No+names

BIOL1001 LIVING SYSTEMS LAB 9: SEX, REWARDS AND POLLINATION = = // Geranium sp. //

Plant species: __//Geranium// //sp.//__ Plant family: Geraniaceae Common name: Geranium, Cranesbills Distribution: Tropical regions, different species are native to different tropical parts of the world. Habit: Mounding habit with lobed foliage, size differs throughout species type Flowers: Dependent on species (varying from purples to white to pinks), species examined in practical a strong red colour, also often with distinctive veining Fruit: None Seed: None

Confusingly, Geraniums are also the names of some members of the //Pelargonium// family.

//Geranium sp.// are fertilised by the larvae of some Lepidoptera species including brown-tail and mouse moth.
 * Pollination and Fertilisation**

In Figure 1 the lifecycle of the //Geranium sp.// can be observed, beginning as a bud and progressing to a flower of approximately 4cm in diameter followed by an aged flower that is seen to be wilting. As the flower develops, pollen is formed as a bean shape (shown in Figure 2 and Figure 3) in the anther (shown in Figure 4). The stamen, containing the filament and anther can be found in the centre of the flower clustered in a circle. Starting from the centre and moving outwards in the flower, a progression in which the filament is seen to either fuse with a petal or grow and become a petal, whilst also maintaining the anther (as seen in Figure 4). The clustering of stamen in the centre of the flower allows for an increased pollen production, the spacing and size of these pollen containing sections suggests that smaller insects such as bees or butterflies would be integral in pollination of neighbouring flowers rather than much larger animals such as birds. The female reproductive part of this flower is the pistil containing the stigma, style and ovary which is located in the centre of the flower (Figure 5 and Figure 6), and is a single stalk with 5 curled elements on the top. These curled sections shown in Figure 7 are seen to be glossy and covered in small fine hairs, this mechanism aids in the flowers ability to pick up as much pollen as possible for fertilisation. The pistil is surrounded by stamen in which the anthers are generally at the same height or lower than the stigma (Figure 8). This suggests that whilst self-pollination may be possible, variation is increased by allowing pollen to be carried to neighbouring flowers for fertilisation. Chemical recognition systems within the flower may also be employed to avoid self-pollination or fertilisation.
 * Floral Morphology and** **Visitations**

The //Geranium// is of the dicot cotyledon type, meaning all parts (petals, leaves, etc.) are multiples of 4 or 5.


 * Variability of Floral Morphology**
 * || Whole Flower (Length) || Petals (Height) || Petals (Width) || Stem (Length) || Stamen (Length) ||
 * Flower 1 || 48 mm || 20 mm || 20 mm || 32 mm || 8 mm ||
 * Flower 2 || 43 mm || 19 mm || 10 mm || 30 mm || 9 mm ||
 * Flower 3 || 45 mm || 19 mm || 20 mm || 31 mm || 8 mm ||
 * Flower 4 || 51 mm || 19 mm || 15 mm || 35 mm || 8 mm ||
 * Mean || 46.75 mm || 19.25 mm || 16.25 mm || 32 mm || 8.25 mm ||
 * Standard Deviation || 3.5 || 0.5 || 4.79 || 2.16 || 0.5 ||

//Geranium sp.//, sheds its anthers, sometimes its stamens as well, as a barrier to self-pollination. This young flower is about to open its anthers, but has not yet fully developed its pistil. Once //Geranium sp. // have opened their anthers, but not yet their stigmas there is a change of colour that signals to pollinators that it is ready for visits. The //Geranium sp. // then sheds its stamen, and deploys the tips of its pistil without accepting pollen from its own anthers. It may still receive pollen from younger flowers on the same plant. There was only a small amount of pollen to be gathered from this sample and this may be a result of this particular sample group being too underdeveloped or as a result of pollen falling off in the transportation stages. Due to human limitations, the estimate number of pollen grains within the pollen of //Geranium sp.// was not calculated.
 * Pollen Morphology**

There was no nectar found on our samples of //Geranium sp.//This may be a result of the plant drying out over the course of the observations or due to the fact that //Geranium sp.// is a highly cultivated and common garden plant.
 * Nectar Characterisation**

There are a number of other potential sources of error throughout these observations and measurements, including human error, misuse or inaccuracy of equipment, and the drying or damage of plants throughout this practical.

Figure 1. Life cyle of Geranium sp. with a scale bar shown in centimetres on x- and y-axis.

Figure 2. Pollen of //Geranium sp.// viewed at 40X objective.

Figure 3. Pollen of //Geranium sp.// viewed at 40X objective.

Figure 4. Transition of filament as it fuses to petal, whilst also maintaining the anther. Figure 5. Female reproductive organs, stigma, style and ovary of a //Geranium sp//. as viewed under a microscope.

Figure 6. Female reproductive organs, stigma, style and ovary of a //Geranium sp//.

Figure 7. Part of the female reproductive organs of a //Geranium sp//. viewed under a microscope.

Figure 8. Pistil, stamen and anthers of //Geranium sp.//