Many living things undergo a process known as development
in which a single cell replicates and divides to form a multicellular organism
with various structures and functions that the original cell did not have.
You are one such organism, growing from a fertilized egg cell in your mother's
womb to the full-sized adult you are today. Along the way, your cells
changed from having features like the original fertilized egg to having
those of the developed cells that make up human tissues like nerve
and skin. This process is known as differentiation.
Plants are also multicellular organisms, and they too undergo this differentiation process. There are many similarities between the way plants and animals like yourself differentiate, and therefore, they make excellent creatures to study the cycle of growth and development.
You will be studying this cycle in a lab in the next few days, and to be ready for it, there are some ideas with which you need to be familiar. The following questions will help you do so.
1. What function does DNA play in all organisms?
2. How does fertilization occur in flowering plants and what does it produce?
3. Why is there identical DNA in all cells of the same plant (provided there are no mutations)?
4. What occurs during cellular differentiation?
5. Does a developing plant embryo undergo differentiation? Explain your answer.
6. What is germination?
7. Describe the physical appearance and function of the radicle and hypocotyl in germinating and sprouting seeds?
8. How can cells create tissues that have different morphology and physiology in spite of the fact that the DNA in all the cells in any organism are identical?
9. Make a labeled diagram of a young radicle and identify the regions where you think the most growth is taking place?
10. If respiration rate (consumption of O2/min/mg tissue) is directly related to rate of growth in a plant, what part of the radicle would have the highest respiration rate? Explain your answer.
11. Hormones play a critical role in the growth and development of plants as well as other organisms; what are the specific hormones that influence radicle development and what effect do they have?.
12. Pick two embryonic plant structures and decide on an interesting question you could ask about their respective developmental rates; then write a hypothesis that addresses your question (explaining why it does) and write a brief summary of a procedure you could use to test it.