Seedling growth in conifers and angiosperms: impacts of contrasting xylem structure
T. J. Brodribb A B D , N. M. Holbrook B and R. S. Hill CA Department of Plant Science, University of Tasmania, PO Box 252-55, Hobart, Tas. 7001, Australia.
B Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, USA.
C Department of Environmental Biology, University of Adelaide, SA 5005, Australia.
D Corresponding author. Email: brodribb@fas.harvard.edu
Australian Journal of Botany 53(8) 749-755 https://doi.org/10.1071/BT05049
Submitted: 4 March 2005 Accepted: 4 July 2005 Published: 14 December 2005
Abstract
Competitive interaction between conifers and angiosperms has moulded the structure of global vegetation since the Cretaceous. Angiosperms appear to enjoy their greatest advantage in the lowland tropics, an advantage often attributed to the presence of vessels in their xylem tissue. By monitoring the seedling growth of three members of the pan-tropical conifer family Podocarpaceae and three tropical angiosperm tree species, our aim was to determine whether these conifer and angiosperm seedlings showed distinct patterns of growth and light adaptation that might be attributed to the presence/absence of vessels. Angiosperm seedlings were consistently more efficient in terms of leaf area carried per unit stem investment, as well as more responsive to light climate than the conifer seedlings. Apparently linked to this were larger growth rate, stem hydraulic conductivity and stomatal conductance in the angiosperm sample. Stem hydraulic conductivity and maximum stomatal conductance were highly correlated among species and light treatments explaining the association between highly conductive vessel-bearing wood and high rates of gas exchange. We conclude that xylem vessels contribute to higher rates of gas exchange and more efficient production of leaf area in our sample angiosperms than in conifers. However, this advantage is limited by shade.
Acknowledgments
This research was funded by an Australian Research Council grant. T. J. B. is a Putnam Fellow at the Arnold Arboretum, Harvard University.
Ashton DH, Kelliher KJ
(1996) Effects of forest soil desiccation on the growth of Eucalyptus regnans (F.Muell.) seedlings. Journal of Vegetation Science 7, 487–496.
Becker P,
Tyree MT, Tsuda M
(1999) Hydraulic conductances of angiosperms versus conifers: similar transport sufficiency at the whole-plant level. Tree Physiology 19, 445–452.
| PubMed |
Bond WJ
(1989) The tortoise and the hare: ecology of angiosperm dominance and gymnosperm persistence. Biological Journal of the Linnean Society 36, 227–249.
Brodribb TJ, Feild TS
(2000) Stem hydraulic supply is linked to leaf photosynthetic capacity: evidence from New Caledonian and Tasmanian rainforests. Plant, Cell & Environment 23, 1381–1388.
| Crossref | GoogleScholarGoogle Scholar |
Brodribb TJ, Hill RS
(1997) Light response characteristics of a morphologically diverse group of Southern Hemisphere conifers as measured by chlorophyll fluorescence. Oecologia 110, 10–17.
| Crossref | GoogleScholarGoogle Scholar |
Brodribb TJ, Hill RS
(1999) The importance of xylem constraints on the distribution of conifer species. New Phytologist 143, 356–372.
| Crossref |
Brodribb TJ, Holbrook NM
(2005) Water stress deforms tracheids peripheral to the leaf vein of a tropical conifer. Plant Physiology 137, 1139–1146.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Brodribb TJ,
Holbrook NM,
Zwieniecki MA, Palma B
(2005) Leaf hydraulic capacity in ferns, conifers and angiosperms: impacts on photosynthetic maxima. New Phytologist 165, 839–846.
| Crossref |
PubMed |
Cochard H,
Froux F,
Mayr S, Coutard C
(2004) Xylem wall collapse in water-stressed pine needles. Plant Physiology 134, 401–408.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Ebitt RL, Ogden J
(1998) Comparative seedling growth of five endemic New Zealand podocarp species under different light regimes. New Zealand Journal of Botany 36, 189–201.
Feild TS,
Arens NC,
Doyle JA,
Dawson TE, Donoghue MJ
(2004) Dark and disturbed: a new image of early angiosperm ecology. Paleobiology 30, 82–107.
Herwitz SR
(1993) Growth rates of selected Australian tropical rainforest tree species under controlled conditions. Oecologia 96, 232–238.
| Crossref | GoogleScholarGoogle Scholar |
Hubbard RM,
Ryan MG,
Stiller V, Sperry JS
(2001) Stomatal conductance and photosynthesis vary linearly with plant hydraulic conductance in ponderosa pine. Plant, Cell & Environment 24, 113–121.
| Crossref | GoogleScholarGoogle Scholar |
Knoll, AH (1986). Patterns of change in plant communities through geological time. In ‘Community ecology’. pp. 126–141. (Harper and Row: New York)
Körner Ch,
Scheel JA, Bauer H
(1979) Maximum leaf diffusive conductance in vascular plants. Photosynthetica 13, 45–82.
Lusk CH,
Wright I, Reich PB
(2003) Photosynthetic differences contribute to competitive advantage of evergreen angiosperm trees over evergreen conifers in productive habitats. New Phytologist 160, 329–336.
| Crossref | GoogleScholarGoogle Scholar |
Panshin, AJ ,
and
De Zeeuw, C (1980).
Pittermann J, Sperry JS
(2003) Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers. Tree Physiology 23, 907–914.
| PubMed |
Sperry JS,
Donnelly JR, Tyree MT
(1988) A method for measuring hydraulic conductivity and embolism in xylem. Plant, Cell & Environment 11, 35–40.
Sperry JS,
Nichols KL,
Sullivan JEM, Eastlack SE
(1994) Xylem embolism in ring-porous, diffuse-porous, and coniferous trees of northern Utah and interior Alaska. Ecology 75, 1736–1752.
Stebbins, GL (1974).
Tyree MT,
Patino S, Becker P
(1998) Vulnerability to drought-induced embolism of Bornean heath and dipterocarp forest trees. Tree Physiology 18, 583–588.
| PubMed |
Tyree MT,
Snyderman DA,
Wilmot TR, Machado J
(1991) Water relations and hydraulic architecture of a tropical tree (Schefflera morototoni). Plant Physiology 96, 1105–1113.
Zimmermann MH, Jeje AA
(1981) Vessel-length distribution in stems of some American woody plants. Canadian Journal of Botany 59, 1882–1892.
