(Group V: Duan Xiaoshan, Li Jin, Dong Shan, Deng Shan)

The semester is coming to an end, and so is our group's experiment. Because of the time, we didn't finish all the indoor experiments as planned, but focused on two experiments. Although all the experiments ended in failure, we learned a lot from them, gained a lot of experience, summed up the lessons and gained a lot.

1. Gravity of seeds: We have done this experiment for more than three times, because the seeds can't germinate at the same time due to various factors. In order to make the seeds grow under the same conditions, we have to wait for other seeds to germinate before observing and doing experiments, but in the end, some seeds that have germinated are soaked. Therefore, a lot of time and energy are wasted.

Second, the cultivation of tomato deficiency: our group put most of its energy into this experiment this semester. It seems that it took a whole semester from the preparation of nutrient solution to the development of seeds into seedlings, but it ended in failure.

Lessons learned:

1. Seeds can't germinate if they are half immersed in water. Although half of them are naked, some of them are undergoing anaerobic respiration, which will produce toxic substances and make the seeds rot.

4. Usually, when preparing culture solution, because the amount of some trace elements is very small, the general laboratory always divides the elements into several parts and mixes them together in proportion. For example, M.S. culture medium is divided into four parts: organic, inorganic, trace and Fe-EDTA. However, when doing nutrient deficiency, because each culture medium lacks different elements, it cannot be prepared like vegetarian culture medium. Therefore, we adopted the method of "preparing the representative solution of each element separately, and adding which one is needed", which was also affirmed by the teacher. Few trace elements were added in the preparation of various nutrient-deficient solutions, so we used a gun and learned how to use it. The gun can only be placed vertically, and can't sway back and forth, so as to prevent the residual liquid from flowing back into the gun, which will not only be confused with the new solution when it is used next time, but also cause some damage to the gun.

Through analysis, the reason for the failure of the nutrient deficiency experiment may be: when we prepare the culture medium, the organic matter grows out because of the long preparation time and high temperature (placed on the experimental platform instead of the refrigerator), but we usually put the cultivated plants on the window sill of the laboratory, and the direct sunlight breaks the organic matter with fungi, resulting in almost the same situation of plant death, without showing all kinds of nutrient deficiency phenomena.

Besides, we also planted Dou Yun. Although the dormitory is in the shade, our plants are growing well. After planting plants, I realized that water and sunshine are really indispensable intangible conditions for plants, because when we first planted them, we always forgot to water them, and our wheat would not rise for a day.

As for the outdoor, we have made some phased observations on campus plants, mainly focusing on two different kinds of Acer negundo, Magnolia grandiflora and Euonymus japonicus. It is observed that the flowering period of Magnolia grandiflora is particularly long this year. Magnolia grandiflora is a deciduous tree, which usually blooms in March-April, but it still blooms in May and June this year. During the observation period, we experienced a new life with Euonymus japonicus. There are two kinds of Acer truncatum in our school, one is the trees and green leaves outside the School of Biology, and the other is the shrubs and purple leaves in the loan department of the library. According to the survey data, this Acer truncatum is called Acer truncatum. We observed the growth stages of these two plants in a comparative way.

After this semester's independent experiment, although the experimental results are not very ideal, they have really benefited a lot. First of all, we didn't have our own experience in designing experiments and cultivating experimental materials, so we exercised our initiative in exploring science. Secondly, team spirit is very important. In fact, doing experiments, like playing games, requires mutual cooperation and tacit understanding. It is absolutely not enough to rely on one person. Thirdly, although the experimental results can explain the problem, it is important to master the experimental methods and be serious and rigorous in academic research; Finally, the enhancement of practical ability.

The above are some lessons from this semester's experiment, which we will keep in mind and strive to achieve some results in future experiments.