Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-2145
    Keywords: Cenchrus ciliaris ; Megasporogenesis ; Megagametogenesis ; Apospory ; Apomixis ; Embryo sac development ; Salt stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sexual and aposporously apomictic plants of buffelgrass (Cenchrus ciliaris L.) form megaspore tetrads. In sexual plants the chalazal megaspore develops into a single Polygonum type embryo sac. In aposporous plants the megaspores degenerate, and one or more un-reduced nucellar cells form Panicum type embryo sacs. Apospory is conditioned by gene A; the dominant allele of gene B is epistatic to A and preserves sexual reproduction. We recently observed that heavy application of (NH4)2SO4 to the soil induced multiple embryo sacs in a sexual line. Therefore we tested the effect of salt stress on embryo sac formation in sexual and aposporous genotypes. One molar solutions of CaCl2, NaCl, (NH4)2SO4, NH4Cl, NaNO3, or Na2SO4 were applied to the soil of greenhouse plants every day or two starting at the archespore stage. Some of the pistils in salt-treated plants of sexual genotypes AaBb, aaBb, and aabb showed features not seen in untreated controls: (1) multiple Polygonum type embryo sacs in 1%–7% of pistils depending upon the salt; (2) embryo sacs without antipodals (0%–7%); (3) embryo sacs protruding through the micropyle (1%–16%). Some pistils of salt-treated obligately aposporous lines, but not controls, developed Polygonum type embryo sacs (4%–13%) and protruding embryo sacs (0%–6%). There was no ion specificity for induction of abnormal features. We postulate that salt stress suppresses the developmental priority of nucellar embryo sacs over megaspores in aposporous lines and of the chalazal megaspore over other megaspores in all lines. This may permit megaspores of aposporous plants to form reduced Polygonum type gametophytes, and permit more than one megaspore to form reduced embryo sacs in all lines. Protrusion of sacs and failure of antipodal formation in reduced embryo sacs may be the consequence of uncoordinated expansion of the embryo sacs and surrounding tissue.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of clinical monitoring and computing 16 (2000), S. 33-43 
    ISSN: 1573-2614
    Keywords: Instrumentation ; alveolar volume ; airway dead space ; data acquisition ; data analysis ; signal processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine
    Notes: Abstract Objective.An IBM PC-based real-time data acquisition, monitoringand analysis system was developed for the assessment of cardio-respiratoryfunction, i.e. airway dead space, alveolar volume and pulmonary blood flow,using oscillating inert inspired gas forcing signals. Methods.Theforcing gas mixture was generated by an in-house sinusoid gas delivery unit.The system interfaced with a mass spectrometer and an airway flow transducer,and performed real-time tracking of the breath-by-breath end-inspired,end-expired and mixed-expired concentrations. It calculated thecardio-respiratory parameters using two, i.e. continuous and tidal, in-housemathematical models of the lungs. The system's performance was evaluatedusing a mechanical bench lung, laboratory subjects and awake adults breathingspontaneously. Its predictive accuracy was compared with the measured volumesof the bench lung; single breath CO2 test for airway dead space andN2 washout for alveolar volume in laboratory subjects and awakeadults; and thermal dilution technique for pulmonary blood flow in laboratorysubjects. Results.Close agreements were found between the true andpredicted airway dead space, i.e. mean differences of –12.39%, 14.47%and –17.49%, respectively, and that of alveolar volume, i.e.–8.03%, –3.62% and 7.22%, respectively, in the bench lung,laboratory subject and awake adult studies; and that of pulmonary blood flow(–23.81%) in the laboratory subjects using the continuous lung model.Even closer agreements were observed for airway dead space (–5.8%) andalveolar volume (–4.01%) of the bench lung and for pulmonary blood flow(–8.47%) in the laboratory subjects using the tidal lung model.Conclusions.A system was developed to deliver, monitor and analyseon-line, and in real-time, output data from the sinusoid forcing technique.The technique was administered using the system in various subjects, andproduced favourable predictions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...