Elevated CO induce alterations in the hormonal regulation of stomata in drought stressed tomato seedlings.

The atmospheric CO level is rising, and the consequent climate change is causing an increase in drought events. Furthermore, the CO level is known to induce changes in the physiological responses to stress in plants. Exogenous melatonin is suggested to play roles in the response of plants to abiotic stresses, including drought.

Stomatal effects and ABA metabolism mediate differential regulation of leaf and flower cooling in tomato cultivars exposed to heat and drought stress.

Co-occurring heat and drought stresses challenge crop performance. Stomata open to promote evaporative cooling during heat stress, but close to retain water during drought stress, which resulted in complex stomatal regulation under combined heat and drought. We aimed to investigate stomatal regulation in leaves and flowers of perennial, indeterminate cultivars of tomatoes subjected to individual and combined heat and drought stress followed by a recovery period, measuring morphological, physiological, and biochemical factors involved in stomatal regulation.

Exogenous Melatonin Alters Stomatal Regulation in Tomato Seedlings Subjected to Combined Heat and Drought Stress through Mechanisms Distinct from ABA Signaling.

The understanding of stomatal regulation in climate stress is essential for ensuring resilient crops. The investigation of the stomatal regulation in combined heat and drought stress aimed to link effects of exogenous melatonin on stomatal conductance (g) and its mechanistic interactions with ABA or ROS signaling. Melatonin-treated and non-treated tomato seedlings were subjected to moderate and severe levels of heat (38°C for one or three days) and drought stress (soil relative water content of 50% or 20%) applied individually and in combination.

Interactive effects of elevated CO concentration and combined heat and drought stress on tomato photosynthesis.

Background: Extreme weather events are predicted to increase, such as combined heat and drought. The CO concentration ([CO]) is predicted to approximately double by 2100. We aim to explore how tomato physiology, especially photosynthesis, is affected by combined heat and drought under elevated [CO] (e [CO]).