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Beijing Forestry University (2009)

Reproductive Characteristics of Populus Euphratica in Ejina Oasis


Titre : Reproductive Characteristics of Populus Euphratica in Ejina Oasis

Auteur : 曹德昌;

Grade : Master’s Theses 2009

Université : Beijing Forestry University

Reproduction is the most basic behavior for population regeneration, and it is an essential phase in the whole biological life-history, as well as one of the key issues in the population forming, developing and evolution. The main object of this study is Populus euphratica, which is the dominant species in the riparian forests in Ejina Oasis which lies in the extreme arid areas of NW China. In the paper we mainly studied the reproductive characteristics of P. euphratica, including the temporal pattern of seed dispersal and the regeneration mechanism and the growth characteristics of root suckers.P. euphratica disperses vast amount of vigorous seeds under the help of the wind in the reproduction seasons, and it prolongs the duration of seed dispersal by the temporal heterogeneity among individuals and also among communities, and thus enhances the chance of water supply, such as flood and rain, for seed germination. However, as the channels passing the local P. euphratica forests are cemented, the natural flooding regime and the washland habitats are changed, which results in the lose of the safe habitats for seed germination, and leads to the final failure of sexual regeneration.There are root suckers of P. euphratica found in approximately 86% of local forest gaps. P. euphratica searches for favorable habitats by the extension of its lateral roots in the superficial layer of the soil, meanwhile adventitious buds are developed in the last stage roots. When in favorable habitats, these adventitious buds sprout and grow into a new individual. Most root suckers die of the drought stress and salification of the soil. Only those root suckers in some forest gaps where so many root sucker come out that the ground is shadowed could regenerate successfully. And the cover plants such as Sophara alopecuroides and pasture exert much influence on the growth of root suckers. The former eliminates weak root sucker to help with the rational distribution of limited resources among the strong ones, while the latter interrupts the regeneration of root suckers severely.On basis of the former research, this paper reveals two reproductive strategies of/ ! euphratica : the temporal heterogeneity of seed dispersal and the concentrative regeneration of root suckers. We believe that P. euphratica should have great potential for reproduction, and it could regenerate successfully when natured rationally and protected strictly.

Mots clés : Populus euphratica Oliv.; population regeneration; root suckers; seed rain; reproductive strategies;

Présentation (CNKI)

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