Hoarseness is a harsh, rough, raspy quality to the voice. Hoarseness is generally caused by irritation of, or injury to, the vocal cords. This trauma to the vocal cords leads to a change in the pitch of the voice. The voice box, or larynx, is the portion of the respiratory (breathing) tract containing the vocal cords that produce sound.
The gametophytes in seed plants, like pine trees and oak trees, are unisexual and microscopic. They are found inside part of the sporophyte and rely completely on the sporophyte for nutrients. For example, in a pine tree, the male gametophyte that produces sperm is found inside a pollen grain.lternation of generations is a type of life cycle found in all plants and some algae species. This process involves a multicellular diploid generation called a sporophyte and a multicellular haploid generation called a gametophyte.
A comparison of the male gametophytes among seed plants has been carried out but focused on the evolution of pollen grain polarity and siphonogamy (see Rudall and Bateman 2007). In gymnosperms, a review on pollen tube growth and development is available (see Fernando et al. 2005a), but it is limited to the conifers.n gymnosperms, pollen grains represent the developing male gametophytes that are surrounded by a complex wall, the pollen wall, composed of an outer layer called the exine (which is subdivided into ectexine and endexine) and the inner layer is the intine (Faegri and Iverson 1989).