Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus.
Laboratorio de Ciencias Agrogenómicas, Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México, León, Mexico.
Physiol Plant. 2022 Sep;174(5):e13762. doi: 10.1111/ppl.13762.
Water stress may greatly limit plant functionality and growth. Stomatal closure and consequently reduced transpiration are considered as early and sensitive plant responses to drought and salinity stress. An important consequence of stomatal closure under water stress is the rise of leaf temperature (T ), yet T is not only fluctuating with stomatal closure. It is regulated by several plant parameters and environmental factors. Thermal imaging and different stress indices, incorporating actual leaf/crop temperature and reference temperatures, were developed in previous studies toward normalizing for effects unassociated to water stress on T , aiming at a more efficient water stress assessment. The concept of stress indices has not been extensively studied on the model plant Arabidopsis thaliana. Therefore, the aim of this study was to examine the different indices employed in previous studies in assessing rosette transpiration rate (E) in Arabidopsis plants grown under two different light environments and subjected to salinity. After salinity imposition, E was gravimetrically quantified, and thermal imaging was employed to quantify rosette (T ) and artificial reference temperature (T T ). T and several water stress indices were tested for their relation to E. Among the microclimatic growth conditions tested, RWSI ([T - T ]/[T - T ]) and RWSI ([T - T ]/[T - T ]) were well linearly-related to E, irrespective of the light environment, while the sole use of either T or T in different combinations with T returned less accurate results. This study provides evidence that selected combinations of T , T , and T can be utilized to assess E under water stress irrespective of the light environment.
水分胁迫可能极大地限制植物的功能和生长。气孔关闭以及随之而来的蒸腾作用减少被认为是植物对干旱和盐胁迫的早期和敏感反应。水分胁迫下气孔关闭的一个重要后果是叶片温度（T）升高，但 T 的变化不仅与气孔关闭有关。它受到几个植物参数和环境因素的调节。在之前的研究中，已经开发出了热成像和不同的应激指数，这些指数结合了实际的叶片/作物温度和参考温度，以对与水分胁迫无关的 T 的影响进行归一化，旨在更有效地评估水分胁迫。在模式植物拟南芥中，应激指数的概念尚未得到广泛研究。因此，本研究的目的是检验之前研究中使用的不同指数，以评估在两种不同光照环境下生长并受到盐胁迫的拟南芥植物的冠层蒸腾速率（E）。在施加盐胁迫后，通过称重法定量 E，并利用热成像技术定量测量冠层（T）和人工参考温度（T T）。测试了 T 和几种水分胁迫指数与 E 的关系。在测试的微气候生长条件中，无论光照环境如何，RWSI ([T - T ]/[T - T ]) 和 RWSI ([T - T ]/[T - T ]) 与 E 呈良好的线性关系，而单独使用 T 或 T 与 T 的不同组合得出的结果则不太准确。本研究提供的证据表明，T、T 和 T 的选定组合可用于评估水分胁迫下的 E，而与光照环境无关。
