Frankincense is tapped from the very scraggly but hardy Boswellia tree by slashing the bark, which is called striping, and allowing the exuded resins to bleed out and harden. These hardened resins are called tears. There are numerous species and varieties of frankincense trees, each producing a slightly different type of resin. Differences in soil and climate create even more diversity of the resin, even within the same species.The trees start producing resin when they are about 8 to 10 years old. Tapping is done 2 to 3 times a year with the final taps producing the best tearsHeavily tapped trees have been found to produce seeds that germinate at only 16% while seeds of trees that had not been tapped germinate at more than 80%.
anthocyanins have been shown to act as a "sunscreen", protecting cells from high-light damage by absorbing blue-green and UV light, thereby protecting the tissues from photoinhibition, or high-light stress.
Floral Color Changes inBoswellia sacra FlueckFlora-Morphology, Distribution, Functional Ecology of Plants Volume 206, Issue 9, September 2011 Botany 2110 Samantha Kane
Facts about Boswellia sacra Also known as Frankincense; found in the Bible Part of the Burseraceae family Used for perfume and medicine Popular in trade
Facts about Boswellia sacra Found in South Arabia and North East Asia Found in extreme locations Population is decreasing because of overgrazing and human destruction National Park in WadiDowkha
Boswellia sacra Flowering stage begins in the winter until April Fruiting bodies are ripe by March Characteristics: green calyx radial symmetry five white petals ten stamens that have yellow anthers one pistil nectariferous ring is present in the ovary and can change colors from yellow to red to black
Purpose & Hypothesis Purpose: to figure out why the nectariferous ring changed colors Hypothesis: the color change helped lure pollinators towards the flower with the reward of nectar
The Study Took place along the coasts of Dhofar and in the WadiDowkha National Park Flowers were collected in February and March from 2006-2010 Nectar and pollination were observed in the morning (7:30-8am) and sunset (6-6:30) for a week Microscopical observations were observed in labs in Florence
Under the Microscopes Different stains were used to see detail under the light microscopes including: ToluidineBlue for testing lignin Mercuric Bromophenol Blue for proteins Acriflavinestain for total polysaccharides Alcian Blue for acidic polysaccharides Fluorol Yellow-088 for lipids
Methods The pistils and nectariferous discs were covered in glutaraldehyde (a disinfectant and preservative) stained with PAS (Periodic Acid Schiff) to see undissolvablepolysaccharides stained with Blue Nile Sulfate to see the neutral and acidic lipids The nectariferous rings were cut off and covered in an alkaline and an acidic solution to test for anthocyanins. (may appear in different colors depending on pH)
Results of Flower Organs (Nectariferous Ring) Located between the stamens and the ovary (3mm in diameter) Changes color from yellow to red depending on the maturity of the flower Before anthesis, (flower opens its petals) the nectariferous ring is fully developed Trichomes are covered in a cuticle layer where nectar drops can be found The drops show a positive response to the PAS reagent, Alcian Blue, and Mercuric Mromopenol Blue. (shows polysaccharides exist!) Stomata always open with guard cells appearing outward
Results of Flower Organs (Pistil) The stigma (top of pistil) has a positive response towards the Alcain Blue, and Blue Nile Sulfate stains (test acidic polysaccharides and neutral lipids) After fertilization, the ovary swells transforms into a fruit with a seed in each open compartment
Results of Flower Organs (Anthers) Anthers on the flower are all the same size with longitudinal dehiscence (spontaneously opening) yellow in color with trichomes sparsely located anthers swell due to the large amount of pollen dehiscence takes place
Color Changes The nectariferous ring is already a yellow color when the petals begin to open; many liquid drops found Changes to orange and few drops are present. Nectar begins to be reabsorbed. Largest amount of pollen germination occurs. Anthers empty and the stigma changes its green color to a brown Changes to red and is completely dry and lacking nectar. Anthers begin to fall and stigma dry up and darken Only fifteen hours are needed for the color changes
Color Changes Lastly, the nectariferous ring will turn brown with black patches. The surface is wilted and rough. The ovary is growing into the fruit Takes two days to change from yellow to brown Red stage changes to a green-blue color once dipped into an alkaline medium and will change back to red once rinsed in acid showing that there are many anthocyanins present.
Field Observations (Pollinators) Many pollinators Main pollinators in the day- bees, wasps, and ants Other visitors-butterflies and little flies pollinators preferred flowers with the yellow nectariferous ring , the red were not visited at all
Conclusions Color changes help lead the pollinators towards the rewarding flowers Mutualistic relationship (plants get pollinated and pollinator gets pollen and nectar as nutrients) Insects are attracted to the yellow and orange phase; no nectar reward in the red phase The color change occurs because of high amounts of anthocyanins that flowers with nectar rewards and an attractive color for pollinators have a greater chance of reproducing and outcompeting other plants