#Question id: 10913
#Unit 6. System Physiology – Plant
Several transport steps are involved in the movement of photosynthate from the mesophyll chloroplasts to the sieve elements of mature leaves; The following steps are invoved with sucrose transportation is given;
a) During the day, triose phosphate is transported from the chloroplast to the cytosol, where it is converted to sucrose.
b) During the night, carbon from stored starch exits the cytosol primarily in the form of maltose and is converted to sucrose
c) Sucrose moves from the mesophyll cells to the sieve elements in the smallest veins of the leaf. This is called short-distance transport pathway
d) With respect to unloading, sucrose and other solutes are translocated away from the source through the vascular system to the sink is referred to as long-distance transport
Which of the following combination is correct?
#Question id: 10914
#Unit 6. System Physiology – Plant
Early research on phloem loading focused on the apoplastic pathway, probably because it is very common in
#Question id: 10915
#Unit 6. System Physiology – Plant
Pathways for phloem unloading and short distance transport. The sieve element–companion cell complex (SE–CC) is considered a single functional unit. The presence of plasmodesmata is assumed to provide functional_______Y_______. An absence of plasmodesmata between cells indicates an______Z________.
#Question id: 10916
#Unit 6. System Physiology – Plant
A photosynthetic sugar sucrose can be hydrolyzed into glucose and fructose in the apoplast by a sucrose-splitting enzyme, this enzyme known as;
#Question id: 10917
#Unit 6. System Physiology – Plant
Photosynthetic sugar molecules are transported via phloem to other parts of the plants. The following aspects are associated with sucrose unloading in phloem and its transport;
a) The presence of plasmodesmata is assumed to provide apoplastic transport. An absence of plasmodesmata between cells indicates an nonfunctional symplastic continuity
b) Phloem unloading and short-distance transport can occur via symplastic as well as apoplastic pathways
c) Both unloading and the short-distance pathway appear to be completely symplastic in some young eudicot leaves, such as sugar beet and tobacco
d) An apoplastic step is required in developing seeds because there are no symplastic connections between the maternal tissues and the tissues of the embryo
Which of the following combination is INCORRECT?
#Question id: 10918
#Unit 6. System Physiology – Plant
The import into sinks such as developing roots, tubers, and reproductive structures, In many ways the events in sink tissues are simply the reverse of the events in sources. The following steps are involved in the import of sugars into sink cells such as;