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The Effects Of Garlic clove On Lettuce Seed Germination

This research project is focused on determining the result of garlic clove volatile on germination of lettuce seeds. Based on the background information referenced below as well as general knowledge of basic properties of plants we are going to hypothesize that the existence of garlic volatile comes with an inhibiting effect on germination of lettuce seeds, either completely destroying the young sprout or greatly impairing its growth potential. This hypothesis, once backed by experimental evidence, will bear a significant potential of predicting connection between certain sets of plant life. Such knowledge could be particularly useful in agricultural activity.

As a fairly recent biological strategy, allelopathy was coined by Austrian herb physiologist Hans Molisch in 1938. Nonetheless it was not until 1984 when E. L. Grain defined allelopathy as the result of one herb (including microorganisms) on another seed through the release of a chemical substance compound into the environment. It is said that allelopathy can cause both stimulatory and inhibitory effect on the target plant, with regards to the awareness of the compound (qtd. in Jefferson 275). The consequences of allelopathy on germination and development of plants may occur through a number of mechanisms including reduced mitotic activity in root base and hypocotyls, suppressed hormone activity, reduced rate of ion uptake, inhibited photosynthesis and respiration, inhibited protein formation, reduced permeability of cell membranes and/or inhibition of enzyme action (qtd. within an 53).

Several options rely on experimental data and research to state that allelopathic aftereffect of one flower on another is basically dependent on such condition as rain, essentially providing a medium for allelopathic agent to access its recipient faster and over a more substantial area. Affecting roots of plant life via washing down of allelopathic chemical has shown to inhibit goal plant's progress or even chances of survival. "Occurrence of autotoxicity and allelopathy. . . under field conditions may rely upon two major factors: (1) size and density of plant life; (2) dirt and climatic conditions that control accumulation or disposition of allelopathic substances" (Hegazy 11).

In spite of some unfinished research and skepticism in the technological circles about the idea of allelopathy, I will be conducting experiment targeted to illustrate this phenomenon generally and support my hypothesis of inhibitory allelopathic aftereffect of garlic volatile on germination of lettuce seeds specifically.


4 Petri meals with covers

4 circles of Whatman filtration paper

80 lettuce seeds

2 grams of garlic

Approximately 15ml distilled water

Masking tape

Aluminum foil


Triple beam balance


To do the test we used four Petri dishes lined with Whatman filter paper. In the middle of each dish we'd placed light weight aluminum foil base, circular in shape, around 30 mm in diameter and with surfaces raising from its outer perimeter up to roughly 10 mm. In both experimental groupings these bases were used as pots for garlic volatile. Twenty lettuce seeds were spread equally across filter newspaper inside each one of the meals, and two out of four meals were also recipients for garlic volatile in form of approximately 1 g of smashed garlic that was measured using triple beam balance and carefully placed in the aluminium basic. Our goal was to gauge the effect of garlic volatile (the 3rd party changing) on germination of lettuce seed products (centered variable). To make sure good statistical balance we doubled the experimental group that comprised garlic clove as well as the control group with lettuce seed products and tinfoil base only. Thus we replicated our experiment to a complete of 80 iterations, 1 / 2 which belonged to experimental group and another fifty percent to regulate group.

All of the Petri dishes were sealed utilizing a masking tape and located into identical conditions for a complete of fourteen days. By doing so we could actually minimize the effect of nuisance parameters such as temps, dampness and light strength on the results of the experiment, or to become more exact to impact both experimental and control groupings evenly by those factors in order to minimize any versions in conditions of the experiment compared to that of the unbiased variable. Inside our case all dishes were put on a single home window sill, at roughly equal distance from both a glass and the furnace grates. Each day of classes, measurements were extracted from all four dishes, to include range of germinated seeds, sprout minimum amount and maximum size within each dish as well as changes in color, stench and appearance. This experiment should be easily repeatable due to the fact that it requires little space, few commonly available materials to create it up and easily accessible abundant source of seeds and garlic clove.


Table 1 summarizes our experimental data. Refer to the legend below the table for code description and detailed notes:

Table 1

Note that no additional observations were designed for the first day of reading due to the lack of comparative information. Test group rules are the following:

E 1 = Experimental group (lettuce seeds with garlic volatile), established 1

E 2 = Experimental group (lettuce seeds with garlic volatile), arranged 2

C 1 = Control group (lettuce seed products without garlic volatile), place 1

C 2 = Control group (lettuce seeds without garlic volatile), set 2

The experiment lasted fourteen days and then for the clearness of visual representation, the graph portion is logically sectioned off into two parts for every respected week. Week one includes data from observations 1 through 4 that have been created from 07 Jan 2010 to 13 Jan 2010, and week two will be included in observations 5-7, that have been created from 14 Jan 2010 to 20 Jan 2010.

In addition to quantitative data gathered through the span of the experiment there have been certain observations of odor and appearance that are observed in Desk 1 under miscellaneous observations and are tackled in more detail here. For instance in the end four meals were sealed off to get started the experiment, the first reading suggested small leakage of garlic clove volatile out of the dish designated as E 1. Though at first germinating and growing, lettuce seed products in both E 1 and E 2 dishes quickly degraded at the onset of week two of experiment, and during previous readings were no more feasible for germination or sprout length reading. However they areas of filter newspaper underneath of that which was lettuce sprouts became stained yellowish with stain circles diffusing outwards as seed decay advanced.

The pursuing graphs will illustrate the progression of seed germination and sprout span throughout the test grouped by week one and week two. The resulting graph will incorporate this progress and visualize the whole experiment from begin to end.

Seed germination amounts through the course of week one

Sprout period through the course of week one

Seed germination numbers through the span of week two

Sprout duration through the course of week two

Consolidated germination graph for the complete experiment

Consolidated sprout size graph for the complete experiment


Given the two separate isolated storage containers in form of Petri dish, each comprising twenty seed products of lettuce for both experimental and the control communities, it can be stated with a good degree of assurance our group's test was reasonably guarded from effect of nuisance parameters and possesses a considerable enough amount of total experiments complete to alleviate the statistical error component.

Before beginning the test, my prediction was that garlic would have a inhibitory allelopathic influence on the progress of other plant life. After gathering information and data over the last two weeks, I have factual support of the hypothesis. The seeds inside Petri dish filled with garlic grew no more than one centimeter, in comparison to 3. 5 centimeters in the control group. On top of that, there was fewer seed germination in the dish with garlic set alongside the others. After three weeks, almost all of the sprouts with garlic clove had died, while the control group sustained to develop and sprout leaves. Because of this, my interpretation is that garlic will in fact come with an inhibiting allelopathic effect on the germination and growth of lettuce seeds.

Let us review other small factors that can have an effect on the results. As graphs suggest, both germination rate and sprout span were higher in dish coded E 1. This is the same dish that was found to truly have a garlic odor leak through the first measurement. It's possible that leakage of garlic volatile outside of the dish space and resulting motion of air inside the dish allowed for more essential potential for the reason that dish in its first as well as perhaps most important stage of germination when compared with a tightly sealed E 2. Inevitable rearrangement of seeds on the filtration system newspaper floor during measurements may experienced an impact on the quality of germination and sprouting, however, as all eighty seeds in all four dishes were similarly managed it is safe to consider such effect equal for all the iterations. It is worth noting our experimental Petri food were positioned in the direct vicinity of other experimenter's setups and were subjected to potential random affect from those and also other students present in the room when data was not being collected and the conditions cannot be directly governed. Hence, it is possible that additional garlic volatile, presence of another experimenter's special control communities with carrots or simple potential for another student shedding our dish to the ground inside our group's absence inspired the leads to some extent. To alleviate this, a locked area access to which is only granted to the customers of the research team could be utilized should this test be repeated by others to help expand examine and test the hypothesis.

It has been mentioned that smashed mass of garlic, situated in the tinfoil bases of meals E 1 and E 2, modified its color to dark brown by the end of the test. Additionally, when you compare the humidity condition between experimental and control groupings it was easily notable that there was substantially less drinking water in the experimental meals, both in form of condensation and water within the filtration system newspaper. Therefore another summary that requires further verification is the fact garlic clove volatile could be absorbing massive amounts of water from its surroundings during the process of its evaporation, thus leaving less for the lettuce seeds in the dish and increasing its inhibiting effect. Perhaps this is the cause of rapid loss of life and decay of the lettuce seed products in the experimental group as its onset coincided with garlic quickly changing color.

The above results and conclusions also go consistent with similar research conducted by a great many other scientists in neuro-scientific agriculture and biology. The hypothesis of inhibiting allelopathic effect of garlic clove on lettuce seeds is now recognized and proven by own experimental data and facts.

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