Adhikari Subodh, Russell F Leland
Department of Land Resources and Environmental Sciences, Montana State University, PO Box 173120, Bozeman, Montana, 59717-3120 USA.
Department of Biological Sciences, Wichita State University, 1845 Fairmount, Wichita, Kansas, 67260-0026 USA.
Am J Bot. 2014 Dec;101(12):2079-87. doi: 10.3732/ajb.1400210. Epub 2014 Nov 26.
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Interactions that limit lifetime seed production have the potential to limit plant population sizes and drive adaptation through natural selection. Effects of insect herbivory to apical meristems (apical meristem mining) on lifetime seed production rarely have been quantified experimentally. We studied Cirsium altissimum (tall thistle), whose meristems are mined by Platyptilia carduidactyla (artichoke plume moth), to determine how apical damage affects plant maternal fitness and evaluate both direct and indirect mechanisms underlying these effects.•
In restored prairie, apical mining was manipulated on tall thistles by applying insecticide, water, or no spray to apical meristems. We quantified effects on lifetime seed production, plant architecture, and flowering phenology. Seed germinability and seedling mass were evaluated in a greenhouse.•
Apical meristem miners decreased lifetime seed production of C. altissimum, but not seed quality. Higher mortality rates of damaged plants contributed to reduced seed production. Apical damage reduced plant height and increased the proportion of blooming flower heads in axial positions on branches. Apical damage delayed flowering and shortened flowering duration.•
Apical meristem mining reduced plant maternal fitness. The shift in the identity of blooming flower heads from terminal to axial positions contributed to this reduction because axial heads are less fecund. Shorter, meristem-mined plants may have been more susceptible to competition, and this susceptibility may explain their higher mortality rates. The kinds of changes in architecture and phenology that resulted from apical damage to C. altissimum have been shown to affect floral visitation in other plant species.
研究前提：限制种子终生产量的相互作用有可能限制植物种群规模，并通过自然选择推动适应性进化。昆虫对顶端分生组织的取食（顶端分生组织挖掘）对种子终生产量的影响很少通过实验进行量化。我们研究了高蓟（Cirsium altissimum），其分生组织会被菊芋羽蛾（Platyptilia carduidactyla）挖掘，以确定顶端损伤如何影响植物母体适合度，并评估这些影响背后的直接和间接机制。
方法：在恢复的草原上，通过对高蓟的顶端分生组织喷洒杀虫剂、水或不进行喷洒来控制顶端挖掘。我们量化了对种子终生产量、植物结构和开花物候的影响。在温室中评估种子发芽能力和幼苗质量。
主要结果：顶端分生组织挖掘者降低了高蓟的种子终生产量，但不影响种子质量。受损植物较高的死亡率导致种子产量降低。顶端损伤降低了植物高度，并增加了枝条轴向位置上开花头状花序的比例。顶端损伤延迟了开花并缩短了开花持续时间。
结论：顶端分生组织挖掘降低了植物母体适合度。开花头状花序从顶端位置向轴向位置的转变导致了这种降低，因为轴向头状花序的繁殖力较低。较短的、分生组织被挖掘的植物可能更容易受到竞争影响，这种易感性可能解释了它们较高的死亡率。高蓟顶端损伤所导致的结构和物候变化已被证明会影响其他植物物种的访花情况。
