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  • 1
    Electronic Resource
    Electronic Resource
    Gravity and light control of the developmental polarity of regenerating protoplasts isolated from prothallial cells of the fern Ceratopteris richardii (1998)
    Springer
    Plant cell reports 17 (1998), S. 711-716 
    Details
    ISSN: 1432-203X
    Keywords: Key words Protoplasts ; Fern gametophytes ; Prothallial protoplasts ; Gravity ; Light gradients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A procedure has been developed for isolating protoplasts from prothalli of Ceratopteris richardii which can be cultured and are capable of regeneration. Protoplasts were isolated from 2-week-old gametophytes in a medium containing wall-digesting enzymes in 0.5 m sucrose, followed by purification of the released protoplasts by floating them up into a 0.5 m sorbitol layer. Regeneration occurred over a period of 10–24 days, and, under optimal osmotic conditions, followed the developmental pattern seen during spore germination, in that the first division gave rise to a primary rhizoid. Thus, prothallial protoplasts are comparable to germinating spores as suitable models for studies of developmental polarity in single cells. As in germinating spores, the polarity of development in regenerating protoplasts is influenced by the vectors of gravity and unilateral light. However, the relative influence of light in fixing this polarity is greater in regenerating protoplasts, while in germinating spores, the influence of gravity is greater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050470
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    Paper (German National Licenses)
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  • 2
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    Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores (1998)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.
    Keywords: Life Sciences (General)
    Type: Planta (ISSN 0032-0935); Volume 205; 4; 553-60
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    The influence of gravity and light on developmental polarity of single cells of Ceratopteris richardii gametophytes (1997)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: No abstract available
    Keywords: Life Sciences (General)
    Type: The Biological bulletin (ISSN 0006-3185); Volume 192; 1; 139-40
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Limited period of graviresponsiveness in germinating spores of Ceratopteris richardii (1994)
    In:  Other Sources
    Details
    Publication Date: 2019-08-15
    Description: Rhizoids of the fern Ceratopteris richardii Brogn. usually emerge 40 h after germination is initiated by light, and more than 90% of them emerge growing in a downward direction. However, when the spores are germinated on a clinostat, the emerging rhizoids show no preferential orientation. This indicates that under normal 1 g conditions the initial growth direction of rhizoids can be oriented by gravity. If the orientation of the spores is changed 3 h or less after the start of germination, the growth direction of most emerging rhizoids becomes downward relative to the new orientation. However, if the orientation of the spores is changed by 180 degrees 8 h or more after germination is initiated by light, most rhizoids emerge growing upward; i.e., the same direction as if there had been no orientation change. Emerged rhizoids also do not change their direction of growth if their orientation is changed. These results indicate that the growth direction of emerging rhizoids is set by gravity prior to actual emergence, and that the time of full orientation responsiveness is limited to a period ranging from the initiation of germination to about 3-4 h after the start of germination. There is a gravity-oriented nuclear movement beginning at about 13 h after germination, and this movement appears to predict the initial growth direction of rhizoids.
    Keywords: Life Sciences (General)
    Type: Planta (ISSN 0032-0935); 195; 150-2
    Format: text
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  • 5
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    Gravity and light control of the developmental polarity of regenerating protoplasts isolated from prothallial cells of the fern Ceratopteris richardii (1998)
    In:  Other Sources
    Details
    Publication Date: 2019-08-15
    Description: A procedure has been developed for isolating protoplasts from prothalli of Ceratopteris richardii which can be cultured and are capable of regeneration. Protoplasts were isolated from 2-week-old gametophytes in a medium containing wall-digesting enzymes in 0.5 M sucrose, followed by purification of the released protoplasts by floating them up into a 0.5 M sorbitol layer. Regeneration occurred over a period of 10-24 days, and, under optimal osmotic conditions, followed the developmental pattern seen during spore germination, in that the first division gave rise to a primary rhizoid. Thus, prothallial protoplasts are comparable to germinating spores as suitable models for studies of developmental polarity in single cells. As in germinating spores, the polarity of development in regenerating protoplasts is influenced by the vectors of gravity and unilateral light. However, the relative influence of light in fixing this polarity is greater in regenerating protoplasts, while in germinating spores, the influence of gravity is greater.
    Keywords: Life Sciences (General)
    Type: Plant cell reports (ISSN 0721-7714); 17; 9; 711-6
    Format: text
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    NASA TECHNICAL REPORTS
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