Sodium hydrosulfide priming improves the response of photosynthesis to overnight frost and day high light in avocado (Persea americana Mill, cv. ‘Hass’)

Abstract

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 (H2S), 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 CO2 assimilation, a lower accumulation of hydrogen peroxide as well as lower photoinhibition, as compared to untreated plants. The ability to maintain a high CO2 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.

Physiological Characterization of Young ‘Hass’ Avocado Plant Leaves Following Exposure to High Temperatures and Low Light Intensity

“…The CO 2 -assimilation rate in the young avocado plants ranged between 5 and 8 μmol m −2 s −1 , similar to previously published results for young potted ‘Hass’ plants [ 22 , 23 ]. CO 2 assimilation was only significantly reduced at 49 °C and above, suggesting this as the temperature threshold for heat stress damage in young avocado plants.…”

Hydrogen sulfide (H2S) signaling in plant development and stress responses

“…When plants suffer from various abiotic stresses, the imbalance of redox state and the disorder of ion transport will largely restrict the photosynthesis of plants. Exogenous H 2 S can promote photosynthesis with a higher chlorophyll content in a variety of plants (Chen et al 2015b ; Liu et al 2020b ; Parveen et al 2017 ), even in lower algae (Dooley et al 2013b , 2015 ; Joshi et al 2020 ), suggesting that the promotion of H 2 S on plant photosynthesis appeared in a very early period of plant evolution to improve plant survival. Chen et al ( 2011 ) have revealed the role of H 2 S in photosynthesis in Spinacia oleracea .…”

Hydrogen sulfide and nitric oxide signal integration and plant development under stressed/non‐stressed conditions

“…Muñoz-Vargas et al (2019) have noticed inhibition of NADP-malic enzyme activity by H 2 S and NO in sweet pepper. Furthermore, the role of H 2 S was examined in regulating photosynthesis under overnight frost and daytime high light in avocado (Joshi et al 2019). Finally, Kataria et al (2019) have reported crucial role of nitrate reductase-dependent production of NO in regulating magnetopriming-induced salt tolerance in soybean.…”