Stomata are sections in plants leaves that regulate the amount of water vapor and gases entering in and out of green plant leaves. Stomata are very essential in the control of water loss through the plant leaves in a process of transpiration. In light plants, transpiration is highest in the presence of sunlight because the guard cells fully open the stomata. Dark plants use the inverted stomatal rhythm and the openings of the stomata are wider in the dark. The opening of the stomata in leaves increases with time: at the beginning, fewer are open but after sometime majority become open. The stomata opening vary under different circumstances. Dark plants do not depend on light for the opening of the stomata while the leaves of light plants depend on light for the regulation of opening and closing of the stomata.
Materials and methods
The experiment applied the use of foils to cover the freshly obtained leaves in both light and dark conditions. After covering the specific leaves to be studied, a stop watch was immediately set and records taken. The record taking entailed observations of the leaves under a microscope before counting and entering of the results in the tables. In each case, when a given time reached the foil was removed from the leaf and taken to be viewed under a microscope to note and mark the counted stomata. The procedure was repeated until the set span of time of determination of the stomatal number was reached.
I. Light and dark plants
dark plants are the kinds of plants that are able to respire, giving out carbon dioxide without the sunlight energy. The activities of dark plants are optimum in the dark and naturally occur at night. The dark plants are also referred to as light-independent as they are capable of carrying out their metabolic activities and even photosynthesis without light. While light plants are the types of plants that are capable of giving off oxygen during the day in presence of sunlight.
i). Table 1
At T0, the Groups: 1, 2 and 3 observes the number of open stomata to be, 4, 3 and 79 respectively.
The time of the whole experiment ranges from T0 to T90.
At T45 the readings from the microscope by the three groups indicate; 34, 31, and 98 for the groups 1, 2, and 3 respectively.
The number of open stomata at T90 are 54, 53 and 100 for the groups 1, 2, and 3
b. Confidence in means
The results portray similar characteristics under the same conditions of the leaf from a plant in the dark. The resemblance in result is variable in intensity that is only shown with the number of open stomata. At the beginning of the experiment, there are fewer open stomata that increases with time. The attribution of this is that all the three leaves are equally affected by the environmental conditions.
c. Differences in means
The differences are that in the beginning, the group 1 observed four open stomata, the second group detected tree while the third group realized seventy nine. The leaf that was used by the group 3 had a greater surface area of the stomata exposed outside and thus were observed. This shows that the group three leaves were obtained from a light depended plant.
II. Covered vs. uncovered leaves
When the experiment was carried out with the leaves covered, at T0 there was no observable change realized by group 1. The numbers of open stomata began increasing and finally became conatant at T75 and T90 registering a total of 11 stomata open. The results in group 2 showed an increase in the number of stomata with time. However, group 3 there was a reduction in the number of open stomata from 10 to three at T75 before it rose to 12 at T90.
The group one observed the increasing in the number of stomata from 4 at T0 then to 7, 15 at T15 and T30 the number of open stomata maximized to 30 at T75 before the number started reducing at T90. The leaf in group 2 revealed increases in the number of open stomata, the open stomata numbers finally stagnated at thirty five at T75 and T90. However, the leaf used by the group 3 in the experiment shown decreasing numbers of the opening stomata from 14 in the beginning of the experiment to 4 at the end.
i). Table 2
b. Confidence in means
the variations means that the plants leaves that were used in groups 1and 2 were light dependent while the one used in group 3 is light independent
c. Differences in means
The difference between the results obtained in the cases shows that the leaves used in the experiments have different mechanisms that trigger their opening and closure.
I. Light vs. dark plants
The light plants depend on the light rays for the opening and closure of their stomata. The light rays are utilized byte leaves to form simpler carbohydrates in photosynthesis process. The sugars accumulate in the guard cells making them more concentrated hence creating an osmotic gradient. They draw water from the neighboring cells, become turgid and opens. The dark plants use the inversed rhythm of stomatal opening and closure. In presence of light they close and in the table two, this is shown but they begin opening due to desire for gaseous exchange. The leaves used in group one reaches a stagnant point of 11 as this is what can be supported by the intense of the light. There are other issues such as errors that might have arose due to omissions that have lead to less than 100% inaccuracy.
Nevertheless, it is true that dark plants do not depend on light for the opening of stomata while the light plants depend on light as demonstrated by the experiment.