Climate change due to the increasingly rapid levels of greenhouse gases (particularly CO2) in our atmosphere is a serious current global concern. How might Stomatal density serve as a bio-indicator for monitoring the response of plants to changes in greenhouse gas concentrations in the future? (Hint: How does Stomatal density vary with CO2 concentration?)

Free-Air Carbon dioxide (CO2) Enrichment (FACE) experiments have revealed (some) plant responses to CO2 enrichment. Which of the following plant responses would you not expect in the CO2-enriched world of the future? a. Decreased ratio of trace nutrients to carbohydrate content in fruit. b. Increased water consumption used in photosynthesis. C. Increased biomass from CO2 fixing. d. CO2 uptake by plants will match anthropogenic emissions. e. Increased growth rate from CO2 fixing.

According to the results of the graph, what happened to the water potential over time and which treatment generated less and greater water stress? Explain the answers. Water potential in stem at noon "Manzanilla de Sevilla" La Reina de santa Cruz. 2016. -2 -3 -4 -5 -6 -7 -8 -Mpa 1-jun. 16-jun. 1-jul. 16-jul. 31-jul. 15-ago. 30-ago. 14-sep. 29-sep. 14-oct. 29-oct. 13-nov. 28-nov. -RD2-Secano --Etcmax -RD1 Evolution of the water potential at solar noon of the different treatments. The bars correspond to the standard deviation.

Choose all the correct statements for the graph above:  A.in a mutant plant that makes TWICE the normal number of stomata on the leaf, we would expect the line to shift down (i.e. water potential would become more negative). B. During the period starting with time B and ending with time D, the water potential in the leaf is increasing. C.Transpiration rates are the highest around time B. D.At time A we expect to see the greatest volume of water moving up the xylem to this leaf.