1999 Fiscal Year Final Research Report Summary
Male gametophyte development and sperm induction in Cvcas
Project/Area Number |
10640655
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
生物形態・構造
|
Research Institution | University of the Ryukyus |
Principal Investigator |
TAKASO Tokushiro University of the Ryukyus, Tropical Biosphere Research Center, Professor, 熱帯生物圏研究センター, 教授 (50295341)
|
Project Period (FY) |
1998 – 1999
|
Keywords | Cycas / fertilization / gametophyte / gymnosperm / sperm |
Research Abstract |
A salient feature in the reproduction of gymnosperms is the long period between pollination and fertilization lasting two-12 months. During this period pollen develops slowly in the ovule. It is known in some conifers that soon after the female gametophyte becomes matured and secretes liquid in the ovule, the male gametophyte forms gametes and fertilization takes place. In Cycas fertilization takes place, just after the space between the male and female gametophytes are filled with liquid. The purpose of the study is to apply the result known in conifers to Cycas, or whether sperm is induced from the male gametophyte by liquid secreted from the female gametophyte in Cycas. The idea is examined by the following two manners; 1) induction of sperm from the mature male gametophyte by applying homogenates of the male gametophyte, 2) comparison of structures in the female gametopytes between the stage before liquid is secreted and the stag liquid is secreted. The induction of sperm is not achieved by applying the pure homogenate of the female gametophyte, but it is achieved by the mixture of the homogenate and 10% sucrose solution. It takes for 12 hours for this induction. Though, this results alone suggests the proposed idea, observed decrease in size of starch grains also suggests the idea. It is most likely that starch gains change into sugars, and the sugars are component of the secreted liquid.
|