Kim Kwan Su, Park Si Hyung, Jenks Matthew A
Department of Medicinal Plant Resources, Mokpo National University, Muan, Republic of Korea.
J Plant Physiol. 2007 Sep;164(9):1134-43. doi: 10.1016/j.jplph.2006.07.004. Epub 2006 Aug 10.
Sesame (Sesamum indicum L.) is one of the most important oilseed crops, having seeds and oil that are highly valued as a traditional health food. The objective of this study was to evaluate leaf cuticular wax constituents across a diverse selection of sesame cultivars, and the responses of these waxes to drought-induced wilting. Water-deficit was imposed on 18 sesame cultivars by withholding irrigation for 15d during the post-flowering stage, and the effect on seed yield and leaf waxes compared with a well-watered control. Leaf cuticular waxes were dominated by alkanes (59% of total wax), with aldehydes being the next-most abundant class. Compared to well-irrigated plants, drought treatment caused an increase in wax amount on most cultivars, with only three cultivars having a notable reduction. When expressed as an average across all cultivars, drought treatment caused a 30% increase in total wax amount, with a 34% increase in total alkanes, a 13% increase in aldehydes, and a 28% increase in the total of unknowns. In all cultivars, the major alkane constituents were the C27, C29, C31, C33, and C35 homologs, whereas the major aldehydes were the C30, C32, and C34 homologs, and drought exposure had only minor effects on the chain length distribution within these and other wax classes. Drought treatments caused a large decrease in seed yield per plant, but did not affect the mean weight of individual seeds, showing that sesame responds to post-flowering drought by reducing seed numbers, but not seed size. Seed yield was inversely correlated with the total wax amount (-0.466*), indicating that drought induction of leaf wax deposition does not contribute directly to seed set. Further studies are needed to elucidate the ecological role for induction of the alkane metabolic pathway by drought in regulating sesame plant survival and seed development in water-limiting environments.
芝麻（Sesamum indicum L.）是最重要的油料作物之一，其种子和油作为传统健康食品备受珍视。本研究的目的是评估多种芝麻品种叶片角质层蜡质成分，以及这些蜡质对干旱诱导萎蔫的响应。在花后阶段通过停止灌溉15天对18个芝麻品种施加水分亏缺，并将其对种子产量和叶片蜡质的影响与充分浇水的对照进行比较。叶片角质层蜡质以烷烃为主（占蜡质总量的59%），醛类是第二丰富的类别。与充分灌溉的植株相比，干旱处理使大多数品种的蜡质含量增加，只有三个品种显著减少。以所有品种的平均值表示，干旱处理使蜡质总量增加30%，烷烃总量增加34%，醛类增加13% , 未知物总量增加28%。在所有品种中，主要的烷烃成分是C27、C29、C31、C33和C35同系物，而主要的醛类是C30、C32和C34同系物，干旱暴露对这些及其他蜡质类别的链长分布影响较小。干旱处理使单株种子产量大幅下降，但不影响单粒种子的平均重量，表明芝麻通过减少种子数量而非种子大小来响应花后干旱。种子产量与蜡质总量呈负相关（-0.466*），表明干旱诱导的叶片蜡质沉积并不直接促进结实。需要进一步研究以阐明干旱诱导烷烃代谢途径在调节芝麻在水分受限环境中的植株存活和种子发育方面的生态作用。
