Question

Match the following:

Column I	Column II
a. Girdling experiment	p. active transport
b. Cobalt chloride paper method	q. mass flow hypothesis
c. Carrier protein	r. unequal transpiration on leaf surfaces
d. Munch	s. translocation in phloem

• A. $a=r,b=p,c=s,d=q$
• B. $a=s,b=r,c=p,d=q$
• C. $a=s,b=p,c=q,d=r$
• D. $a=q,b=p,c=s,d=r$

Answer 1

Answer: (B)

In girdling or ringing experiments (Malphighi, 1675), a ring of bark is cut and the phloem is removed. The region above the ring gets swelled with nutrients and the region below the ring gets shriveled without nutrients. This clearly shows the involvement of phloem in translocation and the nutrients moves in one direction, towards root.
Cobalt chloride paper test method is performed to show the unequal transpiration on leaf surfaces. Cobalt chloride is blue in an anhydrous condition but becomes pink in contact with water. The color change in the paper from blue to pink clearly indicates the paper has received water from the surface of the leaf.
Two types of transport proteins are there, the carrier proteins and channel proteins. The carrier proteins bind to a solute that has to be transported and delivers to the outer side of the membrane. The channel proteins allows the diffusion of the solutes based on their sizes.
The mass flow or pressure flow hypothesis was put forward by Munch (1927). This hypothesis describes the movement of sap via phloem. A highly concentrated organic compound like sugar in the phloem from a source (aerial parts) forms a diffusion gradient that drives water from the adjacent xylem, developing turgor pressure in the phloem (hydrostatic pressure).