Plants experience a vast array of conditions that can alter their growth and development, including temperature and availability of water, nutrients, and light. They are also exposed to pollutants such as acid rain formed largely as a result of burning fossil fuels and volcanic eruptions. Acid rain can strip minerals and nutrients from the soil, and eat away the outer waxy layer of tissue that protects a plant. Acid rain is still a major environmental problem in certain regions. How does acid rain affect plant growth? Researchers tested the effects of acid rain (pH 2.0) on seedlings of two different species, camphor tree (Cinnamomum camphora) and chinaberry tree (Melia azederach), using distilled water as a control. Results of the experiments are shown here. Note that acid rain caused a significant reduction of growth in chinaberry trees (*** means P < 0.001), but not in camphor trees. What was the approximate percentage of growth reduction observed in the chinaberry trees treated with acid rain?

Question

Plants experience a vast array of conditions that can alter their growth and development, including temperature and availability of water, nutrients, and light. They are also exposed to pollutants such as acid rain formed largely as a result of burning fossil fuels and volcanic eruptions. Acid rain can strip minerals and nutrients from the soil, and eat away the outer waxy layer of tissue that protects a plant. Acid rain is still a major environmental problem in certain regions. How does acid rain affect plant growth? Researchers tested the effects of acid rain (pH 2.0) on seedlings of two different species, camphor tree (Cinnamomum camphora) and chinaberry tree (Melia azederach), using distilled water as a control. Results of the experiments are shown here. Note that acid rain caused a significant reduction of growth in chinaberry trees (*** means P < 0.001), but not in camphor trees. What was the approximate percentage of growth reduction observed in the chinaberry trees treated with acid rain?

Accepted Answer

Welcome back. Let's look at our next problem. An experiment was conducted to investigate the effect of simulated acid rain on plants. A mixture of sulfuric acid, nitric acid and distilled water was used as acid rain. The ph of the prepared mixtures is two point oh three point oh four point oh five point oh six point oh. After the treatment, it was observed that the chlorophyll content of the control is significantly higher than those with acid treatments. The plant height decreased significantly at all acidity levels with respect to the control set. The highest reduction was observed at ph two point oh, which of the following describes the relationship between plant growth and ph. So, we've got a lot of information, a lot of data here. So, it's good to zoom in on what's the final question? The relationship between plant growth and ph Well, what do we know about these two things in this experiment? Well, we know that ph was it several different values ranging from 7.0 in the control, Decreasing down to 2.0 at the lowest found. And then when we talk about plant growth, um that was measured by measuring plant height and it said that the plant height decreased significantly at all acidity levels with respect to the control. So we know it was the highest or the greatest When PH was 7.0 and then it decreased At all acidity levels. It said the highest reduction was observed at Ph two point. So we see that the height was the least When the Ph was equal to 2.0. so as the ph decreased, the height decreased and therefore growth decreased. So it says which of the following describes the relationship between plant growth and ph while they both were decreasing when we look at our answer choices, choice A. Says they are directly proportional. And this is what we observe because directly proportional means that both things you're looking at um increase or decrease together in the same direction. So when one increases the other increases, or when one decreases the other decreases and that's what we have here. As ph decreases height decreases, choice B says they're inversely proportional. Well, that's not our answer. That would be the opposite situation. And inversely proportional relationship means when one increases the other decreases choice C. Says they are equal no plant growth and ph were not equal. Kind of doesn't even make sense actually. Ah And choice D. They have no apparent relationship. Well, they do have a relationship because we saw that the ph level did affect the growth of the plant to choice D. Is not our answer. So again, which the following describes the relationship between plant growth and ph and this experiment choice A. They are directly proportional, since as ph decreased, the growth also decreased. See you in the next video

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