Root-fed salicylic acid in grape involves the response caused by aboveground high temperature

Area of Science:

• Plant Physiology
• Biochemistry
• Environmental Stress Biology

Background:

• Salicylic acid (SA) is a key plant hormone involved in various physiological processes, including stress responses.
• Understanding the systemic movement of plant hormones like SA is crucial for plant adaptation to environmental changes.
• High temperature stress significantly impacts plant growth and development, necessitating investigation into hormone signaling pathways.

Purpose of the Study:

• To investigate the transport and distribution of salicylic acid (SA) from grape roots to aboveground tissues under high-temperature stress.
• To determine the physiological pathway (xylem vs. phloem) responsible for SA translocation.
• To elucidate the role of root-derived SA as a signaling molecule in response to aerial heat stress.

Main Methods:

• Grape plant roots were supplied with radiolabeled (14)C-salicylic acid ((14)C-SA).
• Plants were subjected to controlled high-temperature treatments for varying durations.
• Radioactivity measurements in different tissues and auto-radiography were employed to track SA movement.

Main Results:

• SA transport from roots to aboveground tissues increased progressively with heat treatment duration.
• The most significant accumulation of SA was observed in the top and middle leaves during the early stages of heat stress.
• SA translocation from root to shoot was confirmed to be primarily dependent on the xylem vascular system, not the phloem.

Conclusions:

• Root-derived SA plays a fundamental role in the plant's response to high-temperature stress experienced in aboveground tissues.
• The systemic movement of SA via the xylem is a critical component of the plant's signaling mechanism under heat stress.
• This study highlights the importance of root-to-shoot hormone transport in mediating plant adaptation to adverse environmental conditions.