Fig. 1.1 shows a diagram based on a photomicrograph of a root hair cell. On Fig. 1.1, name the cell structures X, Y and Z.
Within the symplast pathway, water moves through the cells of the different tissues in the root before it reaches the xylem vessels of xylem tissue. Name the root tissues, in the correct order, through which water travels in the symplast pathway.
In the apoplast pathway, water travels along the cell walls of neighbouring plant cells and through the spaces between cells. This pathway is more efficient than the symplast pathway. Explain the structural characteristics of plant cell walls that make the apoplast pathway efficient for water transport.
Electron microscopy of root hair structure has shown endoplasmic reticulum (ER), several small Golgi bodies, and many vesicles. Root hair cells of barley plants secrete enzymes called acid phosphatases, which catalyse the release of inorganic phosphate ions from organic phosphates in the soil. Root hair cells of sorghum plants secrete a hydrophobic lipid compound called sorgoleone, which reduces the growth of nearby plants. Explain why the proportion of rough ER to smooth ER may differ in the root hair cells of barley plants compared with those of sorghum plants.
Student X said that acid phosphatases and sorgoleone could leave root hair cells by the same mechanism. Student Y said that acid phosphatases and sorgoleone leave root hair cells by different mechanisms. Suggest the reasons given by student X and by student Y to justify their statements.