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Gansu Agricultural University (2009)

Germination Characteristics of Seed Banks in Mining Wasteland of Arid Environments

张涛; Zhang Tao

Titre : Germination Characteristics of Seed Banks in Mining Wasteland of Arid Environments

Auteur : 张涛; Zhang Tao

Grade : Master’s Theses 2009

Université : Gansu Agricultural University

Résumé
Theory and technology of ecological restoration in mining wasteland of arid area is a hot issue at present. The difficulty of eco-environment management in this area was caused by the lack of water resources, heavy metal stress and optional plants limited . To study and screen plant resources, and discover the dominant germplasm resources and ecological restoration technology which would be used in administrating the large scale mining wasteland, is the base for ecological restoration in this area. In this thesis,characteristics of soil seed in heavy metal stress environment was studied, though which the ability of natural restoration was discussed. Based on field survey of vegetation in different mining wasteland,composition characteristics of plants, size, seasonal dynamic changes and diversity of soil seed bank in heavy metal environment were analyzed. Furthermore, the relationship between the soil seed bank and above-ground vegetation and potential of soil seed bank for restoration of mining wasteland were studied. The main results as follows:1 Characteristic of soil seed banks in different heavy metal environment1) Reserves of soil seed bank in different plots is very different. The ordination as follow:experimental field of old tailing land(847seeds/m2)> Greening area in Longshou mining region ( 362seeds/m2 ) > mining wasteland of Longshou mining region (347seeds/m2)> gravel beds of the old tailing land (347seeds/m2)> natural vegetation area around the new tailing land(336seeds/m2)> nature vegetation area of Longshou mining region (261seeds/m2) > cultivated Chinese Tamarisk forest land (254seeds/m2). Comparably, the reserves of soil seed bank in this region are lower than the other deserts.2) Ordination of Simpson diversity index of the soil seed banks as follow : natural vegetation area around the new tailing land > nature vegetation area of Longshou mining region > mining wasteland of Longshou mining region > cultivated Chinese Tamarisk forest. Shannon-Wiener diversity had the same trend as Simpson diversity . Peilow evenness index as follow : natural vegetation area around the new tailing land > natural vegetation area of Longshou mining region > mining wasteland of Longshou mining region > experimental field of old tailing land > Greening area in Longshou mining region > gravel beds of the old tailing land> cultivated Chinese Tamarisk forest .But the Margalef index of the soil seed bank was different.3)The seasonal trend of soil seed bank reserves in different plots is roughly similar. Except the Greening Greening area in Longshou mining region, the soil seed reserves of other plots were the most in October, Then began to decrease, the least was in May, and then began to increase. It was according with the growth and seed of above-ground vegetation. Seeds were mainly distributed in 0 to 5cm soil layer, which accounted for 76.5%. The number of seeds gradually decreased with increasing of soil depth. The number of seeds in 5 to 10cm soil layer accounted for 23.5%. It is nearly no seed in below 10cm soil layer.2. Response of characteristics of soil seed to heavy metal environment1) The soil seeds was different in the different heavy metal environments. In March, May, July and October, the similarity coefficient of soil seed bank in the different mining wastelands were 0.1143 to 0.7273, 0 to 0.3333、0.1538 to 0.6667 and 0.0690 to 0.5000, respectively.2) Content of Ni, Cu and Cd in different mining wasteland of Jinchang were analyed. The content of Ni in soil : nature vegetation area of Longshou mining region > mining wasteland of Longshou mining region > Chinese Tamarisk forest > gravel beds of the old tailing land> natural vegetation area around the new tailing land> natural vegetation area of Longshou mining region > experimental field of old tailing land. It was 1.5 to12.91 times of background value ; The content of Cu in soil : GH> LK> LZ> LS> LL> GZ>SY. It is 2.36 to18.24 times of background value. The content of Cd in soil : GH> LZ> LS> GZ> LL>LK>SY. It is 5.7 to 113.28 times of background value.3)On the basis of studying on heavy metal content of tailing in Jinchang, correlationship between heavy metal content and the soil seed bank were analyzed, result of which was significantly negative correlation between them.4)In different seasons, the similarity coefficient of the standing vegetation and soil seed bank in mining area in different heavy metal stress was from 0.11to 0.52. This showed that the above-ground vegetation had positive correlation with soil seed banks.5)According the density characteristics and the species composition of soil seed bank, soil seed bank in different mining area contributed a lot for the above-ground vegetation. The soil seed bank mainly including annual herbs and perennial herbs belongs to meddle level. The soil seed bank has certain germination ability according the result of seeding investigation, and which can provide basic condition for vegetation restoration in this area.

Mots clés : arid environments; mining wasteland inJinchang; ecological restoration; soil seed bank; heavy metal stress;

Présentation (CNKI)

Page publiée le 13 septembre 2014, mise à jour le 14 février 2018