Is the inside of a plant cell more like a liquid or a solid? While this may sound like an odd question, new research demonstrates it can be either, depending on how much light you shine on it. Chloroplasts within plant cells constitute an active form of matter that undergoes dramatic phase transitions.Is the inside of a plant cell more like a liquid or a solid? While this may sound like an odd question, new research demonstrates it can be either, depending on how much light you shine on it. Chloroplasts within plant cells constitute an active form of matter that undergoes dramatic phase transitions.