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TLS Online TPP Program

#Question id: 12527

Which of the following is the incorrect prediction about ABA translocation in vascular tissue by both the xylem and the phloem?

#Unit 6. System Physiology – Plant
  1. ABA synthesized in the roots can also be transported to the shoot via the xylem
  2. the concentration of ABA in the xylem sap of well-watered sunflower plants is between 1.0 and 15.0 nM, while in in waterstressed plants increases to as much as 3000 nM (3.0 µM )
  3. Concentration of 15.0 nM ABA in the apoplast is sufficient to close stomata, all of the ABA in the xylem stream reaches the guard cells
  4. ABA also is transported in a conjugated form, then released by hydrolysis in leaves.
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TLS Online TPP Program

#Question id: 13190

#Unit 10. Ecological Principles

During the evolution of life on Earth, the photosynthetic organisms initially responsible for raising atmospheric oxygen concentrations from less than 1 percent to about 20 percent were
TLS Online TPP Program

#Question id: 13189

#Unit 10. Ecological Principles

The relative abundance of C plant species increases with latitude because of the associated temperature gradient. A study in North America found that at  42°  North,  C3  plants  become more  abundant than  C4  plants. Given  an  increase in  mean global  temperatures by  10°C and no  other changes in  environmental conditions,  the latitude at which C3 plants become more abundant:
TLS Online TPP Program

#Question id: 13188

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance


Which of the following factors is most likely to generate the seed survivorship curve shown? 
TLS Online TPP Program

#Question id: 13187

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance


Which of the following factors is most likely to generate the seed density curve shown? 
TLS Online TPP Program

#Question id: 13186

#Unit 10. Ecological Principles

The following figure is a model of seedling establishment as a function of distance from a parent tree. Initial seed density measures the number of seeds falling to the ground. Seed survivorship measures the proportion of seeds that survive to the adult stage at each distance

This model predicts that recruitment of new individuals into the population should be
TLS Online TPP Program

#Question id: 13185

#Unit 10. Ecological Principles

If a drop in sea level led Island 1 to double in area, the MacArthur-Wilson model predicts that the number of bird species found there would