Mode of Pollen-Tube Growth in Pistils of Myrica rubra (Myricaceae): A Comparison with Related Families

Abstract

Myrica differs from other families in that the pollen tubes arrest their growth on the nucellar surface, probably digesting nutrient from nucellar cells. There is little information on five other families of Fagales. An extensive study is needed to better understand the diversity and function of the mode of pollen-tube growth within the order.

Delayed fertilization and pollen‐tube growth in pistils of Fagus japonica (Fagaceae)

“…Comparison with modes of pollen-tube growth in other Fagales-A similar mode of pollen-tube growth has been reported in other Fagales: Casuarina equisetifolia (Casuarinaceae; Sogo et al, 2004b), Alnus firma and A. sieboldiana (Betulaceae; Sogo and Tobe, 2005), and Myrica rubra (Myricaceae; Sogo and Tobe, 2006c). These species all had intermittent growth of pollen tubes in pistils in three (M. rubra), four (A. firma, A. sieboldiana), or five steps (C. equisetifolia).…”

“…Furthermore, among the plant groups with delayed fertilization (Table 1), a wide range of times is observed in which fertilization is delayed after pollination, from a few days (e.g., Juglans [Langdon, 1934;Nast, 1935], Carya [McKay, 1947], Persea [Sedgley, 1979], Anacardium [Wunnachit et al, 1992]) up to over 1 year (e.g., Quercus [Conrad, 1900;Berridge, 1914;Langdon, 1939;Stairs, 1964;Cecich, 1997]). In contrast, as in the Fagales, long-term delays appear to be accomplished by repeated cessation and resumption of pollen-tube growth at more sites within the pistil, particularly within the ovule, i.e., at the chalaza (Sogo et al, 2004a, b;Sogo and Tobe, 2005), at the nucellar surface (Sogo and Tobe, 2006c), or near the micropyle. In contrast, as in the Fagales, long-term delays appear to be accomplished by repeated cessation and resumption of pollen-tube growth at more sites within the pistil, particularly within the ovule, i.e., at the chalaza (Sogo et al, 2004a, b;Sogo and Tobe, 2005), at the nucellar surface (Sogo and Tobe, 2006c), or near the micropyle.…”

“…Recently, we reported modes of pollen-tube growth in pistils of Casuarina equisetifolia (Casuarinaceae; Sogo et al, 2004b), two Alnus species (Betulaceae; Sogo and Tobe, 2005), and Myrica rubra (Myricaceae; Sogo and Tobe, 2006c), all of which are of the Fagales, and Eucommia ulmoides (Eucommiaceae, Garryales; Sogo and Tobe, 2006b). These studies showed that the growth of pollen tube(s) occasionally ceased within the pistil during the period of delay in fertilization; the pollen tube(s) thus grow intermittently from the stigma to the embryo sac in close association with the development of the ovules and/or embryo sac(s).…”

“…These studies showed that the growth of pollen tube(s) occasionally ceased within the pistil during the period of delay in fertilization; the pollen tube(s) thus grow intermittently from the stigma to the embryo sac in close association with the development of the ovules and/or embryo sac(s). Thus, a more extensive study of Fagales and other plant groups is required (Sogo and Tobe, 2006c) to determine the consistencies and differences among individual plant groups. Furthermore, all modes of pollen-tube growth in the Fagales differed from that in Eucommia.…”

Mode of pollen tube growth in pistils ofTicodendron incognitum(Ticodendraceae, Fagales) and the evolution of chalazogamy

“…In a series of previous papers, we reported diverse modes of pollen tube growth in pistils of the Fagales: Casuarinaceae (Sogo, Jaffré & Tobe, 2004a; Sogo et al. , 2004b), Betulaceae (Sogo & Tobe, 2005), Myricaceae (Sogo & Tobe, 2006a, b) and Fagaceae (Sogo & Tobe, 2006c). In the Fagales (at least in the Betulaceae, Casuarinaceae, Fagaceae and Myricaceae), fertilization is delayed for a period between 2 weeks and 15 months after pollination as a result of the retarded development of ovules or embryo sac(s) (Benson, 1894; Swamy, 1948; Stairs, 1964; Boavida, Varela & Feijo, 1999; Williams, Friedman & Arnold, 1999; for a review see Sogo & Tobe, 2006c).…”