Yes, all plants produce ethylene gas. It's a naturally occurring hormone in plants and plays a crucial role in regulating various aspects of plant growth and development.

Here's why:

* Ethylene is a ubiquitous plant hormone: It's found in all plant tissues and is produced throughout the plant's life cycle.

* Essential for various processes: Ethylene regulates processes like fruit ripening, leaf senescence (aging), flower wilting, and even seed germination.

* Production can be triggered: While constantly present, its production can be significantly increased by various factors such as stress (mechanical injury, flooding, etc.), age, and exposure to certain chemicals.

However, it's important to note that the amount of ethylene produced varies greatly depending on the plant species, its developmental stage, and environmental conditions.

So, while all plants produce ethylene, the amount and timing of its production can differ considerably.