Protein Synthesis in Imbibing Embryos and Axes

That ribosomes present in dry embryos, dry whole seeds and dry dicot storage organs still retain their potential for protein synthesis is now widely 

mRNA omitted from complete system from 48-h imbibed seeds 2480 

The complete system contains 0.3 mg ribosomes from dry seeds (lines 1-5) or 48-h imbibed seeds (line 6), 0.8 mg supernatant (cytoplasm) protein, 125 pg mRNA, 0.5 pCi C-leucine, 10-15 pmol/ml Mg. Incubation at 37° for 30 min. Cycloheximide (15 pg), an inhibitor of protein synthesis on 80S ribosomes, is added to one tube. The effect of omitting ribosomes was not tested. Based on Jachymczyk and Cherry, 1968 [62] 

In vitro protein synthesis in the presence of added ribosomes and mRNA (or polysomes) and ATP/GTP can be supported by supernatant (cytoplasmic, or post-ribosomal) fractions obtained from dry peanut seeds (Table 5.6) and dry wheat embryos [76]. Consequently, components of the cytoplasm essential for protein synthesis (e.g. initiation and elongation factors, tRNA, amino acids, and aminoacyl tRNA-synthesizing enzymes—synthetases) must be present in the dry seed, presumably in sufficient quantities to permit resumption of protein synthesis in the seed upon imbibition. 

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