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Evidence that the mature leaves contribute auxin to the immature tissues of pea (Pisum sativum L.)

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Jager, CE and Symons, GM and Glancy, NE and Reid, JB and Ross, JJ (2007) Evidence that the mature leaves contribute auxin to the immature tissues of pea (Pisum sativum L.). Planta, 226. pp. 361-368. ISSN 0032-0935

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Abstract

In plants such as the garden pea (Pisum sativum L.), it is widely thought that the auxin indole-3-acetic acid (IAA) is synthesised mainly in the immature tissues of the apical bud and then transported basipetally to other parts of the plant. Consistent with this belief are results showing that removal of the apical bud markedly reduces the IAA content in the stem. However, it has also been suggested that the mature leaves may synthesise substantial amounts of IAA, which enters the basipetal transport stream after being transported to the shoot apex in the phloem. To examine this theory, we defoliated pea plants and measured the effect on IAA content in the remaining shoot tissues. IAA levels were reduced in the internodes, and to a lesser extent in the apical bud, after defoliation, suggesting that mature leaves are indeed an important source of auxin for the shoot. Consistent with this idea, we have demonstrated that mature, fully expanded leaves are capable of de novo IAA synthesis. Furthermore, we report evidence for the presence of IAA in the phloem sap of pea. Together these results support those of Cambridge and Morris, suggesting that mature leaves are a source of the IAA in the basipetal transport stream.

Item Type: Article
Keywords: Auxin · Auxin homeostasis · Basipetal auxin transport · Defoliation · Mature leaves · Pisum
Journal or Publication Title: Planta
Publisher: Springer
Page Range: pp. 361-368
ISSN: 0032-0935
Identification Number - DOI: 10.1007/s00425-007-0487-1
Additional Information:

The original publication is available at www.springerlink.com

Date Deposited: 07 Apr 2008 14:27
Last Modified: 18 Nov 2014 03:34
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