Figure 8-3 is complex but easy to understand. Figure 8-3B shows a tree trunk, and this year is its fourth year of growth. A transverse section at the base of Figure 8-3B would show how many layers (growth rings) of wood (circle one: 1, 2, 3, 4)? Would a transverse section through the top of Figure 8-3B show any layer of wood this year? Would it show a layer of wood at the end of next year? Would there be any transverse section that does not show the pith and primary xylem; that is, are pith and primary xylem ever lost or destroyed by the formation of wood? The orange layer is labeled “Provascular tissue” in the top right of Figure 8-3B, but what is it labeled in the middle and lower right diagrams?

Figure 8-3B

Transcribed Image Text:

F000 (A) This year's growth One-year old growth 2-year old growth 3-year old growth (B) Fascicular cambium Procambium- Pith Cortex and epidermis Primary phloem Primary xylem Vascular cambium Cortex, epidermis and bark Interfascicular cambium, just forming Secondary phloem- Secondary xylem formed this year Secondary phloem Secondary xylem formed last year Secondary phloem Secondary xylem formed 2 years ago Primary xylem Secondary phloem Secondary xylem Primary phloem Provascular tissue- Primary xylem - Pith Primary phloem. Secondary phloem Secondary xylem Primary xylem - Pith Cortex Epidermis- Vascular cambium Cork cambium Periderm Remnant cortex and epidermis wearing away Cork cambium Secondary phloem Vascular cambium Secondary xylem- Primary xylem - Pith- Periderm-