Poinsettia

=Poinsettia (//**Euphorbia pulcherrima**//**)**= Group members: Alise, David, Morgan and Michelle

====**Poinsettias, well known for their appearance in Christmas celebrations, are shrubby non-succulent plants originating from Mexico which produce brightly coloured bracts. These colourful bracts are commonly mistaken as the flower of the plant (Kimberley, 2009).**====


 * Plant species:** //Euphorbia pulcherrima//
 * Plant family:** //Euphorbia//
 * Common name:** Poinsettia
 * Distribution:** Mexico
 * Habit:** Uniform growth. In its native habitat, it can reach 3m tall.



**//Above://** Flowers surrounded by red bracts (modified leaves). The bracts range from 22 to 56mm long (measured with vernier callipers).
//**Above:**// Stigma, bracts and male structures of //Poinsettia.//

//**Above:**// Male structure of //Poinsettia// containing pollen, at 40x magnification.


 * //Above://** Overall scale of //Poinsettia//.


 * //Above://** Approximate size of stigma.

**Table 1: The variability of floral morphology. Floral structures were measured using vernier callipers.**

 * = Measurements ||= Leaves (mm) ||= Nodes (mm) ||= Bracts (mm) ||= Nectaries (mm) ||
 * = 1 ||= 121.8 ||= 4.9 ||= 22.0 ||= 3.1 ||
 * = 2 ||= 119.4 ||= 5.0 ||= 56.1 ||= 4.0 ||
 * = 3 ||= 123.1 ||= 4.8 ||= 36.4 ||= 2.9 ||
 * = 4 ||= 101.0 ||= 5.0 ||= 33.7 ||= 3.4 ||
 * = 5 ||= 113.2 ||= 4.6 ||= 48.2 ||= 3.6 ||
 * = Average ||= 115.7 ||= 4.9 ||= 39.28 ||= 3.4 ||
 * = SD ||= 9.1 ||= 0.2 ||= 11.8 ||= 0.4 ||

//**Above:**// Process of pollination and fertilisation in //Poinsettias//. ====The small volume of nectar present in the plant, as well as the scarcity and microscopic size of pollen, suggests that the plant would attract visitors such as insects, rather than large animals like birds, to aid in the pollination of the plant. Through mutualistic interactions, the poinsettia is able to pollinate and successfully reproduce by attracting insects with its large, bright red bracts. These bracts, distributed around the sexual flowering organs of the plant, benefits the plant by attracting visitors to the nectaries, which are located around the male stamens- where pollen grows on the anthers- and also around the female stigmas. Through the promise of food rewards, insects play their part by transporting pollen between the poinsettia's flowers and therefore participate as key players in the sexual reproduction of the plant.====

====__**Pollen:**__ Poinsettias produce small, round granules of pollen, abundantly present on the anthers of the male stamens. The number of pollen grains could be measured by counting the number of pollen in one section of a slide and then making an estimate of how much pollen there is on the whole surface of the slide. Pollen samples were removed from the anthers by brushing them with a 2 x mm square of fuschin gel. The fuschin gel covered in pollen was then placed on a slide and gently melted on a heat plate. The melted gel was then covered with a cover slip and the stained pollen was viewed under a microscope at 40X magnification.====

//**Above:**// Pollen at 40x magnification. //Poinsettias// produce microscopic round granules of pollen.

__**Nectar:**__
====Nectar was extracted from the plant using appropriate sized glass capillary tubes. Due to the small size of the nectaries from the poinsettia plant and the small volume of nectar available, we used the smallest glass capilary tube (10 µL) for nectar extraction. Refractometers were then used to measure the sugar content in the extracted nectar. Approximatetly 1 µL was extracted from individual nectaries, which made it difficult to ascertain the sugar concentration of the nectar.====

__**References:**__
Kimberley, M. (2009). Poinsettia. //Horticulture Week,//, 18-19. Retrieved from []

//Updated by Michelle 24/10/12 4:53PM//