Facultad de Ciencias, Laboratorio de Bioquímica Vegetal, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago, Chile.
Int J Biometeorol. 2020 Aug;64(8):1401-1408. doi: 10.1007/s00484-020-01920-1. Epub 2020 May 6.
A dynamic thermal time model (DTTM) has been developed to predict cold-hardiness in dormant grapevine buds, which uses daily mean temperatures as the only input variable. However, it has been recently reported that cold-hardiness in grapevine buds depends not only on low temperatures (LTs), but also on the content of the plant phytohormone abscisic acid (ABA). An important parameter in the DTTM is the ecodormancy boundary (EDB), which represents the chilling degree days (DDc) required for the transition of the buds from endo to ecodormancy. In this study, the bud cold-hardiness of grapevines was measured by the low-temperature exotherm (LTE) in the subtropical Elqui and in the temperate Maipo valleys of Chile, and the values fitted to the DTTM. Moreover, the ABA content was determined in dormant buds throughout the dormant season. The results demonstrated that the DTTM worked better in the Maipo than in the Elqui valley, and that the content of ABA in the buds was higher in the vines grown in the Elqui valley. On the other hand, the optimized EDB parameter value varied from year to year when it was estimated as chilling accumulated, but when it was estimated as time, it remained constant in the Maipo valley. Based on the results, we conclude the following: (a) the proper functioning of the DTTM requires that the ABA content profile in the dormant buds should be kept constant from year to year, (b) the highest content of ABA in the buds collected in the Elqui valley is probably due to abiotic stresses, (c) the EDB parameter corresponds to the accumulated cold until before the buds begin their deacclimation process and not until they release from endodormancy, (d) the release of the buds from endodormancy does not depend on the accumulated cold, but on the elapsed time.
一个动态热时间模型（DTTM）已经被开发出来，用于预测休眠期葡萄芽的抗寒性，该模型仅使用日平均温度作为唯一的输入变量。然而，最近有报道称，葡萄芽的抗寒性不仅取决于低温（LTs），还取决于植物激素脱落酸（ABA）的含量。DTTM 中的一个重要参数是生态休眠边界（EDB），它代表了芽从内生休眠向生态休眠过渡所需的冷却度日（DDc）。在这项研究中，通过低温放热（LTE）测量了智利亚热带埃尔基和温带迈波谷的葡萄芽的耐寒性，并将这些值拟合到 DTTM 中。此外，在休眠季节的整个休眠期间，测定了休眠芽中的 ABA 含量。结果表明，DTTM 在迈波谷的效果优于埃尔基谷，并且在埃尔基谷生长的葡萄芽中 ABA 的含量更高。另一方面，当累积冷量估算时，优化的 EDB 参数值每年都在变化，但当作为时间估算时，在迈波谷保持不变。基于这些结果，我们得出以下结论：（a）DTTM 的正常运行需要休眠芽中 ABA 含量的稳定，（b）在埃尔基谷收集的芽中 ABA 的最高含量可能是由于非生物胁迫，（c）EDB 参数对应于开始去驯化过程之前累积的冷量，而不是从内生休眠中释放出来的冷量，（d）芽从内生休眠中释放出来不取决于累积的冷量，而是取决于经过的时间。
