between both seed vascular bundles, was found at significantly higher rates in the highly fertilized trees than in normally fertilized trees, suggesting that the crevice along the ventral suture causes pit splitting thereafter. Fruit with pit splitting had larger cheek diameter but lower juice TSS (total soluble solids) and titratable acidity at harvest.