Effect of Different Salinity levels on some Photosynthetic Characters of Canola (Brassica napus L.) Cultivars

Document Type : Research Article

Authors

• F Tahmasbi
• P Hassibi
• M Meskarbashee

Shahid Chamran University of Ahvaz

10.22067/gsc.v14i1.35444

Abstract

Introduction
Salinity is one of the most important factors limiting crop production in arid and semiarid regions of the world that affects crop yield. Salt tolerance of Brassica species are very complex due to genetic relationships. Because of low erucic acid (less than 2% of total fatty acids) and glucosinolates contents (less than 3 µmol g-1), oil of Canola has many consumers around the world. Because Canola have tolerance potential against toxicity of salinity and its minerals, its growth can be successful in saline condition. According to the recent ongoing drought and the need to use low quality irrigation water for crops such as Canola, aim of this experiment was to evaluate the effect of salinity on changes in carbon fixation process and photosynthetic pigments of three Canola genotypes under salinity as well as determine most salt tolerant genotype for use in saline regions.
Materials and Methods
An experiment was conducted in the greenhouse of Shahid Chamran University during 2007-2008 growing season in factorial test based on a completely randomized design with four replications. The first factor (genotype) included Hayola 401, RGS0003 and Shiraly and the second factor (salinity levels) had four levels of salinity (50, 100 and 150 mM NaCl) as well as distilled water as a control. Sources of salinity were NaCl and CaCl2 with equal ratio as most resembles to lower water quality resources in the region. Date and time of stress were considered four weeks after planting (four-leaf stage). A Stepped irrigation method using saline water was done every 12 days over three steps period. To perform this study 10 liters volume pots were used. Three pots per each treatment, and totally 144 pots were used. SAS (version 9.1), Excel and MSTAT-C software's was used for statistical analysis. The comparison of means was done by Duncan method.
Results and Discussion
The results showed that content of chlorophyll a, b and carotenoids in all three genotypes increased to 100 mM, while decreased at 150 mM. Health and invulnerability of main photosynthetic pigments at 100 mM NaCl, can be considered as an important reason for salt tolerance in the evaluated canola cultivars. Reducing the absorption of water due to stress caused by salinity reduced nutrient uptake. Toxicity of chlorine and sodium also leads to inhibition of plant growth and dry matter. Magnesium concentration raised with increasing salinity compared to control. It seems that the magnesium concentration in stomatal guard cells decreased osmotic potential and play a role in the biosynthesis of organic compounds such as glutamic acid. So, despite ABA-induced stomatal closure, the stomatal openings, even in small amounts remain photosynthesis activities. Probably, magnesium has a key role in the continuing photosynthesis of Canola under salinity. The leaf starch in the genotype Shiraly significantly increased to 150 mM salinity level. Reduction of starch in high levels of salt stress interferes with enzymes efficiency involved in the starch biosynthesis, such as starch synthase and ADP- glucose pyrophosphorylase. The trend of variation in stomatal conductance was similar to 50 mM in the early flowering, but a sharp decrease was observed at late flowering compare to control. When stress started on the four-leaf stage, the plant for some time kept stomatal conductance at maximum level, but continuation stress period led to close stomata. Thus, reducing the amount of leaf relative water content can be considered as the reason of different stomatal conductance among the different levels of salt stress. A significant positive correlation between relative water content and stomatal conductance confirms this results. On the other hand to avoid stress and better use of the limited amount of available water, the plants closed stomata to prevent more water loss.
Conclusions
It seems that genotype Shiraly using some mechanisms to avoid stress, such as maintaining relative water content, as well as increase the content of chlorophyll a and b up to 100 mM. Moreover, the concentration of magnesium up to 150 mM, has endured salinity.

Keywords

• Chlorophyll a and b
• Magnesium
• salinity
• Starch
• stomatal conductance

20.1001.1.20081472.1395.14.1.12.9

---

References

1. Ahmadi, H., and Niazi Ardekani, J. 2006. The effect of water salinity on growth and physiological stages of eight Canola (Brassica napus L.) cultivars. Irrigation Science 25: 11-20.

2. Arnon, A. N. 1967. Method of extraction of chlorophyll in the plants. Agronomy Journal 23: 112-121.

3. Ashraf, M. 1994. Breeding for salinity tolerance in plants. CRC Critical. Review Plant Science, 13: 17-42.

4. Ashraf, M. 2001. Relationships between growth and gas exchange characteristics in some salt-tolerant amphidiploid Brassica species in relation to their diploid parents. Environmental and Experimental Botany 45: 55-163.

5. Ashraf, M. 2004. Some important physiological selection criteria for salt tolerance in plants. Flora Journal, 99: 361-376.

6. Ashraf, M., and Ali, Q. 2007. Relative membrane permeability and activities of some antioxidant enzymes as the key determinants of salt tolerance in canola (Brassica napus L.). Environmental and Experimental Botany 63: 266-273.

7. Ashraf, M. and Mc Neilly, T. 2004. Salinity tolerance in some brassica oilseeds. Critical. Review Plant Science 23: 154-174.

8. Blumwald, E., Aharon, S. G., and Apse, M. P. 2000. Sodium Transport in Plant Cells. Biochimica et Biophysica Acta, 1465 (2000): 140-151.

9. Chaves, M. M., Maroco, J. P., and Pereira, J. S. 2003. Understanding plant response to drought: from genes to the whole plant. Plant Biology 30: 239-264.

10. Ding, Y., Luo, W., and Xu, G. 2006. Characterization of magnesium nutrition and interaction of magnesium and potassium in rice. Annals of Applied Biology 149: 111-123.

11. Doganlar, Z. B., Demir, K., Basak, H., and Gul, I. 2010. Effects of salt stress on pigment and total soluble protein contents of three different tomato cultivars. African Journal of Agricultural Research 5: 2056-2065.

12. Dubey, R. S. 1997. Photosynthesis in plants under stressful conditions. In: P. M. page et al. (ed.) Handbook of photosynthesis. New York: Marcel Dekker, pp.859-875.

13. Francois, B. B. 2007. Effect of salinity on germination and seedling growth of canola. PhD thesis. Agricultural Sciences at the University of Stellenbosch p: 73.

14. Francois, L. E. 1994. Growth, seed yield, and oil content of canola grown under saline conditions. Agronomy Journal 86 (2): 233-237.

15. Hassibi, P., Nabipoor, M., and Moradi, F. 2010. Study of some cryoprotectives role to induce low temperature tolerance in rice (Oryza sativa L.) seedlings. Electronic Journal of Crop Production 3 (1): 39-56. (in Persian with English abstract).

16. He, T., and Cramer, G. R. 1992. Growth and mineral nutrition of six rapid-cycling Brassica species in response to seawater salinity. Plant Soil Science 139: 285-294.

17. Irshad, M., Eneji, A. E., Khattak, R. A., and Khan, A. 2009. Influence of nitrogen and saline water on the growth and partitioning of mineral content in Maize. Journal of Plant Nutrition 32: 458-469.

18. Jamil, M., Rehman, S. H., and Rha, E. S. 2007. Salinity effect on plant growth, PSII photochemistry and chlorophyll content in sugar beet (Beta vulgaris L.) and cabbage (Brassica Oleracea capitata L.). Pakistan Journal of Botany 39: 753-760.

19. Kattab, H. 2007. Role of glutathione and polyadenylic acid on the oxidative defense systems of two different cultivars of canola seedlings grown under saline condition. Australian Journal of Basic and Applied Sciences 1 (3): 323-334.

20. Kishimoto, K., Ishijima, S., and Ohnishi, M. 2003. Characterization of membrane ATP-ase activities of spinach chloroplasts. International journal of biological macromolecule 3 (2): 61-68.

21. Le-Dily, F., Billard, J. P., Le-Saos, J., and Huault, C. 1993. Effects of NaCl and gabaculine on chlorophyll and proline levels during growth of radish cotyledons. Plant Physiology and Biochemistry 31: 303-310.

22. Maathuis, F. J. M., and Amtmann, A. 1999. K+ nutrition and Na+ toxicity. The basis of cellular K+/Na+ ratios. Annual Botany 84: 123-133.

23. Mahmood, S. S., and Athar, H. R. 2003. Intra specific variability in sesame (sesamum indicum L.) for various quantitive and qualitive attributes under differential salt regimes. Journal of Science Research 14 (2): 177-186.

24. Misra, A. N., Latowski, D., and Strzalka, K. 2006. The xanthophylls cycle activity in Kidney Bean and Cabbage leaves under salinity stress. Russian Journal of Plant Physiology 53: 102-109.

25. Pessarakli, M. M., Morgan, P. V., and Gilbert, J. J. 2005. Dry- Matter yield, protein synthesis, starch, and fiber content of barley and wheat plants under two irrigation regimes. Journal of Plant Nutrition 28 (7): 1227-1241.

26. Pinheiro, C., Chaves, M. M., and Ricardo, C. P. 2001. Alterations in carbon and nitrogen metabolism induced by water deficit in the stems and leaves of (Lupinus albus L.). Journal of Experiment Botany 52: 1063-1070.

27. Qasim, M., Ashraf, M., Ashraf, M. U., Rehman, Y. S., and Rha, E. S. 2003. Salt induced changes in two canola cultivars differing in salt tolerance. Biologia Plantarum 46 (4): 629-632.

28. Qi-lin, D., Chen, C., Bin, F., Ting-ting, L., Xia, T., Yuan-ya, G., Ying-kun, S., Jin, W., and Shi-zhang, D. 2009. Effects of NaCl treatment on the antioxidant enzymes of oilseed rape (Brassica napus L.) seedlings. African Journal of Biotechnology 20: 5400-5405.

29. Ritchie, S. W., and Nguyen, H. T. 1990. Leaf water content and gas exchange parameters of two wheat genotypes differing in drought resistance. Crop Science 30: 105-111.

30. Saeedipour, S., Nabipour, M., and Moradi, F. 2007. Effect of salinity stress on some physiological mechanisms aspects of different Iranian Rice cultivar. PhD thesis. Shahid Chamran University. Ahvaz, Iran. p.116. (in Persian with English abstract).

31. Shamsoddin saied, M., and Farahbakhsh, H. 2009. Salt stress effect on yield and some agronomic and physiologic traits of two corn hybrid at Kerman region. The plant production 32 (1). 13-24. (in Persian).

32. Sheligl, H. Q. 1986. Die verwertung orgngischer souren durch chlorella lincht. Planta Journal 47-51. (in Germani).

33. Singh, A., and Dubey, K. 1995. Changes in chlorophyll a and b contents and activities of photosystems І and П in rice seedlings induced by NaCl. Photosynthetica 31: 489-499.

34. Tahmasbi, F. 2010. Physiological investigation of saline water irrigation from NaCl and CaCl2 sources on three genotypes of canola (Brassica napus L.) in Ahvaz climate condition. M.Se thesis. Shahid Chamran University. Ahvaz, Iran. p.114 (in Persian with English abstract).

35. Tahmasbi, F., Hassibi, P., and Meskarbashee, M. 2013. The evaluation of some physiological and biochemical variations of salt water irrigation tolerance in three canola genotypes. The Plant Production 36 (2): 75-86. (in Persian).

36. Valdez-Aguilar, L., Grieve, A. C. M., Poss, J., and Layfie, D. A. 2009. Salinity and alkaline pH in irrigation water affect marigold plants: II. Mineral Ion Relations. Hortscience 44 (6): 1726-1735.

37. Zhao, G. Q., Ma, B. L., and Ren, C. Z. 2007. Growth, gas exchange, chlorophyll fluorescence and ion content of naked oat in response to salinity. Crop Science 47: 123-131.

38. Zhu, J. K. 2002. Salt and drought stress signal transduction in plants. Annual Review of Plant Physiology and Plant Molecular Biology 53: 247-273.