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111.
The peanut (Arachis hypogaea L.) produces flowers aerially, but buries the recently fertilized ovules into the soil, where fruit and seed development
occur. The young seeds are carried down into the soil at the tip of a specialized organ called the gynophore. Although the
gynophore has a typical shoot anatomy, it responds positively to gravity like a root. In this study, we explore the role of
the plant growth regulator indole-3-acetic acid (IAA) in the growth and the gravitropic response of the peanut gynophore.
With an immunolocalization technique using an IAA monoclonal antibody, we localized IAA within the tissues of vertically oriented
and gravistimulated gynophores. We found that in vertically oriented gynophores, IAA labeling occurs in the periphery of the
gynophore, in the entire cortex and epidermis. Within 20 min of horizontal reorientation, the IAA signal gradually increases
in the upper cortex/epidermis and diminishes in the lower cortex/epidermis. At 1.5 h after gravistimulation, all of the IAA
immunolocalization signal is detected in the upper cortex and epidermis – none is detected in the lower side. Growth rate
measurements also indicate that after 1–2 h of reorientation, the growth rate maximum on the upper side corresponds temporally
and spatially to the growth rate minimum on the lower side. Experiments using radioactively labeled IAA corroborate an upper-side
redistribution of this hormone upon horizontal reorientation. These results are analyzed with respect to the current theories
of plant gravitropic response, and a model for a possible gravity-induced IAA redistribution from the lower to the upper side
of the peanut gynophore is proposed.
Received: 25 January 1999 / Accepted: 24 February 1999 相似文献
112.
The peanut (Arachis hypogaea L.) seeds harvested at the last stage of maturation were divided into five grades by size. The content of total protein, salt-soluble protein, arachin, conarachin I and 2s globulin in these seeds were measured. No obvious differences in germination percentage and the length of radicle and hypocotyl within 3d germination in dark were observed among the five grades of seeds. But there were significant differences in the seedling growth after two weeks of germination in light. There was a very close correlation between the storage protein in cotyledons and the seedling growth. When seeds germinated in light, the efficiency of mobilization of the salt-soluble protein in the cotyledons was higher than that in the cotyledons of the seeds germinating in dark. All of the salt-soluble protein in cotyledons was used up after 14d seedling growth in light. SDS-PAGE of salt-soluble protein showed that 23.5, 38.5 and 41 kD subunits of arachin were first mobilized during germination. The 18 kD subunits of arachin were not mobilized until the above-mentioned subunits were used up. The 60.5 kD subunit of conarachin I and 2s globulin were degradated within 2 to 3 days during germination. 相似文献
113.
用发光酶基因(luxAB)标记法研究慢生花生根瘤菌的竞争结瘤能力 总被引:6,自引:1,他引:6
luxAB基因标记是一种新型基因标记技术,在很多研究领域都有着良好的应用前景。研究通过三亲本杂交将luxAB基因成功地向慢生型花生根瘤菌进行了转移,并获得了一株带LuxAB基因标记的菌株Cspr7-1。对Cspr7-1进行性状、标记基因的遗传稳定性检测,结果表明,LuxAB基因不仅能有效表达,而且性状稳定。在无氮水培条件下进行标记菌株与土著根瘤菌的竞争结瘤试验。结果证实,Cspr7-1在植物根系上的占瘤率平均达到61.3%,比土著根瘤菌的竞争结瘤能力强,而且Cspr7-1在主根上的侵染能力远较侧根上的强,平均高出22.3%-39.6%。 相似文献
114.
Greilhuber J 《Annals of botany》2005,95(1):91-98
BACKGROUND: The 6 years since the last Angiosperm Genome Size Discussion Meeting in 1997 have experienced the decline of the then widely held idea of the 'plastic' genome. Several published cases of intra-specific variation in cultivated plants have been questioned on re-investigation with an improved technical approach. At the same time, technical problems caused by staining inhibitors present in the plant material have been recognized. In the accumulation of genome size data more critical methods and rules for best practice are urgently needed. INFRA-SPECIFIC VARIATION RE-VISITED: This review is about (a) the basic requirement for repeatability of results and the need for self-criticism on the part of the investigator and (b) the critical points in the technical procedure, particularly the quantitative Feulgen reaction. Case studies are presented on Dasypyrum villosum (refuting a previously reported 'plastic genome' phenomenon), on Glycine max (refuting previously claimed intraspecific variation) and on Arachis hypogaea and A. duranensis, in which reported C-values are too high by roughly two-fold. In A. hypogaea the reported intraspecific genome size variation could not be confirmed. Furthermore, a claimed negative correlation between altitude and genome size in A. duranensis was shown to be based on an arbitrary omission of data points that did not fit the correlation (although a correlation was found). BEST PRACTICE METHODOLOGY: The finding of previously published questionable studies was the incentive for a re-consideration of the quantitative Feulgen procedure with regard to best practice in genome size studies. Clarification here of the critical steps of the method should help to improve the data in the literature. It must be stressed that the most important requirement is the need for a self-critical attitude of researchers to their data. 相似文献
115.
Zheng?QiushengEmail author Ju?Bao Liang?Likun Xiao?Xianhua 《Plant Cell, Tissue and Organ Culture》2005,81(1):83-90
Our objective is to develop an Agrobacterium-based transformation system for peanut. Ascorbic acid (AA), sodium selenite (Se), DL--tocopherol (TOC) and glutathione (GSH) were used as antioxidants during the plant regeneration and co-cultivation with Agrobacterium tumefaciens. Percentage of explants with buds or shoots increased from 50 in control group to 88, 90, 87 and 76 in GSH, TOC, Se or AA treated groups, respectively. The percentage of GUS-positive plantlets increased from 3.9 (in control) to 14.5, 10.3, 12.4 and 3.9 in GSH, TOC, Se or AA groups, respectively. Some of the callus in AA group became brown and died 2 months later. GSH, TOC and Se not only eliminated the formation of H2O2 produced in wound tissue during preparation of leaflets and co-cultivation with Agrobacterium tumefaciens and decreased malondialdehyde (MDA) formation, but also enhanced superoxide dismutase (SOD) and catalase (CAT) activities. As a result, GSH, TOC or Se increased the frequency of plant regeneration and transformation efficiency of peanut (Arachis hypogaea L.) explants by Agrobacterium tumefaciens. AA is an unsuitable antioxidant in Murashige and Skoog (MS) medium due to the stimulation of oxidation in the presence of iron in MS medium. 相似文献
116.
117.
Madhumita?Joshi Chen?Niu Geraldine?Fleming Sulekha?Hazra Ye?Chu C.?Joseph?Nairn Hongyu?Yang Peggy?Ozias-AkinsEmail author 《In vitro cellular & developmental biology. Plant》2005,41(4):437-445
Summary The ability to non-destructively visualize transient and stable gene expression has made green fluorescent protein (GFP) a
most efficient reporter gene for routine plant transformation studies. We have assessed two fluorescent protein mutants, enhanced
GFP (EGFP) and enhanced yellow fluorescent protein (EYFP), under the control of the CaMV35S promoter, for their transient
expression efficiencies after particle bombardment of embryogenic cultures of the peanut cultivar, Georgia Green. A third
construct (p524EGFP.1) that expressed EGFP from a double 35S promoter with an AMV enhancer sequence also was compared. The
brightest and most dense fluorescent signals observed during transient expression were from p524EGFP. 1 and EYFP. Optimized
bombardment conditions consisted of 0.6 μm diameter gold particles, 12410 kPa bombardment pressure, 95 kPa vacuum pressure,
and pretreatment with 0.4 M mannitol. Bombardments with p524EGFP.1 produced tissue sectors expressing GFP that could be visually selected under the fluorescence
microscope over multiple subcultures. Embryogenic lines selected for GFP expression initially may have been chimeric since
quantitative analysis of expression sometimes showed an increase when GFP-expressing lines, that also contained a hygromycin-resistance
gene, subsequently were cultured on hygromycin. Transformed peanut plants expressing GFP were obtained from lines selected
either visually or on hygromycin. Integration of the gfp gene in the genomic DNA of regenerated plants was confirmed by Southern blot hybridization and transmission to progeny. 相似文献
118.
119.
The effects of 11 different auxins and one cytokinin-like compound were tested at four concentrations for their ability to
induce primary and repetitive somatic embryos from mature, dry peanut (Arachis hypogaea L.) epicotyls of genotype AT120. Treatment with picloram and centrophenoxine at 83.0 and 124.4 μm resulted in the greatest number of embryos per explant and the highest percentage of explants responding. In a follow-up
experiment, picloram, centrophenoxine, and dicamba were tested at 83.0 and 124.4 μm on four peanut genotypes (AT120, 59-4144, GK7, and VC1). Picloram and centrophenoxine induced similar numbers of globular-stage
and total embryos from each genotype, while dicamba was less effective. Similar results were observed with percentage of responding
axes. Genotypes AT120 and VC1 yielded more clusters of repetitive embryos than GK7 and 59-4144. After 5 months, embryos derived
from repetitive embryogenic cultures were converted into mature plants.
Received: 8 February 1999 / Revision received: 9 June 1999 / Accepted: 30 June 1999 相似文献
120.