The relationship between lipoxygenase (LOX) activity and ABA accumulation was studied in the roots of Malus hupehensis (Pampan. Rehd.) seedling using both intact young roots and cell-free system. The result showed that LOX activity and ABA content increased simultaneously after treatment of 30% PEG 6000, 0.6 mol/L mannitol, and 0.2 mol/L NaCl, respectively. NDGA (nordihydroguaiaretic acid), an inhibitor of LOX, inhibited simultaneously both the activity of LOX and the enhancement of ABA level under the stresses. Likewise adding soybean LOX to root cell-free system led to the increase of ABA content. The results suggested that LOX may be a key enzyme in ABA biosynthesis under water stress.
水分胁迫下湖北海棠根系脂氧合酶活性与ABA 积累的关系
杨洪强 贾文锁 张大鹏*
（中国农业大学果树分子发育生物学实验室，北京100094）
摘要：采用无细胞体系 (cell-freesystem)及非离体根 ,研究了湖北海棠 (Malushupehensis (Pampan .)Rehd .)实生幼苗根中脂氧合酶 (LOX)活性和脱落酸 (ABA)生物合成及胁迫诱导ABA积累的关系。结果表明 ,水分胁迫 (30 %PEG处理或 0 .6mol/L甘露醇处理 )及盐胁迫 (0 .2mol/LNaCl)诱导ABA积累的同时 ,LOX活性也上升 ,两者呈一致关系。LOX专一抑制剂去甲愈创木酸 (NDGA)在抑制LOX活性的同时也阻断了胁迫诱导的ABA积累。无细胞体系加入LOX可直接引起ABA的积累。以上结果说明LOX很可能是ABA生物合成及调控胁迫诱导ABA积累的一个关键酶。
关键词： 湖北海棠根系；脂氧合酶；ABA；胁迫；无细胞体系
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