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1.
Summary The obtention of embryogenic competence in Actinidia deliciosa var. deliciosa cv. Hayward is reported. Axillary buds from shoots submitted to cold (4°C) and starvation for 1.5 months, developed leaves with embryogenic competence. These leaves, cultured in darkness for 1.5 months on a medium containing zeatin as a sole growth regulator, originated compact structures from which embryos developed. The plating orientation and sectioning of leaves strongly affected the expression of the embryogenic potential. A selected fraction of the protoplasts isolated from these leaves was able to develop in an embryogenic way. The germination of the embryos is still only occasional.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- 2-iP
6-dimethylallyl aminopurine
- IAA
indole-3-acetic acid
- NOA
naphthoxyacetic acid
- SEM
Scanning Electron Microscopy 相似文献
2.
Chloramphenicol acetyl transferase (CAT) gene was used as a reporter gene to assess the conditions for polyethylene glycol (PEG)-mediated transfection of kiwifruit protoplasts. The effect of plasmid concentration and the presence of carrier DNA were each assessed by analysing CAT activity in transfected protoplasts using thin-layer chromatography (TLC) autoradiographic detection of acetylated chloramphenicol. A gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) non-radioactive method was developed for monitoring CAT gene activity. This method provides a high speed of analysis (30 min) and precise means of detecting acetylated products at the nanomolar level, enabling quantification at very low transfection rates. Using this method we optimized plasmid and PEG concentration and also assessed the effect of heat shock on transfection. The best CAT activity was obtained using 30% polyethylene glycol 4000 and by submitting protoplasts to heat shock (45 °C, 5 min) prior to transfection. 相似文献
3.
Summary
Agapanthus umbelatus pollen tubes (PTs) display a number of different growth patterns when germinated in an electric field of 750 mV· mm–1. When pollen is germinated near the cathode (82.44% of orientation to the cathode side) or near the anode (55.35% of orientation to the anode), growth is oriented parallel to the applied field but when germinated at an intermediate position, there is random growth. An increase and decrease in the orientation rates as well as reversion of the polarized growth were observed when the growth conditions were systematically altered. These findings reflect the influence of different ionic currents present in the germination medium. These ionic currents induce the formation of ionic gradients, which were monitored by ion-HPLC. The individual omission of Ca2+, K+, Mg2+ and Cl– suppresses or alters the oriented growth pattern. The presence of ionic gradients is not by itself suficient to trigger the polarization of tube growth as the presence of an electric field which drives the ionic currents is essential for this to occur.Abbreviations PT
Pollen tube
- DNS
3,5-dinitro salycilic acid;
- TP
transient polarization
- HPLC
high precision liquid chroma tography
- DC
direct current 相似文献
4.
5.
Codon usage in the vertebrate hemoglobins and its implications 总被引:2,自引:0,他引:2
A study of codon usage in vertebrate hemoglobins revealed an evolutionary
trend toward elevated numbers of CpG codon boundary pairs in mammalian
hemoglobin alpha genes. Selection for CpG codon boundaries countering the
generally observed CpG suppression is strongly suggested by these data.
These observations parallel recently published experimental results that
indicate that constitutive expression of the human alpha-globin gene
appears to be determined by regulatory information encoded within the
structural gene. The possibility is raised that, in the absence of
selection, CpG decay can be used to date the evolutionary origin of a
mammalian alpha pseudogene from its active alpha gene.
相似文献
6.
Copper deficiency in wheat ( Triticum aestivum L. cv. Nazareno Stramppeli) markedly affects photosynthetic activity. Flag leaves of copper-deficient plants showed a 50% reduction of the photosynthetic rate expressed as mg CO2 dm−2 h−1 . The activities of PSI and PSII, determined for isolated chloroplasts, as well as fluorescence measurements on intact leaves of copper-deficient plants, indicated a low activity of photosynthetic electron transport. Ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity was not affected by copper deficiency but copper deficiency affected the chloroplast ultrastructure, especially at the level of grana, where a disorganization of thylakoids is evident. 相似文献
7.
M.J. ALMEIDA AND C.S. PAIS. 1996. Yeasts were isolated from a variety of home-made bread doughs and identified. A pure culture of Saccharomyces cerevisiae was found in 18% of the doughs. The same species predominated in 80% of the doughs examined whereas Issatchenkia orientalis, Pichia membranaefaciens and Torulaspora delbrueckii were present in about 40% of the samples. About one quarter of the isolates displayed killer activity, strains of P. anomala showing the broadest spectra. Two isolates of S. cerevisiae and three of T. delbrueckii gave biomass values in sucrose medium similar to or higher than those obtained with commercial compressed baker's yeast strains. 相似文献
8.
Joana Pais De Faria Vitor H. Paiva Sara N. Veríssimo Catarina S. Lopes Rita Soares João Oliveira Ivo dos Santos Ana C. Norte Jaime A. Ramos 《Ibis》2023,165(1):312-321
Gulls, as largely flexible opportunistic individuals, have been increasingly breeding in many cities around the world, but it is still unclear whether urban habitats are of equal or higher quality than traditional natural habitats or represent an ecological trap with immediate reproductive benefits but longer-term detrimental consequences to health. Here we present a study of breeding parameters (nest density, egg dimensions, clutch size, hatching success and adult body condition) and physiological parameters (erythrocyte sedimentation rate, heterophil/lymphocyte ratio, haemoglobin concentration and measurements of oxidative stress) as indicators of the general health condition of Yellow-legged Gull Larus michahellis adults and chicks from natural and urban colonies. Yellow-legged Gulls in the largest urban area (Porto) laid smaller eggs and clutches, showed a significantly lower occurrence of inflammatory processes in chicks, and showed a slower early chick growth than in the natural colony of Deserta. This suggests that urban gulls might be facing important trade-offs between the advantages of breeding in lower density urban colonies, with fewer intraspecific interactions and a lower disease transmission probability, and the disadvantages of having an anthropogenic diet usually lower in nutritional value. 相似文献
9.
Morphology, ontogeny and histochemistry of secretory trichomes of Geranium robertianum (Geraniaceae)
Geranium robertianum bears three types of glandular uniseriate trichomes which originate from a single protodermal cell and develop through periclinal divisions. Type I trichomes are procumbent and have an oval apical cell, two stalk cells and a basal cell. Type II trichomes are erect and have a pear shaped apical cell, two stalk cells and a basal cell. Type III trichomes are much longer than the other two types and have an elongated apical cell, five long stalk cells and a basal cell. Type I and type II trichomes are common on leaves while III trichomes are more abundant on flower structures.
Type I and type II trichomes secrete terpenoids and phenols. Type III trichomes are characterized by the accumulation of anthocyanins in the apical cell and secrete flavonoids. 相似文献
Type I and type II trichomes secrete terpenoids and phenols. Type III trichomes are characterized by the accumulation of anthocyanins in the apical cell and secrete flavonoids. 相似文献
10.
Dora Batista Maria João Sousa Maria Salomé Pais 《In vitro cellular & developmental biology. Plant》1996,32(1):37-41
Summary Plant regeneration was achieved from both a spontaneous clone (Bragan?a) and Brewer's Gold variety ofHumulus lupulus. The results obtained for these two different genotypes were compared. The organogenic ability of petiole and stem segments
was tested on three different basal media supplemented with 0.025 mg (0.14 μM) indole-3-acetic acid/L and 2 mg (8.87 μM) 6-benzylaminopurine (N6-benzyladenine)/L. These conditions induced rather heterogeneous responses, which depended mainly on the explant source and
the genotype. Because of the high organogenic competence revealed by the spontaneous clone on modified Murashige and Skoog
medium, several hormones in different combinations were tested to optimize conditions for adventitious shoot regeneration
in this clone. The best relation between the average shoot number/callus and the regeneration rate was achieved with 0.025
mg (0.14 μM) indole-3-acetic acid/L and 2 mg (8.87 μM) 6-benzylaminopurine/L or with 0.02 mg (0.11 μM) indole-3-acetic acid/L and 1.5 mg (6.97 μM) kinetin/L, which enabled 72 and 59% of regeneration, respectively. The regenerated plantlets could be acclimatized with
90% success. 相似文献