ExplanationA.True. Sucrose entry in

ExplanationA.True. Sucrose entry into phloem increases the solute concentration that draws water from adjacent xylem. This creates hydrostatic pressure in the phloem to transport sucrose from source to sink over the long distances in plants.B.False. In the apoplasmic phloem loading, sucrose molecules are transported via plasmodeamata (PD) from mesophyll cells (M) to the phlorm parenchyma cells (PP). Sucrose molesules are subsequently imported across the plasma membrane of the companion cells (CC) against their concentration gradient.C.True. Sucrose molecules are present at high concentrations in mesophyll cells (M)and move down a concentration gradient to enter thick walled sieve element (TST). Thismechanism does not require energy for sucrose to enter TST.D.False. As with phloem loading process, phloem unloading occurs through both symplast and apoplast depending on the type of sinks. Sucrose unloading is typically symplastic in growing and respiring organs such as meristematic tissues, young leaves. In storage organs, sucrose unloading is known to occur through apoplast and require energy for several steps.ReferenceDavid M. Braun, Lu Wang and Yong-Ling Ruan, 2014. Understanding and manipulating sucrose phloem loading, unloading, metabolism, and signalling to enhance crop yield and food security. Journal of Experimental Botany, Vol. 65(7), pp. 1713-1735, doi: 10.1093/jxb/ert416