Exam 33: Control Systems in Plants

Where might you put a green, unripe fruit to ripen it?

Which example of an evolutionary adaptation decreases herbivory?

Which hormone prevents a seed released in the fall from germinating immediately?

Which substance induces "bolting," the rapid elongation of a plant stem?

Under which condition would plant cells treated with auxin be able to enlarge?

Which experiment might be performed by a biologist who is interested in determining which plant organs (stems, buds, leaves, etc.) are responsible for sensing photoperiod?

-Which plant in Went's experiment shows auxin stimulating elongation in the left side of the plant only?

-In the figure, the shoot emerged through the soil toward the light rather than growing down in the direction of the roots due to

Which statement concerning biological clocks is false?

When a nursery worker pinches off the terminal buds on a young plant to make it grow bushy, which plant hormone, when produced, is mainly responsible for growth of side branches?

In plant research labs, plants are often grown in light-proof chambers where the hours of light and dark are carefully controlled. A new researcher goes into a chamber and accidentally turns on the light during the "dark" period. How should the researcher respond to get the plants back to their controlled schedule quickly?

A student taking a plant physiology class is interested in investigating what will happen if the apical bud is removed from a growing plant and supplementary hormones are introduced. He set up his experiment with two groups of plants of the same species. In groups A and B, the apical buds were removed and the cut apical ends were wrapped with hormone-impregnated cotton. The plants were observed over a 5-week period for growth and development. In group A, many axillary buds and leaves appeared along the sides of the stem, and the plants had minimal root growth. In group B, minimal growth occurred in the shoot and roots, and no axillary buds formed. -What hormone was in the cotton used to wrap the apical ends of the group A plants?

The plant growth response to touch is known as

Christmas cactus is a short-day plant that usually blooms in the winter. Which strategy might induce it to bloom for the 4th of July?

Which list correctly orders the events leading to leaf fall in deciduous trees?

Fall is coming, with the prospect of frost, so you decide to pick the last tomatoes on the vine even though they are still green. If you wanted to ripen these tomatoes, which method would be most effective?

In leaf abscission, the abscission layer forms where the

Application of herbicides made from plant hormones may have unintended consequences because

Ethylene triggers the ripening of fruit for many plant species but does not seem to play an important role for the ripening of grapes. Scientists hypothesized that the trigger for the ripening of grape fruits is abscisic acid (ABA). They sprayed unripe Cabernet Sauvignon grapes with different concentrations of ABA and tracked several fruit characteristics over time: percent of fruits that are purple, concentration of anthocyanin (a purple pigment) per fruit, weight of each fruit, and total soluble solids per fruit as measured by °Brix. °Brix measurements indicate the amount of sugar in the fruit, and determine how much alcohol a wine will have. Higher values of each measurement indicate a greater degree of ripening. The scientists' results are shown in these four graphs. Source: Wheeler, S., Loveys, B., Ford, C., & Davies, C. (2009). The relationship between the expression of abscisic acid biosynthesis genes, accumulation of abscisic acid and the promotion of Vitis vinifera L. berry ripening by abscisic acid. Australian Journal of Grape and Wine Research, 15(3), 195-204. -Should the wine industry recommend the use of ABA to speed up ripening of grapes for wine making?

Grass shoots bend toward the light because, on the shadowed side, a(n)