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sur le développement des zones arides et semi-arides

Titre : Effect of Germination Heterochrony on the Life History and Offspring Fitness of Desert Annual Erodium Oxyrhinchum （Geraniaceae）

Auteur : 马海洋

Grade : Master 2022

Université : Xinjiang Agricultural University

Résumé partiel
Germination heterochrony is an important life history strategy for plants growing in unpredictable habitats and can help to regulate plant population dynamics and community structure.In order to investigate the influence of germination heterochrony on plant life history and its positive effect on short-lived plants grow in extreme desert environment,this study selected Erodium oxyrhinchum M.Bieb,a dominant species of early spring in the Gurbantunggut Desert,as the study material.This species belong to Geraniaceae family,playing an important role in the stability and maintenance of desert ecosystems.In natural population,the species has been found to germinate continuously during all times of the year,except for the snow-covered winter months when it fails to germinate.However,most studies have focused on the life history characteristics of this species during spring and/or autumn germination,and there is a lack of research on the differences in the life history of this species caused by germination diachrony.Therefore.In this study,three typical times of germination,summer,autumn and spring,were selected to compare differences in the life histories of plants that germinated during this period through a combination of indoor and outdoor experiments.The main findings are as follows.（1）The life cycles of summer-germinated plants（Su G）,autumn-germinated plants（Au G）and springgermianted plants（Sp G）of E.oxyrhinchum were 108 d,275 d and 85 d,respectively.The morphological characteristics such as plant height,root length,leaf area and vegetative organs biomass of Au G were significantly greater than those of Su G and Sp G（P＜0.05）.The single flower biomass,pollen number as well as size and fertility of plants that germinated in different times showed as : Au G ＞ Sp G ＞ Su G,and with significant differences among them（P＜0.05）.They all had 10 ovules,but the size of ovules of Au G was significantly larger than that of Sp G and Su G（P＜0.05）,which indicated that Au G captured and accumulated more resources and allocated more biomass to floral organs,while the Su G did opposite.（2）The biomass of fruits,seeds and embryos of Su G,Au G and Sp G of this species showed as : Au G ＞Sp G ＞ Au G,with a significant difference among them（P＜0.05）.This indicates that Su G allocated less proportion of resources to fruits,seeds as well as embryos

Mots clés : Erodium oxyrhinchum ;Germination heterochrony ;Ephemeral;Life history ;Offspring fitness ;

Présentation (CNKI)