Question 1

Which plant hormone is primarily responsible for fruit ripening, and how can its action be manipulated to delay ripening in agricultural settings?

Accepted Answer

Ethylene; by blocking ethylene receptors with synthetic chemicals

Question 2

A plant's apical meristem is removed by herbivory. What hormonal changes occur, and what is the resulting growth pattern?

Accepted Answer

Auxin levels decrease, allowing cytokinins to promote axillary (lateral) growth

Question 3

Which environmental condition triggers phototropism in plants, and what is a typical response?

Accepted Answer

Light; stem bending toward a window

Question 4

A farmer wants to delay the ripening of apples during storage. Which compound should they use, and what is its mechanism?

Accepted Answer

HarvistaTM; blocks ethylene receptors

Question 5

If a plant is exposed to drought, which hormone is likely to be involved in its response, and what is a typical adaptation?

Accepted Answer

Abscisic acid; stomatal closure

Question 6

Which hormone interaction explains why lateral buds grow more vigorously after the apical meristem is removed?

Accepted Answer

High auxin inhibits cytokinin, so removal of auxin allows cytokinin to promote lateral growth

Question 7

A gardener places a ripe banana in a bag with green bananas. What is the expected outcome and why?

Accepted Answer

The green bananas will ripen faster due to increased ethylene exposure

Question 8

Which plant response is triggered by gravity, and what is the typical direction of growth?

Accepted Answer

Gravitropism; roots grow downward

Question 9

A plant treated with chlormequat will exhibit which of the following changes?

Accepted Answer

Stunted elongation and stronger grain stalks due to gibberellin inhibition

Question 10

Which equation best represents the relationship between hormone concentration and plant response, assuming a linear model?

Accepted Answer

$$ y = mx + b $$

Question 11

A Douglas fir tree exhibits a bushy shape with suppressed vertical growth. Which scenario best explains this morphology?

Accepted Answer

Deer browsing removed the apical meristem, reducing auxin and promoting lateral growth

Question 12

Which hormone is used commercially to break dormancy in seeds and promote germination?

Accepted Answer

GA4+7 (gibberellin agonist)

Question 13

Which plant response is most likely to occur when a plant experiences touch?

Accepted Answer

Thigmotropism; tendril coiling

Question 14

Which hormone is inhibited by ReTain, and what is the agricultural benefit?

Accepted Answer

Ethylene; delays fruit ripening

Question 15

A plant exposed to far-red light will most likely exhibit which response?

Accepted Answer

Root growth downward due to gravitropism

Question 16

Which hormone is most likely to be used to ripen fruit quickly in commercial agriculture?

Accepted Answer

Ethephon (ethylene agonist)

Question 17

Which plant hormone is most directly involved in chemical defense signaling after herbivory?

Accepted Answer

Ethylene

Question 18

Which equation would best describe the exponential increase in ethylene concentration during fruit ripening?

Accepted Answer

$$ y = e^x $$

Question 19

Which hormone is most likely to be inhibited to produce stout, strong grain stalks in cereal crops?

Accepted Answer

Gibberellin

Question 20

A plant's response to water availability is called hydrotropism. Which adaptation is most likely?

Accepted Answer

Roots grow toward areas of higher moisture

Plant Senses & Hormones – Guided Study Notes

Study Guide - Practice Questions