Practical Essays

Practical Essays Practical Essay Practical Essay Practical Name: Institution: Course: Date: Practical Introduction The aim of embryo culture is to obtain a plant after isolating and growing an embryo in vitro. It involves the cultivation of embryos from seeds and ovules in aseptic conditions. The culture medium depends on the type of plants, and the age of the embryo. A person can use mature or immature embryos. People practice embryo culture for different reasons. Some do it because they want to know more about the plant. Growing the embryos outside the ovules gives a person the chance to learn the nutrient composition of the plant at every stage of development, identify the requirements of the plant and identify the different stages of growth. Embryo culture provides a way of getting hybrid seedlings and overcoming seed dormancy. This enables the production of crops with superior qualities. The practice of embryo culture is important because it used to recover distant hybrids and haploid plants. This practice is important because it shortens the breeding cycle of the plants (Bhojwani Razdan, 1 996). Materials and Methods We used snow peas pods and five plates of pea culture medium. We adjusted the culture medium to a pH of 5.7. Embryos grow well in a medium with a pH of 5 to 7 (Razdan, 2003). It contained 110g/L of vitamins, 11% sucrose, 50ml/L of coconut water containing agar, and casein hydrolysale. One needs to select the right culture medium that will support orderly and progressive development of the embryo. One should ensure that the medium is able to nourish the embryo. Sucrose is a source of energy and it supplements the vitamins. Using high quantity of vitamins can inhibit the growth. Therefore, one should use vitamins minimally. Other materials included scalpels, plates, grid paper, and aluminum foil. We rinsed the pods with water, and then sterilized them in 70% ethanol for two minutes. We then washed the pods again with distilled water and treated them with 2% hypochlorite solution. After the treatment, we washed the seeds again using distilled water. We opened the cotyledons, and removed the embryo hearts from the snow peas pods while exercising caution not to damage the embryos. We used a scalpel tip to cut the embryos horizontally into two parts. We measured the embryos using a grid paper. It is important and mandatory to measure the embryos before putting them in culture, so that one can determine the level of growth after the appointed time. We then photographed the embryos using the digital camera. We then put the two embryos in different culture media. We sealed the plates with the aluminum foil and incubated them at 22o for three weeks. After this time, we re-measured the embryos to check their growth. Results Embryo culture results- Initial Size (mm2)Final size (mm2)Difference (mm2) 2 25 23 2 25 23 3 35 32 1 10 9 4 20 16 9 30 21 9 25 16 10 30 20 8 36 28 12 150 138 4 60 56 Discussion There was only one healthy cotyledon. The other cotyledons were contaminated in different ways or damaged by heat. The contamination of the embryos may have happened during the cutting process. Although we sterilized and treated the embryos, we did not take the same effort in ensuring that the materials we were using were not contaminated. This affects the results of the culture. We did not get the results we had anticipated. The embryos did not grow as well as we had expected them to do. Some of the embryos were damaged by heat. We had sealed them with aluminum foil and put them under 22o. It seems that we exaggerated the level of heat required, or we used the wrong materials to seal the embryos. Contamination affects the growth of the embryos because it introduces bacteria. The bacteria breed on the embryos, and destroy the cells of the embryos. This hinders growth. We were not careful when extracting the embryos from the pods, and we saw this after seeing some of the damaged cotyl edons. This destroyed the embryonic tissues and prohibited the embryos development. We had used embryos of different sizes, ranging from 1 mm2 to 12 mm2. At the end of the experiment, the sizes of the final cotyledons did not correspond to the sizes of the embryos. However, we experienced the highest growth rate of 150 mm2 from the largest embryo, and the lowest growth rate of 10 mm2 from the smallest embryo. It seems that the contamination and the heat affected the growth of the embryos. Growth of the embryos occurs when there is cell division in the embryos. The development of the embryos occurs when cells specialize. This explains why there was growth in the cells, although they were contaminated, and why the largest embryos showed the highest growth rates. The size of the embryos determines the growth rate of the embryos. Large embryos have many cells, while the smaller embryos have fewer cells. Therefore, the larger embryos have a higher chance of developing (Kohl, 2007). References: Bhojwani, S. S., Razdan, K. M. (1996). Plant tissue culture: Theory and practice. Boston, MA: Elsevier Kohl, B. (2007). Embryo culture: Making babies in the twenty-first century. New York, NY: Farrar, Straus and Giroux Razdan, K. M. (2003). Introduction to plant tissue culture. Enfield, NH: Science Publishers, Inc.