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Salt Tolerance in Tomatoes
Herbicide Resistance in Crops
Natalie's Gift for Class of 2011
On Cell Respiration
Neurobiology and Behavior
Microbes and Biotechnology
JUNIORS STUDY TEAMS
Sarah's Sure Shots
Maddie's Mad House
Salt Tolerance in Tomato Plants
SALT TOLERANCE IN TOMATO
Salty tomatoes yum! no silly salt tolerance in tomato refers to the Genetically modified tomato plant that has the ability to grow in a salinity environment. Scientists have used biotechnology to develop tomato plants with enhanced tolerance to salty conditions. Scientists have noticed that plants with high tolerance to salt stress possess naturally high levels of a substance called glycinebetaine, also known as a "transport protein", plants with intermediate levels of salinity tolerance have intermediate levels, and plants with poor tolerance to salinity have little or no glycinebetaine at all. Through biotechnology, scientists have engineered tomato plants that produce higher levels of the naturally occurring "transport protein." The gene that controls increased production of the transport protein was taken from Arabidopsis, a relative of the cabbage that is commonly used in plant research.The transport protein uses energy available in the cells to move salt -- in the form of sodium ions -- into compartments within the cells called vacuoles. the salt is stashed inside the vacuoles it is isolated from the rest of the cell and unable to interfere with the plant's normal biochemical activity.These genetically engineered salt-tolerant plants actually remove salt from the soil. And because
their salt-storing activity occurs only in the plants' leaves, the quality of the tomato fruit is maintained.
The diagram below shows how the genetically modified tomato relieves the "stress" caused by a high amounts of salinity levels ( GMO Compass).
PROBLEMS THAT IT INTENDS TO SOLVE
Plants use water as a solvent, a transport medium, an evaporate coolant, physical support, and as a major ingredient for photosynthesis. Without sufficient water, agriculture is impossible. Irrigation has enabled the transformation of arid regions into some of the world's most productive agricultural areas. However, irrigation also increases the salinity of soils and water by depositing in the fields soluble salts such as sodium, calcium, magnesium, potassium, sulfate and chloride that the water has picked up from the soils and rocks it has passed through. Eventually these salts accumulate in the irrigated soils at levels that decrease the vigor and productivity of the crops grown there. Salty irrigation water wreaks havoc on most plants by upsetting their ability to take in water through their root cells. In fact, if salt concentrations in the soil are very high, flow of water into the plant is actually reversed and the plant dehydrates and dies as water is drawn out of its cells. This is due to the fact that the concentration salt on the outside of the cells in the roots is greater than inside, so it will attract the water to the outside of the cell.
Soil salinity is a major constraint to food production because it limits crop yield and restricts use of land previously uncultivated. The United Nations Environment Program estimates that approximately 20% of agricultural land and 50% of cropland in the world is salt-stressed (Flowers and Yeo, 1995).The idea of genetically modifying tomatoes to increase salt tolerance will also be able to be applied to other , more common crops, like rice, tomatoes, or soy plants. This will allow plants to grow in the salty soil, so even if the entire world had an excess amount of salt, the growth of the genetically modified crops would not be affected.
This progressive loss of farmable land is on a collision course with the expanding global population, which over the next 30 years is expected to require an increase in food production of 20 percent in developed countries and 60 percent in developing nations ( UC Davis). Without the genetically modified crops, only a small amount of plants would be able to grow, however most plants would end up dying due to the high soil salinity, which inhibits the metabolic processes of plants, such as protein synthesis (Hannink).
Sarah's comment on Problem #3: Yes, the combination of loss of farmable land and increase in population equals lots of starving people, but shouldn't we attempt to adress the second problem as well? Overpopulation leads to scarcity of resources like drinking water, waste issues (landfills, anyone?) and environmental problems like global warming from all of the fossil fuels we are burning. Experts believe we are going to have 15 billion people on this planet in less than a century, and I know that no one wants to talk about, for example, limiting the number of babies people can have like they do in China- but isn't it time we at least consider solutions to the problem? In addition to salty tomatoes?
Plant biologists are using the salt tolerance tomato plant as the first step to developing ways of making plants better suited to salinity environments. With agriculture being relegated to marginal land and with the prospect of salinity water and soil, plants that carry salt tolerant traits are considered crucial ways of securing the world's food./
POINT OF VIEWS
Many biologists as does Dr. BLUMWALD see this new genetically modified tomato as something that will benefit the agriculture aspects of today's society: What we have done is--essentially, it's common sense. Any plant that has to grow in such adverse conditions faces two problems. The first is that sodium is very toxic for the metabolism of the cell. Sodium will inhibit key reactions, killing plant cells. The other problem is that due to the high osmoticum outside, the high sodium chloride concentrations, the plant cannot take water. In fact, the plant is going to lose water. So what we have done is instructed the plant through genetic modification to produce more of a plant protein--this is not a fish protein, just is a protein from the plant--that now is going to make the sodium ions that enter the plant's cell go into an organelle that the plant cell has, called a vacuum. By doing that, which is by accumulating the sodium in this vacuum inside the plant cells, we accomplish two things. First of all, we are removing the sodium from the other part of the cells, which are critical for the metabolic reactions of the cell. And second, now, that pool of sodium starts sucking water literally from the soil to the plant. So the plant now can use the salty water to grow.
POV # 2- Costly!!
My stance is that a crop that can grow in salinity environment will answer one of the major problems with agriculture production. The process through which the salt is taken out of the water and stored in the leaves rather than the fruit itself, ensures that the fruit is safe to eat. However, the amount of money invested into this plant indicates that this new tomato plant will cost more money than the normal tomato plant. So for those parts of the world that can't afford to buy this plant, their problem won't be solved ( Brain).
POV#3- Fear of people
An ethical implication associated with salt tolerance in tomato plants is that the product is still part of a new practice that hasn't been throughly processed yet so. When tobacco was first introduced, people didn't see anything wrong it, but as time went on the negative effects of the use of tobacco were seen. right now genetically altering the tomato may not seem to have any down sides but we can't be sure yet. The picture below shows an embryo inside the tomato, as in due to biotechnology, a fear of the people that the tomato plants will turn into a new specie
POV #4 - Not dealing with the actual problem.
The need for genetically modified crops with a resistance to salt is occurring because of the increase in soil salinity all over the world. Although creating these GMO's would solve the food problem, the actual problem here is that the soil is becoming too salty. By creating these salt resistant tomatoes, only the surface problem is being dealt with, however there is a deeper problem that should be addressed. Instead of thinking how food is going to grow in the salty soil, scientist should be trying to find a solution to decrease the amount of salt in the soil. If people are only worrying about the food, they may be missing an even bigger problem that might arise from the increased soil salinity. For example, the salt in the soil may run off into freshwater rivers, streams, and lakes (Nielsen), completely destroying the ecosystem by making all bodies of water saltwater. This would result in the deaths of many freshwater animals, fishes, and plants, and it would even effect us humans. Without freshwater sources, it would be harder for us to drink normal water. all of the water would have to be carefully filtered, which would end up costing a lot of money. It would start with the salt in the soil, but that salt would gradually be introduced into freshwater systems, destroying the ecosystem. And all of this could be avoided if scientists would begin to look at The problem of the soil salinity, instead of which plants could grow in the soil.
Adam Weisse comment on POV 4- The problem is with the soil, I can agree with that, but it could take time to discover what can be done to reduce the amount of salt found in the soil. During this time, are the tomato plants expected to struggle to grow? While the matter of soil salinity should be addressed, the tomato plants still need to grow, and the best way to facilitate that is to modify them in this way. This ensures that while the problem of the soil salinity is being discussed, the plants will continue to grow.
Flowers, T.J. and Yeo, A.R. (1995) Breeding for salinity resistance in crop plants: where next? Aust. J. Plant Physiol. 22, 875-884.
"GMO Compass" http://www.gmo-compass.org/eng/agri_biotechnology/breeding_aims/151.stress_resistance.html
Hannink, Nerissa. "How Plants Cope with Salinity."
The Society for Experimental Biology
. July 2005. Web. 28 Jan. 2011. <
Nielsen, D.L., M.A. Brock, G.N. Rees, and D.S. Baldwin.
. Rep. 2003. Web. 29 Jan. 2011.
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Brian Tokar (Institute for Social Ecology) The Edmonds Institute (Revised version, 2001)
. 28 Jan. 2011. <
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