Seeds of weed species require light to terminate dormancy and give way to germination. It is documented that sensitivity to light in Polygonum aviculare seeds increases during dormancy release. However, it is not known whether this sensitivity is lost during dormancy induction. The aim of this study was to investigate and quantify the changes in dormancy level of P. aviculare seeds during secondary dormancy induction as measured by changes in sensitivity to light in relation to soil temperature. Polygonum aviculare seeds were stratified at 5ºC until obtaining a minimum dormancy level. The seeds were then induced into secondary dormancy by burying them in pots containing soil which were stored at 10, 15, 20 and 25ºC for different time‐periods. Polygonum aviculare seeds were exhumed periodically, exposed to different light treatments (Pfr/P_{total‐pythochrome} = 0.76, 0.03 and 7.6 × 10⁻⁴) or darkness, and incubated at 15ºC to test germination. Our results showed that the high sensitivity to light acquired during dormancy release and decreased during dormancy induction at a rate that was temperature‐dependent. These changes in sensitivity to light were quantified as a function of the accumulation of thermal‐time over a base‐temperature of 7.9ºC during dormancy induction and were coupled with previous thermal‐time index established for the dormancy release process. Both thermal‐time indices allowed us to develop a model for the prediction of cyclic changes in sensitivity to light in relation to the thermal environment experienced by the seeds during burial. This model constitutes a valuable tool for predicting weed emergence in the field and to design management practices accordingly.

中文翻译：

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何首乌种子休眠诱导过程中的光敏度变化：建立种子库光敏度与土壤温度相关的年度变化预测模型

杂草种子需要光才能终止休眠并让其萌发。有文献证明，休眠释放过程中虎杖种子对光的敏感性增加。但是，尚不知道在诱导休眠期间是否会失去这种敏感性。这项研究的目的是调查和量化次生休眠诱导期间小球藻种子休眠水平的变化，该变化通过对光的敏感性相对于土壤温度的变化来衡量。将何首乌种子在5ºC分层，直到达到最低休眠水平。然后将种子埋入装有土壤的盆中，使它们进入次要休眠状态，这些盆在10、15、20和25ºC下存放了不同的时间。定期挖出何首乌种子，接受不同的光照处理（_Pfr / P_总原色 = _0.76、0.03和7.6×10 ^-4）或黑暗，然后在15ºC下孵育以测试发芽。我们的结果表明，对休眠释放期间获得的光的高灵敏度，以及在休眠诱导期间以与温度相关的速率降低。这些对光敏感性的变化被量化为在诱导休眠期间在7.9ºC的基础温度上的热时间累积的函数，并与为休眠释放过程建立的先前热时间指数相结合。两种热时间指标都使我们能够开发一个模型，用于预测相对于埋藏期间种子所经历的热环境的光敏感度的周期性变化。该模型构成了预测野外杂草出现并据此设计管理实践的有价值的工具。