A plant exposed to a fungal toxin exhibits significantly reduced translocation of potassium ions () despite normal transpiration rates. The toxin MOST likely affects which process?
Stomatal opening and closing
Water potential gradient in the xylem
Activity of membrane transport proteins involved in uptake into xylem
Root pressure generation
Related Questions
The main driving force for the ascent of sap in tall trees is:
Root pressure
Capillary action
Transpiration pull
Active transport by xylem cells
The process by which mineral ions are transported from the soil to the xylem is primarily:
Diffusion
Osmosis
Active transport
Passive transport
Which of the following is a micro-nutrient required by plants?
Calcium
Magnesium
Manganese
Potassium
Which mineral is a constituent of the ring structure of chlorophyll?
Iron
Magnesium
Manganese
Zinc
Which element is LEAST likely to be remobilized within the plant?
Nitrogen
Phosphorus
Potassium
Calcium
Which condition would MOST significantly inhibit the translocation of sucrose in phloem?
Decreased sucrose concentration in source cells
Increased sucrose concentration in sink cells
Application of a metabolic inhibitor that blocks ATP synthesis in companion cells
Exposure to light
Direction of translocation of organic food or solutes, is
Upward
Downward
Radial
All of these
Which of the following is NOT a characteristic of the phloem tissue involved in translocation?
Bidirectional transport
Living cells
Active process
Unidirectional flow in the whole phloem
A researcher is studying phloem transport in a plant using radioactive . After introducing the radioisotope to a mature leaf, where would the LEAST radioactivity be detected after a short period?
Apical meristem
Young developing leaves
Roots
Mature leaf cells lacking plasmodesmatal connections to the phloem
The active transport of minerals into root cells is primarily driven by:
Transpiration pull
Root pressure
Proton pumps generating an electrochemical gradient
Capillary action in xylem vessels
