The answer is one. In a plant life cycle, there are two distinct stages. A gametophyte is haploid and a sporophyte is diploid whereby one sporophyte generation occurs between one gametophyte generation. A mature sporophyte produces haploid spores which grow into the haploid gametophyte. The haploid gametophyte produces haploid gametes which after the fusion create a zygote which develops into the diploid sporophyte.
