Question

F) Name the two vascular tissues
in plants . How are they different
from each other? ​

Answer 1

Answer:

Vascular tissue is an essential way for the transport of inorganic and organic compounds. Organic acid transport in the transpiration stream is correlated with the transport of various metallic nutrients including zinc, copper, or iron (López-Bucio et al., 2000 and the references therein). In addition to increase in citric acid content in the xylem sap of Cd-treated Sesuvium portulacastrum mentioned previously (ca. 8-fold, Mnasri et al., 2015), other species revealed similar responses. Quercus suber showed significant increase in the xylem sap citrate concentration under both Cd doses and malate and malonate also increased under higher Cd (50 μM) dose (Gogorcena et al., 2011; see Table 11.5). On the contrary, citrate concentration in the xylem or phloem sap of Ricinus communis was not affected by exogenous Cd ranging from 0.1 to 10 μM (Hazama et al., 2015), indicating the involvement of other potential metal chelators such as thiols. Interspecific differences of organic acid content are also often high, e.g., citrate and malate xylem sap concentration were ca. 10-fold and 15-fold higher in the tree Quercus suber than in a herbaceous species Sesuvium portulacastrum (Table 11.5). Phloem sap is typically richer in organic compounds than xylem as observed in Ricinus communis (Hazama et al., 2015).