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Hormones are regarded as the necessary signal molecules for different organisms. Hormones and ferments in fruits are mainly used for ripening. Additionally, plant tissues use hormones for communication, and signalization of the required state: ripening, metabolism, germination, and so on. Ethylene is one of the key hormone groups that are used by plants for several functions. Since ethylene is a gas, it diffuses faster than liquids. The experiment, which is described in this paper, is aimed at defining the functions of ethylene associated with avocado ripening. Therefore, various concentrations of ethylene will be used. As is stated by Biale (139), ethylene presence is the main reason for auxin redistribution, hence, the growth and ripening of the fruit will be epinastic. The independent variable of the experiment is the number of avocados, while the dependent variable is the rate of softening and ripening.
The tissues of avocado will soften due to the effect that ethylene produces on the tissues and cells of the fruit. It is emphasized by Erickson and Tadaaki (93), that avocados do not ripen while attached to the branches, and ethylene increases the speed of ripening. This will be tested by placing avocados under the test bell jars and adding ethylene under some of the jars.
Methods and Materials
- Bell jars
- Probe knife
- Previously to the experiment beginning, half of the avocados that are taken for the test should be peeled. One test avocado will stay unpeeled, and the other will be peeled also (test avocados will not be subjected to ethylene reaction). Test measurements will involve scaling of the force needed to take equal amounts of a probe. Additionally, all avocados will be weighed and measured.
- Step 1:
- Define the test part of the fruits tested (external flesh, and internal flesh – from the side of a pit).
- Step 2:
- Measure force needed to take probe (ripening level of each fruit)
- Step 3:
- Place each fruit under a bell jar for making the conditions of the experiment equal (sunlight, temperature, pressure).
- Step 4:
- Leave jars for 2 days. This period will be enough for ethylene production, and for the ripening of the fruits.
- Step 5:
- Measure the force required for taking the probe
It is expected that avocados placed under the jars with a certain amount of ethylene will become softer in comparison with the fruits that were not subjected to ethylene reaction. Internal and external probes will require comparatively equal efforts, while peeled avocados will be softer in comparison with unpeeled fruits. This is explained by the fact that skin will be a natural barrier to ethylene.
The ruler will be used for defining the measures of each fruit, as if softening is caused by drying, the measures will decrease. Scales are required for defining the possible dehydration rate, as well as for weighting the test probes. The larger probe taken with the same effort will mean better ripening of fruit. Hence, the experimental fruit results will be compared with the results of the test avocados.
The results should support the hypothesis. If it is not confirmed, the test and experiment avocados will show the same results while taking the probe. (Claypool, 180) These results may be the reason for the improper experimental environment, hence, the test should be repeated.
Biale, James. The Climacteric Rise in Respiration Rate of Avocado Fruit. Journal of Agricultural Research. 1999 39:137-142.
Claypool, Leiton. A Colorimetric Method for CO Determination ¡n Respiration Studies. Journal of scientific Farming. 2004 40:177-186.
Erickson, Louis, Tadaaki Yamashita. Effect of Temperature on the Ripening of Mass Avocados. Journal of Agricultural Research 2001. 48:92-94.