School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia.
Ann Bot. 2011 Oct;108(5):933-44. doi: 10.1093/aob/mcr198. Epub 2011 Aug 5.
Karrikinolide (KAR(1)) is a smoke-derived chemical that can trigger seeds to germinate. A potential application for KAR(1) is for synchronizing the germination of weed seeds, thereby enhancing the efficiency of weed control efforts. Yet not all species germinate readily with KAR(1), and it is not known whether seemingly non-responsive species can be induced to respond. Here a major agronomic weed family, the Brassicaceae, is used to test the hypothesis that a stimulatory response to KAR(1) may be present in physiologically dormant seeds but may not be expressed under all circumstances.
Seeds of eight Brassicaceae weed species (Brassica tournefortii, Raphanus raphanistrum, Sisymbrium orientale, S. erysimoides, Rapistrum rugosum, Lepidium africanum, Heliophila pusilla and Carrichtera annua) were tested for their response to 1 µm KAR(1) when freshly collected and following simulated and natural dormancy alleviation, which included wet-dry cycling, dry after-ripening, cold and warm stratification and a 2 year seed burial trial.
Seven of the eight Brassicaceae species tested were stimulated to germinate with KAR(1) when the seeds were fresh, and the remaining species became responsive to KAR(1) following wet-dry cycling and dry after-ripening. Light influenced the germination response of seeds to KAR(1), with the majority of species germinating better in darkness. Germination with and without KAR(1) fluctuated seasonally throughout the seed burial trial.
KAR(1) responses are more complex than simply stating whether a species is responsive or non-responsive; light and temperature conditions, dormancy state and seed lot all influence the sensitivity of seeds to KAR(1), and a response to KAR(1) can be induced. Three response types for generalizing KAR(1) responses are proposed, namely inherent, inducible and undetected. Given that responses to KAR(1) were either inherent or inducible in all 15 seed lots included in this study, the Brassicaceae may be an ideal target for future application of KAR(1) in weed management.
卡罗品内酯（KAR(1)）是一种源自烟雾的化学物质，可促使种子发芽。KAR(1)的一个潜在应用是同步杂草种子的发芽，从而提高杂草防治工作的效率。然而，并非所有物种都容易用 KAR(1)发芽，并且尚不清楚是否可以诱导那些看似无反应的物种做出反应。在这里，我们使用一个主要的农业杂草家族——十字花科，来检验这样一个假设，即对 KAR(1)的刺激反应可能存在于生理休眠的种子中，但在所有情况下都不一定会表现出来。
测试了八种十字花科杂草物种（甘蓝 Tournefortii、萝卜 Raphanus raphanistrum、东方播娘蒿 Sisymbrium orientale、播娘蒿 S.erysimoides、野萝卜 Rapistrum rugosum、非洲独行菜 Lepidium africanum、小甘菊 Heliophila pusilla 和 Carrichtera annua）的种子对 1 µm KAR(1)的反应，这些种子是新鲜采集的，并且经过模拟休眠缓解和自然休眠缓解，包括干湿循环、干后熟、冷层积和暖层积以及为期两年的种子埋藏试验。
在所测试的八种十字花科物种中，有七种在种子新鲜时被 KAR(1)刺激发芽，其余物种在经过干湿循环和干后熟后对 KAR(1)有反应。光照影响种子对 KAR(1)的发芽反应，大多数物种在黑暗中发芽更好。在整个种子埋藏试验中，有无 KAR(1)的发芽都呈现季节性波动。
KAR(1)的反应比简单地说明一个物种是否有反应或无反应更为复杂；光照和温度条件、休眠状态和种子批次都影响种子对 KAR(1)的敏感性，并且可以诱导对 KAR(1)的反应。提出了三种概括 KAR(1)反应的类型，即固有型、诱导型和未检测型。鉴于在本研究中包含的所有 15 个种子批中，KAR(1)的反应要么是固有型，要么是诱导型，十字花科可能是未来在杂草管理中应用 KAR(1)的理想目标。
