Crop yield is critically related to the physiological responses and disease resistance of the crop, which could be strongly affected by high temperature conditions. We observed the changes in the growth of barley under higher than ambient air-temperature conditions using a temperature gradient field chamber (TGFC) during winter and spring. Before the stem extension stage of barley growth, Cladosporium sp. spontaneously appeared in the TGFC. The severity of disease became serious under warmer temperature conditions. Further, the stomata closed as the severity of the disease increased; however, stomatal conductance at the initial stage of disease was higher than that of the normal leaves. This was likely due to the Iwanov effect, which explains that stressed plants rapidly and transiently open their stomata before longer-term closure. In this study, we tested three optical methods: soil-plant analysis development (SPAD) chlorophyll index, photochemical reflectance index (PRI), and maximum quantum yield (Fv/Fm). These rapid evaluation methods have not been used in studies focusing on disease stress, although some studies have used these methods to monitor other stresses. These three indicative parameters revealed that diseased barley exhibited lower values of these parameters than normal, and with the increase in disease severity, these values declined further. Our results will be useful in efficient monitoring and evaluation of crop diseases under future warming conditions.

中文翻译：

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光学传感技术，用于评估克氏孢子虫引起的疾病的严重程度。在温暖条件下的大麦中。

作物产量与作物的生理反应和抗病性至关重要，高温条件可能会严重影响作物的生理响应和抗病能力。我们在冬季和春季使用温度梯度场室（TGFC）观察了大麦在高于环境空气温度条件下生长的变化。在大麦生长的茎延伸期之前，Cladosporiumsp。自发出现在TGFC中。在温暖的温度条件下，疾病的严重性变得严重。此外，随着疾病严重程度的增加，气孔关闭。然而，病害初期的气孔导度高于正常叶片。这可能是由于Iwanov效应所致，这说明受胁迫的植物在长期关闭之前迅速而短暂地打开了它们的气孔。在这项研究中，我们测试了三种光学方法：土壤植物分析发展（SPAD）叶绿素指数，光化学反射指数（PRI）和最大量子产率（Fv / Fm）。这些快速评估方法尚未用于关注疾病压力的研究中，尽管一些研究已使用这些方法来监测其他压力。这三个指示性参数表明，患病的大麦显示出的这些参数值低于正常值，并且随着疾病严重程度的增加，这些值进一步下降。我们的结果将有助于在未来变暖条件下有效监测和评估作物病害。