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101.
Grapevine bud fruitfulness is determined by the differentiation of uncommitted meristem (UCM) into either tendril or inflorescence.
Since tendril and inflorescence differentiation have long been considered sequential steps in inflorescence development, factors
that control the progression of floral meristem development may regulate the final outcome of UCM differentiation, and thus
affect fruitfulness. A comparison of the expression profiles of the master regulators of floral meristem identity (FMI) during
development of fruitful and non-fruitful buds along the same cane allowed associating the expression of a homolog of terminal flower 1 (TFL1, a negative regulator of FMI) to fruitful buds, and the expression of positive FMI regulators to non-fruitful buds. Combined
with (a) cytokinin-induced upregulation of VvTFL1A expression in cultured tendrils, which accompanied cytokinin-derived tendril
transformation into branched, inflorescence-like structures, (b) positive regulation of VvTFL1A expression by cytokinin, which
was demonstrated in transgenic embryonic culture expressing GUS reporter under the control of VvTFL1A promoter, and (c) a
significantly higher level of active cytokinins in fruitful positions, the data may support the assumption of cytokinin-regulated
VvTFL1A activity’s involvement in the control of inflorescence development. Such activity may delay acquisition of FMI and
allow an extended branching period for the UCM, resulting in the differentiation of inflorescence primordia. 相似文献
102.
103.
Margarita?Velcheva Zehava?Faltin Aliza?Vardi Yuval?EshdatEmail author Avihai?Perl 《Plant Cell, Tissue and Organ Culture》2005,83(3):293-301
A system for in vitro regeneration of Aloe arborescens was developed using young inflorescences as explants. Different phytohormone combinations of N-phenyl-N′-1,2,3-thiadiazol-5-yl urea (TDZ), benzyladenine (BA), 6-(γ,γ-dimethylallyl-amino)purine riboside (2iPR), zeatin ribozide (ZR), N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) and kinetin (K), with or without ancymidol, were examined in order to induce plant regeneration. Efficient shoot regeneration was initiated on Murashige and Skoog (MS) medium supplemented with BA or TDZ. MS medium enriched with 19.6, 22.2 μM BA and 3.92 μM ancymidol (MSBA5/1 medium), promoted organogenesis enabling 87.3% of the explants to regenerate 6.04 ± 1.79 shoots/explant. Subsequent shoot elongation and plant regeneration were strongly affected by the medium composition used for shoot induction. Optimal elongation (three to four shoots per explant) was obtained when shoots, initiated on MSBA5/1 medium, were subsequently transferred onto MS containing only 4.4 μM BA. Rooting was performed on MS media lacking growth regulators. Histological analysis revealed that the initiated shoots originated from the receptacle tissue surrounding the residual vascular tissue of the flower buds. 相似文献
104.
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107.
ATP synthesis and utilization in the early stage of seed germination in relation to seed dormancy and quality 总被引:1,自引:0,他引:1
M. Perl 《Physiologia plantarum》1986,66(1):177-182
In addition to the possible activities of the well-known biochemical cycles, the ATP-synthesizing system in dry seeds consists of a pathway which oxidizes malate and provides phosphoenolpyruvate (PEP). This system seems to be regulated primarily by the malate dehydrogenase (EC 1.1.1.37) activity, which together with the PEP carboxylase (EC 4.1.1.38) provides PEP and NADH. This latter compound may play a role as the "sparker" for the whole cycle.
Breaking seed dormancy does not seem to be related to the rate of ATP synthesis per se but to facilitate enzyme-substrate interaction, probably caused by intracellular compartment-fusion. The compartmentation process is probably a result of the seed ripening and maturation functions.
The ATP accumulated at the early stage of seed germination is a result of ATP synthesis and ATP utilization. Thus, ATP accumulation may result from a high rate of synthesis (high quality seeds) or from a low utilization ability (low-quality seeds). Also, since 95% of the synthesized ATP is utilized concomitantly with its synthesis, the accumulated amount is relatively insignificant and does not indicate seed quality. This conclusion is also supported by many experimental results in which no such correlation was found. 相似文献
Breaking seed dormancy does not seem to be related to the rate of ATP synthesis per se but to facilitate enzyme-substrate interaction, probably caused by intracellular compartment-fusion. The compartmentation process is probably a result of the seed ripening and maturation functions.
The ATP accumulated at the early stage of seed germination is a result of ATP synthesis and ATP utilization. Thus, ATP accumulation may result from a high rate of synthesis (high quality seeds) or from a low utilization ability (low-quality seeds). Also, since 95% of the synthesized ATP is utilized concomitantly with its synthesis, the accumulated amount is relatively insignificant and does not indicate seed quality. This conclusion is also supported by many experimental results in which no such correlation was found. 相似文献
108.
109.
CORRECTION OF POLYRIBOSOME DISTRIBUTIONS AS OBSERVED IN CELL SECTIONS BY ELECTRON MICROSCOPY 总被引:2,自引:0,他引:2 下载免费PDF全文
William Perl 《The Journal of cell biology》1964,22(3):613-621
Clusters of ribosomes observed by electron microscopy in thin sections of rabbit reticulocytes are of the same order of size as the section thickness of 600 A. Many of the observed clusters must therefore have been transected by the section surfaces and observed as clusters containing fewer ribosomes. A probability method of correcting for this effect is given. Comparison of the results with grid observations of ribosome distributions indicates sufficiently good agreement for application to cell section observations. 相似文献
110.
Jane Vishnevetsky Thomas L. White Jr. Aaron J. Palmateer Moshe Flaishman Yuval Cohen Yigal Elad Margarita Velcheva Uri Hanania Nachman Sahar Oded Dgani Avihai Perl 《Transgenic research》2011,20(1):61-72
The most devastating disease currently threatening to destroy the banana industry worldwide is undoubtedly Sigatoka Leaf spot disease caused by Mycosphaerella fijiensis. In this study, we developed a transformation system for banana and expressed the endochitinase gene ThEn-42 from Trichoderma harzianum together with the grape stilbene synthase (StSy) gene in transgenic banana plants under the control of the 35S promoter and the inducible PR-10 promoter, respectively. The superoxide dismutase gene Cu,Zn-SOD from tomato, under control of the ubiquitin promoter, was added to this cassette to improve scavenging of free radicals generated during fungal attack. A 4-year field trial demonstrated several transgenic banana lines with improved tolerance to Sigatoka. As the genes conferring Sigatoka tolerance may have a wide range of anti-fungal activities we also inoculated the regenerated banana plants with Botrytis cinerea. The best transgenic lines exhibiting Sigatoka tolerance were also found to have tolerance to B. cinerea in laboratory assays. 相似文献