ShmoopTube

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Try this shmoopy question on for size...

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If you like this passage, hit pause.

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It'll last longer.

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If PIN1 clustering is important for the patterning

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of leaves and plants, and stress is also important for patterning, what effect

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should mechanical stress have on PIN1 clustering?

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And here are the potential answers...

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This is a problem dealing with a lot of causes and effects.

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It wants to know if we can determine...what causes what.

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Let's take a look at what we know:

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PIN1 is important for patterning.

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Stress is important for patterning.

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Can the scientists help us out?

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Of course they can!

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Scientist 2 says: "If we intentionally stress the SAM, we see that the leaves begin to take

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on a pattern that is highly stress-dependent." So stress causes patterning.

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Well, PIN1 is what makes patterning happen.

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So if we stress the plant...i.e. injure it, patterns will occur...

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...and to make the patterns occur, we need PIN1.

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Which answer aligns with this idea?

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Well, mechanical stress doesn't cause PIN1 to

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run away to the roots of the plant, so D is wrong.

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What about C?

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"PIN1 should accumulate near the SAM regardless of stress."

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There's something majorly wrong with this answer.

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If we read the question carefully, it's asking us to

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find the effect of mechanical stress on PIN1.

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Option B. "PIN1 should be created by auxin."

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Yeah, that's fine and dandy, but it doesn't answer our question about mechanical stress.

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Which leaves us with A. Injuries, or stresses, do cause PIN1 to accumulate.

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A's our answer.

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If you need us, we'll be over here, squeezing this stress ball.

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