Kandra L, Wagner G J
Agronomy Department, University of Kentucky, Lexington 40546-0091.
Arch Biochem Biophys. 1988 Sep;265(2):425-32. doi: 10.1016/0003-9861(88)90145-2.
Detached glandular trichome head preparations and epidermal strips with and without trichome heads were used to identify glandular trichome heads as the site of sucrose ester biosynthesis in tobacco. Carbon dioxide in solution as well as sucrose, glucose, and acetate were shown to serve as precursors to both sucrose esters and duvatrienediol diterpenes in detached trichome heads or epidermal strips, and gaseous CO2 was also efficiently utilized by epidermal strips. Thus, glandular heads can biosynthesize these principal exudate components from a molecule as simple as CO2. While formation of duvatriendiols from all precursors tested and conversion of sucrose and glucose to sucrose esters was light dependent, utilization of acetate to label the 6-O-acetyl group of the glucose moiety of sucrose esters occurred equally well in light and dark. The data suggest that CO2 and/or monosaccharides produced in trichome head cells and perhaps that supplied by other epidermal cells can act as carbon sources for sucrose ester and duvatrienediol biosynthesis which occurs in the glandular trichome head.
分离的腺毛头部制剂以及有和没有腺毛头部的表皮条带被用于确定腺毛头部是烟草中蔗糖酯生物合成的位点。溶液中的二氧化碳以及蔗糖、葡萄糖和乙酸盐被证明是分离的腺毛头部或表皮条带中蔗糖酯和杜瓦三烯二醇二萜的前体，气态二氧化碳也能被表皮条带有效利用。因此，腺毛头部可以从像二氧化碳这样简单的分子生物合成这些主要的渗出物成分。虽然从所有测试前体形成杜瓦三烯二醇以及蔗糖和葡萄糖向蔗糖酯的转化都依赖于光照，但乙酸盐用于标记蔗糖酯葡萄糖部分的6-O-乙酰基在光照和黑暗条件下效果相同。数据表明，腺毛头部细胞中产生的二氧化碳和/或单糖，或许还有其他表皮细胞提供的二氧化碳和/或单糖，可以作为蔗糖酯和杜瓦三烯二醇生物合成的碳源，而这种生物合成发生在腺毛头部。
