Exam 39: Plant Responses to Internal and External Signals

Plant hormones produce their effects by ________. I altering the expression of genes II modifying the permeability of the plasma membrane III modifying the structure of the nuclear envelope membrane

A particular species of virus carries a gene for salicylate hydroxylase, an enzyme that breaks down salicylic acid. Will this virus be more or less virulent to plants than other viruses?

The hormone that helps plants respond to drought is

Arrange the following steps that occur during drought tolerance in plants in a correct sequence. I hormone ABA accumulation in the leaves II causes stomata to close III reduction in transpiration IV preventing further water loss

________ prevents seeds from germinating until conditions are favorable for the growth of the plant.

Generalized defense responses in organs distant from the infection site are called ________.

Experiments on the positive phototropic response of plants indicate that ________.

Which one of the following hormones regulates cell division in plants?

The detector of light during de-etiolation (greening)of a tomato plant is (are)________.

If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering?

A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as a long-day (short-night)plant. Which of the following has the best chance of creating iris blooms in winter?

Which type of mutant would be most likely to produce a bushier phenotype?

Plant hormonal regulation differs from animal hormonal regulation in that ________.

The rapid leaf movements resulting from a response to touch (thigmotropism)primarily involve ________.

The biological clock controlling circadian rhythms must ultimately ________.

When an arborist prunes a limb off a valuable tree, he or she may paint the cut surface. The primary purpose of the paint is to ________.

Suppose a plant had a photosynthetic pigment that absorbed far-red wavelengths of light. In which of the following environments could that plant thrive?

As cytokinins are primarily produced in roots, what route would they travel to influence lateral shoot formation in a recently topped tree?

Mammalian eyes sense light because the photoreceptor cells have molecules called opsins, which change structure when exposed to light. Which of the following plant molecules would be analogous to mammalian opsins in their light-sensing ability?

The signaling molecule for flowering might be released earlier than usual in a long-day plant exposed to flashes of