Effects Of Testa On Bean Seed Germination

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The Effect of Treatment of the Testa on Bean Seed Germination By Dominique Tarr Hypothesis: A bean seed with testa treated in a lower pH will germinate faster than a bean seed with testa treated by a higher pH. Literature Review: The germination of a bean seed is affected by multiple factors. The seed will first experience a dormancy period. The function of this period is to protect the seed until environmental conditions are favourable for germination. The end of this dormancy period is determined by genetics through the production of the hormones abscisic acid and gibberellins - which play a role in the seed’s sensitivity to its environment (Laubner-Metzger and Finch-Savage, 2006). The dormancy period reaches its end when the testa is ruptured – the first step in seed germination. The testa is diploid maternal tissue (the Seed Biology Place, 2012) made from schlerenchyma cells (Wada et al., 2011) that acts as a protective outer covering that prevents harm to the embryo during unfavourable conditions. It does this by being impermeable to water and by restricting oxygen needed for germination (Wada et al., 2011). When conditions are favourable imbibition takes place - water enters the bean seed through a small hole in the testa known as the micropyle. The water causes the embryo to expand until the testa ruptures allowing the embryonic root of the plant (the radicle) to emerge (Gerhardt ). Study conducted on Arabidopsis seeds with mutations of the testa showed a difference in seed dormancy and germination. Therefore the chemical compositions and structural defects of the testa had an effect on the permeability and thickness of the testa which affected germination ( Debeaujon et al., 2000; Wada et al., 2011). In industry specif... ... middle of paper ... ... the results. In a repeat of the experiment I would place the seeds in a place where they would receive more light. It is also possible that the rotting of the seeds was due to the lack of sunlight therefore a sunnier position in a repeat test would be necessary. In order to get a better idea of how treatment of the testa affects seed germination I should have tested more treatments such as mechanical treatment and other acidic and basic pHs. I may also have affected the results by not watering the seeds at the same time every day which was a control I should have complied to. The reliability of this experiment could also be improved by testing with different types of seeds. Overall this experiment has been a learning experience that I have valued. I have learnt more about germination and seeds as well as creating a reliable experiment and identifying my mistakes.

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