What is the main characteristic of Dumb Cane?

Dumb Cane, also known as Dieffenbachia, is primarily known for containing calcium oxalate crystals, which are toxic if ingested. When chewed or bitten, these crystals can cause swelling in the mouth and throat, leading to temporary speech impairment. This characteristic is particularly notable and serves as a warning for anyone handling the plant to be cautious, especially around pets and children.

The other options do not represent the most distinctive or well-known features of Dumb Cane. While it may have some impact on transpiration, humidity, or light adaptability, these traits are secondary to the significant health implications caused by its toxins. Thus, the presence of harmful substances leading to speech impairment is what truly sets Dumb Cane apart.