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1.
YUDAI OKUYAMA MAKOTO KATO NORIAKI MURAKAMI 《Botanical journal of the Linnean Society. Linnean Society of London》2004,144(4):449-460
The first example of pollination by fungus gnats in the eudicots is reported. The genus Mitella (Saxifragales) is characteristically produces minute, inconspicuous, mostly dull-coloured flowers with linear, sometimes pinnately branched, petals. To understand the function of these characteristic flowers, we studied the pollination biology of four Mitella species with different floral traits and different sexual expression: dioecious M. acerina , gynodioecious M. furusei var. subramosa , and hermaphroditic M. stylosa var. makinoi and M. integripetala. Flower-bagging experiments showed that wind pollination did not occur in the dioecious and gynodioecious species. Two years of observations of flower visitors at six study sites in Japan revealed that the principal pollinators of all four Mitella were specific species of fungus gnats (Mycetophilidae), which landed on the flowers with their long spiny legs settling on the petals. Characteristically, numerous pollen grains were attached to the fungus gnats in specific locations on the body. Although, on average, 1.3–2.6 fungus gnats visited each inflorescence per day, the fruit set of both bisexual and female flowers exceeded 63%. These results suggest that fungus gnats are highly efficient pollinators of Mitella spp., and that Mitella flowers are morphologically adapted to pollination by fungus gnats. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 449–460. 相似文献
2.
SHOKO YASUKAWA HIDETOSHI KATO RYOHEI YAMAOKA HAJIME TANAKA HIROHITO ARAI SHOICHI KAWANO 《Plant Species Biology》1992,7(2-3):121-140
Abstract Volatile substances emitted from the flowers of eight Magnolia taxa ( M. sieboldii ssp. japonica, M. praecocissima var. praecocissima and var. borealis, M. tomentosa, M. salicifolia, M. obovata, M. denudata, and M. grandiflora ) and one Michelia species ( M. compressa ) (Magnoliaceae) were examined and identified using GC-MS. Volatile substances of these Magnolia and Michelia species consist primarily of monoterpenoids and sesquiterpenoids produced by the mevalonate pathway, acetogenins by the acetate-malonate pathway, and phenyl-propanoids by the shikimate pathway. These Magnolia and Michelia species all possessed various combinations of volatile monoterpenoids, acetogenins, and phenylpropanoids, except for Magnolia obovata , which emitted primarily sesquiterpenoids. Free amino acids in pollen of 12 Magnolia and one Liriodendron species were also analyzed, and their value as food sources for pollinators evaluated.
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
Pollinators visiting the flowers of five Magnolia species were collected in their native sites and identified. Their behaviors and roles as pollinating agents were assessed. 相似文献
3.
SHIGENOBU TONÉ SHOJI TANAKA YOSHIHIRO KATO 《Development, growth & differentiation》1988,30(3):261-270
The cell cycle and cell population kinetics have been analyzed in the interdigital regions of chick limb-buds during the course of programmed cell death both in normal and the 5-bromodeoxyuridine (BrdU)-treated embryos. Our previous study has shown that a single administration of BrdU at day 6 1/3 inhibited the programmed cell death occurring in normal development of limb-buds.
Pulse- as well as continuous labelings with tritiated thymidine (3 H-TdR) were used. The results obtained from the analyses made on both normal and experimental embryos have demonstrated the presence of a particular DNA-synthetic period, around day 6 1/3, closely related to the programmed death occurring on day 7 1/3. In normal embryos, new cell populations, which did not belong to any phases of normal cell cycle, made their appearances in the process of programmed cell death. A possible correlation between programmed cell death and the cell cycle has been discussed in relation to the morphogenesis of limbs in both normal and BrdU-treated embryos. 相似文献
Pulse- as well as continuous labelings with tritiated thymidine (
4.
YUJI MISHINA TAKASHI KATO AKIO URABE FUMIMARO TAKAKU SHUNJI NATORI MASUO OBINATA 《Development, growth & differentiation》1986,28(1):1-6
Erythroid cells were fractionated by preformed Percoll density gradient from livers of 12.5 day old mouse fetuses. With combination of lysing of mature erythroid cells, the CFU-E (colony forming unit of erythroid) was enriched as high as 30% pure. The mRNA levels of the rt-genes previously cloned as genes expressed in the reticulocytes are estimated in the fractionated erythroid cells. These rt-genes show a drastic change in expression during erythroid differentiation; Their expression was not detectable at the CFU-E cell stage. But it reached to maximum at the polychromatic erythroblast (stage I) and then decreases with maturation. The result suggests that mRNA synthesis of these rt-genes may be induced after the stimulation of erythropoietin. 相似文献
5.
A cutting of Phaseolus mungoproduced about 4 adventitious rootsat the basal 1 mm region when the basal part of the cuttingwas dipped in water. Rootlets became visible after a 36 hr lagperiod in untreated cuttings. Treatment with 2-thiouracil or5-bromodeoxyuridine increased the number of roots formed onthe cutting and prolonged the lag period. Effects of 2-thiouraciland 5-bromodeoxyuridine were reversed by simultaneously applieduracil and thymidine. The number of roots decreased and thelength of lag period was shortened. The increases in the numberof roots by 2-thiouracil or 5-bromodeoxyuridine was reducedby gibberellic acid, which did not cause a decrease in the numberof roots to be formed on control cuttings. Roots formed at thebasal region seem to suppress further root formation at theupper part of the hypocotyl. Inhibitors used here probably workby blocking the formation of these bottommost roots. (Received April 30, 1971; ) 相似文献
6.
The present work was undertaken to find if there are relations between light and auxin action on elongation of coleoptilar node and mesocotyl with Avena seedlings. Red light inhibited the elongation of mesocotyl and simultaneously decreased the rate of transport of diffusible auxin through the node. Red light also inhibited the transport of exogenously given IAA through the nodal region. The light inhibition of IAA transport was closely related to the increase of IAA immobilization. As the age proceeds, the ability of IAA immobilization increased with the decrease in the rate of mesocotyl elongation, even if the seedling was grown in complete darkness. The nature of radioactive substances found in the IAA-C14 treated tissue was examined by paper chromatography. The above results strongly suggested that the increase of IAA immobilization might result in the inhibition of mesocotyl elongation. 相似文献
7.
KAMEMOTO FRED I.; KATO KENNETH N.; TUCKER LOIS E. 《Integrative and comparative biology》1966,6(2):213-219
The possible role of the neurosecretory system in regulationof salt and water has been studied in the annelids and crustaceans.In the earthworm, Lumbricus terrestris, a brain factor influences'the salt and osmotic concentration of the blood and coelomicfluid. Removal of the brain results in the increase of waterinflux with a decrease in the salt and osmotic concentrationsof the body fluids. The decreases in salt and osmotic concentrationscan be prevented by the implantation of the brain or the injectionof brain homogenates. In the freshwater crayfish, Procambarus clarkii, a factor, presumablysecreted in the brain and released in the eyestalk, seems tomaintain the normal permeability of the body surfaces to water.Eyestalk removal, which eliminates the release site, resultsin the increased influx of water with a decrease in the saltconcentration of the blood. A brain factor also seems to beinvolved in maintaining the sodium and osmotic concentrationsof the blood. In the semi-terrestrial grapsid crab, Metopograpsus messor,the thoracic ganglion, under the control of an eyestalk element,secretes a factor involved in increasing the permeability ofthe body surfaces to water. The removal of the eyestalks, theimplantation of the thoracic ganglion, or the injection of extractsof thoracic ganglia, results in changes in the osmotic concentrationof the blood tending toward that of the medium. In all threespecies studied, the neuroendocrine factors seem to be involvedprimarily in the regulation of the permeability of the bodysurfaces to water. 相似文献
8.
A strain of carrot cells (Daucus carota cv. Kintoki) grew exponentially in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D, 1 mg/1) with a doubling time of about 2 days. When those cells were transferred to a medium lacking 2,4-D, they continued to grow at almost the same rate for about a week. When the cells were again transferred to the auxin-free medium, the rate of cell division gradually decreased. After the cell division had ceased, cells were returned to the ordinary 2,4-D medium. A burst of cell divisions occurred after about 2 days. Timing of DNA synthesis and of mitosis suggested that the cells had been arrested at G1 phase. In a medium containing indoleacetic acid instead of 2,4-D, the auxin was rapidly degraded and the culture was similarly synchronized as in the auxin-omitted medium. 相似文献
9.
Cytochrome oxidase and succinate dehydrogenase activities increasedduring aging of sliced tissue for sweet potato root after respectivelag phases of about 8 and 10 hr. The increase in the formerwas stepwise. On the other hand, malate dehydrogenase activityincreased slowly without a lag phase. Spectrophotometric determinationof heme contents in mitochondria indicated that the hemes increasedafter a lag phase for at least 8 hr during aging Treatment of tissue slices with cycloheximide at a concentrationof 106 M prior to aging resulted in an extension of thelag phase in the increase of cytochrome oxidaseactivity andin complete inhibition of the increase of malate dehydrogenaseactivity. The antibiotic, at a concentration of 105 M,completely suppressed the increases. Chloramphenicol (6 ? 103M) also blocked the increases, except for that in malate dehydrogenaseactivity at an early stage of aging (Received December 22, 1970; ) 相似文献
10.
Abstract: Astacidean and thalassinidean macrurans (Glyphea sp., ?Eryma sp. and Protaxius sp.) and a new longodromitid crab, Planoprosopon kashimaensis, are recorded from the Upper Jurassic (upper Kimmeridgian to lower Tithonian) of Fukushima Prefecture, northeast Japan. Material was collected from the Tatenosawa Sandstone Member of the Nakanosawa Formation, Somanakamura Group, from which abundant Tethyan‐type marine invertebrates are known. Planoprosopon kashimaensis sp. nov. closely resembles P. heydeni (von Meyer), a common form in the Upper Jurassic of the Tethyan realm in Europe, and represents the oldest record of a brachyuran from the circum‐Pacific region. Similarities to contemporaneous decapod assemblages in southern Germany indicate that closely comparable, parallel decapod faunas in the Tethyan realm, inclusive of brachyurans, had already been established in the western circum‐Pacific region by the Late Jurassic. 相似文献