Agricultural Research Organization (ARO), Volcani Center, Institute of Plant Sciences, Rishon LeZion, Israel.
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot, Israel.
Physiol Plant. 2020 Feb;168(2):394-405. doi: 10.1111/ppl.13023. Epub 2019 Nov 3.
Radiation frost events, which have become more common in the Mediterranean Basin in recent years, inflict extensive damage to tropical/subtropical fruit crops. During radiation frost, sub-zero temperatures are encountered in the dark, followed by high light during the subsequent clear-sky day. One of the key processes affected by these conditions is photosynthesis, which, when significantly inhibited, leads to the enhanced accumulation of reactive oxygen species (ROS) and damage. The use of 'chemical priming' treatments that induce plants' endogenous stress responses is a possible strategy to improve their coping with stress conditions. Herein, we studied the effects of priming with sodium hydrosulfide (NaHS), a donor of hydrogen sulfide (H S), on the response of photosynthesis to overnight frost and day high-light conditions in 'Hass' avocado (Persea americana Mill). We found that priming with a single foliar application of NaHS had positive effects on the response of grafted 'Hass' plants. Primed plants exhibited significantly reduced inhibition of CO assimilation, a lower accumulation of hydrogen peroxide as well as lower photoinhibition, as compared to untreated plants. The ability to maintain a high CO assimilation capacity after the frost was attained on the background of considerable inhibition in stomatal conductance. Thus, it was likely related to the lower accumulation of ROS and photodamage observed in primed 'Hass' plants. This work contributes toward the understanding of the response of photosynthesis in a subtropical crop species to frost conditions and provides a prospect for chemical priming as a potential practice in orchards during cold winters.
近年来，在地中海盆地辐射霜事件变得越来越普遍，对热带/亚热带水果作物造成了广泛的破坏。在辐射霜期间，在黑暗中会遇到零度以下的温度，随后在接下来的晴天会出现高光。受这些条件影响的关键过程之一是光合作用，当光合作用受到显著抑制时，会导致活性氧（ROS）和损伤的积累增强。使用“化学引发”处理来诱导植物的内源性应激反应是提高其应对应激条件的一种可能策略。在此，我们研究了用氢硫化钠（NaHS）引发对“哈斯”鳄梨（Persea americana Mill.）光合作用对隔夜霜和白天高光条件的响应。我们发现，用单一叶面喷施 NaHS 引发对嫁接“哈斯”植物的响应有积极影响。与未处理的植物相比，引发的植物表现出 CO 同化抑制显著降低、过氧化氢积累降低和光抑制降低。在背景下，在气孔导度受到相当大抑制的情况下，能够在获得霜后保持高 CO 同化能力，这可能与在引发的“哈斯”植物中观察到的 ROS 和光损伤积累较低有关。这项工作有助于理解亚热带作物物种对霜条件下光合作用的响应，并为寒冷冬季果园中的化学引发提供了一种潜在实践前景。
