Devadze Grigorij, Dannehl Dennis, Nerlich Annika, Schmidt Uwe, Streif Stefan
Automatic Control and System Dynamics, Chemnitz University of Technology, Chemnitz, Germany.
Humboldt-Universität zu Berlin, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Division Biosystems Engineering, Berlin, Germany.
Front Plant Sci. 2025 Feb 26;16:1543699. doi: 10.3389/fpls.2025.1543699. eCollection 2025.
This is the first study who presents an approach to predict secondary metabolites content in tomatoes using multivariate time series classification of greenhouse sensor data, which includes climatic conditions as well as photosynthesis and transpiration rates. The aim was to find the necessary conditions in a greenhouse to determine the maximum content of secondary metabolites, as higher levels in fruits can promote human health. For this, we defined multiple classification tasks and derived suitable classification function. Cross-validated high accuracy results demonstrate the effectiveness of the approach. Considering a period of three weeks, we found that PPFD levels between 396.0 μmol/ms and 511.2 μmol/ms as well as transpiration rates ranging from 4.4 mg HO/ms to 7.47 mg HO/ms were observed as optimal for the contents of beta carotene, lutein, and lycopene. Optimal contents for naringenin and phloretin diglucoside can be achieved at lower PPFD ranges from 229.4 μmol/ms to 431.2 μmol/ms and from 35.76 μmol/ms to 262.28 μmol/ms and at lower transpiration rates from 4.71 to 6.47 mg HO/ms and from 3.04 to 4.26 mg HO/ms, respectively. It was discovered for the first time that, photosynthesis rates also play a significant role in the accumulation of secondary metabolites. Photosynthesis rates between 0.39 μmol CO/ms and 1.21 μmol CO/ms over three weeks were crucial for the optimal accumulation of phenolic acids such as caffeic acid derivates, coumaric acid hexoside, ferulic acid hexoside and coumaroylquinic acids as well as for quercetin and flavonoid. An optimal temperature range between 20.94 and 21.53°C and a PPFD from 250.0 to 375.2 μmol/ms was classified as beneficial to synthesize these compounds. Optimal light intensity for the total phenolic acids (129.35 - 274.34 μmol/ms) and for the total flavonoids (31.24 - 249.31 μmol/ms), the optimum relative humidity levels are between 83.45 - 91.29% and 87.13 - 91.29%, respectively. Based on these results, this study provides the first evidence that the impact of a single climate factor on secondary metabolites in tomato fruits should not be considered in isolation, but rather, all climatic factors during a growth period must be taken into account to predict the optimal accumulation of individual phenolic compounds and carotenoids in tomatoes. Our results have laid the headstone to help growers target their climate controls to maximize the health-promoting phytochemicals in tomatoes.
这是第一项提出利用温室传感器数据的多变量时间序列分类来预测番茄中次生代谢物含量的研究，这些数据包括气候条件以及光合作用和蒸腾速率。目的是找出温室中决定次生代谢物最大含量的必要条件，因为果实中较高水平的次生代谢物可以促进人类健康。为此，我们定义了多个分类任务并推导了合适的分类函数。交叉验证的高精度结果证明了该方法的有效性。考虑为期三周的时间段，我们发现，对于β-胡萝卜素、叶黄素和番茄红素的含量而言，观察到光合光子通量密度（PPFD）水平在396.0 μmol/ms至511.2 μmol/ms之间以及蒸腾速率在4.4 mg HO/ms至7.47 mg HO/ms之间是最佳的。柚皮苷和根皮苷二葡萄糖苷的最佳含量可以在较低的PPFD范围内实现，即分别在229.4 μmol/ms至431.2 μmol/ms以及35.76 μmol/ms至262.28 μmol/ms之间，并且在较低的蒸腾速率下实现，分别为4.71至6.47 mg HO/ms以及3.04至4.26 mg HO/ms。首次发现光合作用速率在次生代谢物的积累中也起着重要作用。在三周内，0.39 μmol CO/ms至1.21 μmol CO/ms之间的光合作用速率对于酚酸如咖啡酸衍生物、香豆酸己糖苷、阿魏酸己糖苷和香豆酰奎尼酸以及槲皮素和类黄酮的最佳积累至关重要。20.94至2l.53°C之间的最佳温度范围以及250.0至375.2 μmol/ms的PPFD被分类为有利于合成这些化合物。总酚酸（129.35 - 274.34 μmol/ms）和总黄酮（31.24 - 249.31 μmol/ms）的最佳光照强度下，最佳相对湿度水平分别在83.45 - 91.29%和87.13 - 91.29%之间。基于这些结果，本研究首次提供了证据，即不应孤立地考虑单一气候因素对番茄果实中次生代谢物的影响，相反，必须考虑生长期间的所有气候因素，以预测番茄中单个酚类化合物和类胡萝卜素的最佳积累。我们的结果为帮助种植者针对性地进行气候控制以最大化番茄中促进健康的植物化学物质奠定了基础。
