Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


miami1155661114.pdf (17.95 MB)

ETD Abstract Container

Abstract Header

Cryptic Dioecy in Consolea (Cactaceae): Sex Determination & Evolutionary Implications

Strittmatter, Lara I.
http://rave.ohiolink.edu/etdc/view?acc_num=miami1155661114

Abstract Details

2006, Doctor of Philosophy, Miami University, Botany.
Field observations of Consoleaspp. (Cactaceae) show that wild populations are composed of fruit bearing plants (female morph) and fruitless plants (male morph). Embryological studies of C. millspaughii, C. moniliformis, C. nashii, C. picardae, and C. rubescensshow that at anthesis, female morph flowers have anthers without pollen grains and have open stigma lobes, whereas male morph flowers have aborted ovules and in most cases closed stigma lobes. The microspore mother cells of the female morph flower degenerate at the onset of meiosis and do not reach the tetrad stage. This degeneration is correlated with early degeneration, in the form of accelerated, invasive growth of the tapetal cells. In addition, the anther fails to enter the dehiscence program resulting in shriveled, unopened anthers that lack pollen grains. Normal patterns of programmed cell death are disrupted in these male-sterile anthers. Ovules from male morph flowers show normal development until the formation of a mature megagametophyte. At this stage, several signs of degeneration become evident: the embryo sac cavity enlarges, abnormally large starch grains accumulate in the central cell, external integument cells near the chalaza become lignified, and the spiral canal hairs start to disintegrate. As a result, at anthesis, male morph ovules are minute, aborted, papery and incapable of being fertilized in all the studied species. Staminate expression appears to be controlled by a common, genetically determined heterochronic ovule developmental program affecting the relative timing of ovule receptivity and flower opening. Therefore, flowers of the female morph are functionally pistillate, flowers of the male morph are functionally staminate, and both go through a critical sex determination stage after their initiation as morphological hermaphrodites. In occasional plants of some species, staminate flowers may reach anthesis with a few functional apical ovules capable of seed formation. Such plants are described as leaky males. Thus, the main breeding system in Consoleais cryptic dioecy, with some taxa subdioecious. We hypothesize a single origin for this breeding system based on the uniformity of the anther and ovule abortive processes in pistillate and staminate flowers respectively.
Ralph Hickey (Advisor)
149 p.
Consolea; Breeding System; Cactaceae; Cryptic Dioecy; Male sterility; Female sterility; Anther development; Ovule development; PCD; Heterochrony; Embryology; Unisexual flowers development; Sex determination; Dioecy evolution; Leaky males

Recommended Citations

Citations

  • Strittmatter, L. I. (2006). Cryptic Dioecy in Consolea (Cactaceae): Sex Determination & Evolutionary Implications [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1155661114

    APA Style (7th edition)

  • Strittmatter, Lara. Cryptic Dioecy in Consolea (Cactaceae): Sex Determination & Evolutionary Implications. 2006. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1155661114.

    MLA Style (8th edition)

  • Strittmatter, Lara. "Cryptic Dioecy in Consolea (Cactaceae): Sex Determination & Evolutionary Implications." Doctoral dissertation, Miami University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1155661114

    Chicago Manual of Style (17th edition)

miami1155661114
521
© 2006, all rights reserved.
This open access ETD is published by Miami University and OhioLINK.