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Carbohydrate partitioning and developmental physiology of Nerine bowdenii Will. Watson


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Blake, Martin Richard 1999 , 'Carbohydrate partitioning and developmental physiology of Nerine bowdenii Will. Watson', PhD thesis, University of Tasmania.

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Nerine spp. are a bulbous genus that is grown commercially in
Australia on a limited scale. However, environmental conditions in
the south-eastern region of the continent, including the island
state of Tasmania, are ideal for production of cut-flowers.
However, large scale cultivation of the genus has been precluded to
some extent not only by unpredictable flowering under field
conditions but also unsatisfactory inflorescence scape lengths for
export markets. The objective of these studies was to begin to
elucidate some of the factors involved in the control of flowering in
Nerine bowdenii Will. Watson, and to investigate the process of
scape elongation.
The Nerine bulb consists of a number of recently initiated and
previously emerged annual units. The concentric leaf bases are
retained and serve as a source of carbohydrates for the
development of the units. Dry weight analysis of the bulb
components over time showed that all outer units were utilised for
current season leaf and inflorescence growth. Photoassimilates
and carbon from senescing leaves appeared to predominantly
accumulate in these organs but were not critical to flowering under
glasshouse conditions. The major carbohydrates detected in bulbs were starch, sucrose,
fructose, glucose, and fructans. Sucrose was found to be the
major form of carbon transport in the vascular tissue of mature
leaves. Fructan was present in very high concentrations in all organs, and the presence of this polymer has not been previously
reported in this genus.
To investigate the role of the reserve carbohydrate supply in
inflorescence abortion C-sucrose was applied to the outer scales
of bulbs. Bulbs containing an aborting inflorescence showed
increased sink activity by leaf/floral primordia. C data indicated
that outer-scale derived sucrose rapidly became dispersed
throughout the bulb, with accumulation of radio-actively soluble
sugars in the roots and basal plate.
Expansion of leaves and scape was shown to be initially dependant
on cell divisions within a plate meristem located at the base of the
organs. This was followed by expansion of the cells. Control of
flower height was able to be manipulated by the imposition of
shading on plants, which resulted in longer scape lengths as a
consequence of increased cell divisions. The data also suggested a
potential role of shading in the regulation of leaf number.

Item Type: Thesis - PhD
Authors/Creators:Blake, Martin Richard
Keywords: Plants, Flowering of, Amaryllidaceae, Bulbs (Plants)
Copyright Holders: The Author
Copyright Information:

Copyright 1999 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (Ph.D.)--University of Tasmania, 1999. Includes bibliographical references

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