Fig. 6. (A) Longitudinal section stained with Safranin, Fast Green, and Orange G, of a cold-hardened oat crown frozen at –13°C and then allowed to recover for 3 wk at 13°C in planting medium. This section is from the plant in Fig. 1F. This plant survived the freeze test and would have produced functional reproductive tissue, despite extensive freeze-damage to the crown core (B). (C, D) Normal metaxylem, and procambium (immature xylem or phloem), from various parts of the crown core. (E) Normal phloem and parenchyma from a tiller that appeared to be elongating. The unlabeled bar in each subpanel is 100 µm.