Effect of Temperature on Seed Germination; Report

Introduction
The key question that the research attempted to answer is the effect of temperature on seed germination. According to Dahal et al. (1996), many biological processes, including seed germination, are affected by temperature since respiration is dependent on temperature, which influences the seeds’ metabolic rates. Based on Dahal et al. (1996), there is a correlation between seed germination and respiration rates in response to the variation of temperature. After further research, the respiration rates do not seem to limit the time for radical protrusion (Qu et al., 2008). Similarly, it was observed that conserving seed reserves under conditions that can delay or complete seed germination, such as low or high temperature is important to control germination. Additionally, the recommended temperature for germination is 10-20 degrees Celsius, and beyond these temperature levels, seeds survivability is affected ( Pérez-García &González-Benito, 2006). Based on seed, germination is affected by temperature in three main ways, production of hormones, moisture and enzyme activity. Seeds need to be imbibed in water for them to germinate, and therefore sufficient moisture is recommended. In the case of a warm climate, the moisture necessary for germination evaporates and decreases germination, which affects germination negatively ( Ellis & Barrett, 1994). In a cool climate, moisture is present in the environment, which influences seed germination to occur. In hormone production, there are two hormones responsible for seed germination; gibberellins and abscisic acid. Gibberellins influences germination and the genes responsible for the production of these hormones are dependent on the level of the external environment temperature. In the case of high temperature, the genes are not produced, so the production of gibberellins is inhibited. When there is a cool climate, the production of these genes is activated and the production of the germination hormone gibberellins. The abscisic acid, on the other hand, influences dormancy and therefore limits germination. In warm climates, the acid is produced, whereas, in a cool climate, acid production is limited. Also, enzymes are needed to degrade the endospermic tissue of a seed and rapture its seed coat, causing scarification. In cases of high temperatures, the enzymes become inactive and therefore, germination does not take place. The research on the effect of temperature on seed germination was deemed important since farmers need to understand the vast effects temperature has on their seed germination and how to combat the temperature effects, for example, by use of greenhouses. The hypothesis that was being tested by this research is that the germination rate of seeds varies with temperature. The hypothesis has been tested to be true since the different levels of temperature, as discussed, determine whether a seed germinates or not.

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