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51.
52.
Yun-He Li Qi-Zhu Chen Jie-Ning Xiao Yun-Feng Chen Xiao-Ju Li Christian Staehelin Xue-Lin Huang 《Plant Growth Regulation》2008,54(2):165-177
Cotyledon segments derived from zygote embryos of mango (Mangifera indica L. cv. Zihua) were cultured on agar medium for 28 days. Depending on different pre-treatments with plant growth regulators,
two distinct patterns of adventitious roots were observed. A first pattern of adventitious roots was seen at the proximal
cut surface, whereas no roots were formed on the opposite, distal cut surface. The rooting ability depended on the segment
length and was significantly promoted by pre-treatment of embryos with indol-3-acetic acid (IAA) or indole-3-butyric acid
(IBA) for 1 h. A pre-treatment with the auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) completely inhibited adventitious
root formation on proximal cut surfaces. A second pattern of roots was observed on abaxial surfaces of cotyledon segments
when embryos were pre-treated with 2,700 μM 1-naphthalenacetic acid (NAA) for 1 h. Histological observations indicated that
both patterns of adventitious roots originated from parenchymal cells, but developmental directions of the root primordia
were different. A polar auxin transport assay was used to demonstrate transport of [3H] indole-3-acetic acid (IAA) in cotyledon segments from the distal to the proximal cut surface. In conclusion, we suggest
that polar auxin transport plays a role in adventitious root formation at the proximal cut surface, whereas NAA levels (influx
by diffusion; carrier mediated efflux) seem to control development of adventitious roots on the abaxial surface of cotyledon
segments. 相似文献
53.
NAA和6-BA对蝴蝶兰原球茎增殖的影响(简报) 总被引:1,自引:0,他引:1
以"瑞丽美人"蝴蝶兰(Phalaenopsis wilsonii)幼嫩花梗侧芽为外植体诱导原球茎,在附加6组不同浓度植物生长调节剂的MS培养基进行原球茎增殖培养。结果表明,添加6-BA 2.0mg/L、6-BA 0.5mg/L NAA 1.0mg/L、NAA 2.0mg/L的繁殖系数较高,均达4倍以上,其中6-BA 0.5mg/L NAA 1.0mg/L的增殖效果最明显,繁殖系数达4.806;体积大的接种外植体比体积小的繁殖系数高;5%椰乳有利于原球茎增殖。 相似文献
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56.
Shingo Kobayashi Aya Mizuike Hiroyuki Horiuchi Ryouichi FukudaAkinori Ohta 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2014,1841(9):1264-1271
In eukaryotic cells, phospholipids are synthesized exclusively in the defined organelles specific for each phospholipid species. To explain the reason for this compartmental specificity in the case of phosphatidylcholine (PC) synthesis, we constructed and characterized a Saccharomyces cerevisiae strain that lacked endogenous phosphatidylethanolamine (PE) methyltransferases but had a recombinant PE methyltransferase from Acetobacter aceti, which was fused with a mitochondrial targeting signal from yeast Pet100p and a 3 × HA epitope tag. This fusion protein, which we named as mitopmt, was determined to be localized to the mitochondria by fluorescence microscopy and subcellular fractionation. The expression of mitopmt suppressed the choline auxotrophy of a double deletion mutant of PEM1 and PEM2 (pem1Δpem2Δ) and enabled it to synthesize PC in the absence of choline. This growth suppression was observed even if the Kennedy pathway was inactivated by the repression of PCT1 encoding CTP:phosphocholine cytidylyltransferase, suggesting that PC synthesized in the mitochondria is distributed to other organelles without going through the salvage pathway. The pem1Δpem2Δ strain deleted for PSD1 encoding the mitochondrial phosphatidylserine decarboxylase was able to grow because of the expression of mitopmt in the presence of ethanolamine, implying that PE from other organelles, probably from the ER, was converted to PC by mitopmt. These results suggest that PC could move out of the mitochondria, and raise the possibility that its movement is not under strict directional limitations. 相似文献
57.
In this study, we report the effect of cholesterol content on the dynamic and structural properties of a dimyristoyl-phosphatidylcholine and distearoyl-phosphatidylcholine mixture in large unilamellar vesicles. The range of cholesterol concentrations studied varied around approximately 33.3 mol%, where it has been postulated that an abrupt change in bilayer organization occurs. Steady-state fluorescence measurements demonstrated a typical behavior; at low temperatures in the main phase transition, the cholesterol concentration did not affect the gel phase, but at 37.5 °C (phase coexistence) and in the liquid crystalline phase, the presence of cholesterol produced an increase in the fluorescence anisotropy of DPH and the generalized polarization of Laurdan. The greater effect was observed in the liquid crystalline phase, in which the bilayer became a mixture of fluid-like and liquid-ordered phases. The results obtained at approximately 33.3 mol% of Cholesterol demonstrated that the Generalized Polarization of Laurdan, the DPH lifetime, the limiting anisotropy and the rotational correlation time, as well as the fluorescence quenching of DPH by TEMPO, are at maxima, while the fluorescence intensity of dehydroergosterol and the lipid solubility in TritonX-100 are at minima. These results correlate well with the hypothesis of domain segregation in the DMPC/DSPC/Cholesterol LUV system. In this context, we postulate that at 33.3 mol% of Cho, the proportion of ordered domains reaches a maximum. 相似文献
58.
Mesophyll cells have been isolated from Psoralea bituminosa plant by gentle homogenization in a liquid nutrient medium. Between 60 and 70% of the cells can be isolated from leaves using this method, of which 50 to 60% can be recovered morphologically intact. Under light the separated cells have rates of oxygen evolution under light of 3500 μl O2 mg?1 chlorophyll h?1 (measured with a Clark-type electrode). During growth, this rate decreases rapidly, as does cell pigments (chlorophylls and carotenoids). As a first step in obtaining a photoautotrophic cell suspension, growth factors affecting cell division in free sugar medium were investigated. The starting culture contained between 1 and 2 × 106 cells ml?1. The best increase in cell number was obtained on a medium composed of Joshi and Ball's elements and vitamins and containing 1 mg l?1 of naphthalene acetic acid, 0.1 mg l?1 of benzylaminopurine and the grinding juice. The optimum culture pH was between 5 and 5.3. 相似文献
59.
Do-Wan Lee Sang-Young Kim Jae-Hwa Kim Taehyeong Lee Changbum Yoo Yoon-Ki Nam Jin-Young Jung Hae-Chung Shin Hwi-Yool Kim Dai-Jin Kim Bo-Young Choe 《Neurochemistry international》2013
The aim of present study was to quantitatively investigate the neurochemical profile of the frontal cortex region in a rat model of long-term alcohol consumption, by using in vivo proton magnetic resonance spectroscopy (1H-MRS) at 4.7 T and ex vivo1H high-resolution magic angle spinning (HR-MAS) technique at 11.7 T. Twenty male rats were divided into two groups and fed a liquid diet for 10 weeks. After 10 weeks, in vivo1H MRS spectra were acquired from the frontal cortex brain region. After in vivo1H MRS experiments, all animals were sacrificed and 20 frontal cortex tissue samples were harvested. All tissue examinations were performed with the 11.7 T HR-MAS spectrometer and high-resolution spectra were acquired. The in vivo and ex vivo spectra were quantified as absolute metabolite concentrations and normalized ratios of total signal-intensity (i.e., metabolitesNorm), respectively. The absolute quantifications of in vivo spectra showed significantly higher glycerophosphocholine plus phosphocholine (GPC + PCh) and lower myo-inositol (mIns) concentrations in ethanol-treated rats compared to controls. The quantifications of ex vivo spectra showed significantly higher PChNorm, ChoNorm and tChoNorm, and lower GPCNorm and mInsNorm ratio levels in ethanol-treated rats compared to controls. Our findings suggest that reduced mIns concentrations caused by the long-term alcohol consumption may lead to hypo-osmolarity syndrome and astrocyte hyponatremia. In addition, increased choline-containing compound concentrations may reflect an increased cell turnover rate of phosphatidylcholine and other phospholipids, indicating an adaptive mechanism. Therefore, these results might be utilized as key markers in chronic alcohol intoxication metabolism. 相似文献
60.
Odile Faivre-Rampant Claire Kevers Catherine Bellini Thomas Gaspar 《Plant Physiology and Biochemistry》1998,36(12):873-877
The rooting recalcitrant rac Nicotiana tabacum cv Xanthi mutant has been multiplied in vitro under the form of shoots in parallel to wild-type. rac Shoots grew at a lower rate and did not root whatever the treatments when compared to those of wild-type shoots. They were characterized by a higher lignin level, a higher total specific peroxidase activity with higher activity of both acidic and basic isoperoxidases (although missing and supernumerary isoenzymes were observed), and higher ethylene production. These observations might be causally related to growth inhibitions as similar incidences have been noted in different stress-induced growth limitation, through cell wall rigidification and auxin catabolism. The relationship between these aspects and rooting recalcitrance remains to be explored. 相似文献