Effects Of Nacl Stress On Different Provenances Qing Qian Liu Seedling Growth And Physiological Impact

Cyclocarya paliurus (Batal.) Iljinskaja is native to China and is the sole species in its genus. The species has become one of endangered species because of hard reproduction and propagation. However, its multiple values make the species have a big potential market. Until now,no information has been presented on the salt resistance of the species.Therefore, the paper deals with the growth and physiological responses of seedlings of C. paliurus (Batal.)Iljinskaja from different provenances under NaCl stress by the ways of hydroponics in growth chambers. The purpose of this study is to ascertain whether the growth of different provenance C. paliurus (Batal.) Iljinskaja seedlings is significantly inhibited and the physiological metabolism is seriously disturbed. The results will provide the basis for expanding the proper planting area, being ex situ conservation and exploitation and utilization of C. paliurus (Batal.) Iljinskaja. According to the indexes determined in the study, the conclusions were drawn as follows:1. In general, with increasing NaCl, the ratio of length to width of leaf, the leaf area increment, the height increment, the caliper increment, the total biomass increment and the survival percentage of tested provenance seedlings decreased. After 28 days of 0.3% and 0.5% NaCl stress, the survival percentage of seedlings of Huangshan provenance, Kunming provenance and Jiujiang provenance was 70%, 50%, 33%, and 25%, 7.5%, 0%, respectively.2. After 24 days of NaCl stress, with increasing NaCl, the leaf chlorophyll content, the chlorophyll fluorescence parameters such as Fv/Fm, qP andФPS decreased, and the values of Fv/Fm, qP andФPS were significant dependent on NaCl concentrations, e.g. CK>S1>S2>S3. However, the values of Fv/Fm andФPSâ…¡were significant in tested provenance seedlings, and the values of Fv/Fm andФPSâ…¡of Kunming provenance and Huangshan provenance were more than that of Jiujiang provenance.3. After 27 days of NaCl stress, with increasing NaCl, the values of Pn, WUE and Gs of the leaf photosynthesis characteristics decreased with order of CK>S1>S2>S3. After 27 days of 0.5% NaCl stress, the values of Pn and WUE of Kunming provenance were more than that of Huangshan provenance and Jiujiang provenance.4. At the later period, with increasing NaCl stress, the values of leaf relative conductance rate, leaf soluble sugar content and leaf proline content increased, and the values were significant dependent on NaCl concentrations,with order of S3>S2>S1>CK. The other physiological indexes, but for leaf relative conductance rate, were significant in tested provenance seedlings.The value of the relative water deficit under 0.5% NaCl stress and 0.3%NaCl stress was 5.3 times and 4.6 times of CK, respectively. The value of leaf relative conductance rate under 0.5%NaCl stress was 2.30 times under 0.1% NaCl stress and 2.37 timesof CK, respectively. The value of leaf soluble sugar content under 0.1%, 0.3% and 0.5%NaCl stress was 1.31 times, 2.65 times and 3.41 times of CK, respectively. The value of the proline content under 0.5%NaCl stress was over 20 times of CK. In general, the order was: Huangshan provenance>Jiujiang provenance>Kunming provenance. The tolerance to NaCl of Huangshan provenance was more than Kunming provenance and Jiujiang provenance.5. The stronger NaCl concentration was, the higher rhizosphere pH was. After 28 days of NaCl stress, within the range of salt threshold, the Na⁺ and Cl^- mainly distributed in root, stem and petiole, but fewer in leaf. With the increasing of salt concentration, thus the content of Na⁺ and Cl^- in leaf quickly increased. The lower the ratio of K⁺/Na⁺ and Ca²⁺/Na⁺ in leaf was, the stronger NaCl stress was. The ratio of K⁺/Na⁺ and Ca²⁺/Na⁺ in leaf was significant among different NaCl concentration. The order was: CK>S1>S2>S3;whereas, under 0.5%NaCl stress, the ratio of K⁺/Na⁺ and Ca²⁺/Na⁺ in leaf was significant among tested provenances seedling, the order was: Huangshan in Anhui>Kunming in Yunnan>Jiujiang in Jiangxi.6. In conclusion, C.paliurus (Batal.)Iljinskaja is sensitive to NaCl stress. The salinity threshold for normal growing and developing of tested provenances seedlings is about 1.0g·l^-1NaCl. The ability of resistance to NaCl was: Huangshan provenance in Anhui better than Kunming provenance in Yunnan and Jiujiang provenance in Jiangxi.