Fig. 25. Density traces of heat-stable proteins extracted from the crowns of winter wheat plants of different ages. Seed was sown on 5, 15, and 25 August and 5 September and sampled on 30 October (a), 16 April (b), and 4 May (c). Electrophoresis was as described in the legend to . COR proteins are indicated by arrows. Molecular weights of proteins are indicated above the the density tracings.