林生山黧豆幼苗2,4—二氨基丁酸的合成及其与胁迫条件的关系

林生山黧豆幼苗用［3H］－天门冬氨酸标记后，高丝氨酸在6h内迅速增加。高丝氨酸合成速率降低后，2，4－二氨基丁酸的合成量上升，于18h达到高峰。赖氨酸和苏氨酸与二氨基丁酸的合成表现有协同反馈机制。结果支持了天门冬半醛转氨生成二氨基丁酸的假说。盐胁迫、渗透胁迫和热激增加了二氨基丁酸的合成，可能是因为不同胁迫条件都造成了细胞脱水，从而促进了二氨基丁酸的合成。

Biosynthesis of 2,4-diaminobutyric acid and its relationship with stress in Lathyrus sylvestris L.seedlings

Seedlings (3 wk old) of Lathyrus sylvestris L. were labelled with 3H] -aspinic acid for 3, 6, 9, 12, 15, 18, 21 and 24 h. Radio active free amino acids extracted with ethanol were separated by polyamide thin-layer two-demensboal chromatography and radio activities were measured by liquid scintillation. Results showed that synthesis of DABA (2, 4-diaminobutyric acid) was the highest 18 h after labelling, following Hse peak value 6 h after labelling. Synthesis of Lys and Thr and that of DABA thowed an inverse relationship, indicating a possible cooperative feedback mechanism. Results supported the hypothesis of biosynthesis of DABA by a transamino reactdri from aspartic semialdehyde. Salt, osmotin and high temperature increased the biosynthesis of DABA.DABA probably played a role in overall protective responses of cells during dehydration caused by stress conditions.