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  • 1
    Electronic Resource
    Electronic Resource
    An evaluation of gene expression during somatic embryogenesis of two temperature-sensitive carrot variants unable to complete embryo development (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 82 (1991), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The synthesis of putative stage-specific polypeptides during somatic embryogenesis of the carrot (Daucus carota L. cv. Danvers) was investigated in the temperature-sensitive variants OB-2 and OB-3. These variants undergo normal embryo development to produce mature plantlets at the permissive temperature (24°C), but are arrested at the oblong stage to form elongated embryos without cotyledons at the restrictive temperature (33°C). Using two-dimensional polyacrylamide gel electrophoresis of in vivo labelled polypeptides, the patterns of stage-specific polypeptides in both lines were compared in: (1) oblong embryos grown at continuous 24°C vs oblong embryos exposed to 33°C during their temperature-sensitive period (i.e. embryos of identical morphology but different developmental fates); and (2) heartshaped embryos grown at constant 24°C vs enlarged oblong embryos exposed to 33°C during their temperature-sensitive period (i.e. embryos of the same age but different morphologies). The 22 putative stage-specific, polypeptides observed in this study fall into four classes: (1) line-specific, (2) age-specific, (3) unsynchronized, and (4) synchronized polypeptides. Only the last class, which consists of 4 polypeptides, exhibits synthesis patterns which are consistent with the polypeptides being causally involved in somatic embryo development. It is concluded that stage-specific behavior as assayed by PAGE analyses of simple ‘present or absent’ comparisons is insufficient to identify most of the polypeptides that may be relevant for somatic embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1991.tb02938.x
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  • 2
    Electronic Resource
    Electronic Resource
    Initial events in the tip-swelling response of the filamentous gametophyte of Onoclea sensibilis L. to blue light (1983)
    Springer
    Planta 159 (1983), S. 300-307 
    Details
    ISSN: 1432-2048
    Keywords: Blue light photoreceptor ; Cell expansion ; Gametophyte (fern) ; Onoclea ; Proton pump ; Pteridophyta ; Tip growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several inhibitors were applied to filamentous gametophytes of the fern Onoclea sensibilis in the attempt to characterize how electrical phenomena might be involved in the tip-swelling response to blue light (BL). The membrane potential of the apical cell in the typical fern filament rests near-120 mV in darkness, but irradiation with blue light causes the membrane to hyperpolarize at a steady rate of 2.6 mV min-1 until it reaches a new stable value between-130 and-135 mV. In darkness, 10-4M salicylhydroxamic acid (SHAM), an inhibitor of BL-mediated absorbance changes in putative plasma-membrane fractions from maize coleoptiles, has no observable effects on the membrane potential or on filamentous growth. A SHAM pretreatment before BL irradiation causes approx. 70% inhibition of the membrane hyperpolarization as well as a comparable reduction in the growth response; however, SHAM has no effect in experiments where its application follows the onset of the electrical response. Exposing the filaments to 10-5M Na3VO4, an inhibitor of the plasma-membrane ATPase, depresses the membrane potential in darkness. Depending on the timing of application, Na3VO4 prevents the initiation of or blocks further increases in the BL-mediated hyperpolarization. Application of Na3VO4 causes an immediate cessation of growth in both darkness and BL. These findings implicate the involvement of a plasmalemma-bound flavin-cytochrome complex and ATP-driven proton pump in the initial events of this growth response to blue light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393167
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  • 3
    Electronic Resource
    Electronic Resource
    Cell expansion in the filamentous gametophyte of the fernOnoclea sensibilis L. (1982)
    Springer
    Planta 155 (1982), S. 449-458 
    Details
    ISSN: 1432-2048
    Keywords: Blue light photoreceptor ; Cell expansion ; Gametophyte (fern) ; Onoclea ; Phytochrome ; Pteridophytes ; Tip growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Filamentous gametophytes of the fernO. sensibilis were exposed to paired combinations of light of different qualities, hormones and cations in the attempt to elucidate the underlying processes that regulate cell expansion. Simultaneous treatments with high-pH buffers or the auxin antagonistp-chlorophenoxyisobutyric acid abolished blue-light-mediated expansion but did not influence growth in red light. In contrast, the red-light response was preferentially altered by the ethylene absorbant KMnO4 or the Ca2+ chelator ethyleneglycol-bis(β-aminoethyl ether) N,N′-tetraacetic acid. The Ca2+ ionophore A23187 caused a significant reduction in cell expansion under both blue and red irradiation. A marked promotion of expansion was mediated by high concentrations of indole-3-acetic acid, but this effect was dependent on the presence of low-pH buffers. The ethylene-generating agent 2-chloroethylphosphonic acid decreased the magnitudes of both photoresponses; this inhibition was further enhanced by high Ca2+ concentrations. These findings and those with other plants are interpreted in terms of two independent control mechanisms for cell expansion: 1) a blue light photoreceptor-auxin-hydrogen ion system, and 2) a phytochrome-ethylene-calcium ion system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01607567
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  • 4
    Electronic Resource
    Electronic Resource
    A microtechnique for the analysis of free and conjugated indole-3-acetic acid in milligram amounts of plant tissue using a benchtop gas chromatograph-mass spectrometer (1997)
    Springer
    Planta 204 (1997), S. 1-7 
    Details
    ISSN: 1432-2048
    Keywords: Key words:Arabidopsis (auxin analysis) ; Auxin analysis ; Avena (auxin analysis) ; Mass spectrometry ; Stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. A microtechnique was developed for the quantification of indole-3-acetic acid (IAA) in plant samples of one milligram fresh weight or less. The method permitted quantification of both free and conjugated IAA using a benchtop gas chromatograph-mass spectrometer. New methods for sample purification with high recovery at microscale levels, together with simple changes that result in enhanced sensitivity of the instrumentation, allowed for a significant reduction in the amount of plant material required for analysis. Single oat (Avena sativa L.) coleoptile tips could be studied with this method and were found to contain free and total IAA levels of 137 and 399 pg · mg−1 fresh weight, respectively. A single 5-d-old Arabidopsis thaliana (L.) Heynh. seedling was shown to contain 61 pg · mg−1 fresh weight free IAA and 7850 pg · mg−1 fresh weight of total IAA following basic hydrolysis. This microtechnique provides a way to accurately measure IAA levels in very small structures and individual seedlings, thus making it a valuable research tool for elucidating the role and distribution of auxin in relation to growth and development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004250050223
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  • 5
    Electronic Resource
    Electronic Resource
    Uptake and metabolism of benzyladenine during shoot organogenesis in Petunia leaf explants (1992)
    Springer
    Plant growth regulation 11 (1992), S. 105-114 
    Details
    ISSN: 1573-5087
    Keywords: Cytokinin ; benzyladenine ; metabolism ; shoot organogenesis ; Petunia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Benzyladenine (BAP) uptake and metabolism were characterized during the key stages of shoot organogenesis in leaf explants of Petunia ‘MD1’. Using leaf explant transfer experiments, it was shown that exposure to 2.2 μM BAP for 6, 8 or 10 days induced shoot formation on 27, 80 and 100% of the explants respectively, with a concomitant increase in the number of shoots per explant. BAP uptake and metabolism were characterized in leaf explants after 1, 3, 6 or 10 days exposure to [3H]BAP or 10 days exposure plus an additional 2 days on basal medium (10+2). BAP and 9-β-D-ribofuranosyl-BAP ([9R]BAP) were detected at days 1 and 3 only. Therefore, the BAP free base was not detectable during the shoot induction period between days 6 and 10, as defined by leaf transfer experiments. The BAP ribotide pool was largest on day 1 and decreased to day 10+2. It is possible that the BAP ribotide pool provided either the active cytokinin itself or acted as a short-term storage form for the active cytokinin in petunia shoot organogenesis. Other metabolites detected in petunia leaf tissue included 7-β-D-glucopyranosyl-BAP ([7G]BAP), 9-β-D-glucopyranosyl-BAP ([9G]BAP) and an unidentified metabolite C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024063
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  • 6
    Electronic Resource
    Electronic Resource
    Population and biomass kinetics in fed-batch cultures of Daucus carota L. somatic embryos (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 811-818 
    Details
    ISSN: 0006-3592
    Keywords: somatic embryo ; Daucus carota ; development ; fed-batch culture ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The population dynamics of developing somatic embryos of carrot (Daucur carota L.) was investigated in batch and fed-batch cultures using modified Murashige and Skoog medium. These substrate limitations coincided not only with stoppage of biomass increase, but also with the increase in total concentration of embryos as well as the advancement of the embryo into a more mature stage. Both glucose and ammonium were depleted from the culture. Restoring either glucose, or ammonium and nitrate, as to approximately initial concentrations in fed-batch experiments, did not result in a significant increase of the total normal embryo concentration. On the other hand, medium replacement led to increase in biomass concentration, total embryo number, and improved embryo maturity. The addition of a mixture of glucose, ammonium, and nitrate to the spent medium resulted in variable increases in biomass and embryo number, but always less than those resulting from media replacement. Although the total number of embryos was higher after medium replacement, the fraction of embryos reaching torpedo stage was still only 50%. The need for a better means of population characterization for further kinetic studies is discussed. © 1993 Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410807
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  • 7
    Electronic Resource
    Electronic Resource
    Morphological kinetics and distribution in somatic embryo cultures (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 368-378 
    Details
    ISSN: 0006-3592
    Keywords: Daucus carota L. ; embryos ; kinetics ; morphology ; pattern recognition ; image analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The environmental effects on developing somatic embryos should be characterized not only by the growth based on biomass, but also by the morphological properties and size. We have previously developed a discrete classifier to separate developing embryos into distinct morphological classes. In this study, a continuous descriptor using the distributions of magnitude of features representing morphological characteristics and size information was used to describe the developing embryo populations. The identity of the population was examined by comparing either the distributions of all features or key features. The method was applied to characterize the kinetics of carrot embryo populations cultivated in the presence and absence of triiodobenzoic acid(TIBA), an inhibitor of auxin polar transport. Optimal sample size for morphological characterization was determined by the invariance of feature distributions with further increase in sample size. The overall growth and substrate consumption kinetics were only slightly affected by the presence of TIBA. However, the distribution of morphological features was significantly affected. The features showing the highest statistical significance were related to those corresponding to the roughness. The continuous descriptor for characterizing developing embryo population is potentially useful for quality control in large-scale operations. © 1994 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260440315
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  • 8
    Electronic Resource
    Electronic Resource
    Characterizing patterns in plant somatic embryo cultures: Its morphology and development (1994)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 1728-1740 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: While being developed, plant somatic embryos change shape and increase size. An effective kinetic description of growth and development of somatic embryos is important for process scale-up and optimization. An essential component of such a kinetic description is the developmental characterization of the individual embryos present in culture. Embryo morphological data obtained by image processing techniques were transformed into sizeand size-independent morphological descriptors. Qualitative relations between the descriptors and geometric properties of the embryos were established to interpret the results. For training, a branch-and-bound search technique was used to search for optimal subsets of descriptors, as determined by member clustering and class separability properties evaluated from within-class and between-class scatter matrices. In the classification mode, individuals were identified using a voting nearest neighbor classifier. This nonparametric nearest-neighbor classifier was trained on optimal projections of the feature space established from developmental stage discrimination (branch-and-bound algorithm). Using a test population, normal and abnormal embryos and callus were assigned to six morphological classes. The image-analysis-based classification was in 80-90% agreement compared to the results obtained through visual classification by an experienced operator.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690401013
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  • 9
    Electronic Resource
    Electronic Resource
    An advanced image analysis system for evaluation of somatic embryo development (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 50 (1996), S. 65-72 
    Details
    ISSN: 0006-3592
    Keywords: somatic embryo ; plant cell culture ; image analysis ; pattern recognition ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Somatic embryogenesis is among the most promising means of large scale plant micropropagation. The development of somatic embryos is characterized by their morphological changes. Embryos in culture usually exhibit high heterogeneity and abnormality. As conventional microscopic observation is laborious and subjective, an objective and quantitative morphokinetic description is important for further advancement of this important process technology. We developed an image analysis system capable of measuring morphological and size features of embryos. Subtle environmental effects on embryo development, which are often masked by the subjectivity of microscopic observation, are now discernible by statistically comparing the distributions of these morphological and size features. This image analysis and pattern recognition system was applied to examine the kinetics of a fed-batch culture. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Probing the morphological developmental path of plant embryos by image tracking (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 60 (1998), S. 425-433 
    Details
    ISSN: 0006-3592
    Keywords: embryo development ; pattern formation ; image analysis ; somatic embryogenesis ; carrot ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An image analysis and pattern recognition system was applied to track the morphological changes of individual plant somatic embryos during the course of their development into mature embryos. A Fourier descriptor was used to transform the morphological information into quantitative features (Fourier features), which are amenable to mathematical and statistical analysis. At a given time point, the status of each developing embryo is represented by a point in the multidimension feature space spanned by these Fourier features. Connecting each point representing the individual embryos over time gives a trajectory which depicts the embryos' developmental “path” or history. Large variations in embryo development were observed, which is consistent with the population heterogeneity seen in batch embryo cultures. The rate at which each embryo progresses in the feature space was measured by a developmental vector. For embryos in a given class or developmental stage, the magnitude of the developmental vector exhibited a wide distribution. The results revealed that embryos with a higher developmental rate during the early stage of development had a higher chance of reaching the mature stage in a relatively short time. This single embryo tracking method is potentially a valuable tool in developing a correlation between the embryo's morphological features during the early stage of development and its eventual developmental fate. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 425-433, 1998.
    Additional Material: 9 Ill.
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