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Master
Etats Unis
1975
Reproductive effort in some Chihuahuan Desert annuals
Titre : Reproductive effort in some Chihuahuan Desert annuals
Auteur : McKinney, Helen H.
Université de soutenance : New Mexico State University
Grade : Master of Science (MS) 1975
Résumé
Theoretically, desert annuals should expend more energy in reproduction during periods of environmental stress, such as water stress. In this work, the reproductive effort, in relation to moisture, of various Chihuahuan desert annuals was studied. Comparisons of reproductive effort under amended and natural soil moisture conditions were made. Under the amended water conditions, Euphorbia micromera had a lower reproductive effort. However, Bouteloua barbata and E. aristidiodes increased reproductive effort under watered conditions. Plasticity of reproductive effort was studied by comparison of reproductive effort in closely related species over a 3-year period. Species of the genera Euphorbia, Bouteloua, and Eriogonum responded to seasons with low rainfall by generally increasing reproductive effort. These results follow the expected theory that reproductive effort is higher during periods of moisture stress. Reproductive effort of summer and winter annuals in relation to moisture was also studied. A significant regression of reproductive effort onto a precipitation ratio was found in the summer annuals, but no significant relationship was found in the winter annuals
Mots Clés : annual plant, reproduction, Bouteloua, Eriogonum,reproduction, Euphorbia, reproduction
Page publiée le 13 mai 2016, mise à jour le 25 décembre 2019