L. Gonzalez-zertuche et al., Natural priming of Wigandia urens seeds during burial: effects on germination, growth and protein expression, SEED SCI R, 11(1), 2001, pp. 27-34
To determine whether seeds of the weedy shrub Wigandia urens, from the Vall
ey of Mexico, undergo natural priming when buried in soil, comparative expe
riments were performed with seeds: (1) harvested directly from the plants;
(2) buried in three natural habitat conditions; and (3) laboratory primed w
ith polyethylene glycol. Seeds were sown in a growth chamber and in a shade
house. final germination percentages, emergence, germination and emergence
rates, survival and initial growth were determined. Burial and priming enh
anced the germination and emergence parameters evaluated in the laboratory
and in the shade house. Effects of treatments on survival were not signific
antly different. Nevertheless, burial improved emergence and mean survival,
and induced differences in specific leaf area of seedlings that could have
ecological significance. Heat-stable proteins were extracted and electroph
oresed. Proteins formed in W. urens seeds during burial had molecular weigh
ts (14-21 kDa) similar to those reported for late embryogenesis abundant (L
EA) proteins induced by priming in other species. Nevertheless. the presenc
e and abundance of proteins expressed (14-23, 36 and more than 45 kDa) diff
ered among control, primed and buried seeds. During soil burial, molecular
and physiological responses were induced that were similar to the effects o
f priming.