Investigation of antioxidant activities and biochemical characteristics of drought-stressed fenugreek (Trigonella foenum- graecum L.) in response to biopotasse and iron sulfate
Subject Areas : GeneticMohammed Hossein Aminifard 1 , homeyra. homeyra 2 , Hassan bayat 3 , Ali Reza Samadzade 4
1 - Department of Horticultural Science and Special Plants Regional Research Center, College of Agriculture, University of Birjand, Birjand, Iran
2 - Department of Horticultural Science, College of Agriculture, University of Birjand, Birjand, Iran
3 - Department of Horticultural Science and Special Plants Regional Research Center, College of Agriculture, University of Birjand, Birjand, Iran
4 - Department of Agronomy and Plant Breeding Sciences, College of Agriculture, University of Birjand, Birjand, Iran
Keywords: Fenugreek, Carbohydrate, Secondary metabolites, Biochemical characteristics,
Abstract :
In order to investigate the effect of biopotasse and iron sulfate on antioxidant activity and biochemical characteristics of fenugreek under drought stress conditions, a factorial experiment was conducted as split plot based on randomized complete block design with three replications in 2017. Treatments included drought stress (normal irrigation as non-stress and irrigation in early growth for 14 days as drought stress) as the main factor and biopotasse (0 and 5 kg. ha-1) and iron sulfate (0 and 1.5 per thousand) as sub-factors biofertilizer. Results showed that the effect of drought stress, biopotasse, iron sulfate, and their interaction were significant on anthocyanin and phenolic compounds and flavonoids so that the highest amount of anthocyanin in fenugreek was obtained from 5 kg biopotasse treatment per hectare and 1.5 per thousand iron sulfate in drought stress conditions while the lowest amount was recorded in control treatment under stress conditions. Also, in drought stress, phenolic compounds, and flavonoids increased in fenugreek, as the highest amount of total flavonoid was achieved under drought stress conditions and 5 kg ha-1 biopotasse and 1.5 per thousand iron sulfates. The interaction of drought stress and iron sulfate was significant on the antioxidant activity of the plant, as the highest antioxidant activity (62.8%) was obtained in drought stress and iron sulfate treatment. Also, the highest amount of total carbohydrate in fenugreek was obtained under drought stress conditions and in 5 kg biopotasse treatment, and the lowest trait was obtained under non-stress conditions. Results showed that the highest total chlorophyll content of fenugreek was observed in non-drought stress conditions and 5kg .ha-1 biopotasse and iron sulfate 1.5 per thousand. Based on the findings, drought stress played an important role in increasing phenolic compounds, flavonoids, anthocyanin, and soluble sugar contents of fenugreek and biopotasse biofertilizer and iron sulfate improved biochemical characteristics of the plants.
Abbaszadeh, B., Sharifi-ashurabadi, E., Lebaschy, M.H., Naderi-hajibaqerkandi, M., and Moghaddami, F. (2008). Effect of drought stress on prolin, soluble sugar, chlorophyll and relative water content (RWC) of lemon balm (Melissa officinalis L.). Iranian Journal of Medicinal and Aromatic Plants, 23 (4):504-513. (In Persian).
Ahanger, M., Tyagi, S., Wani, M. and Ahmad, P.(2013). Drought tolerance: role of organic osmolytes, growth regulators, and mineral nutrients. Physiological Mechanisms and Adaptation Strategies in Plants Under Changing Environment, eds Ahmad P., Wani M. R., editors. (New York, NY: Springer, Sci. 1: 25-55
Alizadeh, A. (2002). Relationship between water and water. Imam Reza University Press. Mashhad.Iran, 450 P.
Altuntas, E., Engin, O., Zgo, Z.E., and Taser, F. (2005). Some physical properties of fenugreek (Trigonella foenum-graceum L.) seeds. Journal Food Engineering, 71: 37-43.
Apel, K. and Hirt, H. (2004). Reactive oxygen species: Metabolism, oxidative stress, and signal transduction, Journal Plant Biology. 55:373-399
Arun, K.S. (2002). A Handbook of Organic Farming Pub, Agrobios, India.
Asadi Kavan, Z.h., Ghorbanli, M. and Sateei, A. (2010). The effect of drought stress and exogenous ascorbate on photosynthetic pigments, flavonoids, phenol compounds and lipid peroxidation in Pimpinella anisum L. Iranian Journal of Medicinal and Aromatic Plants, 25 (4): 456-69. (In Persian)
Bideshki, A., Arvin, M.J. and Maghsoudi, K.(2012). Effect of indole-3 butyric acid (IBA) foliar application on growth, bulb yield and allicin of garlic (Allium sativum L.) under water deficit stress in field. Iranian Journal of Medicinal and Aromatic Plants, 28(3): 567-577. (In Persian).
Carrubba, A., LaTorre, R. and Matranga, A. (2002). Cultivation trials of some aromatic and medicinal plants in a semi-arid Mediterranean environment. Proceedings of an International Conference on MAP, Acta Horticulture (ISHS), 978 (1): 4200-6315.
Chegini, A., Ghorbanpour, M., Hatami, M. and Taqizadeh, M.(2017). Effect of Multi-Walled Carbon Nanotubes on Physiological Traits, Phenolic Contents and Antioxidant Capacity of Salvia mirzayanii Rech. f. & Esfand. under Drought Stress. Journal of Medicinal Plant, 16(2),62. (In Persian).
Estrada, B., Pomar, F.J., Merino, F. and Bernal, M.A. (1999). Pungency level in fruits of the Padron pepper with different water supply. Journal of Horticultural Science, 81(4): 385-396.
Ghorbanali, M. and Niakan, M. (2005). Evaluation of drought stress effect on soluble sugars content, protein, prolin and phenolic compounds and nitrate reeducates activity in soybean cultivar Gorgan 3, Iran. Journal of Science Education, 1(2): 537-550
Ghorbanpour, M. (2015). Major essential oil constituents, total phenolics and flavonoids content and antioxidant activity of Salvia officinalis plant in response to nano-titanium dioxide. Indian Journal of Plant Physiology, 20 (3): 249 – 56.
Han, H.S., Supanjani, D. and Lee, K.D. (2006). Effect of coin coculation with phosphate and potassium solubilizing bacteria on mineral uptake and growth of pepper and cucumber. Journal Psychology of Sport and Exercise, 52: 130-136.
Jafarzadeh, L., Omidi, H. and Bostany, A. (2014) The Effect of drought stress and nitrogen fertilizer on some biochemical properties of calendula (Calendula officinalis L.) plant. Journal of Plant Research, 27(1).
Jahanshahi, Sh., Baghreizadeh, M. and Abotalebi, A. (2013) Effect of vermi compost, azotobacter and barvar II on some quantitative and qualitative traits of coriander (Coriandrum sativum L.) medicinal plant. Journal of crop Production Research, 4(4): 391-400.
Jiang, Y. and Huang, B. (2001). Drought and heat injury to two cool-season turf grasses in relation to antioxidant metabolism and lipid peroxidation. Crop Science, 41: 436-442.
Jones, M.M., Osmond, C.B. and Turner, N.C. (1980). Accumulation of solutes in leaves of sorghum and sunflower in response to water stress. Australian Journal of Plant Physiology, 7: 193-205.
Kalinova, J. and Vrchotova, N. (2011). The influence of organic and conventional crop management, variety and year on the yield and flavonoid level in common buckwheat groats. Food chemistry, 127: 602 - 8.
Kamrova, S., Babayan Jolodar, N. and Bagheri, N. (2017). Effect of drought stress on chlorophyll and proline traits in different soybean genotypes. Journal of Agronomy correction research, 9 (23).
Kapoor, R., Giri, B. and Mukerji, K.G. (2004). Improved growth and essential oil yield and quality in (foeniculum vulgare Mill.) on mycorrhizal inoculation supplemented with P fertilizer. Journal of Biotechnology, 93: 307-311.
Kazemalilou, S. and Rasouli-Sedghiani, M.H. (2012). Effect of soil cadmium pollution on some physiological parameters of Hyoscyamus plant (Hyoscyamus niger L.) in presence/absence of growth-promoting microorganisms. Journal of Water and Soil Science, 22(4): 17-30.
Krizek, D.T., Mirecki, R.M. and Britz, S.J. (1997). Inhibitory effects of ambient levels of solar UV‐A and UV‐B radiation on growth of cucumber. Journal of Plant Physiology, 100(4), 886-893.
Leng, P., Itamura, H., Yamamura, H.H. and Deng, X. (2000). Anthocyanin accumulation in apple and peach shoots during cold acclimation. Journal of Horticultural Science, 83: 43 – 50.
Lichtenthaler, H. K. (1987). Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods in enzymology, 148 (34): 350-382.
Liu, C.C., Liu, Y.G., Guo, K., Fan, D., Li, G.Q., Yu, L.,Yang, R. and Zheng, Y.( 2011). Effect of drought on pigments, osmotic adjustment and antioxidant enzymes in six woody plant species in karst -habitats of southwestern China Environmental and Experimental Botany, 71:174-183.
Loggini, B., Scartazza, A., Brugnoli, E. and Navari Izzo, F.(1999). Antioxidative defense system pigment composition and photosynthetic efficiency in two wheat cultivars subjected to drought. Plant Physiology, 119:1091-1100 effects. Journal of Food and Chemical Toxicology, 50: 2503-2507.
Maghami, R., Zahedi, M. and Gheysari, M. (2014). Effects of nitrogen application and irrigation water on grain yield and water use efficiency of safflower in Isfahan. Journal of Plant Production, 4 (11): 1-13. (In Persian)
Marschner, H. (1995). Mineral Nutrition of Higher Plants. 2nd ed., Academic Press, New York, USA
Miller, G., Suzuki, N. and Ciftci‐Yilmaz, S. (2010). Reactive oxygen species homeostasis and signaling during drought and salinity stresses. Journal of Plant Cell and Environment, 33: 453-467.
Mittler, R. (2004). Oxidative stress, antioxidants and stress tolerance. Journal of Plant Sciences, 7: 405-410.
Mocready, R., Guggolz, J., Silviera, V. and Owens, H. (1950). Determination of starch and amylose in vegetables. Application to peas. Journal of Analytical Chemistry, 22: 1156-1158.
Muyayabantu, G.M., Kadiata, B.D. and Nkongolo, K.K, (2013). Assessing the effects of integrated soil fertility management on biological efficiency and economic advantages of intercropped maize (Zea mays L.) and soybean (Glycine max L.) in DR Congo, 3 (3): 520-541.
Nicure, S., 2015. The Effect of Glutenin and Acid Streak Spray on Growth Indices and Petunia × Hybrida. Master's thesis, Department of Horticulture.Islamic Azad University.Karaj Branch
Posmyk, M.M., Kontek, R. and Janas, K.M. (2009). Antioxidant Enzymes activity and phenolic compounds content in red cabbage seedlings exposed to copper stress. Journal Ecotoxicology and Environmental Safety, 72 (2): 596 – 602.
Salehi Shanjani, P. (2005). Izozyme diversity of Menadion reductase, isocitrate dehydrogenase and malate dehydrogenase of Fagus orientalis Lipsky in beech forests of Iran. Journal of Biology, 17: 402 -420.
Saravanakumar, D., Kavino, M., Raguchander, T., Subbian, P. and Samiyappan. (2011). Plant growth promoting bacteria enhance water stress resistance in green gram plants. Journal Acta Physiology Plant, 33: 203–209.
Shamloo, A. and Roozbahani, A. (2016). Effect of amino acids and microelements on the rate of photosynthetic pigments content and yield of red bean (Phaseolus vulgaris L.). Journal of Plant Ecophysiology, 7 (21): 136 - 50.
Sharma, P.K. and Hall, D.O. (1991). Interaction of saltstress and photoinhibition on photosynthesis in barley and sorghum Journal of Plant Physiology, 138 (5): 614 – 19.
Sheikhi-Ghahfarokhi, F. (2014). Effect of seed biopriming by PGPR bacteria on germination indices, growth and yield of Calendula of ficinalis L. M.Sc. Thesis in Seed Science and Technology, Shahrekord University, 93 P.
Sidsel Fiskaa, H., Grethe, I., Borge, A., Knut, A. and Gunnar, B.(2009). Effect of cold storage and harvest data on bioactive compound in curly kale (Brassica oleracea L. var. acephala). Journal of Postharvest Biology and Technology,51: 36-42.
Tajmmlian, M., Iran Nejad parazi, M.D., Malekinejad, H., Rad, M.H. and Sodaie zadeh, H. (2012). Effect of low stress on some physiological parameters of plant (.Fortuynia bungei Boiss) . Journal of Genetics Research and Plant Breeding, 20: 273-283.
Talebi, M., Sagheb Talebi, Kh. and Jahanbazi, H. (2006). Site demands and some quantitative and qualitative characteristic of Persian Oak (Quercus brantii L.)in chaharmahal & Bakhtiari Province (western iran). Iranian Journal of Forest and Poplar Research, 14(1):67-79.
Turkmen, N., Sari, F. and Velioglu, Y.S. (2005). The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Journal of Food chemistry, 93(4): 713-718
Wrosotad, R.E. (1976). Color and pigment analysis in fruit products. Oregon State University Publications Limited, Cornwalis.
Wu, S.C., Cao, Z.H., Li, Z.G., Cheung, K.C. and Wong, M.H. (2005). Effects of bio fertilizer containing N-fixer, P and K solubilizers and AM fungi on maize growth: a greenhouse trial. Journal Geoderma, 125: 155–166.
Xiao, X., Xu, X. and Yang, F. (2008). Adaptive responses to progressive drought stress in two Populus cothayana populations. Silva Fennica, 42: 705-719.
Xoconostle-Cazares, B., Ramirez-Ortega, F.A., Flores-Elenes, L. and Ruiz-Medrano, R. (2010). Drought tolerance in crop plants. American Journal Plant Physiology, 5(5): 241-256.
Zhang, K.M., Yu, H.J., Shi, K., Zhou, Y.H., Yu, J.Q. and Xia, X.J. (2010). Photoprotective roles of anthocyanins in Begonia simper florens. Journal of Plant Sciences, 179(3): 202-208.
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Abbaszadeh, B., Sharifi-ashurabadi, E., Lebaschy, M.H., Naderi-hajibaqerkandi, M., and Moghaddami, F. (2008). Effect of drought stress on prolin, soluble sugar, chlorophyll and relative water content (RWC) of lemon balm (Melissa officinalis L.). Iranian Journal of Medicinal and Aromatic Plants, 23 (4):504-513. (In Persian).
Ahanger, M., Tyagi, S., Wani, M. and Ahmad, P.(2013). Drought tolerance: role of organic osmolytes, growth regulators, and mineral nutrients. Physiological Mechanisms and Adaptation Strategies in Plants Under Changing Environment, eds Ahmad P., Wani M. R., editors. (New York, NY: Springer, Sci. 1: 25-55
Alizadeh, A. (2002). Relationship between water and water. Imam Reza University Press. Mashhad.Iran, 450 P.
Altuntas, E., Engin, O., Zgo, Z.E., and Taser, F. (2005). Some physical properties of fenugreek (Trigonella foenum-graceum L.) seeds. Journal Food Engineering, 71: 37-43.
Apel, K. and Hirt, H. (2004). Reactive oxygen species: Metabolism, oxidative stress, and signal transduction, Journal Plant Biology. 55:373-399
Arun, K.S. (2002). A Handbook of Organic Farming Pub, Agrobios, India.
Asadi Kavan, Z.h., Ghorbanli, M. and Sateei, A. (2010). The effect of drought stress and exogenous ascorbate on photosynthetic pigments, flavonoids, phenol compounds and lipid peroxidation in Pimpinella anisum L. Iranian Journal of Medicinal and Aromatic Plants, 25 (4): 456-69. (In Persian)
Bideshki, A., Arvin, M.J. and Maghsoudi, K.(2012). Effect of indole-3 butyric acid (IBA) foliar application on growth, bulb yield and allicin of garlic (Allium sativum L.) under water deficit stress in field. Iranian Journal of Medicinal and Aromatic Plants, 28(3): 567-577. (In Persian).
Carrubba, A., LaTorre, R. and Matranga, A. (2002). Cultivation trials of some aromatic and medicinal plants in a semi-arid Mediterranean environment. Proceedings of an International Conference on MAP, Acta Horticulture (ISHS), 978 (1): 4200-6315.
Chegini, A., Ghorbanpour, M., Hatami, M. and Taqizadeh, M.(2017). Effect of Multi-Walled Carbon Nanotubes on Physiological Traits, Phenolic Contents and Antioxidant Capacity of Salvia mirzayanii Rech. f. & Esfand. under Drought Stress. Journal of Medicinal Plant, 16(2),62. (In Persian).
Estrada, B., Pomar, F.J., Merino, F. and Bernal, M.A. (1999). Pungency level in fruits of the Padron pepper with different water supply. Journal of Horticultural Science, 81(4): 385-396.
Ghorbanali, M. and Niakan, M. (2005). Evaluation of drought stress effect on soluble sugars content, protein, prolin and phenolic compounds and nitrate reeducates activity in soybean cultivar Gorgan 3, Iran. Journal of Science Education, 1(2): 537-550
Ghorbanpour, M. (2015). Major essential oil constituents, total phenolics and flavonoids content and antioxidant activity of Salvia officinalis plant in response to nano-titanium dioxide. Indian Journal of Plant Physiology, 20 (3): 249 – 56.
Han, H.S., Supanjani, D. and Lee, K.D. (2006). Effect of coin coculation with phosphate and potassium solubilizing bacteria on mineral uptake and growth of pepper and cucumber. Journal Psychology of Sport and Exercise, 52: 130-136.
Jafarzadeh, L., Omidi, H. and Bostany, A. (2014) The Effect of drought stress and nitrogen fertilizer on some biochemical properties of calendula (Calendula officinalis L.) plant. Journal of Plant Research, 27(1).
Jahanshahi, Sh., Baghreizadeh, M. and Abotalebi, A. (2013) Effect of vermi compost, azotobacter and barvar II on some quantitative and qualitative traits of coriander (Coriandrum sativum L.) medicinal plant. Journal of crop Production Research, 4(4): 391-400.
Jiang, Y. and Huang, B. (2001). Drought and heat injury to two cool-season turf grasses in relation to antioxidant metabolism and lipid peroxidation. Crop Science, 41: 436-442.
Jones, M.M., Osmond, C.B. and Turner, N.C. (1980). Accumulation of solutes in leaves of sorghum and sunflower in response to water stress. Australian Journal of Plant Physiology, 7: 193-205.
Kalinova, J. and Vrchotova, N. (2011). The influence of organic and conventional crop management, variety and year on the yield and flavonoid level in common buckwheat groats. Food chemistry, 127: 602 - 8.
Kamrova, S., Babayan Jolodar, N. and Bagheri, N. (2017). Effect of drought stress on chlorophyll and proline traits in different soybean genotypes. Journal of Agronomy correction research, 9 (23).
Kapoor, R., Giri, B. and Mukerji, K.G. (2004). Improved growth and essential oil yield and quality in (foeniculum vulgare Mill.) on mycorrhizal inoculation supplemented with P fertilizer. Journal of Biotechnology, 93: 307-311.
Kazemalilou, S. and Rasouli-Sedghiani, M.H. (2012). Effect of soil cadmium pollution on some physiological parameters of Hyoscyamus plant (Hyoscyamus niger L.) in presence/absence of growth-promoting microorganisms. Journal of Water and Soil Science, 22(4): 17-30.
Krizek, D.T., Mirecki, R.M. and Britz, S.J. (1997). Inhibitory effects of ambient levels of solar UV‐A and UV‐B radiation on growth of cucumber. Journal of Plant Physiology, 100(4), 886-893.
Leng, P., Itamura, H., Yamamura, H.H. and Deng, X. (2000). Anthocyanin accumulation in apple and peach shoots during cold acclimation. Journal of Horticultural Science, 83: 43 – 50.
Lichtenthaler, H. K. (1987). Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods in enzymology, 148 (34): 350-382.
Liu, C.C., Liu, Y.G., Guo, K., Fan, D., Li, G.Q., Yu, L.,Yang, R. and Zheng, Y.( 2011). Effect of drought on pigments, osmotic adjustment and antioxidant enzymes in six woody plant species in karst -habitats of southwestern China Environmental and Experimental Botany, 71:174-183.
Loggini, B., Scartazza, A., Brugnoli, E. and Navari Izzo, F.(1999). Antioxidative defense system pigment composition and photosynthetic efficiency in two wheat cultivars subjected to drought. Plant Physiology, 119:1091-1100 effects. Journal of Food and Chemical Toxicology, 50: 2503-2507.
Maghami, R., Zahedi, M. and Gheysari, M. (2014). Effects of nitrogen application and irrigation water on grain yield and water use efficiency of safflower in Isfahan. Journal of Plant Production, 4 (11): 1-13. (In Persian)
Marschner, H. (1995). Mineral Nutrition of Higher Plants. 2nd ed., Academic Press, New York, USA
Miller, G., Suzuki, N. and Ciftci‐Yilmaz, S. (2010). Reactive oxygen species homeostasis and signaling during drought and salinity stresses. Journal of Plant Cell and Environment, 33: 453-467.
Mittler, R. (2004). Oxidative stress, antioxidants and stress tolerance. Journal of Plant Sciences, 7: 405-410.
Mocready, R., Guggolz, J., Silviera, V. and Owens, H. (1950). Determination of starch and amylose in vegetables. Application to peas. Journal of Analytical Chemistry, 22: 1156-1158.
Muyayabantu, G.M., Kadiata, B.D. and Nkongolo, K.K, (2013). Assessing the effects of integrated soil fertility management on biological efficiency and economic advantages of intercropped maize (Zea mays L.) and soybean (Glycine max L.) in DR Congo, 3 (3): 520-541.
Nicure, S., 2015. The Effect of Glutenin and Acid Streak Spray on Growth Indices and Petunia × Hybrida. Master's thesis, Department of Horticulture.Islamic Azad University.Karaj Branch
Posmyk, M.M., Kontek, R. and Janas, K.M. (2009). Antioxidant Enzymes activity and phenolic compounds content in red cabbage seedlings exposed to copper stress. Journal Ecotoxicology and Environmental Safety, 72 (2): 596 – 602.
Salehi Shanjani, P. (2005). Izozyme diversity of Menadion reductase, isocitrate dehydrogenase and malate dehydrogenase of Fagus orientalis Lipsky in beech forests of Iran. Journal of Biology, 17: 402 -420.
Saravanakumar, D., Kavino, M., Raguchander, T., Subbian, P. and Samiyappan. (2011). Plant growth promoting bacteria enhance water stress resistance in green gram plants. Journal Acta Physiology Plant, 33: 203–209.
Shamloo, A. and Roozbahani, A. (2016). Effect of amino acids and microelements on the rate of photosynthetic pigments content and yield of red bean (Phaseolus vulgaris L.). Journal of Plant Ecophysiology, 7 (21): 136 - 50.
Sharma, P.K. and Hall, D.O. (1991). Interaction of saltstress and photoinhibition on photosynthesis in barley and sorghum Journal of Plant Physiology, 138 (5): 614 – 19.
Sheikhi-Ghahfarokhi, F. (2014). Effect of seed biopriming by PGPR bacteria on germination indices, growth and yield of Calendula of ficinalis L. M.Sc. Thesis in Seed Science and Technology, Shahrekord University, 93 P.
Sidsel Fiskaa, H., Grethe, I., Borge, A., Knut, A. and Gunnar, B.(2009). Effect of cold storage and harvest data on bioactive compound in curly kale (Brassica oleracea L. var. acephala). Journal of Postharvest Biology and Technology,51: 36-42.
Tajmmlian, M., Iran Nejad parazi, M.D., Malekinejad, H., Rad, M.H. and Sodaie zadeh, H. (2012). Effect of low stress on some physiological parameters of plant (.Fortuynia bungei Boiss) . Journal of Genetics Research and Plant Breeding, 20: 273-283.
Talebi, M., Sagheb Talebi, Kh. and Jahanbazi, H. (2006). Site demands and some quantitative and qualitative characteristic of Persian Oak (Quercus brantii L.)in chaharmahal & Bakhtiari Province (western iran). Iranian Journal of Forest and Poplar Research, 14(1):67-79.
Turkmen, N., Sari, F. and Velioglu, Y.S. (2005). The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Journal of Food chemistry, 93(4): 713-718
Wrosotad, R.E. (1976). Color and pigment analysis in fruit products. Oregon State University Publications Limited, Cornwalis.
Wu, S.C., Cao, Z.H., Li, Z.G., Cheung, K.C. and Wong, M.H. (2005). Effects of bio fertilizer containing N-fixer, P and K solubilizers and AM fungi on maize growth: a greenhouse trial. Journal Geoderma, 125: 155–166.
Xiao, X., Xu, X. and Yang, F. (2008). Adaptive responses to progressive drought stress in two Populus cothayana populations. Silva Fennica, 42: 705-719.
Xoconostle-Cazares, B., Ramirez-Ortega, F.A., Flores-Elenes, L. and Ruiz-Medrano, R. (2010). Drought tolerance in crop plants. American Journal Plant Physiology, 5(5): 241-256.
Zhang, K.M., Yu, H.J., Shi, K., Zhou, Y.H., Yu, J.Q. and Xia, X.J. (2010). Photoprotective roles of anthocyanins in Begonia simper florens. Journal of Plant Sciences, 179(3): 202-208.