Metabolism of reduced and inorganic sulphur in pea cotyledons and distribution into developing seedlings
Author for correspondence: Michael Tausz Tel: +43 316380 8794 Fax: +43 316380 9880 Email: firstname.lastname@example.org
- • Sulphur export and redistribution from the cotyledons of pea (Pisum sativum) seedlings was investigated to determine the role of cotyledons as a sulphur source during root–shoot axis development.
- • Thiols and sulphate were analysed using standard biochemical techniques, and 35S fed to cotyledons by injection.
- • After 35S-cysteine injection, c. 50% of the labelled S in the cotyledon was metabolized to 35S-sulphate. This reaction was partly inhibited by aminooxyacetic acid, an inhibitor of cysteine-desulfhydrase. After 35S-sulphate application, c. 1% of the radiolabel was found in cysteine and glutathione in the cotyledon. After 2 h, c. 20% of the 35S was transported into the root–shoot axis independently of whether 35S-sulphate or 35S-cysteine was injected into the cotyledon. After 4 h, 40% of 35S was found outside the cotyledon.
- • Cotyledons of pea seedlings are capable of sulphate assimilation and cysteine degradation. Both sulphate and reduced sulphur were allocated from the cotyledons to the developing tissues of the pea seedlings.