Phenology and reproductive biology of Acacia karroo Hayne (Leguminosae : Mimosoideae)

Show simple item record Robbertse, P.J. (Petrus Johannes), 1932- Du Toit, Elsie Sophia Annandale, J.G. (John George), 1959- 2015-05-05T09:37:17Z 2015-05-05T09:37:17Z 2014
dc.description.abstract The architectural development of Acacia karroo conforms to Troll’s model. Growth of the branches is modular and sympodial with heteroblastic leaves on all long shoots of the tree, including the seedling. Axillary buds tend to proliferate especially on flowering shoots where they form fascicles consisting of up to 10 inflorescences arranged in two parallel serial rows per leaf axil. Most axillary buds are sylleptic and basal buds which give rise to short shoots, each producing two to five cataphylls each season, but no flowers. Inflorescences are only produced on long shoots (modules) of the current season. After flowering the terminal part of the module aborts, trees are usually andromonoecious with capitate inflorescences containing 40 to 100 flowers each, with some male and some hermaphrodite. Some trees produce only male flowers. Anthesis in the same inflorescence, the same tree as well as amongst trees of the same community are synchronised and occur at intermittent intervals, each lasting three or more days at a time. Flowers are protogynous and pollen is produced in polyads, each consisting of 16 pollen grains. Ovaries contain 10 to 14 ovules each. The concave stigma has space for only one polyad which can fertilise all ovules in the ovary after a single pollination event. Fruit set is low with 0 to 10 fruits (pods) per inflorescence. en_ZA
dc.description.librarian hb2015 en_ZA
dc.description.uri en_ZA
dc.identifier.citation Robbertse, PJ, Du Toit, ES & Annandale, JG 2014, 'Phenology and reproductive biology of Acacia karroo Hayne (Leguminosae : Mimosoideae)', American Journal of Plant Sciences, vol. 5, pp. 2074-2093. en_ZA
dc.identifier.issn 2158-2742 (print)
dc.identifier.issn 2158-2750 (online)
dc.identifier.other 10.4236/ajps.2014.513223
dc.language.iso en en_ZA
dc.publisher Scientific Research Publishing en_ZA
dc.rights © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). en_ZA
dc.subject Troll’s model en_ZA
dc.subject Modular growth en_ZA
dc.subject Heteroblasty en_ZA
dc.subject Sylleptic en_ZA
dc.subject Fascicles en_ZA
dc.subject Polyads en_ZA
dc.subject Protandrous en_ZA
dc.subject Synchronised flowering en_ZA
dc.subject Andromonoecy en_ZA
dc.title Phenology and reproductive biology of Acacia karroo Hayne (Leguminosae : Mimosoideae) en_ZA
dc.type Article en_ZA

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