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  • SPACECRAFT DESIGN, TESTING AND PERFORMANCE  (4)
  • Trimorphic incompatibility  (2)
  • Behavior  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Variation in expression of trimorphic incompatibility in Pontederia cordata L. (Pontederiaceae) (1985)
    Springer
    Theoretical and applied genetics 70 (1985), S. 355-362 
    Details
    ISSN: 1432-2242
    Keywords: Trimorphic incompatibility ; Pontederia cordata L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pontederia cordata L. (Pontederiaceae), a perennial diploid, possesses the rare genetic polymorphism tristyly. A controlled pollination programme was conducted over a three year period, under glasshouse conditions, on 36 clones of P. cordata var. cordata to examine the nature of the self-incompatibility system. The three major findings of the pollination study were: (1) the three floral morphs display different levels of self-incompatibility, (2) pollen from the two anther levels within a flower exhibits different compatibility behaviour in self-pollinations, (3) considerable individual genetic variation in the expression of self-incompatibility is evident among clones within floral morphs. Similar results were also obtained from a smaller study on 15 clones of P. cordata var. lancifolia conducted over a 6 month period. In common with other Pontederia species the mid-styled morph (M) of P. cordata produces large amounts of seed when self-pollinated with pollen from long-level anthers. A developmental model is proposed to explain the high level of self-compatibility of the M morph in Pontederia species. Self-pollination of segregating progenies from M and S morphs of known incompatibility status demonstrated that the expression of incompatibility is closely associated with style length. It is suggested that overall differences in incompatibility behaviour among the floral morphs may be due to the pleiotropic effects of major genes controlling sub-characters of the tristylous syndrome, rather than linked modifier genes. However, the variable expression of trimorphic incompatibility within floral morphs suggests that this variation may be polygenic in origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00273739
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Pollinator foraging behavior and pollen collection on the floral morphs of tristylous Pontederia cordata L. (1987)
    Springer
    Oecologia 74 (1987), S. 347-351 
    Details
    ISSN: 1432-1939
    Keywords: Pontederia cordata ; Bombus ; Tristyly ; Pollination ; Behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The foraging behavior of the pollinators of tristylous Pontederia cordata was studied to determine if differences in floral morphology would lead to preferential visitation of the floral morphs. Although nectar production is not different in the three floral morphs, differences in the production and size of pollen grains produced by the three anther levels results in the morphs offering variable amounts of resources to pollen-collecting insects. Bumblebees (Bombus spp.) and the solitary bee Melissodes apicata used P. cordata primarily as a nectar source and therefore did not seem to exhibit any morph preference. In contrast, honeybees visited flowers mainly for pollen and preferred to forage on long-level anthers of the short-and mid-styled morphs. An analysis of the composition of corbicular pollen loads indicated that, relative to the frequency of production in the population: 1) honeybees collected an excess of pollen from long-level anthers; 2) bumblebees collected the three types of pollen without any apparent preference; and 3) M. apicata preferentially collected pollen from the short-level anthers — presumably because their proboscides are modified by the presence of tiny hairs. The results suggest that P. cordata in Ontario is serviced by a diverse, unspecialized pollinator fauna which is not co-adapted to the tristylous floral polymorphism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378928
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Trimorphic incompatibility in Eichhornia azurea (Pontederiaceae) (2000)
    Springer
    Sexual plant reproduction 12 (2000), S. 203-208 
    Details
    ISSN: 1432-2145
    Keywords: Key words Tristyly ; Trimorphic incompatibility ; Pollen trimorphism ; Partial incompatibility ; Clonal aquatic plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Eichhornia azurea (Pontederiaceae) is a mat-forming, clonal aquatic that inhabits lakes, marshes and river systems in many parts of the Neotropics. The species is tristylous with long-, mid-, and short-styled morphs commonly represented in natural populations. To investigate whether E. azurea possesses a trimorphic incompatibility system typical of tristylous species, we conducted a controlled pollination experiment on 15 clones representing the three style morphs from a natural population near Rosario, Argentina. Comparisons of fruit and seed set following self-, illegitimate, and legitimate pollinations clearly demonstrated the presence of trimorphic incompatibility in E. azurea. Self- and illegitimate pollinations produced significantly less fruit and seed than legitimate pollinations in all three style morphs. Pollen from the two anther levels within a flower exhibited contrasting compatibility relations in self-pollinations. In common with several other tristylous species in Pontederiaceae, the expression of self-incompatibility was weakest in the mid-styled morph and strongest in the short-styled morph. We discuss the ecological and evolutionary significance of the partial expression of trimorphic incompatibility in E. azurea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970050001
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  • 4
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    Analytical trade study of the STS payload environment (1976)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The current predicted acoustic environment for the shuttle orbiter payload bay will produce random vibration environments for payload components and subsystems which potentially will result in design, weight and cost penalties if means of protecting the payloads are not developed. Results are presented of a study to develop, through design and cost effectiveness trade studies, conceptual noise suppression device designs for space shuttle payloads. The impact of noise suppression on environmental levels and associated test costs, and on test philosophy for the various payload classes is considered with the ultimate goal of reducing payload test costs. Conclusions and recommendations are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-144233 , MCR-76-166
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Viking dynamics experience with application to future payload design (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Analytical and test techniques are discussed. Areas in which hindsight indicated erroneous, redundant, or unnecessarily severe design and test specifications are identified. Recommendations are made for improvements in the dynamic design and criteria philosophy, aimed at reducing costs for payloads.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-3014 , MCR-77-144
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    A study to define an in-flight dynamics measurement and data applications program for space shuttle payloads (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Data measurement and interpretation techniques were defined for application to the first few space shuttle flights, so that the dynamic environment could be sufficiently well established to be used to reduce the cost of future payloads through more efficient design and environmental test techniques. It was concluded that: (1) initial payloads must be given comprehensive instrumentation coverage to obtain detailed definition of acoustics, vibration, and interface loads, (2) analytical models of selected initial payloads must be developed and verified by modal surveys and flight measurements, (3) acoustic tests should be performed on initial payloads to establish realistic test criteria for components and experiments in order to minimize unrealistic failures and retest requirements, (4) permanent data banks should be set up to establish statistical confidence in the data to be used, (5) a more unified design/test specification philosophy is needed, (6) additional work is needed to establish a practical testing technique for simulation of vehicle transients.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-144892 , MCR-75-444
    Format: application/pdf
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  • 7
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    The development of pyro shock test requirements for Viking Lander Capsule components (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The procedure used to derive component-level pyro shock specifications for the Viking Lander Capsule (VLC) is described. Effects of shock path distance and mechanical joints between the device and the point at which the environment is to be estimated are accounted for in the method. The validity of the prediction technique was verified by a series of shock tests on a full-scale structural model of the lander body.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Institute of Environmental Sciences, Annual Technical Meeting; Apr 14, 1975 - Apr 16, 1975; Anaheim, CA
    Format: text
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