Some plants change their rates of photosynthesis and cellular respiration to survive harsh, challenging weather conditions (Hartl, D. et al., 2016). We wanted to know if banana trees mimic these traits when their leaves are shredded due to natural phenomena like high winds. This experiment observed the rates of GPP divided by mass between shredded leaves and intact leaves from the same banana plant. We predicted the GPP/mass would be higher in the intact leaf samples, while lower in the shredded leaf samples.
The light sensitivity was also recorded as a constant. Samples of each variable were cut and placed in a bio chamber, and their CO2 levels were measured five minutes in the light and five minutes in the dark.
This method was done with six different banana plants: one shredded sample and one intact sample from each plant. The data collected from the procedure was used to calculate the GPP (gross primary productivity), which is NPP – R. NPP (net primary productivity), was calculated from the tests done in the light, and R (respiration) was calculated from the tests done in the dark. The resulting GPP was then divided by the mass of that sample. The GPP was relatively the same in both intact and shredded samples (p-value = 0.128). From this data, it can be concluded that the shredded state of the banana tree leaves has no effect on the GPP of the plant. It can be therefore assumed that the plant does not mimic traits of a plant who is trying to survive in harsh conditions.
The purpose of this experiment is to determine whether shredded banana tree leaves have a different overall GPP from regular, intact leaves. All plants use the metabolic processes of cellular respiration to survive and photosynthesis to store energy for itself excrete oxygen into the atmosphere (Hartl, D. et al., 2016). A plant will usually differ in rates when it is exposed to conditions that may challenge or abstain the plant from its normal rates of producing energy.
While the idea of banana leaves being shredded and staying on the plant may sound bizarre, it is not uncommon among the plants. Banana trees tend to be found in more tropical areas of the world, where high, tropical winds are common and frequent. In circumstances like these, the leaves on the plant act as safety mechanisms so the plant doesn’t blow over; this causes the leaves to shred (Carter). While there are no tropical winds that invade NKU, the campus has experienced many severe storms with high winds. Even though the banana plant is usually found in hotter climates, these plants can still possess their natural survival skills in northern areas such as Northern Kentucky.
It is also important to consider the levels of light that the individual leaves are exposed to, as it may play a factor into the metabolic rates of the plant itself. That way, we have a constant, and if something seems off about the plant compared to the other plants, we can reference the plant’s light sensitivity.
The rate of photosynthesis is recorded as NPP and cellular respiration is recorded as R; GPP is calculated by subtracting R from NPP (Peters and Scholtens). Since samples can vary in mass, the GPP is divided by the mass of the sample in order to get the theoretical GPP per gram.
We predict that the rates of photosynthesis, or GPP/mass, will have decreased rates in the shredded samples, while the GPP/mass in intact samples will be higher. This is our alternative hypothesis. Our null hypothesis would be that the rates are relatively the same.
Based on the results of the experiment, there is no significant difference between the GPP of shredded or intact leaves. While these results may have been surprising, research has been conducted that disproves our alternative hypothesis. When the leaves are torn by the wind, they are torn in such a way that the veins on the leaves are mostly untouched and undamaged (S. Taylor). This means that none of the organs of the plants were damaged in such a way that prevented the process of photosynthesis. In fact, it made it more efficient. This research article provided the discovery that the leaves themselves when shredded took in half the amount of water that a normal leaf would to perform photosynthesis (S. Taylor, 1970).
Also, this plant doesn’t shelter itself when exposed to cold temperatures. On the contrary, it dies. When weather conditions hit just below freezing, the leaves on the plant will start to die off, and when it gets even colder, the whole plant above the ground will most likely die (Baessler, 2016). That is why we had complications with our experiment, because once it got cold on campus, they had to move the trees out of the cold and into a greenhouse for them to stay alive through the winter. Because of this, we couldn’t record the light sensitivity of the last two plants since they were placed in a different location that they were not used to. However, this did not complicate our experiment and we were still able to retrieve the appropriate snatueample size.
Another interesting trend in the experiment was how a couple of the plants had much higher rates of cellular respiration under a certain lamp. For part of the experiment, two different lamps were used, but one had a warm bulb, and one had a more LED/cool bulb. Under the cool bulb, the samples showed signs of high cellular respiration, while in the samples under the warm bulb, the samples had observable rates of photosynthesis that were stronger than cellular respiration. Thankfully, the samples that had more powerful rates of cellular respiration in the light had even higher rates of cellular respiration in the dark, so the plant was still acting as it should in both the light and the dark, and we were able to calculate a normal GPP for these samples.
Overall, the results we received from this experiment were different from what we anticipated, but after the research done later, it makes sense why the banana leaves had similar rates of GPP/mass in both intact and shredded states. It just further proves that these organisms are basically designed in such a way that they can stand harsh conditions and still function properly.