Early effects of boron deficiency on membrane function in higher plants
<p>The transfer of plants to boron-free solutions induces rapid responses in membrane functions without necessarily affecting root growth and anatomy. In sunflowers (<em>Helianthus annuus</em>), root growth slows within 3-6 h. However in maize (<em>Zea mays</em>), no g...
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| Format: | Thesis |
| Language: | English |
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1984
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| _version_ | 1826277753497845760 |
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| author | Heyes, J Julian Andrew Heyes |
| author2 | Loughman, B |
| author_facet | Loughman, B Heyes, J Julian Andrew Heyes |
| author_sort | Heyes, J |
| collection | OXFORD |
| description | <p>The transfer of plants to boron-free solutions induces rapid responses in membrane functions without necessarily affecting root growth and anatomy. In sunflowers (<em>Helianthus annuus</em>), root growth slows within 3-6 h. However in maize (<em>Zea mays</em>), no growth effects are apparent after more than 30 h without boron (-B). In both species early disturbances in ion uptake and cell wall deposition are seen.</p> <p>Ultrastructural studies on sunflower root tips after 5.5 h or 3 d -B are reported. Detailed studies on the absorption of P<sub>j</sub> and K<sup>+</sup> by root tips were complemented by studies on protoplasts isolated from the root tips of +B and -B plants. There were no significant differences in the protoplast yield or viability according to their B status. Ion absorption by protoplasts isolated from roots of +B and -B plants generally resembled that by intact roots of the corresponding B status.</p> <p>Altering the B status of the protoplasts was expected to initiate earlier responses than in the roots where cell wall binding and diffusion times buffer the system against change; but the greater variability inherent in measuring the protoplast responses prevented the detection of subtle changes.</p> <p>The activities of two+ membrane bound arjzymes were investigated; β-glucan synthetase and a K<sup>+</sup>-stimulated, Mg<sup>2+</sup> -dependent ATPase. UDPG incorporation by protoplasts continued for over 18 h and was consistently higher in +B protoplasts and root membranes than -B. However SEM revealed no significant differences in fibre deposition around sunflower and maize protoplasts according to their boron status.</p> <p>(K<sup>+</sup>+Mg<sup>2+</sup>)-ATPase from sunflower roots was found to be reversibly impaired by the loss of B; and preliminary investigations implied that restoration of activity when B was resupplied to the intact roots was correlated with the B content of the membrane fraction, as determined by the (n,α) method.</p> |
| first_indexed | 2024-03-06T23:33:39Z |
| format | Thesis |
| id | oxford-uuid:6ce60488-a5b0-4ba0-94ea-d59ee8622596 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:33:39Z |
| publishDate | 1984 |
| record_format | dspace |
| spelling | oxford-uuid:6ce60488-a5b0-4ba0-94ea-d59ee86225962022-03-26T19:14:11ZEarly effects of boron deficiency on membrane function in higher plantsThesishttp://purl.org/coar/resource_type/c_db06uuid:6ce60488-a5b0-4ba0-94ea-d59ee8622596BoronGrowth (Plants)Plant membranesEnglishPolonsky Theses Digitisation Project1984Heyes, JJulian Andrew HeyesLoughman, BLoughman, B<p>The transfer of plants to boron-free solutions induces rapid responses in membrane functions without necessarily affecting root growth and anatomy. In sunflowers (<em>Helianthus annuus</em>), root growth slows within 3-6 h. However in maize (<em>Zea mays</em>), no growth effects are apparent after more than 30 h without boron (-B). In both species early disturbances in ion uptake and cell wall deposition are seen.</p> <p>Ultrastructural studies on sunflower root tips after 5.5 h or 3 d -B are reported. Detailed studies on the absorption of P<sub>j</sub> and K<sup>+</sup> by root tips were complemented by studies on protoplasts isolated from the root tips of +B and -B plants. There were no significant differences in the protoplast yield or viability according to their B status. Ion absorption by protoplasts isolated from roots of +B and -B plants generally resembled that by intact roots of the corresponding B status.</p> <p>Altering the B status of the protoplasts was expected to initiate earlier responses than in the roots where cell wall binding and diffusion times buffer the system against change; but the greater variability inherent in measuring the protoplast responses prevented the detection of subtle changes.</p> <p>The activities of two+ membrane bound arjzymes were investigated; β-glucan synthetase and a K<sup>+</sup>-stimulated, Mg<sup>2+</sup> -dependent ATPase. UDPG incorporation by protoplasts continued for over 18 h and was consistently higher in +B protoplasts and root membranes than -B. However SEM revealed no significant differences in fibre deposition around sunflower and maize protoplasts according to their boron status.</p> <p>(K<sup>+</sup>+Mg<sup>2+</sup>)-ATPase from sunflower roots was found to be reversibly impaired by the loss of B; and preliminary investigations implied that restoration of activity when B was resupplied to the intact roots was correlated with the B content of the membrane fraction, as determined by the (n,α) method.</p> |
| spellingShingle | Boron Growth (Plants) Plant membranes Heyes, J Julian Andrew Heyes Early effects of boron deficiency on membrane function in higher plants |
| title | Early effects of boron deficiency on membrane function in higher plants |
| title_full | Early effects of boron deficiency on membrane function in higher plants |
| title_fullStr | Early effects of boron deficiency on membrane function in higher plants |
| title_full_unstemmed | Early effects of boron deficiency on membrane function in higher plants |
| title_short | Early effects of boron deficiency on membrane function in higher plants |
| title_sort | early effects of boron deficiency on membrane function in higher plants |
| topic | Boron Growth (Plants) Plant membranes |
| work_keys_str_mv | AT heyesj earlyeffectsofborondeficiencyonmembranefunctioninhigherplants AT julianandrewheyes earlyeffectsofborondeficiencyonmembranefunctioninhigherplants |