AP BIOLOGY

Detailed explanation-1: -Strobilus or cone is the reproductive structure of gymnosperms. Both male and female strobili can be present on the same (seen in Pinus) or on different trees (seen in Cycas). Gymnosperm plants are heterosporous.

Detailed explanation-2: -Inside male cones, male spores develop into male gametophytes. Each male gametophyte consists of several cells enclosed within a grain of pollen. Inside female cones, female spores develop into female gametophytes. Each female gametophyte produces an egg inside an ovule.

Detailed explanation-3: -Cones: The reproductive structures of gymnosperms. Female cones are larger. Meiosis produces megaspores (haploid), which will develop into female gametophytes, which are retained in the female cone.

Detailed explanation-4: -gymnosperm, any vascular plant that reproduces by means of an exposed seed, or ovule-unlike angiosperms, or flowering plants, whose seeds are enclosed by mature ovaries, or fruits. The seeds of many gymnosperms (literally, “naked seeds”) are borne in cones and are not visible until maturity.

Detailed explanation-5: -Furthermore, gymnosperms produce two different types of cones, namely, large female cones and small male cones. Four groups of gymnosperms are known: CYCADOPHYTA: 100 cycad species (cycad, sago palm) GINKGOPHYTA: 1 plant species (ginkgo)