Alba Seeds Research Articles

The metabolism of sinapis alba seeds in water under anaerobic conditions

Tritiated water has been used to study the metabolism of Sinapis alba (White mustard) seeds in water under anaerobic conditions. Although some metabolism does take place under these conditions it does not lead to the formation of a seedling. Moreover it has been found that the active metabolism of S. alba seeds for 24 hr, under anaerobic conditions, does not lead to their death, since on restoration to aerobic conditions they do germinate, albeit much more slowly. Significant differences exist in the pattern of labelling of S. alba seeds under anaerobic conditions, from that under aerobic conditions. Thus, large amounts of tritium accumulate in lactic acid under anaerobic conditions; on transferring the seeds to an oxygen atmosphere the tritium in the lactic acid greatly decreases. It appears that the anaerobic metabolism leads to the accumulation of lactic acid which contributes to the inhibition of the metabolism leading to germination. This was supported by experiments which showed that lactic acid inhibited the germination of S. alba seeds. The possible role of lactic acid in the metabolism of the seeds is discussed.

Studies of the early reactions in the germination of Sinapis alba seeds

Tritiated water has been used as the aqueous medium for the germination of Sinapis alba (Mustard) seeds. 3H-labelled compounds formed during the germination processes have been separated and identified to give information on the biochemistry of reactions taking place during early germination. Since 3H is incorporated into aspartic acid, glutamic acid, γ-aminobutyric acid and alanine in the first 20 min of germination it is concluded that each of these compounds is involved in biochemical reactions during the early steps in germination. Citric acid, malic acid and succinic acid do not incorporate tritium until after 30 min. No tritium could be detected in the lipid fraction until after the third hour of germination. The results indicate that amino acid metabolism is important in the early stages of germination. It is proposed that the seed stores unstable α-oxo-acids as the corresponding amino acids until required for germination. Deamination and transamination produce the α-oxo-acids for the Krebs cycle. This is later supplied with acetate from the degradation of lipid reserves.

THE GERMINATION OF SEEDS OF MELILOTUS ALBA.

The contents of coumarin and coumarinic acid β-glucoside in germinating seeds of Melilotus alba, Arctic variety, have been measured. Non-germinating seeds were found to possess a large amount of free coumarin while in rapidly germinating seeds coumarinic acid β-glucoside was more prevalent. Coumarin and coumarinic acid β-glucoside have been examined as inhibitors of germination of M. alba seeds, the latter compound being much less efficient in this respect. Neither compound caused permanent inhibition of germination but only delayed the visible recognition of germination, this being because of the ability of the seeds to metabolize coumarin.

Injury by Soaking of Populus alba Seeds

AIR-DRIED seeds of Populus alba, stored in closed vessels at + 5° C., are injured when submerged in distilled or tap water (see Table 1).