Abstract Death camas (Zigadenus spp.) is a common poisonous plant in North America with plants occurring in a wide variety of habitats with species of toxic concern occurring primarily in meadows, grasslands, shrublands, and mountains. The toxicity of Zigadenus species has been attributed to a series of steroidal alkaloids. The objective of this study was to evaluate zygacine and total steroidal alkaloid concentrations in different plant tissues of Zigadenus paniculatus as a function of plant maturity. Death camas plants were collected at two locations at different developmental growth stages representing vegetative, flower, seed pod, and shattered seed pod stages. Zygacine represented greater than 50% of the total steroidal alkaloids at all developmental stages. In bulbs, total steroidal alkaloid and zygacine concentrations did not change significantly as a function of plant phenology, and concentrations were lower than what were observed in above ground plant parts. Total steroidal alkaloid and zygacine concentrations in above ground parts were highest at early vegetative growth stages and decreased over the growing season. In plant reproductive parts, total steroidal alkaloid and zygacine concentrations increased until maturity and then decreased as the plant senesced. The concentrations of steroidal alkaloids reported here suggest that the toxic risk associated with death camas is greatest in the early vegetative growth stages followed by the flower and pod stages. There is a toxic risk to livestock as long as the plant is present, and caution should be taken when grazing livestock in areas with death camas until the plant senesces.

中文翻译：

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山麓死亡鸲 (Zigadenus paniculatus) 有毒甾体生物碱的季节性变化

摘要 Death camas (Zigadenus spp.) 是北美常见的有毒植物，其植物分布在各种栖息地，有毒物种主要分布在草地、草原、灌木丛和山区。Zigadenus 物种的毒性归因于一系列甾体生物碱。本研究的目的是评估 Zigadenus paniculatus 不同植物组织中的 zygacine 和总甾体生物碱浓度作为植物成熟度的函数。在代表营养、花、种荚和破碎种荚阶段的不同发育生长阶段的两个位置收集死亡camas植物。在所有发育阶段，齐加辛占总甾体生物碱的 50% 以上。在灯泡中，总甾体生物碱和 zygacine 浓度作为植物物候的函数没有显着变化，并且浓度低于在地上植物部分观察到的浓度。地上部分的总甾体生物碱和 zygacine 浓度在早期营养生长阶段最高，并在生长季节下降。在植物生殖部分，总甾体生物碱和 zygacine 浓度在成熟前增加，然后随着植物衰老而下降。此处报告的甾体生物碱浓度表明，与死亡 camas 相关的毒性风险在早期营养生长阶段最大，其次是花和豆荚阶段。只要植物存在，牲畜就存在中毒风险，