Physiological Responsesof Two Poplar Species To Salt Stress And2D Electrophoresis Analysis Of Extracellular Protein In NL-895Poplar Plantlets

Poplar is the ideal plant to study its genetic improvement by the method of physiology andgenetic engineering. In this study, Populus×euramericana cv.‘Nanlin895’ and clonal S-9poplarseedlings are experiment materials. The effect to their endogenous hormones, enzymes andultrastructure under NaCl stress were studied. Two-dimensional electrophoresis system on theNL-895extracellular protein was also established. The main conclusions were as follows:1.Under100mmol/L NaCl stress, the content of chlorophyll a, chlorophyll b, totalchlorophyll, carotenoids of upper and lower leaves in S-9was higher than that of NL-895.Moreover, the color of the leaves was deeper than NL-895’s. It indicated that S-9poplar wasmore resistance to salt than NL-895poplar. Although the content of H2O2, soluble protein andMDA of upper leaf, lower leaf and roots of S-9poplar were significantly higher than that ofNL-895polpar under NaCl stress, the four enzyme activities of SOD, POD, CAT, APX of S-9poplar were higher than that of NL-895poplar and colud clear more free radicals and reactiveoxygen species and reduced the membrane damage of salt stress. Therefore S-9poplar received ahigher salt tolerance than NL-895poplar.2.Under100mmol/L NaCl stress, the content of ZT, IAA, iPA and ABA in upper leaves ofS-9poplar were higher than that of NL-895; the content of GA was less than NL-895. Thecontent of IAA was not detected in lower leaves of S-9poplar, the contents of ZT, GA, iPA, ABAwere higher than that in NL-895poplar under100mmol/L NaCl stress. This may be due to S-9poplar’s own characteristics--endogenous hormones produce more stress to balance the harmfrom the outside, and therefore S-9poplar had more salt tolerance than NL-895poplar.3.Under100mmol/L NaCl stress, stomata of leaves of NL-895poplar was significantlysmaller than that of control, and the number of stomatais also was less than that.The array ofpalisade tissue cells were relatively compact, many cells were long fusiform. Some cells werebroken with narrow width, containing more filamentous filling; spongy tissue cells arrangedmore regular with thin capsule body; lamellar arranged was irregular, disordered; chloroplastswelling body and lysosome appeared. Transverse process of stem segment after the destruction,xylem and phloem cells arranged irregularly. Xylem and phloem cells were thin, relativelycompact; its pulp was relatively small, and cell wall’s thickness were obviously thick. Granularor filamentous filling of the stem were also more obvious. These structural features showedserious hurt of morphology and microstructure of NL-895poplar’s stem and leaf under100mmol/L NaCl stress.4.The study reported the methods of extracting protein of NL-895leaves, stems and the analysis of extracellular two-dimensional electrophoresis. These proteins spots were mainlydistributed in pH4-7, protein molecular weight in leaves were between20-66KD, with thehighest value of20.1KD; protein molecular weight of stem segment distribute between20-58KD,with the highest value of31.0KD.