بررسی اثرات تنش اسمزی و سمیت یونی ناشی از شوری با استفاده از پاسخ های سریع فتوسنتزی گندم دوروم

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار، دانشکده کشاورزی، دانشگاه شهید چمران اهواز

2 استاد، مؤسسۀ تحقیقات علمی و صنعتی کشورهای مشترک‌المنافع (CSIRO)، کنبرا، استرالیا

چکیده

شوری رشد گیاه را از طریق تنش اسمزی ناشی از وجود نمک در محیط اطراف ریشه و نیز سمیّت یونی ناشی از تجمع نمک در برگ­ها تحت تأثیر قرار می­دهد. ارزیابی ویژگی­های فتوسنتزی به عنوان روشی سریع و غیرتخریبی، توان بالایی برای بهبود بهره‌وری گیاه و تحمل به تنش دارد. به­منظور بررسی اثرات تنش اسمزی کوتاه‌مدت (45 دقیقه) بر ویژگی­های فتوسنتزی، چهار رقم­ گندم دوروم (به نام‌های کولتر، سکلاوی، کاندیکنز، برکولیا) با تحمل شوری متفاوت، در غلظت­های پایین 50 میلی­مولار کلریدسدیم و کلریدپتاسیم در آزمایشی گلدانی ارزیابی شدند. تبادلات گازی و به دنبال آن فتوسنتز بلافاصله با آغاز تنش اسمزی ناشی از هر دو تیمار (بهترتیب به میزان 10-15 و 3-5 درصد) کاهش یافتند، اگرچه با گذشت زمان میزان آنها تا حدودی ترمیم یافت. ویژگی­های فتوسنتزی بهطور مشابه به غلظت­های ایزواسمزی کلریدسدیم و کلریدپتاسیم پاسخ دادند. ارتباط بین غلظت سدیم برگ و پاسخ هدایت روزنه­ای هر چهار رقم، 45 دقیقه پس از رویارویی با هر دو نوع نمک نشان داد که هیچ تأثیر ویژه­‌ای از حضور سدیم در گیاه وجود ندارد. در مجموع به نظر می­رسد مهم­ترین عامل ایجاد پاسخ­های فتوسنتزی در استفاده از مواد اسمزی مختلف، در واقع فشاراسمزی ناشی از تنش در فضای اطراف ریشه‌ بوده است نه اینکه اثرات یونی ناشی از سمیّت سدیم باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Osmotic stress and ion-toxicity effects of salt stress using immediate photosynthetic responses of durum wheat

نویسندگان [English]

  • Afrasyab Rahnama 1
  • Rana Munns 2
  • Richard James 2
1 Assistant Professor, University of Ahvaz, Iran
2 Professors, Australia
چکیده [English]

Salinity affects plant growth by the osmotic stress of salt around the roots as well as by toxicity caused by excessive accumulation of salt in leaves. The study of photosynthetic traits as a rapid and non-destructive tool demonstrates the great potential for improving plant productivity and stress tolerance. A pot experiment was carried out to investigate short-term effects of osmotic stress (45 min) on photosynthetic traits of four durum wheat genotypes (namely Coulter and Seklavi, Candicans and Brkulja) differing in salt tolerance under low concentrations of 50 mM KCl and NaCl. Gas exchange and photosynthesis were reduced immediately after the onset of osmotic stress caused by both treatment (10-15% and 5-10%, respectively), but were recovered immediately over the time. Photosynthetic traits responded similarly to iso-osmotic concentrations of KCl and NaCl. The relationship between Na+ concentration in the leaf and stomatal conductance response in all four genotypes exposed to both salt treatments for 45 min showed no effect of Na+ toxicity within the plant. Stomatal factors limit photosynthesis of salt-stressed plants more than non-stomatal components of photosynthesis. In general, it seems that the main factor affecting of photosynthetic responses using diferrent osmotic was osmotic pressure of the salt outside the roots not the Na+ toxicity.

کلیدواژه‌ها [English]

  • Net photosynthesis
  • Osmotic stress
  • Stomatal conductance
  1. Cramer, G. R. & Quarrie, S. A. (2002). Abscisic acid is correlated with the leaf growth inhibition of four genotypes of maize differing in their response to salinity. Functional Plant Biology, 29: 111–115.
  2. Chen, Z. & Gallie, D. R. (2004). The ascorbic acid redox state controls guard cell signaling and stomata movement. The Plant Cell, 16: 1143–1162.
  3. Davies, W. J., Kudoyarova, G. & Hartung. W. (2005). Long-distance ABA signalling and its relation to other signalling pathways in the detection of soil drying and the mediation of the plant’s response to drought. Journal of Plant Growth Regulation, 24: 285–295.
  4. Dionisio-Sese, M. L. & Tobita, S. (2000). Effects of salinity on sodium content and photosynthetic responses of rice seedlings differing in salt tolerance. Journal of Plant Physiology, 157: 54–58.
  5. El-Hendawy, S. E., Hu, Y. & Schmidhalter, U. (2005). Growth, ion content, gas exchange, and water relations of wheat genotypes differing in salt tolerances. Australian Journal of Agricultural Research, 56: 123–134.
  6. Everard, J. D., R. Gucci., S. C. Kann., Flore, J. A. &Loeschner, W. H. (1994). Gas exchange and carbon partitioning in the leaves of celery (Apium graveolens L.) at various levels of root zone salinity. Plant Physiology, 106: 281–292.
  7. Fricke, W. (2004). Rapid and tissue-specific accumulation of solutes in the growth zone of barley leaves in response to salinity. Planta, 219: 515–25.
  8. Fricke, W., Akhiyarova, G., Veselov, D. & Kudoyarova, G. (2004). Rapid and tissue-specific changes in ABA and in growth rate response to salinity in barley leaves. Journal of Experemental Botany, 55: 1115–23
  9. James, R. A., Rivelli, A. R., Munns, R. & Caemmerer, S. V. (2002). Factors affecting CO2 assimilation, leaf injury and growth in salt-stressed durum wheat. Functional Plant Biology, 29: 1393–1403.
  10. James, R. A., Munns, R., von Caemmerer, S., Trejo, C., Miller, C. & Condon, A. G. (2006). Photosynthetic capacity is related to the cellular and subcellular partitioning of Na+, K+ and Cl salt-affected barley and durum wheat. Plant, Cell and Environment, 29: 2185–2197.
  11. James, R. A., Caemmerer, S. V., Condon, A. G., Zwart, A. B. & Munns, R. (2008). Genetic variation in tolerance to the osmotic stress component of salinity stress in durum wheat. Functional Plant Biology, 35: 111–123.
  12. Jiang, Q., Roche, D., Monaco, T. A. & Durham, S. (2006). Gas exchange, chlorophyll fluorescence parameters and carbon isotope discrimination of 14 barley genetic lines in response to salinity. Field Crops Research, 96: 269–278.
  13.  Munns, R. (2005). Genes and salt tolerance: Bringing them together. Tansley Review. New Phytologist, 167: 645–663.
  14. Munns, R. & Tester, M. (2008). Mechanisms of Salinity Tolerance. Annual Review of Plant Biology, 59: 651–81.
  15. Munns, R., James, R. A., Sirault, X. R. R., Furbank, R. T. & Jones, H. G. (2010). New phenotyping methods for screening wheat and barley for beneficial responses to water deficit. Journal of Experemental Botany, 61: 3499–3507.
  16. Netondo, G. W., John, C. O. & Beck, E. (2004). Sorghum and Salinity: II. Gas Exchange and Chlorophyll Fluorescence of Sorghum under Salt Stress. Crop Scienc, 44: 806–811.
  17. Rahnama, A., James, R. A., Poustini, K. & Munns, R. (2010). Stomatal conductance as a screen for osmotic stress tolerance in durum wheat growing in saline soil. Functional Plant Biology, 37: 255–269.
  18. Rahnama, A., Munns, R., Poustini, K. & watt, M. (2011). A screening method to identify genetic variation in root growth response to a salinity gradient. Journal of Experimental Botany, 62 (1): 69–77.
  19. Reddy, A. R., Chaitanya, K. V. & Vivekanandan, M. (2004). Drought-induced responses of photosynthesis and antioxidant metabolism in higher plants. Journal of Plant Physiology, 161:1189–1202.
  20. Rivelli, A. R., James, R. A., Munns, R. & Condon, A. G. (2002). Effect of salinity on water relations and growth of wheat genotypes with contrasting sodium uptake. Functional Plant Biology, 29: 1065–1074.
  21. Wilkinson, S. & Davies, W. J. (2008). Manipulation of the apoplastic pH of intact plants mimics stomatal and growth responses to water availability and microclimate variation. Journal of Experimental Botany, 59: 619–631.