Ethylene: role in fruit abscission and dehiscence processes

Area of Science:

• Plant Physiology
• Horticultural Science
• Agricultural Science

Background:

• Fruit abscission, including young fruit shedding and mature fruit dehiscence, are critical developmental processes in plants.
• Ethylene is a plant hormone known to influence various developmental stages, including ripening and senescence.

Purpose of the Study:

• To investigate the role of ethylene production in the natural dehiscence of cotton (Gossypium hirsutum L.) and pecan (Carya illinoensis) fruits.
• To determine the relationship between endogenous ethylene levels and the timing of fruit dehiscence.
• To assess the effect of exogenous ethylene application on fruit dehiscence in cotton, pecan, and okra (Hibiscus esculentus L.).

Main Methods:

• Measuring ethylene production rates in developing cotton and pecan fruits.
• Calculating internal ethylene concentrations based on production rates and gas diffusion.
• Applying varying concentrations of exogenous ethylene to induce and study fruit dehiscence.
• Comparing the time course of ethylene production, exogenous ethylene response, and natural dehiscence.

Main Results:

• Two distinct peaks of ethylene production were observed during cotton fruit development, preceding shedding and dehiscence.
• Ethylene production in pecan fruits increased significantly before dehiscence, reaching a peak prior to the process.
• Exogenous ethylene, at concentrations as low as 0.1 µL/L, hastened dehiscence in cotton, pecan, and okra fruits, with saturation occurring at 10 µL/L.

Conclusions:

• Endogenous ethylene levels rise sufficiently before natural fruit dehiscence to initiate the process, suggesting ethylene is a key regulator.
• Ethylene likely plays a significant role in the natural ripening and dehiscence of cotton and pecan fruits.
• The findings also suggest a potential involvement of ethylene in the abscission of young cotton fruits.