Some tomato plant leaves yellow due to a lack of sunlight on mature plants. When the plants become large, bushy, and heavy with fruit, the top portions of the plant can block the lower portions from getting sunlight.This can cause the leaves to yellow, and is really nothing to worry about.ou may need to also check your soil for a lack of nitrogen. Nitrogen will give a plant (everything from grass to vegetable plants) its dark green color, and good growth. A lack of nitrogen in the soil can cause the yellow leaves on tomatoes as well.
One example of phototropism is if you place a plant with sunlight to the right, than it will grow to the right where the sunlight is. Another example of phototropism is if you place a plant under something such as a table with sunlight shining above it, it will grow under and out in the sunlight.
exists and is an alternate of . Phototrophs are the organisms that carry out photosynthesis to acquire energy. They use the energy from sunlight to convert carbon dioxide and water into organic material to be utilized in cellular functions such as biosynthesis and respiration. Most phototrophs are autotrophs, also known as photoautotrophs, and can fix carbon. They can be contrasted with chemoautotrophs that obtain their energy by the oxidation of electron donors in their environments. Photoheterotrophs produce ATP through photophosphorylation but use organic compounds to build structures.