The volume of flame, however, is increased by inert gas, and there is a proportionate diminution of the heating effect. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 Various. Nitrogen by itself is an inert gas, colorless and uninflammable. Scientific American Supplement No. 819 Various.
Plants that have been damaged are particularly susceptible to being infected by tomato early blight alternaria. When a plant is infected with Alternaria Alternata, it will normally appear first on the lower leaves of the plant in the form of plant leaf spots that are either brown or black. These tomato leaf spots will eventually migrate to the stem and even the fruit of the tomato.
The appearance of yellow leaves on your tomato plant is usually not a death sentence. However, it does mean that your plant has a problem in need of attention and correction. Tomatoes need nitrogen; their leaves will turn yellow without it. Mix some compost or used coffee grounds in with the soil to determine if a lack of nitrogen is the problem. If the bottom leaves of your tomato plant turn yellow, it's probably lacking in important nutrients. It may not be getting adequate sunlight.