Abstract Detail



100 years of Baileyan Trends – Wood Evolution, Function and Future

Spicer, Rachel [1], Johnson, Daniel [2], Eckardt, Phoebe [2], Alsamadisi, Noah [2], Noble, Hilary [3], Martin, Celia [4].

Vessel development and auxin transport in the model woody plant Populus.

The origin of the vessel was a critical event in plant evolution and allowed angiosperms to colonize new environments, ultimately contributing to their diversification. Despite this importance, the developmental origin of vessels from their undifferentiated meristematic precursors is poorly understood. In particular, although the later stages of vessel development – wall deposition, wall sculpting and loss of the protoplast – have been described in a handful of species, very little is known about how vessels are specified and vessel dimensions are determined. Here we present evidence in Populus that auxin transport in the cambial zone and developing xylem tissue is likely involved in regulating the spatial arrangement (and hence, specification) and dimensions of vessels. We reduced the rate of auxin transport through the cambium by applying the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) to the epidermis in longitudinal strips and allowed plants to continue growing for 4-5 weeks. Although fibers were largely unchanged, vessels formed following this treatment appeared in wide tangential bands and were tightly clustered, small in diameter and square in cross-section. They were also short: normal vessels (i.e., vessels in control plants and in the untreated longitudinal strips of treated plants) ranged from 1 to 10 cm long whereas treated vessels rarely exceeded 2 cm. Although treated vessels took on the appearance of tracheids in cross-section, a silicone infusion method used to measure their length indicated that they were perforate, although possibly only several cells long in many cases. Although auxin has long been known to specify the location of vascular strands, a role of auxin specific to vessel formation is developmentally distinct. Given that auxin is synthesized in growing shoots and rapidly expanding leaves, its downward transport could serve to coordinate hydraulic capacity in the stem with foliar demand. Better knowledge of which auxin transport proteins are involved in this process and the extent to which NPA affects auxin transport rates are both critical to future progress in this area.


1 - Connecticut College, 270 Mohegan Ave, New London, CT, 06320, United States
2 - Connecticut College, Botany Department
3 - Chicago Botanic Garden, Glencoe, IL
4 - Connecticut College, Biology

Keywords:
xylem
vessel
Populus
Auxin
IAA
cambium
wood.

Presentation Type: Colloquium Presentations
Number: 0010
Abstract ID:502
Candidate for Awards:None


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