Fig. 4. SDS PAGE of heat-stable proteins for a) developing and b) mature soybean seeds from plants exposed to three drought stress treatments at beginning seed fill (R₅) in the greenhouse experiment. WW: well-watered; GS: gradual stress; SS: sudden severe stress treatments. L: large; M: medium; S: small seeds. Equal weight of protein (7 µg) was loaded per lane. Developing seeds were sampled at 2 (R_5.2), 4 (R_5.4), 10 (R_5.6) and 18 d (R_5.8) after the stress treatments were imposed at beginning seed fill (R₅). The lane on the left side indicates the molecular weights (MW) of standard proteins (SP). The lane on the right is used to specify MW of proteins indicated by arrows.