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October 20th, 2017
Sunny with clouds, 8 degrees Celsius (greenhouse temperature is between 24-29 °C)
The organisms I intend to study are Tagetes patula (marigolds) are used to represent a non-weed plant species, and Taraxacum officinale (dandelions) are used to represent a weed species. I am testing the effect that restricting light exposure has on the competition between weed and non-weed species.
I do not have a gradient from which to observe and record changes in my study as I am performing my experiment in a laboratory setting and growing plants in pots. I am testing two conditions: exposure to light (the sun) versus limited exposure to light. Light exposure is my explanatory variable.
I hypothesized that restricting light, with all other variables as equal as possible, will negatively impact the growth of marigolds greater than dandelions. I believe this will occur due to the face that the weedy characteristics of dandelions such as fast growth rates and early maturity will allow the species to outperform the marigolds in adverse conditions.
I predict that restricting the amount of available light (my explanatory variable) will negatively affect both the marigolds and dandelions, however the marigolds more drastically. The weedy characteristics of dandelions will result in beneficial features such as longer roots, more leaves and greater total biomass than the marigolds. A potential response variable in this experiment could be the root length of dandelions. I believe it will be greater in dandelions than in marigolds due to the quick root development of weeds . The number of leaves on marigolds and the total biomass will be greater than that of dandelions, because of the rapid growth rate of weeds.
In this study, the growth of the plant species (root length, number of leaves etc) will be the response variable and exposure to light will be the explanatory variable. This data is therefore considered continuous as there can be a spectrum of growth observed.
*I apologize I do not have access to my field book and therefore cannot post pictures*
This is a very cool idea, I do like how you are growing both plants in pots in order to minimize variability. However, Do you plan on assessing the difference between the two conditions for a single species as well? This would allow you to see if there are a significant difference between the two conditions.