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Research Of Osmotic Adjustment And Adaptability Of Plants Under Salt Stress

Posted on:2013-01-17Degree:MasterType:Thesis
Country:ChinaCandidate:X WuFull Text:PDF
GTID:2230330374961828Subject:Tree genetics and breeding
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In this study, one-year-old seedlings of3salt-exclusion halophytes (Salix sp,Salixpsammophila,Salix cheilophila),3salt-secretion halophytes (Tamarix chinesisLour.,Tamarix austromongolica,Tamarix hispida),and2salt-delution halophytes(Nitrariatangutorum, Nitraria Sibirica Pall.) were subjected to salinity (NaCl)treatments inconcentration of0,100,200,300and400mmol/L. After30days of salt stress, the characteristicsof osmotic adjustment substances,osmotic potential and the ability of osmotic adjustment werestudied. By subordinate function, the salt-tolerance of8tree species was synthetical evaluated.The main results were summarized as follows:1The content and variation of organic osmotic adjustment substances were related to saltresistant type and interspecific differences. The content of proline, betaine and MDA of8treespecies increased under salt stress. Compared with contrast, soluble sugar contents of Tamarixhispida and Nitraria tangutorum were lower in high salt concentration, the others were higher.Soluble protein contents of Salix and Nitraria were increased, so were free amino acid contentsof experimental seedlings except Salix cheilophila. soluble sugar, free amino acid and MDAcontents of Salix were higher than that of the other two types of plants, but its proline, solubleprotein contents were the lowest. the contents of soluble proteins and betaine of Nitraria werethe highest.2The content of Na+and Cl-increased under salt stress, Na+and Cl-contents in stemsand leaves of Nitraria were significantly greater than Salix and Tamarix, this was related to themechanism of salt tolerance of3types plants. Na+and Cl-contents in leaves of Tamarix andNitraria were greater than that in roofs and stems,this preliminary notes the main organ ofsalt-secretion halophytes from salt and salt-delution halophytes storage salt were leaves.The order ofNa+content of Salix from high to low was roof﹥stem﹥leave. The contents of K+、Cl-、Mg2+、Ca2+in leaves were the most. K+content of Salix was decreased, there were interspecificdifferences in K+content of Tamarix and Nitraria.K+/Na+was decreased with increase of salinity concentration.the changes of K+/Na+in roof,stem and leave were in contrast with thatof Na+.The uptake of Na+inhibited the uptake of K+.3Some main osmotic adjustment substances of8tree species were common, but somewere different.Soluble sugar, MDA, Na+and Cl-were common. The similarity of Osmoticadjustment substances was main in tree species of same salt resistant type, but there wereobvious interspecific differences.In addition to the common osmotic adjustment substances, themain osmotic adjustment substances of salt-exclusion halophytes also included free aminoacid and Ca2+, salt-secretion halophytes included proline and betaine, salt-delution halophytesincluded proline, soluble protein, free amino acid and betaine.4Plants under salt stress accumulated osmotic adjustment substances, osmotic potentialdecreased, osmotic adjustment ability increased. The changes of osmotic potential and osmoticadjustment ability were different in differents plants. With increase of salinity concentration,Osmotic potential of Tamarix austromongolica and Tamarix hispid weredecreased,osmotic adjustment ability were increased. Osmotic potential of Salix psammophila,Salix cheilophila and Tamarix chinesis Lour. decreased at first and then increased,osmotic adjustment ability was opposite. Osmotic adjustment ability of salt-secretionhalophytes was greater than that of salt-exclusion halophytes.5The resultes of synthetical evaluation were summarized as follows, the salt-tolerance ofNitraria was great. Salt tolerance was related to salt resistant type and interspecificdifference.The order of salt tolerance of8tree species from high to loee was: Nitrariatangutorum﹥Nitraria Sibirica Pall.﹥Tamarix austromongolica﹥Tamarix hispida﹥Salixsp.﹥Tamarix chinesis Lour.﹥Salix cheilophila﹥Salix psammophila.
Keywords/Search Tags:salt stress, Halophytes, Osmotic adjustment, Salt tolerance
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