PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Plant Development”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1998

The Arabidopsis thaliana cDNAs coding for eIF4E and eIF(iso)4E are not functionally equivalent for yeast complementation and are differentially expressed during plant development.

Two cDNAs (At.EIF4E1 and At.EIF4E2) encoding, respectively, the eukaryotic initiation factors eIF4E and eIF(iso)4E of Arabidopsis thaliana were isolated by complementation of a Saccharomyces cerevisiae conditional mutant. The deduced amino acid sequences of the proteins are homologous to those from monocotyledonous plants, yeast and mammals. The corresponding genes were identified in YAC clones mapping to chromosome IV (At.EIF4E1) and to chromosome V (At.EIF4E2). The yeast strain complemented by At.EIF4E2 grew poorly compared with an isogenic strain expressing At.EIF4E1. Northern and in situ hybridization analysis show that both Arabidopsis At.EIF4E1 and At.EIF4E2 mRNAs are differentially accumulated in plant tissues. The At.EIF4E1 mRNA is expressed in all tissues except in the cells of the specialization zone of the roots; the At.EIF4E2 mRNA is particularly abundant in floral organs and in young developing tissues. This work further demonstrates an association between a high level of EIF4E mRNAs and cell proliferation and suggests that the plant eIF4E isoforms may have distinct functions in cell development and metabolism.

Amino Acid Sequence↗
PubMed2003

Cellulose orientation at the surface of the Arabidopsis seedling. Implications for the biomechanics in plant development.

In diffuse growing cells the orientation of cellulose fibrils determines mechanical anisotropy in the cell wall and hence also the direction of plant and organ growth. This paper reports on the mean or net orientation of cellulose fibrils in the outer epidermal wall of the whole Arabidopsis plant. This outer epidermal wall is considered as the growth-limiting boundary between plant and environment. In the root a net transverse orientation of the cellulose fibrils occurs in the elongation zone, while net random and longitudinal orientations are found in subsequent older parts of the differentiation zone. The position and the size of the transverse zone is related with root growth rate. In the shoot the net orientation of cellulose fibrils is transverse in the elongating apical part of the hypocotyl, and longitudinal in the fully elongated basal part. Leaf primordia and very young leaves have a transverse orientation. Throughout further development the leaf epidermis builds a very complex pattern of cells with a random orientation and cells with a transverse or a longitudinal orientation of the cellulose fibrils. The patterns of net cellulose orientation correlate well with the cylindrical growth of roots and shoots and with the typical planar growth of the leaf blade. On both the shoot and the root surface very specific patterns of cellulose orientation occur at sites of specific cell differentiation: trichome-socket cells complexes on the shoot and root hairs on the root.

Anisotropy↗
PubMed2006

DAWDLE, a forkhead-associated domain gene, regulates multiple aspects of plant development.

Phosphoprotein-binding domains are found in many different proteins and specify protein-protein interactions critical for signal transduction pathways. Forkhead-associated (FHA) domains bind phosphothreonine and control many aspects of cell proliferation in yeast (Saccharomyces cerevisiae) and animal cells. The Arabidopsis (Arabidopsis thaliana) protein kinase-associated protein phosphatase includes a FHA domain that mediates interactions with receptor-like kinases, which in turn regulate a variety of signaling pathways involved in plant growth and pathogen responses. Screens for insertional mutations in other Arabidopsis FHA domain-containing genes identified a mutant with pleiotropic defects. dawdle (ddl) plants are developmentally delayed, produce defective roots, shoots, and flowers, and have reduced seed set. DDL is expressed in the root and shoot meristems and the reduced size of the root apical meristem in ddl plants suggests a role early in organ development.

Alleles↗
PubMed2000

Plant development: A role for sterols in embryogenesis.

The Arabidopsis mutants fackel and sterol methyltransferase 1 have defects associated with body organization of the seedling. Molecular analysis of these mutants has revealed that plant sterols may be key signaling molecules influencing position-dependent cell fate during embryonic development.

Arabidopsis↗
PubMed1998

On becoming a parasite: evaluating the role of wall oxidases in parasitic plant development.

BACKGROUND: The temporal and spatial control of the transition from vegetative to parasitic growth is critical to any parasite, but is essential to the sessile parasitic plants. It has been proposed that this transition in Striga spp. is controlled simply by an exuded oxidase that converts host cell-surface phenols into benzoquinones which act as developmental signals that mediate the transition. An understanding of this mechanism may identify the critical molecular events that made possible the evolution of parasitism in plants. RESULTS: PoxA and PoxB are identified as the only apoplastic phenol oxidases in Striga asiatica seedlings, and the genes encoding them have been cloned and sequenced. These peroxidase enzymes are capable of oxidizing the 60 known inducing phenols into a small set of benzoquinones, and it is these quinones that induce parasitic development. Analysis of the reaction requirements and comparisons to host enzymes, however, lead us to argue that PoxA and PoxB are not necessary for host recognition. CONCLUSIONS: A new model is proposed where constitutive production of an activated oxygen species (in the case of Striga, H2O2) mediates host recognition. This strategy would allow a parasite to exploit abundant host enzymes to produce the diffusible recognition signals by converting a standard host defense into a parasitic offense.

Amino Acid Sequence↗
PubMed2000

Gravimorphogenesis of Cucurbitaceae plants: development of peg cells and graviperception mechanism in cucumber seedlings.

We examined the effect of microgravity on the peg formation of cucumber seedlings for clarifying the mechanism of gravimorphogenesis in cucurbitaceous plants. The spaceflight experiments verified that gravity controls the formation of peg, hypocotyl hook and growth orientation of cucumber seedlings. Space-grown cucumber developed a peg on each side of the transition zone of the hypocotyl and root, indicating that on the ground peg formation is regulated negatively by gravity (Takahashi et al. 2000). It was found that the auxin-regulated gene, CS-IAA1, was strongly expressed in the transition zone where peg develops (Fujii et al. 2000). In the seedlings grown horizontally on the ground, CS-IAA1 transcripts were much abundant on the lower side of the transition zone, but no such differential expression of CS-IAA1 was observed in the space-grown cucumber (Kamada et al. 2000). These results imply that gravity plays a role in peg formation through auxin redistribution. By the negative control, peg formation on the upper side of the transition zone in the horizontally growing seedlings might be suppressed due to a reduction in auxin concentration. The threshold theory of auxin concentration accounted for the new concept, negative control of morphogenesis by gravity (Kamada et al. 2000). Anatomical studies have shown that there exists the target cells destined to be a peg and distinguishable at the early stage of the growth. Ultra-structural analysis suggested that endoplasmic reticulum develops well in the cells of the future peg. Furthermore, it was found that reorganization of cortical microtubules is required for the change in cell growth polarity in the process of peg formation. The spaceflight experiment with cucumber seedlings also suggested that in microgravity positive hydrotropic response of roots occurred without interference by gravitropic response (Takahashi et al. 1999b). Thus, this spaceflight experiment together with the ground-based studies has shown that cucumber seedling is an ideal for the study of gravimorphogenesis, hydrotropism and their interaction. Although peg formation is seen specifically in cucurbitaceous seedlings, it involves graviperception, auxin transport and redistribution and cytoskeletal modification for controlling cell growth polarity. This system could be a useful model for studying important current issues in plant biology.

Cucumis sativus↗
PubMed2000

Response of plant development to environment: control of flowering by daylength and temperature.

The transition from vegetative growth to flowering is often controlled by environmental conditions and influenced by the age of the plant. Intensive genetic analysis has identified pathways that regulate flowering time of Arabidopsis in response to daylength or low temperature (vernalization). These pathways are proposed to converge to regulate the expression of genes that act within the floral primordium and promote floral development. In the past year, genes that confer the responses to daylength or vernalization have been cloned and have enabled aspects of the genetic models to be tested at the molecular level.

Arabidopsis↗
PubMed2004

Autofluorescence of developing plant vegetative microspores studied by confocal microscopy and microspectrofluorimetry.

Phenomenon of autofluorescence from vegetative microspores of spore-breding plant Equisetum arvense has been studied by methods of laser-scanning confocal microscopy (LSCM) and microspectrofluorimetry during the development of the cells. The microspores have demonstrated a difference between structures: blue-fluorescing cover and red-fluorescing chloroplasts. The fluorescence spectra of the studied cells was also measured by original microspectrofluorimeter. The character of the spectra and the color of fluorescence was changed during the microspores germination. The red fluorescence of the microspores was, mainly, due to the presence of chlorophyll and azulenes. The unicellular microspores may be recommended as natural probes of cellular viability and development.

Equisetum↗
PubMed1994

Response of cellular antioxidants to ozone in wheat flag leaves at different stages of plant development.

The effect of ozone (O3) on growth, yield and foliar antioxidants of spring wheat (Triticum aestivum L. cv. Turbo) was investigated in 1990 and 1991 in Braunschweig, Germany. Plants were grown full-season in pots in open-top chambers ventilated with charcoal-filtered (CF) air to which one or two levels of O3 were added. Mean 8 h day(-1) (10.00-18.00 h) O3 concentrations in the CF and CF + O3 treatments were 5.9, 61.2 and 92.5 nl litre(-1) in 1990, and 4.7 and 86.4 nl litre(-1) in 1991. Plants that received the high O3 level showed symptoms of premature senescence of the oldest leaves and yield reductions in both growing seasons. The contents of ascorbate and glutathione and the enzyme activities of ascorbate peroxidase and glutathione reductase were measured in symptomless flag leaves in weekly intervals before and after the beginning of anthesis. Leaf age had a significant effect on all antioxidants investigated. The O3 exposures of about 90 nl litre(-1) increased the activity of ascorbate peroxidase and the concentration of glutathione, but there were no pollutant effects on ascorbate content and glutathione reductase activity. Measurements of the antioxidant levels throughout one day showed no clear indications of diurnal changes in the antioxidative capacity in wheat flag leaves. The results are discussed in relation to the role of antioxidants in O3 detoxification.

Journal Article↗
PubMed2004

Predicting premature mortality from new power plant development in Virginia.

The authors estimated the number of premature deaths from particulate matter less than 2.5 microm (PM2.5) that would result from making 29 proposed fossil fuel power plants in Virginia operational. We used a U.S. Environmental Protection Agency air quality model (Climatological Regional Dispersion model) to calculate changes in ambient concentrations of PM2.5 and Cox proportional hazard modeling to calculate the resulting premature mortality. The model predicted that if all 29 plants were operational, PM2.5 concentrations would rise in 271 counties across 19 states 5 and increased average annual PM2.5 concentrations would result in a rate of 17 deaths per 37,900,026 people aged 30 yr and older (0.45 deaths per million, 95% confidence interval = 0.31, 0.59) per year by the end of 2004, increasing thereafter. Over a 6 yr period, 104 cumulative excess deaths would occur due to operations of these proposed plants. The authors recommend that precautionary principles be considered when policy decisions related to energy production from fossil fuels are made.

Air Pollutants↗
PubMed2003

CHRK1, a chitinase-related receptor-like kinase, plays a role in plant development and cytokinin homeostasis in tobacco.

CHRK1 encodes a receptor-like kinase that contains a chitinase-related sequence in the extracellular domain in Nicotiana tabacum. In this study, we showed that CHRK1 is mainly expressed in the shoot apex region including leaf primordia and young leaves, and germinating seedlings and vascular tissues, based on GUS activity of transgenic tobacco plants carrying the CHRK1 promoter-GUS fusion gene. Transgenic tobacco plants in which CHRK1 expression was suppressed exhibited pleiotrophic developmental abnormality, including formation of proliferating shooty calli from emerging seedlings and severely altered seedling development. At the cellular level, ectopic cell proliferation, reduced cell specificity, and aberrant chloroplast development were observed. The transgenic lines contained 3-fold higher level of cytokinin than the wild-type plants. Consistently, the transgenic seedlings exhibited a typical cytokinin response in the absence of hormone, such as deetiolation under the dark. Based on these results, we propose that CHRK1 is involved in a developmental signaling pathway regulating cell proliferation/differentiation and the endogenous cytokinin levels in tobacco.

Cell Division↗
PubMed2006

Conditional QTL mapping of oil content in rapeseed with respect to protein content and traits related to plant development and grain yield.

Oil content in rapeseed (Brassica napus L.) is generally regarded as a character with high heritability that is negatively correlated with protein content and influenced by plant developmental and yield related traits. To evaluate possible genetic interrelationships between these traits and oil content, QTL for oil content were mapped using data on oil content and on oil content conditioned on the putatively interrelated traits. Phenotypic data were evaluated in a segregating doubled haploid population of 282 lines derived from the F(1) of a cross between the old German cultivar Sollux and the Chinese cultivar Gaoyou. The material was tested at four locations, two each in Germany and in China. QTLMapper version 1.0 was used for mapping unconditional and conditional QTL with additive (a) and locus pairs with additive x additive epistatic (aa) effects. Clear evidence was found for a strong genetic relationship between oil and protein content. Six QTL and nine epistatic locus pairs were found, which had pleiotropic effects on both traits. Nevertheless, two QTL were also identified, which control oil content independent from protein content and which could be used in practical breeding programs to increase oil content without affecting seed protein content. In addition, six additional QTL with small effects were only identified in the conditional mapping. Some evidence was apparent for a genetic interrelationship between oil content and the number of seeds per silique but no evidence was found for a genetic relationship between oil content and flowering time, grain filling period or single seed weight. The results indicate that for closely correlated traits conditional QTL mapping can be used to dissect the genetic interrelationship between two traits at the level of individual QTL. Furthermore, conditional QTL mapping can reveal additional QTL with small effects that are undetectable in unconditional mapping.

Brassica rapa↗
PubMed2002

Epigenetic inheritance of expression states in plant development: the role of Polycomb group proteins.

Polycomb group (PcG) proteins maintain a repressed state of gene expression over many cell divisions. The recent characterisation of several PcG proteins from plants revealed a remarkable structural and functional conservation of PcG proteins between different kingdoms. In both plants and animals, homeotic genes are among the target genes of PcG complexes, although the structure of these genes is not conserved. However, not all PcG proteins identified in animals are present in plants. Furthermore it becomes clear that PcG-mediated repression in plants is more transient compared with the long-lasting effects in animals. This may be related to the absence of PcG proteins thought to be involved in long-term maintenance of PcG repression, suggesting that the mechanisms underlying PcG-mediated repression differ between plants and animals.

Animals↗