Documenting domestication in a lost crop (Polygonum erectum L.): evolutionary bet-hedgers under cultivation
Documenting domestication in a lost crop (Polygonum erectum L.): evolutionary bet-hedgers under cultivation
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DOI：
10.1007/s00334-016-0592-9
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发表时间：
2017-05-01
影响因子：
2.5
通讯作者：
Mueller, Natalie G.
中科院分区：
文献类型：
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作者：
Mueller, Natalie G.
这项研究使用形态计量学和数字图像分析来记录一年生种子作物 Polygonumectum L.（直立虎杖）的驯化综合症，这种作物由美洲原住民种植了约 100 年。北美东部已有 2,500 年历史。这种植物是被称为东部农业综合体的几种种子作物之一，这是一种前玉米农业系统，几千年来一直支持着以密西西比河谷中部为中心的核心地区的社会。已灭绝的驯化亚种 P.ecterum ssp。 watsoniae N. G. Muell.这里描述的，表现出一些经典的驯化标志，包括与其野生祖先相比，更大的果实和减少的发芽抑制剂。驯化的直立草也表现出大大降低的发芽异形性。发芽异态性是植物进化赌注对冲的典型例子：野生直立植物牺牲每代的最大适应度，以减少许多代的适应度方差。它通过生产两种不同类型的水果来实现这一目的：一种是在生产后立即在春天发芽的水果（光滑型），另一种是在发芽前在土壤种子库中保留一个或多个生长季节的水果（结核型）。结核变体可以使种群在不良事件发生后恢复。在耕种过程中，随着人类保存种子并为幼苗创造可预测的微环境，维持这一策略的选择压力得到了放松，从而为古代农民带来了同质的收获和可靠的发芽。
This study uses morphometrics and digital image analysis to document domestication syndrome in an annual seed crop, Polygonum erectum L. (erect knotweed), which was cultivated by Native Americans for c. 2,500 years in eastern North America. This plant is one of several seed crops referred to as the Eastern Agricultural Complex, a pre-maize agricultural system that supported societies in a core area centred on the central Mississippi valley for millennia. The extinct domesticated subspecies P. erectum ssp. watsoniae N. G. Muell. described here, exhibits some classic markers of domestication, including larger fruits and reduced germination inhibitors in comparison to its wild progenitor. Domesticated P. erectum also exhibits greatly reduced germination heteromorphism. Germination heteromorphism is the classic example of evolutionary bet-hedging in plants: wild P. erectum sacrifices maximum fitness per generation for a reduction in fitness variance over many generations. It does so by producing two different types of fruits: ones that germinate immediately in the spring after they are produced (smooth morphs), and ones that remain in the soil seed bank for one or more growing seasons before germinating (tubercled morphs). Tubercled morphs allow populations to recover after adverse events. Under cultivation, the selective pressures that maintained this strategy were relaxed as humans saved seeds and created predictable microenvironments for seedlings, resulting in homogenous harvests and reliable germination for ancient farmers.