The absorption and distribution of applied nitrogen were determined in 4-year-old 'Kawanakajima Hakuto' peach trees grafted on Prunuspersica (L.) Batsch (PP) and P. tomentosa Thunb. (PT) rootstocks and compatible interstock ('Chikuma') /P. tomentosa (IS) by using a 15N tracer in the pot experiments. At fruit harvest, 55.7 to 61.3% of the absorbed nitrogen was partitioned to the leaves. The 15N atom% excess in every scion part and the total amount of absorbed 15N were significantly higher in PP and IS than in PT. These results suggest that the use of a compatible interstock, 'Chikuma', improves absorption and upward movement of applied nitrogen, thus it overcomes incompatibility between 'Kawanakajima Hakuto' and P. tomentosa.
Parentage of 14 pear cultivars, including 8 cultivars derived from intraspecific crosses and 6 from interspecific crosses, was analyzed using 20 SSR (simple sequence repeat) markers. In 10 out of 14 cultivars, the parent-offspring relationships were reconfirmed because the hybrids inherited SSR alleles from their parents without any discrepancy. There were 4 questionable parent-offspring relationships with respect to 7 or more SSR loci. 'Housui' (syn. 'Hosui') is not an offspring from a cross of 'Ri-14' × 'Yakumo' because of discrepancies at 7 loci. Likewise, 'Chojuro' and 'Nijisseiki' could not be confirmed as parents of 'Tanzawa' because of discrepancies at 9 loci. 'Max Red Bartlett' was reconfirmed as a parent of 'Oharabeni' because all SSR loci matched. 'Okusankichi' was not its parent because of discrepancies at 7 loci. Our analyses revealed that 'Le Conte' is not a parent of 'Ninomiya', whereas 'Chojuro' is. In this study, 20 SSR markers were effectively utilized to determine parentage of Japanese pear, and 15 SSR markers could be utilized for interspecific Pyrus hybrids.
The property of slow sand filtration to disinfect a closed soilless culture system was examined in terms of stable and efficient estimation of microbe removal efficiency using a small-scale experimental apparatus. Escherichia coli was chosen as a microbe to be removed. With the freshly-prepared filter, the microbe density in the filtrate reached a plateau level after 3 to 6 hr of operation when that in the influent was kept constant for longer than 3 hr. The height of a plateau level varied with the microbe density in the influent. Duration of a plateau extended as the inoculative period was longer. The microbe removal efficiency of the filtration system increased when the runoff solution from the rockwool culture of rose plants was circulated through the filter for 5 weeks, but no increase occurred when water was used. However, the once-increased efficiency of the filtration system was lost when the runoff solution was changed to water. The microbe removal efficiency of the filtration system fluctuated according to the microbe density in the influent, but the efficiency was affected more by the ripening state of the filter system.
Variations in chloroplast DNA of Dendranthema species were studied by PCR-RFLP analysis to seek the maternal origin of the cultivated chrysanthemum, D. grandlflorum. Ten genes, atpH, matK, petA, petB, psaA, rbcL, rpoE, rpoC, trnK and 76S in the chloroplast DNA of 12 Japanese wild species and 1 cultivar were amplified by PCR. The amplified DNAs that were digested with each of 32 restriction endonucleases revealed 13 site changes among the 13 species in the following 9 gene plus restriction endonuclease combinations: petA-Avall, petA-Haelll, petA-MboII, petA-NdeII, rpoC-EcoRV, trnK-Dral, trnK-HinfI, trnK MboII and trnK-ScrFI. No Japanese wild species showed the same PCR-RFLP pattern of chloroplast DNA as D. grandiflorum.
This study was conducted to establish a system of in vitro micropropagation of Hepatica nobilis. Leaf segments, excised from commercial plants, formed calli at high frequency in MS medium that contained 0.1-10 mg·liter-1 NAA and BA. The highest percentage of bud formation was observed to be about 20% in the medium supplemented with 0.5 or 1 mg·liter-1 NAA and 5 mg·liter-1 BA. Embryoid formation was stimulated on the medium containing 0.1 mg·liter-1 NAA and 0.5 mg·liter-1 BA, or 1 mg·liter-1 NAA and BA. When 1 to 2 mm long adventitious buds were excised from leaf segments and recultured every 8 weeks on MS medium supplemented with BA, GA3 or both for 24 weeks, they developed into shoots (referred to as the primary shoots in this text). The survival rates of the primary shoots were higher in the medium containing both BA and GA3 than in the medium with BA alone. When primary shoots were cultured on MS medium containing 5 mg·liter BA and 10 mg·liter-1 GAs, they formed the highest number of new shoots, referred to as secondary shoots in the text. When excised secondary shoots were cultured in MS medium containing 10 mg·liter-1 NAA or IBA in the dark for a week and then transplanted into MS-medium without any hormones, they developed roots at a high frequency, whereas shoots transplanted to MS-medium with NAA or IBA formed only callus at the base. Following acclimatization, rooted plants that were transplanted into pots and grown in a glasshouse, flowered within 2 years.
The fruit of stony hard peach cultivars 'Odoroki', 'Manami' and 'Yumyeong' usually remain hard and do not synthesize ethylene even after their ground color changes, sugar contents increase, and acidity decreases. Our treatment of such fruit with l, 000 ppm ethylene for three consecutive days at 25°C effectively softened them. Ethylene treatment of 'Yumyeong' fruit with l, 000 ppm for three consecutive days at 5°C did not cause them to soften. Treatment at 15°C softened the fruit, which started one day later than those treated at 25°C. All these treatments did not induce ethylene synthesis of the fruit. When the treatment of 'Yumyeong' fruit with l, 000ppm at 25°C was ceased after the first day, the fruit stopped softening and showed no ethylene synthesis. Treatment of 'Yumyeong' fruit with 1-aminocyclopropane-1-carboxylic acid (ACC), which is the immediate precursor of ethylene, stimulated the fruit to synthesize ethylene and soften. The results show that the fruit of stony hard peach cultivars soften in the presence of ethylene, but they cannot produce endogenous ethylene because of the lack of or low activities of ACC synthase. This suggests that the possibility exists of controlling flesh firmness by changing the duration of ethylene treatment.
DNA markers linked to the L4 gene that controls resistance to pepper mild mottle virus (PMMoV) in Capsicum spp. were screened. Among 516 arbitrary primers, only one primer, that was WA31, amplified a DNA fragment (WA31-1500) specific to the resistant group. A set of primers was designed based on the nucleotide sequence of WA31-1500. The newly synthesized primers amplified a single clear fragment (WA31-1500S) specific to the resistant individuals in the F2 population. This SCAR marker, that was WA31-1500S, was shown to be linked to the L4 gene within a distance of 1.5 cM. WA31-1500S was amplified in 10 accessions possessing L4 gene, but not amplified in the other 11 susceptible accessions. The above findings strongly suggest that the WA31- 1500S is closely linked to L4 gene, and should be useful as a selection marker in the breeding of PMMoV-resistant in Capsicum.
The effects of shading conditions on antioxidative activities of ascorbic acid, β-cryptoxanthin and polyphenols in lemon and apple fruit were studied. The IC50 values of superoxide (O-2)- and 1-diphenyl-2-picrylhydrazyl (DPPH)-radical-scavenging activities in lemon skin from entirely shaded trees (TS) were high compared to the untreated control (UC). Their IC50 values in apple skin were also higher in fruit shaded by paper bags (FS) and in fruit from TS compared to fruit from UC. Ascorbic acid and β-cryptoxanthin concentrations in lemon skin of TS were lower than those of UC. Polyphenolics in apple skins from FS and TS also decreased more than those from UC. These results suggest that shading may regulate the antioxidative components in the fruit, and as a result, may influence antioxidative activity.
Spraying Ca-formate to opening flowers before fertilization thinned blossoms of the Japanese pear 'Kosui'; the thinning effect was greater with increased concentration of the chemical. All flowers abscised by the administration of 10% Ca-formate. Treatments, higher than 5%, caused injuries to sprouting shoots and petals. However, solutions lower than 3% did not show any inhibitory action on shoot growth. The treatments of flower buds by the solutions higher than 3% also thinned flowers to some degree. Flowers of self-compatible 'Osa-Nijisseiki' were similarly abscised by the Ca-formate. About 1.6mg·g-1FW of the Ca-formate was incorporated into the style 2 days after spraying 1% solution, leaving a residue of 1.1 mg·g-1FW after 8 days. Since Ca-formate, higher than 0.05%, exhibits strong inhibition on pollen germination and pollen-tube growth in vitro, it may be the mechanism by which the chemical induces flower thinning. At harvest, fruit size, sugar content, and composition in the juice are unaffected by less than 3% Ca-formate. Thus, we recommend that a Ca-formate solution from 1 to 3% be used as flower thinner on Japanese pear blossoms.
To identify cultivars of wakegi onion (Allium X wakegi Araki), nine virus-free clones (Hiroshima 1 go-Hiroshima 9 go) were examined by fluorescent AFLP (Amplified Fragment Length Poly-morphism) technique, using 16 primer combinations. Twelve out of the 16 primer combinations amplified a total of 678 DNA fragments (peaks) in nine wakegi onion clones. Eight primer combinations produced 11 polymorphic markers available for discriminating the nine clones from each other, except between Hiroshima 1 go ('Shimonoseki') and Hiroshima 2 go ('Kanshirazu'). The AFLP data revealed that 26.3% and 23.5% of the 678 DNA fragments were derived from Japanese bunching onion and shallot, respectively. Five out of 11 polymorphic markers, were seemingly originated from Japanese bunching onion, whereas three from shallot. These results verified that wakegi onion are interspecific hybrids whose parents are the Japanese bunching onion and shallot. Fluorescent AFLP technique is a useful method for discriminating wakegi onion cultivars.
Twenty-three plants from 6 hybrid lines were obtained through an interspecific cross between Camellia chrysantha (Hu) Tuyama (sp.) and C. japonica L. by using the former as the seed parent. The immature embryos were rescued 90 to 130 days after pollination and cultured on a modified 1/2MS basal medium. More adventitious embryos differentiated on ovules excised at Day- 110 and - 120 than did those on Day-90, -100 and -130. More shoots were regenerated when polyvinyl pyrrolidon (PVP) was added to the 1/2MS basal medium. Although the number of shoots from adventitious embryos did not increase by the addition of gibberellic acid, indole butyric acid and benzyladenine, they increased significantly when the pH of the medium was adjusted to 6.5. All regenerated plantlets derived through embryo rescue proved to be interspecific hybrids between C. chrysantha and C. japonica by HPLC analysis of leaf polyphenols and RAPD analysis.
The relationship between flower color and anthocyanin composition of the perianth and spot tissues was investigated in 45 Alstroemerla L. cultivars. Nine anthocyanins, including cyanidin 3-glucoside and delphinidin 3-glucoside that have never been reported in Alstroemeria, were identified. Major anthocyanins of outer perianthes were cyanidin 3-rutinoside and 6-hydroxycyanidin 3-rutinoside in cultivars with red flowers, and 6-hydroxydelphinidin 3-rutinoside in those that were red-purple, and delphinidin 3-rutinoside in purple ones. A small amount of anthocyanin existed even in yellow and white flower cultivars. Spot tissues of the inner perianthes in all cultivars contained cyanidin 3-rutinoside as the dominant anthocyanin along with carotenoids and chlorophylls.