Effects of Heat Stress after Anthesis on PSII Photochemical Efficiency and the Antioxidant Activity of Wheat Cultivars

Abstract

This study was conducted to investigate the effects of heat stress after anthesis on the performance of Photosystem II (PSII) and the enzymatic activity of catalase and ascorbate peroxidase. Two treatments-normal and heat stress-were conducted on four bread wheat cultivars from 7 days after anthesis until maturity. Heat stress led to an acceleration of chlorosis, reduced the efficiency of electron transfer and increased concentrations of malondialdehyde; however, the level of susceptibility varied depending on the cultivars. On the 10th day of heat stress, reductions in fluorescence parameters, depending on the cultivar, were 6.9 to 18.9% for Fv/Fm, 9 to 21% for ΦPSII and 8.3 to 19.4% for F’v/F’m compared to normal conditions. Catalase activity increased after initial exposure to heat stress. However, after 10 days of treatment, catalase activity increased in the Chamran and Aflak cultivars by 32% and 45%, respectively, but it did not change in the Dez cultivar and decreased 22% in Darab2. Ascorbate peroxidase activity decreased in two treatments, while the amount of reduction in heat stress treatment was more than the normal treatment. The highest levels of enzymatic activity were observed in Chamran under heat stress conditions, whereas Darab2 and Dez showed the lowest activity of the enzymes. Chlorophyll fluorescence parameters and chlorophyll index had a significant negative correlation with the levels of malondialdehyde; however, they had a significant positive correlation with the antioxidant activity. 

Keywords

• Ascorbate peroxidase; Catalase; Chlorophyll fluorescence; High temperature

References

1. Allakhverdiev S I, Kreslavski V D, Klimov V V, Los D A, Carpentier R & Mohanty P (2008). Heat stress: An overview of molecular responses in photosynthesis. Photosynthesis Research 98: 541-550
2. Almeselmani M, Deshmukh P S, Sairam R K, Kushwaha S R & Singh T P (2006). Protective role of antioxidant enzymes under high temperature stress. Plant Science 171: 382-388
3. Asthir B, Kaur S & Mann S K (2009). Effect of salicylic and abscisic acid administered through detached tillers on antioxidant system in developing wheat grains under heat stress. Acta Physiologiae Plantarum 31: 1091-1096
4. Baker N R & Rosenqvist E (2004). Applications of chlorophyll fluorescence can improve crop production strategies: an examination of future possibilities. Journal of Experimental Botany 55(403): 1607-1621
5. Beers R F & Sizer I (1952). A spectrophotometric method for measuring the breakdown of hydrogen by catalase. Journal of Biochemistry 195: 133-140
6. Dias A S, Semedo J, Ramalho J C & Lidon F C (2011). Bread and durum wheat under heat stress: A comparative study on the photosynthetic performance. Journal of Agronomy and Crop Science 197: 50-56
7. Farooq M, Bramley H, Palta J A & Siddique H M (2011). Heat stress in wheat during reproductive and grainfilling phases. Critical Reviews in Plant Sciences 30: 1-17
8. Feng C N, Guo W S, Shi J S, Peng Y X & Zhu X K (2000). Effect of high temperature after anthesis on endosperm cell development and grain weight in wheat. Acta Agronomica Sinica 26: 399-405

9. Harding S A, Guikema J A & Paulsen G M (1990). Photosynthetic decline from high temperature stress during maturation of wheat. I. Interaction with senescence processes. Plant Physiology 92: 648-653
10. Heath R L & Packer L (1969). Photoperoxidation in isolated chloroplast. I. Kinetics and stoichiometry of fatty acid peroxidation. Archives of Biochemistry and Biophysics 125: 189-198
11. Hurkman W J, McCue K F, Altenbach S B, Korn A, Tanaka C K, Kothari K M, Johnson E L, Bechtel D B, Wilson J D, Anderson O D & DuPont F M (2003). Effect of temperature on expression of genes encoding enzymes for starch biosynthesis in developing wheat endosperm. Plant Science 164: 873-881
12. Keeling P L, Bacon P J & Holt D C (1993). Elevated temperature reduces starch deposition in wheat endosperm by reducing the activity of soluble starch synthase. Planta 191: 342-348
13. Kumar R R, Goswami S, Kumar N, Pandey S K, Pandey V C, Sharma S K, Pathak H & Rai R.D (2011). Expression of novel ascorbate peroxidase isoenzymes of wheat (Triticum aestivum L.) in response to heat stress. International Journal of Plant Physiology and Biochemistry 3(11): 188-194
14. Liu X & Huang B (2000). Heat stress injury in relation to membrane lipid peroxidation in creeping bentgrass. Crop Science 40: 503-510
15. Maxwell K & Johnson G N (2000). Chlorophyll fluorescence-a practical guide. Journal of Experimental Botany 51(345): 659-668
16. Nakano Y & Asada K (1981). Hydrogen peroxidase is scavenged by ascorbate-specific peroxidase in spinach chloroplasts. Plant Cell Physiology 22: 867-880
17. Sairam R K, Srivastava G C & Saxena D C (2000). Increased antioxidant activity under elevated temperature: a mechanism of heat stress tolerance in wheat genotypes. Biologia Plantarum 43(2): 245-251
18. Salvucci M E & Crafts-Brandner S J (2004). Relationship between the heat tolerance of photosynthesis and the thermal stability of Rubisco activase in plants from contrasting thermal environments. Plant Physiology 134: 1460-1470
19. Tahir I S A & Nakata N (2005). Remobilization of nitrogen and carbohydrate from stems of bread wheat in response to heat stress during grain filling. Journal of Agronomy and Crop Science 191: 106-115
20. Xu Q, Paulsen A Q, Guikema J A & Paulsen G M (1995). Functional and ultrastructural injury to photosynthesis in wheat by high temperature during maturation. Environmental and Experimental Botany 35: 43-54
21. Zamani M M, Nabipour M & Meskarbashee M (2014). Stem water soluble carbohydrate remobilization in wheat under heat stress during the grain filling. International Journal of Agriculture & Biology 16: 401-405
22. Zamani M M, Nabipour M & Meskarbashee M (2015). Effect of heat stress during grain filling on photosynthesis and grain yield of bread wheat (Triticum aestivum L.) genotypes. Iranian Journal of Crop Sciences 17(1): 1-17
23. Zhao H, Dai T, Jing Q, Jiang D & Cao W (2007). Leaf senescence and grain filling affected by post-anthesis high temperatures in two different wheat cultivars. Plant Growth Regulation 51: 149-158