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Comparison Of Osmoregulation And Ion Balance Strategies Of Eight Species Of Alkali-resistant Halophytes During Adaption To Salt-alkalinized Habitat

Posted on:2012-08-01Degree:MasterType:Thesis
Country:ChinaCandidate:H L HuangFull Text:PDF
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This experiment is in order to discuss the diversity of species in the process of adapting to the surrounding environment. Using halophytes (including three species of Chenopodiaceae: Kochia sieversiana,Suaeda glauca,Suaeda salsa and five species of Compositae: Artemisia anethifolia,Artemisia scoparia,Sonchusbrachyotus,Kalimeris integrifolia,Inula japonica) growing on the alkalinized grassland in the northeast of China as materials and selecting soil and plant in the nature as sample, the experiment measured the alkaline-saline indexes of soil and physiological indexes of osmotic adjustment and ion balance of variety of plants. Furthermore, characters of osmotic adjustment and ion balance of all kinds of plants was analysed. Meanwhile, it also compares the different species.The experiment shows: the eight species shared common feature that by accumulating a large quantity of variety of solvent molecules, the process of osmotic adjustment was found under the saline-alkali circumstances, while the different solvent's contribution for the decline of water potential differed from spices to spicesm ,and among different species of the same family ,the common characteristics and the different features were showed.In this experiment, all Chenopodiaceae halophytes accumulated a large number of Na+,K+,Cl-,betaine and organic acid (OA). Na+ and Cl- were the main inorganic osmolytes in vacuoles for the halophytes. Especially Na+ played a absolut role in the process of osmotic adjustment, of which contribution to the osmotic adjustment came up to 30%-45%, and the Chenopodiaceae had higher Na+/K+ ratios than others in shoots. Betaine and OA was the main organic osmolytes for the Chenopodiaceae. While K+,Cl-,betain and SS were the main osmolytes in vacuoles for most species of Compositae halophytes. They had lower Na+/K+ ratios in shoots, and it popularly less than 1. In addition, in all the species, the osmotic contributions of both proline and free AAs were very small.In terms of ion balance: All Chenopodiaceae halophytes, the ion balance contributions of Na+ was 70%-90%. Na+ played crucial roles in ion balance. The dominant donors of negative charge were Cl- and OAs in all Chenopodiaceae halophytes, while the ion balance contributions of Cl- was much higher than OAs, except K. sieversiana. The ion balance contributions of OAs were 67.58% in the K. sieversiana. And the significantly different from Chenopodiaceae was the dominant intracellular cation in Compositae halophytes was K+, K+ played crucial roles in ion balance. For most Compositae species, OAs and Cl- also were the dominant components in maintaining ionic equilibrium. But the contributions were generally little difference between each other. In addition, C. virgata H2PO4-, S. arvensis Mg2+,SO42–, K. integrifolia SO42– and H2PO4-,I. japonicaCa2+ and SO42– were also important in ion balance. SO42– contributions to ion balance nerly was 50%,and it was higher than other anion. The negative charge contributions of NO3- was very small, in the Chenopodiaceae and Compositae.Experiment results full showed 8 kinds of halophyte had a diversity of adaptive mechanismis in osmoregulation and ion balance.
Keywords/Search Tags:salt-alkali stress, halophyte, osmotic adjustment, ion balance, adaptive mechanisms, diversity
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