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Study of Pollen, Germination, , , , , , , , NTRODUCTION, Pollen grain or microspore is the first cell of male gametophyte., , The development of male gametophyte is precocious, i.e., it begins inside the micro- sporangium, or pollen sac., , The pollen grain is uninucleate in the beginning but at the time of liberation it becomes, 2 celled—a small generative cell and a large tube or vegetative cell., , On the stigma, the pollen grain absorbs water and nutrients from the stigmatic secretion, through its germ pores., , The tube cell gives rise to a pollen tube. The generative cell also descends into the pollen tube, and divides into two male gametes., , ‘EXPERIMENT 1.1, , , , P AIM: To study the pollen germination ona slide., , REQUIREMENTS, Fresh seasonal flowers, slide, coverslip, microscope, sucrose,, potassium nitrate, beakers etc., , boric acid, magnesium sulphate,, , _PROCEDURE, , 1. Prepare a nutri, : sulphate and 20 mg potassium nitrat, , - 2. Takea few drops of this solution ona clean slide,, : of a mature flower on it., | 3. Observe the slide in the microscope @, an hour., , ient solution by dissolving 10.g sucrose, 10 g boric acid, 30 mg magnesium, e in 100 ml of water., and dust a few pollen grains from the stamen, , fter 5 minutes and then observe it regularly for about half, , OBSERVATION, a In nutrient medium, the pollen grain germinates. The tube cell enlarges and comes out of the, Pollen grain through one of the germ pores to form a pollen tube. The tube nucleus descends to the tip, - of the pollen tube. The generative cell also passes into it. It soon divides into two male gametes. Each, , : male gamete is lenticular to spherical in outline.