The Germination of Seeds of the Native Plant Acacia
The Germination of Seeds of the Native Plant Acacia decurrens Practical Report Biology 1 Introduction: In a botanical sense, “germination is the process of emergence of growth from a resting stage. ” (http://encyclopedia. laborlawtalk.
com/germination). Under favourable conditions, the seed begins to germinate, and the embryonic tissues resume growth, developing towards a seedling. Soils from a Cumberland Plain Woodland community were investigated to determine the presence of a soil seed-bank; and whether species richness and abundance of plants germinating from it were affected by heating such as that experienced in a fire.
It was found that certain seeds reacted differently, and he the phsyical action of heating, whether at low or high temperatures affected the rate at which the seeds germinated. (Hill & French 2003).
Acacia seeds will not usually germinate without the use of a pre-treatment. As they have a hard outside coating which is generally impermeable to water. For Many Acacia seeds the breaking of the dormancy occurs with heat and although smoke and ash stimulate seed germination for many species with hard coats, heat is the main factor influencing the germination of Acacia decurrens.
In the natural environment, the hard coating of the Acacia seeds may be broken down due to a bush fire allowing the plant to begin rejuvenation (Hill & French 2003). The intention for this experiment was to determine whether the effects of heat increased or decreased the rate at which Acacia decurrens germinated.
The hypothesis to be tested is; “If the Acacia decurren seeds are exposed to heat, then the rate at which they germinate will be increased. ” Hypothesis: If the Acacia decurren seeds are exposed to heat, then the rate at which they germinate will be increased.
Experimental Design and Method: The main utensils used in this experiment were the assortment of 60 Acacia decurrens seeds, cotton wool and 2 petri dishes, which were all supplied by the university. The seeds appeared to be a random sample, differing in shape, size and form. The decision to randomly select and divide the seeds into four groups of 15 was made.
These 4 seed groups were placed into the four separate petri dishes and were titled Heated 1 & 2, and Control 1& 2.
In order to determine the effects of heat, the experiment needed a control group of non heat treated seeds, and also for the experiment to be duplicated to observe whether it was through the purposeful actions which the seeds were subjected to that may cause germination or whether external or uncontrollable factors also caused the seeds to germinated. Therefore of the four seed groups, both Heated 1 & 2 would be subjected to heat treatment process and the Control groups would be used as a standard by which to compare experimental observations.
The Heated 1 & 2 groups of seeds were placed into beakers, and had potable boiling water poured over them. They were then left submersed in this water [which eventually cooled to room temperature] for a period of 24hrs.
The remaining 2 Control groups of seeds, were soaked the in same way but soaked in cold water and again left for 24hrs. All four beakers were filled so that the seeds were fully immersed and covered over by the water.
After 24 hours, each group of seeds were placed into 4 separate Petri dishes. Each Petri dish was covered in a layer of cotton wool, which was moistened with potable water. This moistening of the cotton wool pieces was repeated numerous times daily or whenever wool piece was seen to become dry.
The Petri dishes were labelled: Heated 1, Heated 2, Control 1 and Control 2. The seeds were checked once daily for 10 days to take specific note of germination progress, or of any change in physical appearance.