Effect of NaCl stress on ion distribution in roots and growth of Cyclocarya paliurus seedlings

Abstract

We studied ion distribution in roots and the growth of Cyclocarya paliurus seedlings of three provenances, Huangshan in Anhui, Jiujiang in Jiangxi and Kunming in Yunnan, under conditions of 0, 1, 3 and 5 g/L NaCl stress using X-ray microanalysis. Results show that under NaCl stress of 3 and 5 g/L, the relative contents of Na⁺ and Cl^– in root tissues increased, while the relative content of K⁺, Ca²⁺ and Mg²⁺ decreased. With an increase in salinity, the relative contents of Na⁺ in the epidermis and cortex of the root increased, while the relative content of Cl^– in the stele and cortex of the root increased markedly. Thus, ions in the root tissues were unbalanced and the ratios K⁺/Na⁺ and Ca²⁺/Na⁺ decreased, while Na⁺/(K⁺+Na⁺+Ca²⁺+Mg²⁺) increased. The decrease of the K⁺/Na⁺ ratio and the substantial increase of Cl^– in root tissues contributed to a decline in seedlings survival and reduced the increments for seedling leaf area, height, basal diameter as well biomass. Our preliminary conclusion is that the level of salt tolerance for the tested provenance seedlings was in the order of Huangshan>Kunming>Jiujiang, and the threshold of salt tolerance for C. paliurus seedlings was about 1 g/L.

Key words： NaCl stress; Cyclocarya paliurus; ion distribution; root tissue; X-ray microanalysis

Acknowledgements

We gratefully thank Prof. Yongqiang Mao of the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, for his help in measuring the relative ion content of the roots. Our study was supported by the National Natural Science Foundation of China (Grant No. 30371156) and the Project of Research for New High Technology in Jiangsu Province (No. BG2006314).

References

1 Ashraf M, Harris P J C (2004). Potential biochemical indicators of salinity tolerance in plants. Plant Sci, 166: 3–16

2 Ashraf M, Mcneilly T (1987). Salinity effects on five cultivars/lines of pearl millet (Pennisetum americanum [L] Leeke). Plant Soil, 103: 13–19

3 Blumwald E, Aharon G. S, Apse M P (2000). Na⁺ transport in plant cells. Acta, 1465: 140–151

4 Cai Q Q (1990). Research status and prospect of seabeach resources in China. Res Nat Territ Nat Resour Chin, 2: 33–37 (in Chinese)

5 Chen S, Li J, Wang S (2002). Sodium and chloride distribution in roots and transport in three poplar genotypes under increasing NaCl stress. For Ecol Manag, 168: 217–230

6 Fang S Z, Fu X X (2007). Research progress and prospects on silviculture and utilization of Cyclocarya paliurus resources. J Nanjing For Univ (Nat Sci Ed), 31(1): 95–100 (in Chinese)

7 Fang S Z, Song L Y, Fu X X (2006). Effects of NaCl stress on seed germination, leaf gas exchange and seedling growth of Pteroceltis tatarinowii. J For Res, 17(3): 185–188

8 Greenway H, Munns R (1980). Mechanisms of salt tolerance in nonhalophytes. Annu Rev Plant Physiol, 31:149–190

9 Kuhn A J, Walter H, Bauch J. 2000. The kinetics of calcium and magnesium entry into mycorrhizal spruce roots. Planta, 210: 488–496

10 Kurihara H, Fukami H, Kusumoto A, Toyoda Y, Shibata H, Matsui Y, Asami S, Tanaka T (2003). Hypoglycemic action of Cyclocarya paliurus (Batal.) Iljinskaja in normal and diabetic mice. Biosci Biotechnol Biochem, 67(4): 877–880

11 Lambers H (2003). Dryland salinity: a key environmental issue in southern Australia. Plant soil, 257: 5–7

12 Li L, Xie M Y, Yi X (2002). Study on reducing blood sugar of polysaccharide from Cyclocarya paliurus. Chin Med, 25(1): 39–41

13 Li Q, Chen Y, Wang S (1996). X-ray microanalysis of Ce and ions contents in stem tip meristem and leaves of Populus deltoids Bortr cv. “Lux”grown in nutritrient solutions with different level of Ce(NO₃)₃<Suppl/> treatment. J Beijing For Univ, 5(2): 47–55 (in Chinese)

14 Li Q, Eberhard F, Li T (1991). X-ray microanalysis of ion contents in roots of Populus maximowizii grown under potassium and phosphorus deficiency, Plant Physiol, 138: 180–185

15 Lindsay E F, Ma H, Wang S (1996). X-ray microanalysis of ion distribution in salt tolerancy and salt intolerant poplar genotypes. J Beijing For Univ, 5(2): 23–30 (in Chinese)

16 Morabito D, Jolivet Y, Prat D (1996). Differences in the physiological responses of two clones of Eucalyptus microtheca selected for their salt tolerance. Plant Sci, 114: 129–139

17 Niu X, Bressan R, Hasegawa P (1995). Ion homeostasis in NaCl stress environments. Plant Physiol, 109: 735–742

18 Pan R C. 1995. Plant Physiology. Beijing: Higher Education Press, 30 (in Chinese)

19 Peng Y, Zhu Y, Mao Y, Wang S, Su W, Tang Z (2004). Alkali grass resists salt stress through high [K⁺] and an endodermis barrier to Na⁺. J Exp Bot, 55(398): 939–949

20 Peterson C A, Murrmann M, Steudle E (1993). Location of the major barriers to water and ion movement in young roots of Zea maysL. Planta, 190, 127–136

21 Song X H, Wang X F, Wei M, Zang J B (2005). Effect of adding zeolite on cucumber seedlings growth and ion content under NaCl stress. J Plant Nutr Fert, 11(2): 259–263 (in Chinese)

22 Steudle E (2000). Water uptake by roots: effect of water deficit. J Exp Bot, 51: 1531–1542

23 Tomos A D, Hinde P, Richardson P, Pritchard J, Fricke W (1994). Microsampling and measurements of solutes in single cells. In: Harris N, Oparka K J, eds. Plant Cell Biology—A Practical Approach. Oxford, UK: Oxford University Press, 297–314

24 van Steveninck R F M, van Steveninck M E (1991). Microanalysis. In: Hall J L, Hawes C, eds. Electron Microscopy of Plant Cells. London: Academic Press,415–455

25 Ward J, Hirschi K, Sze H (2003). Plants pass the salt. Trend Plant Sci, 8(5): 200–201

26 Xie M, Li L (2001). Review in studies on chemical constituents and bioactivities of Cyclocarya paliurus. Chin Tradition Herb Drugs, 32(4): 365–366 (in Chinese)

27 Zhu J K, Liu J P, Xiong L M (1998). Genetic analysis of salt tolerance in Arabidopsis: evidence for the critical role of potassium nutrition. Plant Cell, 10: 1181–1191