STPM Biology - Experiment 14: Investigating the structure of flowers

1. Flame of Forest/Delonix regia

Actinomorphic = regular
Definition: Flowers that are radially symmetrical so that they are able to be bisected into similar halves in more than one vertical plane, forming mirror images.  


Mode of fertilization: Delonix regia is pollinated by bees and birds depending on geographical location. It has some interesting adaptations to attract pollinators. The most obvious is that it produces generous amounts of nectar and pollen, which is actually relatively uncommon as making these uses a lot of energy, so this guarantees that it will be visited by pollinators. But attracting the pollinators is only the start! Delonix's red flowers are an attractive colour to birds, and they have thickened organs at the base of the flower (where seeds are produced) to protect them from damage by birds. The long nectar tunnel also ensures that birds have to put their head well into the flower and so get a good coating of pollen, to get to the nectar. Delonix also has special adaptations for bees and slightly changes flower colour as they age - bees can detect this and save time by only visiting young flowers which contain more nectar - this also benefits the plant because young flowers are more fertile than older flowers so it ensures that flowers are pollinated while young. The plant keeps older flowers as the more flowers there are the more attractive it is to bird pollinators. A pretty clever plant I think!  [special thanks to Cathy]


For more info.:http://www.arkive.org/flame-tree/delonix-regia/#text=Biology
                       http://cals.arizona.edu/desertlegumeprogram/pdf/aridus16-1.pdf




2. Orchid flowers/Dendrobium

Zygomorphic =irregular
Definition: Flowers that are bilaterally symmetrical so that they are able to be bisected into similar halves in only one plane, forming mirror images. 



Mode of fertilization: The pollination biology of all orchids is a v interesting and specialist subject and I'm not an expert! Dendrobium is a large group of orchids and I do know that one of the strategies that they employ to ensure fertilisation is to have long flower life (several weeks), but the flowers wilt almost right after pollination - it's expensive to keep flowers alive so they do so for as long as is needed but no more, in contrast to other plants that usually have a set floral life span.  [special thanks to Cathy]



For more info.: http://www.arkive.org/orchid/dendrobium-prasinum/#text=Description