Crop improvement is crucial to ensuring global food security under climate change, and hence there is a pressing need for phenotypic observations that are both high throughput and improve mechanistic understanding of plant responses to environmental cues and limitations. In this study, chlorophyll a fluorescence light response curves and gas-exchange observations are combined to test the photosynthetic response to moderate drought in four genotypes of Brassica rapa. The quantum yield of PSII (_PSII) is here analyzed as an exponential decline under changing light intensity and soil moisture. Both the maximum _PSII and the rate of _PSII decline across a large range of light intensities (0–1,000 μmol photons m^–2 s^–1; β_PSII) are negatively affected by drought. We introduce an alternative photosynthesis model (β_PSII model) incorporating parameters from rapid fluorescence response curves. Specifically, the model uses β_PSII as an input for estimating the photosynthetic electron transport rate, which agrees well with two existing photosynthesis models (Farquhar-von Caemmerer-Berry and Yin). The β_PSII model represents a major improvement in photosynthesis modeling through the integration of high-throughput fluorescence phenotyping data, resulting in gained parameters of high mechanistic value.

作物改良对于确保气候变化下的全球粮食安全至关重要，因此迫切需要表型观察，既要高产量又要提高对植物对环境线索和局限性反应的机械理解。在这项研究中，叶绿素a荧光响应曲线和气体交换观测结果相结合，以测试四种甘蓝型油菜对中度干旱的光合响应。PSII的量子产率_PSII）在此被分析为在变化的光强度和土壤湿度下的指数下降。两者最大_PSII和率_PSII跨越大范围的光强度下降（0-1,000微摩尔光子中号^-2小号^-1 ; β _PSII）是带负干旱影响。我们介绍一种替代光合作用模型（ β _PSII掺入来自快速荧光响应曲线参数模型）。具体地，该模型使用β _PSII作为估计光合电子传递速率，这与两个现有光合作用模型（夸尔冯Caemmerer-Berry和阴）非常一致的输入。该β _PSII 通过整合高通量荧光表型数据，该模型代表了光合作用建模的一项重大改进，从而获得了具有较高机械价值的参数。