Salminen Seppo O, Grewal Parwinder S
Department of Entomology, OARDC/The Ohio State University, Wooster 44691-4096, USA.
J Chem Ecol. 2002 May;28(5):939-50. doi: 10.1023/a:1015201616013.
Tall fescue, Festuca arundinacea, and perennial ryegrass, Lolium perenne. are widely infected with fungal endophytes (Neotyphodium spp.). The symbiosis between plant and fungus leads to synthesis of alkaloids that have been shown to be either toxic or act as feeding deterrents against insect pests. As cultural practices have the potential to regulate production of plant secondary metabolites, we evaluated the influence of mowing frequency on the levels of major alkaloids in tall fescue and perennial ryegrass in the greenhouse. Tall fescue and perennial ryegrass maintained in 15-cm-diam. pots were cut to 5-cm height weekly or biweekly. Samples were taken monthly and the alkaloids extracted and analyzed by reverse-phase LC-MS. In tall fescue, ergovaline, ergonovine, and ergocristine were identified, whereas only ergocristine was identified in perennial ryegrass samples. In tall fescue, we observed a trend showing higher levels in samples cut biweekly than in those cut weekly. A similar pattern was seen in some putative alkaloids that were not identified. In perennial ryegrass, ergocristine and two putative alkaloids followed a pattern similar to that of alkaloids in tall fescue. A survey of a few samples of perennial ryegrass using extractions specific to peramine and lolitrem B yielded evidence suggesting their presence as well as several other identified alkaloids. These data support the hypothesis that decreased mowing frequency enhances alkaloid production/accumulation in tall fescue and perennial ryegrass.
高羊茅（Festuca arundinacea）和多年生黑麦草（Lolium perenne）广泛感染真菌内生菌（Neotyphodium spp.）。植物与真菌之间的共生关系导致生物碱的合成，这些生物碱已被证明具有毒性或可作为对害虫的取食威慑剂。由于栽培措施有可能调节植物次生代谢产物的产生，我们在温室中评估了刈割频率对高羊茅和多年生黑麦草中主要生物碱含量的影响。将种植在直径15厘米花盆中的高羊茅和多年生黑麦草每周或每两周刈割至5厘米高度。每月采集样本，提取生物碱并通过反相液相色谱-质谱联用仪进行分析。在高羊茅中，鉴定出了麦角缬碱、麦角新碱和麦角克碱，而在多年生黑麦草样本中仅鉴定出了麦角克碱。在高羊茅中，我们观察到一种趋势，即每两周刈割的样本中的生物碱含量高于每周刈割的样本。在一些未鉴定出的假定生物碱中也观察到了类似的模式。在多年生黑麦草中，麦角克碱和两种假定生物碱的模式与高羊茅中的生物碱相似。使用针对哌嗪和洛替泊B的特定提取方法对一些多年生黑麦草样本进行的调查提供了证据，表明它们以及其他几种已鉴定出的生物碱的存在。这些数据支持了这样的假设，即降低刈割频率会提高高羊茅和多年生黑麦草中生物碱的产生/积累。
