|Canopy structure and pollination biology of the seagrasses Posidonia australis and P. sinuosa (Posidoneaceae)|
Smith, N.M.; Walker, D.I. (2002). Canopy structure and pollination biology of the seagrasses Posidonia australis and P. sinuosa (Posidoneaceae). Aquat. Bot. 74(1): 57-70
In: Aquatic Botany. Elsevier Science: Tokyo; Oxford; New York; London; Amsterdam. ISSN 0304-3770, more
Inflorescences; Leaf area; Leaves; Pollination; Sea grass; Posidonia König, 1805 [WoRMS]
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The canopy structure and reproductive phenology of the seagrasses Posidonia australis Hook. f. and Posidonia sinuosa Cambridge and Kuo were studied at Warnbro Sound, near Perth, Western Australia. Canopy and inflorescence height, shoot density, leaf area, leaf biomass, inflorescence density and density of other reproductive units were obtained from six (0.04m2) cores of each of the species. Leaf area and biomass were divided into 5 cm height classes and constructed into an in situ canopy profile. Vegetative shoot density was 913 ± 45 shoots m-2 in the P. australis canopy and 1.475 ± 140 shoots m-2 in the P. sinuosa canopy. Total leaf area index of the P. australis canopy (4.1 ± 0.1m-2m-2) was less than that of the P. sinuosa canopy (7.0 ± 0.2m-2m-2). There were fewer flowers in the P. sinuosa canopy (10 ± 2 flowers m-2) than in the P. australis canopy (16 ± 2 flowers m-2). Mean inflorescence length was 36.5 ± 1.2 cm in the P. australis canopy and 13.4 ± 4.7cm in the P. sinuosa canopy. Leaf area index at flower height was significantly higher in the P. sinuosa canopy (0.70 ± 0.07 m-2m-2) than the P. australis canopy (0.25 ± 0.02 m-2m-2). Reproductive phenology was studied from surveys of tagged inflorescence in situ. Anther dehiscence in P. australis canopy occurred from mid August to mid September and in the P. sinuosa canopy from early to late September. Pollen/ovule ratios of P. australis were similar to that of P. sinuosa. Pollen viability was longer in P. australis than in P. sinuosa. The similar pollen production but low leaf area around flowers, longer pollination period of P. australis flowers result in greater pollination success than for P. sinuosa flowers.