Ecophysiological responses and self-protective canopy effects of surfgrass (Phyllospadix torreyi) in the intertidal

• Published in: Marine environmental research Vol. 172; p. 105501
• Main Authors: Ruiz-Montoya, Leonardo, Sandoval-Gil, Jose Miguel, Belando-Torrentes, María D., Vivanco-Bercovich, Manuel, Cabello-Pasini, Alejandro, Rangel-Mendoza, Laura Karina, Maldonado-Gutiérrez, Alejandra, Ferrerira-Arrieta, Alejandra, Guzmán-Calderón, Jose Manuel
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.12.2021; Elsevier BV
• Subjects: Antioxidants; Canopies; Canopy; Carbohydrates; Dehydration; Dehydration stress; Desiccation; Ecophysiology; Herbivores; Leaves; Lipid peroxidation; Lipids; Low tide; Moisture content; Osmoregulation; Osmotic acclimation; Oxidative stress; Peroxidation; Photosynthesis; Phyllospadix; Phyllospadix torreyi; Physiological responses; Physiology; Plant cover; Radiation; Seagrasses; Self-protective canopy; Shoots; Solar radiation; Stress (physiology); Surfgrass; Tidal exposure; Water content; Water potential; Water relations; Tidal exposure; Oxidative stress; Photosynthesis; Osmotic acclimation; Self-protective canopy; Dehydration stress; Water relations; Surfgrass
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/j.marenvres.2021.105501

Intertidal seagrasses are subjected to desiccation and direct solar radiation during low tides. It is assumed that the canopy structure can self-protect the underlying shoots during these events, although there is no evidence on a physiological basis. The physiological responses of the surfgrass Phyllospadix torreyi were examined when emerged during low tide, on i) shoots overlaying the canopy, and ii) shoots sheltered within the canopy. Leaf water potential and water content decreased in external leaves after emersion, and the higher concentration of organic osmolytes reflected osmoregulation. Additionally, these shoots also exhibited a drastic reduction in carbohydrates after re-immersion, likely from cellular damage. Lipid peroxidation and antioxidant activity increments were also detected, while photosynthetic efficiency strongly diminished from direct exposure to solar radiation. Conversely, the sheltered shoots did not dehydrate and solely accumulated some oxidative stress, likely resulting from the warming of the canopy. In conclusion, the leaf canopy structure buffers physiological stress in the sheltered shoots, thus acting as a self-protective mechanism to cope with emersion. •Surfgrass can both acclimate and suffers physiological stress during low tide.•Canopy structure can protect underlying shoots from desiccation and sunlight.•Shoots over the canopy can suffer physiological stress when emerged during low tide.•Underlying shoots keep physiological capabilities when emerged during low tide.