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11.
Mutations associated with floral organ number in rice 总被引:14,自引:0,他引:14
Nobuhiro Nagasawa Masahiro Miyoshi Hidemi Kitano Hikaru Satoh Yasuo Nagato 《Planta》1996,198(4):627-633
How floral organ number is specified is an interesting subject and has been intensively studied in Arabidopsis thaliana. In rice (Oryza sativa L.), mutations associated with floral organ number have been identified. In three mutants of rice, floral organ number 1 (fon1) and the two alleles, floral organ number 2-1 (fon2-1) and floral organ number 2-2 (fon2-2), the floral organs were increased in number centripetally. Lodicules, homologous to petals, were rarely affected, and stamens were frequently increased from six to seven or eight. Of all the floral organs the number of pistils was the most frequently increased. Among the mutants, fon1 showed a different spectrum of organ number from fon2 -1 and fon2 -2. Lodicules were the most frequently affected in fon1, but pistils of more than half of fon1 flowers were unaffected; in contrast, the pistils of most flowers were increased in fon2 -1 and fon2-2. Homeotic conversion of organ identity was also detected at a low frequency in ectopically formed lodicules and stamens. Lodicules and stamens were partially converted into anthers and stigmas, respectively. Concomitant with the increased number of floral organs, each mutant had an enlarged apical meristem. Although meristem size was comparable among the three mutants and wild type in the early phase of flower development, a significant difference became apparent after the lemma primordium had differentiated. In these mutants, the size of the shoot apical meristem in the embryo and in the vegetative phase was not affected, and no phenotypic abnormalities were detected. These results do not coincide with those for Arabidopsis in which clavatal affects the sizes of both shoot and floral meristems, leading to abnormal phyllotaxis, inflorescence fasciation and increased floral organs. Accordingly, it is considered that FON1 and FON2 function exclusively in the regulation of the floral meristem, not of the vegetative meristem.Abbreviation DIC
differential interference contrast
This work was supported in part by Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Science and Culture of Japan. 相似文献
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Yasuo Ezaki 《Ecological Research》1995,10(3):359-368
Settlement of male great reed warblers in the breeding ground was highly asynchronous at Lake Biwa in Japan. It took over
1 month from the appearance of the first male to a saturation in number of males. In resource-defense-polygyny, males are
expected to try to defend as large an area as possible in the optimal habitat. In fact, a small number of the earliest settling
males divided up the breeding ground almost completely as territories among themselves and these were later reduced in size
with the addition of later settlers. The reduction was not due to a seasonal decline of aggressiveness on the part of the
owners but to a higher level of intrusion pressure by later arriving males. The neighbor-neighbor relationship, once established,
was rather stable. Home range overlap was small and territorial contacts were few between neighbors. Territorial boundaries
seem not to shift despite the addition of new males as long as the neighbors were the same. The stable relationships between
neighbors are expected to help the earlier resident to maintain his large and good territories throughout the breeding season
and hence polygyny is favored in this species. 相似文献
16.
N-2′-Acetoxybenzoyl (aspirin) derivatives (degree of substitution 0·35–1·00) of chitosan, N-desulphated heparin and 2-amino-2-deoxy-d-glucose were prepared by methods that gave yields in the range 65–86%. The salicylate of chitosan was isolated with a 98% yeild. Aspirin or salicylic acid was released much more slowly from N-(2′-acetoxybenzoyl)-chitosan than from the salicylate of chitosan, and much faster at 37°C in 0·1 m NaOH solution than in 2% aqueous acetic acid solution. Salicylic acid was isolated from the dialysate (0·1 m NaOH solution) of N-(2′-acetoxybenzoyl)-chitosan. 相似文献
17.
Yasuo Yamamura 《Journal of plant research》1984,97(2):179-191
The growth and matter production were examined forReineckia carnea, an evergreen herb growing on the forest floor in a warm-temperate region. Seasonal change in the biomass of plants growing
in the field was estimated from the harvested sample plants. Carbohydrate contents and respiration rates were measured for
analysis of dry matter economy. Light intensity and temperature on the forest floor were periodically measured.
In mid-spring the biomass reached a maximum which was about half again its minimum value, found in autumn. Two phases, the
productive phase in cooler seasons and the developmental phase in warmer seasons, were distinguished from the annual growth
pattern of this plant. In cooler seasons, positive net production was found without any morphological changes, resulting in
active accumulation of reserves which were mainly soluble sugars. This high net production seems to be closely related to
the favorable light conditions and low respiratory losses. In warmer seasons, though new organs were developed, net production
remained low or was even negative. The morphological development of this plant in these seasons depended mostly on reserves
previously accumulated. This characteristic feature of annual matter economy is considered to be common to evergreen plants
on the forest floor in warm regions. 相似文献
18.
Isao Karube Tadashi Matsunaga Yasuo Otomine Shuichi Suzuki 《Enzyme and microbial technology》1981,3(4):309-312
A nitrogen-fixing bacterium, Azotobacter chroococcum, was immobilized in 2% agar gel. The optimum partial oxygen pressure, pO2, of immobilized cells was 0.2 atm, wherea s that of native cells was 0.05 atm. When continual nitrogen fixation was performed under aerobic conditions, the nitrogenase activity of immobilized cells increased with increasing time. On the other hand, the activity of native cells decreased rapidly. Increase of nitrogenase activity was attributed to growth of the bacteria in the gel matrix. The production rate of total nitrogen compounds by the immobilized bacteria was also increased during the first 4 days. Nitrogen compounds produced by the immobilized cells were mainly amino acids such as γ-aminobutyrate, glutamate and arginine. 相似文献
19.
Yasuo Uchiyama 《Cell and tissue research》1981,218(3):519-527
Summary The ontogeny and distribution of immunoreactive motilin and secretin were studied in the gastro-entero-pancreatic (GEP) system of human fetuses, aged 5–24 weeks, using an indirect immunocytochemical method. Several controls to check for the specificity of the immunoperoxidase staining were performed. The first motilin- and secretin-containing cells were observed in the duodenal and jejunal mucosa in fetuses at a gestational age of 16 weeks. These immunoreactive cells were located in the glands of Lieberkühn and in the villi. No immunoreactive cells were present in the oxyntic and pyloric mucosa, ileum, colon and endocrine pancreas. These observations indicate that the motilin- and secretin-containing cells detected by our antisera appear (i) in the same organs of the fetus where they are also detectable in the adult, and (ii) after the completion of histogenesis of the gastro-entero-pancreatic (GEP) system. 相似文献
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