Saturday, November 14, 2009

Bio plant help !?

A transparent container contained plenty of fresh water for the plants and was placed outside where it received adequate sunshine during the day. plant A is a begonia which is a C3 plant, plant B is a sugarcane which is a C4 plant, and plant C is a cactus which is a CAM plant.





After 4 weeks, the only plant alive was the cactus. Records indicate that the begonia died first and then the sugarcane. Based on what you know about these different kinds of plants, explain what happened. How was the cactus able to survive and why did the begonia die first?

Bio plant help !?
well since this is Biology... i know your instructor would want you to know the C3, C4, and CAM processes, and not just common gardening sense...





first (i wont go into the exact processes of the C3, C4, CAM) all are modified forms of the "Calvin" cycle, the cycle that utilizes the resulting products of photosynthesis (ATP, NADPH) and CO2 and using enzymes to produce simple sugars...





anyways, the C3 process and considered to the the oldest process used by plants (this process is used most by tropical plants) , this process can run out of control with too much sun, these plants are susceptible to to something called PHOTORESPIRATION this occurs during stressful times when too much sun (causing the stomata to close) and increasing levels of O2 in the leaves... the calvin cycle will be revamped to produce CO2, this robs vital energy from the plant and can eventually lead to death... the plant probably did fine for a few days and soon became stressed and died very quickly





the C4 plants, are not susceptible to photorespiration... but instead utilize another pathway to produce CO2 inside the mesophyll cells near the bundle sheaths... this is why all C4 plants have bundle sheaths with mesophyll cells, becuase of this C4 plants can tolerate drier and hotter conditoions. in this scenario i would conclude the sugarcane slowly ran out of water becamed very stressed and then shriveled and died.





next the catus which utilizes the CAM process where the plant respires only during the night... it is not susceptible to the photorespiation but during the day utilizes the C4 process thus allowing it to take much more harsh extremes.. after the experiment was over the cactus could have happily sat there with no change, an interesting fact some cacti can go a year without a drop of water...
Reply:C3 plants require more water for photosynthesis than C4 plants. The cactus, a CAM plant, evolved in arid conditions and is adapted to survive on a minimum of water.


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