Hibiscus spp



Group Members:
Lachlan Desailly
Amelia Hei
Mihaela Jovanovski
James McGloin
Ketherine Li
Carmen Lau


General Information:
Plant species: Hibiscus spp.
Plant family:Malvaceae
Common name: Hibiscus
Distribution: common, garden plant
Source: garden
Flowers: Large and common on aHibiscus plant
Fruit: dries into pods which break open and disperse seeds
Seeds: each fruit contains several seeds


Appearance

DSCF6642.JPG
Figure 1: A hibiscus flower showing petals, anthers, stigma and style, with ovum concealed behind the base of the petals

Floral Morphology and visitation:

The Hibiscus petals are very large therefore give a large surface area which makes it easy for birds to locate and hover around. The pollen is dispersed by a large number of anthers which increases the possibility for birds to make contact with the pollen, thus increasing the chances of pollination. There are five stigmas, thus increasing the chance of pollination.

Table 1: The length of specific parts of various Hibiscus spp. measured via calipers.
Flower
Length(mm)
Width(mm)
Height(mm)
Stigma-anther distance(mm)
Tube length (mm)
1
111.5
114.5
105.0
9
73
2
122.0
120.0
113.0
8
79
3
114.0
90.0
101.0
5
81
4
84.0
91.0
87.0
8
73
5
130.0
122.0
106.0
11
90
6
113.5
131.5
113.0
13
91
Average
112.5
111.5
104.17
9
81.17
SD
15.57
17.17
9.64
2.75
7.9
Variability:
The variability is not extreme but there is a slight range in measurements. Specific lengths of floral parts were measured using calipers.
DSCF6664.JPG
Figure 2: A developing set of anthers and stigmas in a young bud of a hibiscus flower

Reproduction

awesome pollen 2.jpg
Figure 3: A pollen grain from Hibiscus spp, viewed under compound light microscope (40x magnification)

Pollen morphology:

The pollen is of a yellow hue and spherical shape with regularly spaced short protusions on it's surface. You could make an estimate of the number of pollen grains by taking sample and make and estimate of the size of the pollen and the amount visible counted under a light compound miscrope. The size of a pollen grain is approximately 200┬Ám.

Pollination and fertilisation:

In order for the flowers of Hibiscus to develop into mature seeds the pollen needs to be transported to the stigma. This is done via rather specific types of birds that have the specific behavioural characteristics that allow for cross pollination rather than self-pollination.

Nectar characterisation:

Nectar was located below the carpel above the sepals however due to wilting and abundant prescence of insect pollinators such as ants, limited amounts were found to which prevented the use of refractometers.