What is the main force by which most of the water within xylem vessels moves toward the top of a tree?
evaporation of water through stoma
Which of the following statements about xylem is incorrect?
It transports mainly sugars and amino acids.
According to the pressure flow hypothesis of phloem transport,
solute moves from a high concentration in the source to a lower concentration in the sink.
Transpiration in plants requires all of the following except
active transport through xylem cells.
Photosynthesis begins to decline when leaves wilt because
stomata close, restricting CO2 entry into the leaf.
The detector of light during de-etiolation (greening) of a tomato plant is (are):
If a farmer wanted more loosely packed clusters of grapes, he would most likely spray the immature bunches with
In plant roots, the Casparian strip is correctly described by which of the following?
It ensures that all water and dissolved substances must pass through a cell membrane before entering the stele.
Root hairs are most important to a plant because they
increase the surface area for absorption.
All of the following normally enter the plant through the roots except
The movement of water across biological membranes can best be predicted by
The apical bud of a shoot produces _____, resulting in the inhibition of lateral bud growth.
Plants growing in a partially dark environment will grow toward light in a response called phototropism. Which of the following statements is true regarding phototropism?
Auxin causes a growth increase on one side of the stem.
If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?
If ØP = 0.3 MPa and ØS = -0.45 MPa, the resulting Ø is
A long-day plant will flower
when the night is shorter than a critical value.
Given that early land plants most likely share a common ancestor with green algae, the earliest land plants were most likely
nonvascular plants that grew leafless photosynthetic shoots above the shallow fresh water in which they lived.
According to the acid growth hypothesis, auxin works by
increasing wall plasticity and allowing the affected cell walls to elongate.
The value for Ø in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ø = -0.23 MPa), the net water flow would
be from the tissue into the sucrose solution