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111.
Summary The ability to recover male gametophyte derived plants, which is necessary to get transformed haploid plants, was verified for a hybrid of maize. Using the isolated microspore culture technique, a 9 × 10–5 plant regeneration frequency was obtained. Maize microspores were bombarded with tungsten particles using a PDS He/1000 apparatus. GUS expression in the microspores was maximum with 1.1 m diameter tungsten microprojectiles for 1100 and 1350 psi helium pressures at a 6 cm distance between the launch point and the target cells. Increasing the amount of DNA coated on the microparticles from 1.66 to 4 g DNA/mg of particles allowed a two-fold and four-fold increase of the GUS-expressing microspore frequency for 1100 and 1350 psi helium pressure bombardment, respectively. Optimal concentration of solidifying agent in the bombardment support culture medium was found to be 1%. Cell density ranging from 25000 microspores/bombardment to 100000 microspores/bombardment did not affect the frequency of GUS-expressing microspores. Using these optimal conditions, the maximum frequency of GUS-expressing microspores was found to be about 9 × 10–4, while maintaining an embryo formation frequency about 5 × 10–4.Abbreviations GUS
-glucuronidase
- PEG
polyethylene glycol 相似文献
112.
Summary Plasma membranes of maize (Zea mays L., cv. Sil Anjou 18) roots were isolated by aqueous two-phase partitioning. Multi elemental analysis by proton induced X-ray emission (PIXE) was used for the investigation of elemental composition of plasma membranes. Fe, Cu, and Zn as well as P, S, and Ca were identified. We did not find significant amounts of V, Mn, Se, Mo, or W.Abbreviations EDTA
ethylenediaminetetraacetic acid
- HCF III
hexacyanoferrate III (ferricyanide, K3[FeCN6])
- Hepes
2-[4-(2-hydroxyethyl)-1-piperazine]-ethanesulfonic acid
- PIXE
proton induced X-ray emission (proton microprobe)
- STA
siliciotungstic acid
- Tris
tris (hydroxymethyl)aminomethane 相似文献
113.
M. Sari-Gorla D. L. Mulcahy M. Villa D. Rigola 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(6-7):936-940
Various factors (pollen diameter, in vitro germination and tube length, in vivo growth rate in selfed and nonselfed styles) which could possibly contribute to the competitive ability of pollen were investigated on 30 Zea mays L. inbred lines. The only factor with which pollen diameter was positively correlated was in vitro pollen-tube growth. Traits related to the early stages of growth (in vitro germination, in vitro tube length, early in vivo pollen growth rate) were all positively correlated with each other, and these early characteristics were negatively correlated with late in vivo tube growth rate, which is largely influenced by the stylar genotype. 相似文献
114.
A. Cavallini L. Natali C. Balconi E. Rizzi M. Motto G. Cionini F. D. Amato 《Protoplasma》1995,189(3-4):156-162
Summary Chromosome endoreduplication is a very common process in higher plants but its function and genetic control are still to be clarified. In our experiments we analyzed, by Feulgen cytophotometry, chromosome endoreduplication in endosperm cells of two maize genotypes, IHP and ILP, having high and low protein content in their seed, respectively. Chromosome endoreduplication occurs in both lines within 24 days after pollination, attaining a maximum ploidy level of 384C (7 DNA replication rounds) in IHP and of 192C (6 replication rounds) in ILP. In the mature seed, endosperms of the two lines show different mean ploidy level. In reciprocal crosses between IHP and ILP the f1 endosperms have mean ploidy levels analogous to that of the maternal parent, showing that the difference in ploidy level between the two genotypes is maintained. After selfing of the f1 plants, the difference in ploidy level between the two F2 populations is reduced. In F2 the mean ploidy level is as variable as in f1, indicating the absence of genetic segregation. From our data, it is apparent that both the genetic constitution (cytoplasmic and nuclear) of the maternal parent and the genotype of the individual endosperms influence the ploidy level. An analysis of the protein content in endosperms carried out on the same seed sample as analyzed cytophotometrically showed that the protein content increases, during seed development, parallel to chromosome endoreduplication and varies, in the two lines, in reciprocal crosses and their progeny, according to the same trend as mean ploidy level, suggesting a correlation between the two parameters. 相似文献
115.
Manfred Heinlein 《Molecular & general genetics : MGG》1995,246(1):1-9
The Ac elements present in the unstable wxm7 and wx-m9 alleles of maize trigger different patterns of Ds excision in trans. To determine whether this differential regulation is a feature of the Ac alleles themselves or is mediated by genetically distinct factors, maize plants heterozygous for the wx-m7 and wx-m9 alleles were crossed to tester strains homozygous for Ds reporter alleles. Kernels showing the variegation pattern characteristic for the Ac elements carried in the wx-m7 and wx-m9 alleles were found to be present in the ratios expected from the genetic constitution of the strains. The aleurone variegation caused by excision of the Ds reporter element and the endosperm variegation caused by excision of Ac from the wx-m7 and wx-m9 alleles themselves segregated with the original wx-m alleles. In addition, stable Wx and wx derivatives of wx-m9 that have lost Ac no longer exert any trans effect on the wx-m7 allele (and vice versa). Therefore it is concluded that the observed variegation patterns are autonomously determined by specific trans effects of the particular Ac element. 相似文献
116.
Ana María Bravo-Angel Heinz-Albert Becker Reinhard Kunze Barbara Hohn Wen-Hui Shen 《Molecular & general genetics : MGG》1995,248(5):527-534
A reverse genetic system for studying excision of the transposable elementDs1 in maize plants has been established previously. In this system, theDs1 element, as part of the genome of maize streak virus (MSV), is introduced into maize plants via agroinfection. In the presence
of theAc element, excision ofDs1 from the MSV genome results in the appearance of viral symptoms on the maize plants. Here, we used this system to study DNA
sequences requiredin cis for excision ofDs1. TheDs1 element contains theAc transposase binding motif AAACGG in only one of its subterminal regions (defined here as the 5′ subterminal region). We showed
that mutation of these motifs abolished completely the excision capacity ofDs1. This is the first direct demonstration that the transposase binding motifs are essential for excision. Mutagenesis with
oligonucleotide insertions in the other (3′) subterminal region resulted in elements with either a reduced or an increased
excision efficiency, indicating that this subterminal region also has an important function. 相似文献
117.
The mechanism by which chemical energy is converted into an electrochemical gradient by P-type ATPase is not completely understood. The effects of ATP analogs on the canine kidney (Na++ K+) ATPase were compared to effects of the same analogs on the maize (Zea mays L. cv. W7551) root H+-ATPase in order to identify probes for the ATP binding site of the maize root enzyme and to determine potential similarities of ATP hydrolysis mechanisms in these two enzymes. Six compounds able to modify the ATP binding site covalently were compared. These compounds could be classed into three distinct groups based on activity. The first group had little or no effect on catalytic activity of either enzyme and included 7-chloro-4-nitrobenz-2-oxa-1.3-diazole. The second group, which included azido adenine analogs. fluorescein isothiocyanate and 5′-p-fluorosulfonylbenzoyladenine, were inhibitors of ATP hydrolysis by both enzymes. However, the sensitivity of the (Na++ K+) ATPase to inhibition was much greater than that exhibited by the maize root enzyme. The third group, which included periodate treated nucleotide derivatives and 2′,3′-o-(4-benzoylbenzoyl)adenosine triphosphate. inhibited both enzymes similarly. This initial screening of these covalent modifiers indicated that 2′,3′-o-(4-benzoylbenzoyl)adenosine triphosphate was the optimal covalent modifier of the ATP binding site of the maize root enzyme. Certain reagents were much more effective against the (Na++ K+) ATPase than the maize root enzyme, possibly indicating differences in the ATP binding and hydrolysis pathway for these two enzymes. Two ATP analogs that are not covalent modifiers were also tested: the trinitrophenyl derivatives of adenine nucleotides were better than 5′-adenylylimidodiphosphate for use as an ATP binding probe. 相似文献
118.
Effects of moderate drought on ascorbate peroxidase and glutathione reductase activities in mesophyll and bundle sheath cells of maize 总被引:2,自引:0,他引:2
Mesophyll and bundle sheath cells of maize leaves ( Zea mays L.) both contain the enzymes ascorbate peroxidase (AP; EC 1.11.1.11) and glutathione reductase (GR; EC 1.6.4.2) which are involved in hydrogen peroxide detoxification. Since bundle sheath cells of maize are deficient in photosystem II and have high CO2 levels, oxidative stress may be less severe in these cells than in mesophyll cells. The present study was conducted to determine if AP and GR activity levels preferentially increase in mesophyll cells relative to bundle sheath cells when plants are subjected to moderate drought. Although drought inhibited the growth of greenhouse-grown plants, it did not affect the levels of protein, chlorophyll or AP. GR was unaffected by drought in whole leaf tissue and mesophyll cells, but did increase slightly in bundle sheath cells. This slight increase is of questionable biological importance. AP and GR activity levels were similar in mesophyll cells, bundle sheath cells and in whole leaf tissue. The data suggest that moderate drought has little effect on enzymes of the hydrogen peroxide scavenging system and that mesophyll and bundle sheath cells may be exposed to similar levels of hydrogen peroxide. 相似文献
119.
Uptake kinetics of iron-phytosiderophores in two maize genotypes differing in iron efficiency 总被引:5,自引:0,他引:5
Iron inefficiency in the maize ( Zea mays L.) mutant ysl is caused by a defect in the uptake system for Fe-phytosiderophores. To characterize this defect further, the uptake kinetics of Fe-phytosiderophores in ysl was compared to the Fe-efficient maize cultivar Alice. Short-term uptake of 59 Fe-labeled Fe-deoxymugineic acid (Fe-DMA) was measured over a concentration range of 0.03 to 300 μM. Iron uptake in Fe-deficient plants followed Michaelis-Menten kinetics up to about 30 μM and was linear at higher concentrations, indicating two kinetically distinct components in the uptake of Fe-phytosiderophores. The saturable component had similar Km (∼ 10 μM) in both genotypes. In contrast. Vmax was 5.5 μmol Fe-DMA g−1 dry weight [30 min]−1 in Alice, but only 0.6 μmol Fe-DMA g−1 dry weight [30 min]−1 in ysl . Uptake experiments with double-labeled 59 Fe-[14 C]DMA suggest that in both cultivars Fe-DMA was taken up by the roots as the intact chelate. The results indicate the existence of a high-affinity and a low-affinity uptake system mediating Fe-phytosiderophore transport across the root plasma membrane in maize. Apparently, the mutation responsible for Fe inefficiency in ysl affected high-affected uptake and led to a decrease in activity and/or number of Fe-phytosiderophore transporters. 相似文献
120.
Intron-dependent transient expression of the maize GapA1 gene 总被引:2,自引:0,他引:2