Preferably plant seeds are stored in the glassy state to slow deterioration reactions. Thus, it is valuable to know at which moisture content (MC) seeds reach the glassy state and if this is universal or species-specific. We investigated the glass transition temperature (Tg) of seeds using several methods. Dynamic mechanical analysis of intact seeds with a 3 °C/min heating rate was the most suited analysis method for brassica seeds. This method was applied to seeds from four Brassica oleracea (brassica), two Lactuca sativa (lettuce) varieties and one Daucus carota (carrot) variety, equilibrated to several MCs. As oil does not mix with water, it will not contribute to the glass transition. Hence, MC should be based on the dry matter only present in the hydrophilic phase, thus excluding oil, to more accurately describe the Tg curve. This results in significant differences for different species based on MC excluding the oil content, which is a novel approach. Lettuce has a higher oil content and thus a significantly higher Tg curve than brassica. However, the curves are rather similar when based on MC including oil, as observed in previous studies. Thus, a universal Tg curve can be advised as a rule of thumb if no other information is available. For precise drying and storage optimisation, the species-specific Tg curve can be used.

中文翻译：

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水分对各种园艺种子玻璃化转变的普遍或物种特异性影响？


植物种子最好以玻璃状状态储存以减缓变质反应。因此，了解水分含量 （MC） 种子在哪些情况下达到玻璃状状态以及这是普遍的还是物种特异性的，是有价值的。我们使用多种方法研究了种子的玻璃化转变温度 （Tg）。以 3 °C/min 的加热速率对完整种子进行动态机械分析是最适合芸苔属种子的分析方法。该方法应用于 4 个 Brassica oleracea（芸苔）、2 个 Lactuca sativa（生菜）品种和 1 个 Daucus carota（胡萝卜）品种的种子，并与几个 MC 平衡。由于油不与水混合，因此不会促进玻璃化转变。因此，MC 应基于仅存在于亲水相中的干物质，因此不包括油，以更准确地描述 Tg 曲线。这导致基于 MC 的不同物种存在显著差异，不包括油含量，这是一种新颖的方法。生菜的含油量更高，因此 Tg 曲线明显高于芸苔属植物。然而，正如在以前的研究中观察到的那样，当基于 MC 包括油时，曲线非常相似。因此，如果没有其他信息可用，则可以根据经验建议使用通用 Tg 曲线。为了精确干燥和储存优化，可以使用物种特异性 Tg 曲线。