%3Cb%20class%3D%22title%22%3EPlant%20nutrition%3C%2Fb%3E%3Cbr%2F%3EUsing%20the%20CIRAS-2%20photosynthesis%20meter%2C%20the%20gas%20exchange%20that%20takes%20place%20through%20the%20stomata%20in%20the%20leaves%20of%20the%20apple%20tree%20is%20measured%20-%20the%20tree%20removes%20carbon%20dioxide%20from%20the%20atmosphere%20and%20turns%20it%20into%20sugar%20with%20the%20help%20of%20light%20energy%20%28photosynthesis%29.%20Sugar%20provides%20the%20tree%20with%20energy%20for%20its%20growth%20and%20metabolic%20processes.%20The%20tree%20releases%20oxygen%20as%20a%20product%20of%20photosynthesis.