We investigated longevity, ethylene production and ethylene sensitivity of flowers among 42 pot carnation cultivars. Our results indicate that there was a large genetic variability in flower longevity and ethylene synthesis in pot carnation cultivars. Five cultivars (‘Polaris’, ‘Camille Pink’, ‘Chiffon’, ‘Bambino’ and ‘Nina’) had a mean flower longevity of more than 9.7 days. These cultivars with long flower longevity showed low ethylene production at senescence and showed neither petal in-rolling nor rapid wilting, which are typical symptoms of ethylene-dependent senescence. Instead, these flowers faded and turned brown along their petal edges. Significant negative correlations were observed between flower longevity and ethylene production at senescence, and between flower longevity and autocatalytic ethylene production. Although large genetic variability in ethylene sensitivity was observed in diploid cultivars, there was no correlation between flower longevity and ethylene sensitivity. Our data showed that polyploidy level in pot carnation cultivars does not have a profound influence on flower longevity or ethylene sensitivity. This study suggests that improvement of flower longevity of pot carnation using cross breeding techniques would be feasible.
We investigated the cause of poor fruit set in Japanese plum ‘Kiyo’ (Prunus salicina Lindl.). Early fruit drop of ‘Kiyo’ was heavier than that of ‘Taiyo’. Fruit drop of ‘Taiyo’ and ‘Kiyo’ in 56 days after full bloom was 80.4 and 95.5%, respectively. There was little difference between ‘Kiyo’ and ‘Taiyo’ in the incidence of imperfect flower and ‘Holly wood’ pollen tube elongation on the style. However, ‘Kiyo’ demonstrated pollen grains that were nonuniform in size and shape. ‘Taiyo’ showed 91.6% stainability and 47.6% pollen germination rate, respectively, whereas those of ‘Kiyo’ were 70.4 and 3.2%, respectively. Furtheremore, developed seeds obtained from ‘Kiyo’ varied in weight from 0.02 to 0.59 g, and the percentage of developed seed of ‘Kiyo’ (71.3%) was less than that from ‘Taiyo’ (93.0%). Chromosome observation of immature leaflets demonstrated that ‘Kiyo’ was triploid with 24 chromosomes.
In this study, we reported the selective breeding process and root contents in a new Japanese wild radish line. According to the root shape and late flowering characteristic, a new Japanese wild radish line was selected from several wild populations of Japanese wild radish growing beside Lake Shinji and in the areas surroundings Shimane Peninsula, Japan. The shape and weight of the roots in the selected line remained almost fixed during fiscal year 2006. Reduced ascorbic acid, isothiocyanate, total soluble solids and total phenol concentrations in the roots of the selected line were higher than that of ‘Taibyousoubutori’, and equivalent to ‘Karamaru’. Fructose, glucose and sucrose were detected in the roots of the selected line, and the compositions of these sugars were similar to those of ‘Karamaru’. The root contents of the selected line changed during the harvesting period. Based on these results, we concluded that the new Japanese wild radish line is available as a new spice crop.
We investigated several antibiotics including carbenicillin (CBPC), clavulanic acid/amoxicillin (CVA/AMPC), cefotaxime (CTX), meropenem (MEPM), vancomycin (VCM) and doxycycline (DOXY) for Agrobacterium elimination during apple transformation. The growth of Agrobacterium tumefaciens EHA101 was suppressed at 1,500 mg·L−1 of CBPC, 750 mg·L−1 of CVA/AMPC, less than 500 mg·L−1 of CTX, 50 mg·L−1 of MEPM and 200 mg·L−1 of DOXY, but growth was not suppressed at 1,500 mg·L−1 of VCM. In the shoot length, there was no difference among antibiotic-free, CBPC, CTX and VCM treatments. However, the shoot length in the high-concentration treatment of CVA/AMPC and DOXY was significantly shortened. However, the number of shoots increased as the concentration of MEPM rose. In CTX treatment, the shoot regeneration rate from leaf segments was lowered in comparison with antibiotic-free treatment; however, the regeneration rate was maintained to some degree even after high-concentration CTX treatment. The regeneration rate from leaf segments after MEPM treatment was superior to the antibiotic-free treatment. After DOXY treatment, leaf segments did not grow at all and finally died. These findings indicated that bacterial cell wall synthesis inhibitors such as CTX and MEPM were effective in eliminating Agrobacterium.
We present a new nursery grafting method for persimmon (Diospyros kaki Thunb.) propagation. This study examined the effects of grafting time and leaves of rootstock on the graft-take ratio and growth of grafted plants. Between April and September, we were able to graft a scion of ‘Fuyu’ persimmon onto a current seedling of ‘Hourenbou’ rootstock, which was between 110 and 195 days old. Although grafting onto a current seedling without leaves yielded a low graft-take ratio, 80 to 100% of scions grafted onto rootstock with leaves were established successfully. Between rootstock with and without leaves, a significant difference was noted in the callus-forming ratios 20 days after grafting. A callus was observed in all nursery plants grafted onto rootstock with leaves, irrespective of the bud-break feasibility.
We investigated the effects of seed wing removal on the recovery of germination in Lilium × formolongi hort. Untreated seeds demonstrated the highest germination activity at 18°C but this was inhibited under temperatures of 22 and 24°C. Wing removal accelerated seed germination at temperatures of 18, 22, and 24°C. Wing removal caused cavities between the seed coats and these cavities facilitated water uptake. Among the water extracts from seed wings, substance(s) contained in the ethyl acetate layer inhibited seed germination. Abscisic acid (ABA) denied the effect of wing removal though gibberellin (GA3) did not. These results suggested that wing removal improved seed germination rate by accelerating water absorption, and decreasing germination inhibitors.
A new fertigation management was tested to verify the availability of frequent moisture and nutrition management in rhizosphere of Chinese cabbage and eggplant in open field soil culture. Under fertigation management, the soil moisture level remained constantly stable in the open field. It was shown that growth and mineral absorption of both crops were significantly improved in this system. Although the amounts N of Chinese cabbage and eggplant cultivated using this system were 54% and 71% of basal fertilization, respectively, yields were equal to those obtained with the conventional treatment.
The responses of cucumber on forced culture involving a range of carbon dioxide concentrations and length of supplementation times in a greenhouse, a long-term supplementation from 7:30 a.m. to 14:30 p.m. at 500 ppm, and a short-term supplementation from 7:30 a.m. to 10:30 a.m. at 1,000 ppm, were examined together with those on non-enriched treatment. Both carbon dioxide enrichments increased the marketable fruit yield by 39–55%. Even if expenditure due to carbon dioxide enrichment is subtracted, the gross return was 58,000–96,000 yen per 100 m2 higher than non-enriched culture. In the long-term supplementation the growth yield was larger, and the amount of carbon dioxide used was less than in the short-term supplementation. Long-term supplementation at 500 ppm was cost-effective.
The remote measurement of the three-dimensional shapes and volumes of attached fruits was examined using software for stereo photogrammetry. It read the three-dimensional coordinates of many surface points on viewing fruit from two sides, the front and back, those of fruit boundary lines, and, if necessary, those of the cavity surfaces and ridge lines surrounding the fruit cavities. The volume of each square pole, composed of four adjacent surface points, was calculated by a computer program within area on each fruit side, and totaled as the fruit volume. If necessary, a similar volume was calculated within the cavity area, and totaled as the cavity volume. The latter was used to deduce the net fruit volume from the former. The relations between the measured volumes and remotely measured volumes of detached fruits were satisfactory. A field photography device was devised, which consisted of a tripod, a ground control-point set and a board on which the camera slid from left to right. Remote measurements of the volume of attached fruits were carried out successfully using this device. Other fruit shapes excluding the volume could be measured easily using the software.
The relation between the swelling of graft union and trunk girth or shear strength at graft union was investigated. The trunk girth of trees grafted onto JM7 was largest and the coefficient of variance among scion cultivars and among tested trees was small. Meanwhile, the trunk girth of trees grafted onto JM5 was the smallest and varied greatly. All graft combinations showed overgrowth of rootstock, and the combinations on JM2 tended to show less overgrowth of rootstock than that on other rootstock cultivars. Swelling was small in JM2 and JM7 and the coefficient of variance among scion cultivars was also small. Although the degree of swelling of trees grafted onto JM1, JM5 and JM8 varied greatly among graft combinations, the degree of swelling did not necessarily affect the trunk girth. The shear strength at graft union was highest in trees grafted onto JM2 and low in that grafted onto JM1 and JM5. These results clarified that graft combinations having larger swelling of graft union had lower shear strength, which made it easy for the tree to break at the graft union, although swelling of graft union did not always make the tree weak.
Effect of two kinds of Apple plus (No.4 and No.6), reagents developed for overcoming apple self-incompatibility by inactivating stylar S-RNase, on fruit set was tested in the Japanese pear ‘Kousui’. First, the inhibitory action of Apple plus on the RNase activity of proteins prepared from ‘Kousui’ style was monitored. Both reagents reduced the RNase activity dose-dependently; Apple plus No.4 and No.6 lowered the activity to about half of the control at 0.1 and 1%, respectively. Next, the promotive effect of Apple plus was tested on fruit set in self-pollinated ‘Kousui’ flower. When the trees were sprayed 0, 1, or 2 days before anthesis at 0.1 or 0.5%, all treatments caused 10-40% fruit set and treatment with 0.5% Apple plus No.4 one day before anthesis was most effective, with 40% fruit set 4 weeks after pollination. However, Apple plus at a concentration higher than 1% caused injuries to flowers and young leaves, and did not show sufficient fruit setting. The number of intact seeds at harvest was 0 to 3 in fruit induced by Apple plus, in contrast to 2 to 7 in cross-pollinated fruit. Apple plus also produced fruit in non-pollinated flowers, indicating that the reagent induces not only partial breakdown of self-incompatibility but also parthenocarpy in ‘Kousui’ pear. The fruit induced showed considerably inferior growth; fruit weight was about 70% of the fruit obtained by cross-pollination at harvest. It is concluded that overcoming self-incompatibility by Apple plus is insufficient and the reagent, at least in the present form, will not be useful in practical culture of the pear.
To improve the growth and development of pansy (Viola × wittrockiana Gams) and cyclamen (Cyclamenpersicum Mill.) nursery plants in summer, we investigated the effects of increased water evaporation from medium on medium temperature and plant growth. Medium temperature declined when the polyethylene pot was removed using the soil cast with heat-adhesive polyester fiber. Air blowing on the surface of the medium promoted a cooling effect. Although either removing the pot or blowing air was likely to enhance the growth and development of these plants, simultaneous application of both treatments was more effective during high temperature periods. In pansy plants, these treatments lowered the leaf temperature and plant death rate, and increased the shoot dry matter. The number of leaves and floral buds, and shoot dry matter of cyclamen plants cultivated with these treatments were larger than those of non-treated plants.
The effects of low temperature treatment of cuttings, including potted cuttings, on growth and flowering of Hypericum andorosaemum L. ‘Excellent Flair’ were examined. Potted cuttings were exposed to ambient temperature from October 15, 2004 to March 9, 2005. These were repotted in 12 cm-plastic pots and grown under long day conditions in a greenhouse at a minimum temperature of 15°C. The number of nodes of the lateral branch at anthesis of the first floret and days to flowering were increased compared to those of controls treated at ambient temperature. Cuttings were treated under low temperature conditions at 2.5, 5 or 10°C for 0, 1, 2, 5 or 7 weeks. The number of roots increased when treated at 5°C or less that after for 5 weeks and days to flowering were reduced when treated at 5°C for 5 or 7 weeks, compared with the other treatments. Potted cuttings were treated at 2.5, 5, 10 or 15°C for 1, 3, 5 or 7 weeks, or were untreated (control), remaining in the greenhouse for the entire experimental period. Days to flowering of plants treated at 2.5°C for 7 weeks or 5°C for 5 or 7 weeks and the number of nodes on the lateral branch at flowering were reduced after treatment at 5°C for 5 weeks compared to that of controls or those receiving other treatments. Based on the above findings low temperature treatment of cuttings increased the number of roots cuttings and reduced the days to flowering in Hypericum ‘Excellent Flair’.
Watermelon fruits were grown in enclosed conditions within 15-, 17.5-, and 20-cm-sided wooden boxes to mechanically restrict their growth. All treatments produced cube-shaped fruits, and the resulting fruit size corresponded to the box size. The flesh color of fruits did not differ between the 20-cm-sided box treatment and the control, but the central region of fruit in the 15- and 17.5-cm-sided box treatments remained yellow. In the 15- and 17.5-cm-sided box treatments, sugar accumulation was higher in the central and/or intermediate regions of fruit compared with the control. On the other hand, in the 20-cm-sided box treatment, sugar accumulation in the central and/or intermediate regions of fruit was nearly equal to the control, and a larger amount of sugar accumulated in the outer regions. The organic acid contents of fruit also varied according to the treatments, and the 15- and 17.5-cm-sided box treatments resulted in marked increases of lactic and succinic acids. These results suggest that treatment using the 20-cm-sided box was useful for the production of sweet fruit with a lower level of organic acid in watermelon.
To clarify the temperatures responsible for delayed flowering and the production of proliferate inflorescences (i.e. capitula with involucral bracts borne among the ray and disc florets) in summer-to-autumn-flowering Chrysanthemum morifolium Ramat. ‘Seiun’, the effects of a range of day and night temperature regimes, and exposure to high temperatures at different stages of floral development, on flowering and inflorescence characteristics were investigated. Rooted cuttings of ‘Seiun’ were planted on early-June and grown with the night-break treatment to maintain vegetative growth in a greenhouse. Subsequently, the plants were transferred to phytotron rooms on June 19 and were grown at six constant day (6:00-18:00)/night (18:00-6:00) temperature regimes in short days. In addition, plants were subjected to high-temperature treatment of 35/25°C for two weeks at four temporal stages: from the end of night-break treatment (ENBT), from two to four weeks after the ENBT, from four to six weeks after the ENBT, and from six to eight weeks after the ENBT. The plants bearing proliferate capitula were counted when the number of involucral bracts in the capitulum exceeded 25. Flowering of ‘Seiun’ was delayed in plants grown in short days at a day temperature of 30°C or more, or at a night temperature of 20°C or more. Proliferate capitula were formed in plants exposed to a high day or night temperature exceeding 35°C or 25°C, respectively, during the period from two to four weeks after ENBT (at the late stage of involucre formation or early stage of floret formation). As a practical application, involucral inflorescences of plants in summer-to-autumn-flowering ‘Seiun’ could be reduced using cheesecloth to achieve a 50% cut of daylight in the greenhouse for 3 weeks from ENBT.
The effect of irradiation by black light fluorescent lamp on the coloration and hardness of detached strawberry fruits was studied. Only the coloring of fruits (var. Toyonoka) that had started to pigment was accelerated by lamp irradiation. Maintaining the irradiation distance and ambient temperature after treatment was very important to obtain the maximum effect, and the action of lamps was restricted to the irradiated parts. The accelerating effect of a lamp on coloration was observed in all 3 of other varieties examined, and in some varieties, the level of anthocyanin concentration in fruits was greater than that in ripening stage. However, the lamp did not affect the hardness of fruits.
Effect of sucrose treatment during wet transport on the vase life of cut gypsophila flowers was investigated. Antimicrobial compounds CMI/MI (an isothiazolinonic germicide) in combination with aluminum sulfate (CMI/MI-AS) was included in all transport solutions. First, when the effects of sucrose on the vase life of cut flowers harvested at the normal stage and at an earlier stage many floret buds were present, were investigated. Treatment with sucrose plus CMI/MI-AS promoted floret opening and increased the fresh weight regardless of harvest stage. Secondly, the effects of sucrose treatments at different temperatures (10 or 20°C) for different periods (24, 48 or 72 h) during transport on vase life were investigated. Treatment with sucrose plus CMI/MI-AS increased fresh weight and number of open florets and extended the vase life in comparison to CMI/MI-AS without sucrose under all transport conditions except for that at 10°C for 24 h. These results show that sucrose plus CMI/MI-AS treatment during wet transport is effective in promoting floret opening and extending the vase life of cut gypsophila flowers.
Mobilization of storage reserves in Japanese chestnut fruit was observed by scanning electron microscope during the storage period. We stored chestnuts at −20, 2, 8 and 20°C to examine the effects of temperature on mobilization of reserves during 12-week period after harvest. At harvest (shedding stage), the cotyledonary parenchyma cells were filled with amyloplast (plastid containing a amount of substantial starch granules) and it’s amount was gradually increased from the center region (adaxial region) of the cotyledon to the outer region (abaxial region) of the cotyledon. As the storage period progressed, the number of amyloplast per cell was declined in fruit stored at 2, 8 and 20°C and the rate of decline differed at each storage temperatures. Namely, higher temperatures facilitated starch decomposition. This is thought to occur because the storage temperature affects the respiration rate and starch decomposition products provide substrates for respiration. In nuts stored at −20°C, mobilization of reserves was not recognized during the storage period. The rate of starch decomposition also differed among regions of the cotyledon. At the outer region of cotyledon, the rate of decomposition was high and the inner region was low. Corresponding to the high rate of starch decomposition, an abundance of cytoplasm was observed between and surface of the amyloplast. It is suggested that the amount of cytoplasm was related to starch decomposition activities.