In flowering plants, pollen grains are made up of three distinct parts ​ — a nucleus of sperm cells and two layers that make up the wall or shell of the grain.
फुलझाडांमध्ये, पराग कणांचे तीन भाग असतात — शुक्रकोशिकांचे प्रकल आणि दोन संरक्षक वेष्टने.