Abstract:
Light‐intensity‐dependent (low, normal and high) differences in thiol and amino acid
metabolism during drought were compared in wheat seedlings. The drought‐tolerant
genotype (Plainsman) recovered better than the sensitive one (Cappelle Desprez) after
the stress as shown by growth and photosynthetic parameters, the levels of which
were greater in low and high light, respectively. Glutathione as an antioxidant contrib‐
uted to this difference, since its level was twofold greater in Plainsman throughout the
experiment. In addition, the accumulation of most amino acids even increased in nor‐
mal light during drought in Plainsman, while such change occurred in Cappelle Desprez
only in high light. The higher contents of proline, glutamate and γ‐aminobutyrate are
especially important because of their involvement in the protection against drought.
The transcription of certain genes related to amino acid and glutathione metabolism
and various antioxidants was even induced by higher light intensities before drought,
which can contribute to the subsequent increase in the amount of the correspond‐
ing metabolites during stress. Increase in light intensity activated various protective
mechanisms including greater accumulation of glutathione, proline and other amino
acids during drought, which contributed to the efficient recovery of wheat after stress.
