INTRODUCTION

Wheat (Triticum aestivum L.), an important staple food crop, is the main source of food and energy with a large number of end use products like chapathi, bread, bis- cuits, pasta etc. High temperature is a common stress for plants, restricting growth and productivity in many regions. Wheat is sensitive to high temperature (both early and late) but magnitude of damage will depend on background ambient temperature, stage of development and variety, (Awad et al.2007 and Farooq et al. 2011, Kasim et al., 2013 and Chakrawarty et al., 2013).

ARTICLE INFORMATION:

*Corresponding Author: afjalahmaed24@yahoo.in Received 1st November, 2015

Accepted after revision 5th December, 2015 BBRC Print ISSN: 0974-6455

Online ISSN: 2321-4007 NAAS Journal Score : 3.48

©A Society of Science and Nature Publication, 2015. All rights reserved.

Online Contents Available at: http//www.bbrc.in/

High growing temperature reduces the duration of all developmental stages in wheat. Rhizobacteria, when introduced by plant inoculation in a soil containing competitive micro"ora, exert a bene!cial effect on plant growth and are termed plant growth promoting rhizo- bacteria (PGPR) . PGPR are naturally occurring soil bac- teria that aggressively colonize plant roots and bene!t plants by providing growth promotion. Pseudomonas aeruginosa (strain 2CpS1), a gram-negative, unipolar motility aerobic rod (Pseudomonadacae family), iso- lated and characterized locally and reported to grow at a temperature as high as 42ºC was undertaken for a pot

171

Meena, Ahmed and Prakash

experiment to observe its effectiveness on growth pro- motion of wheat under high temperature condition in vitro, (Balla et al. 2008 and Sikder et al. 2010).

MATERIALS AND METHODS

A pot experiment was conducted in the Net house of Institute of Agricultural Sciences, Banaras Hindu University,Varanasi. Disease free and healthy seeds of wheat (Triticum aestivum L.) cultivar HUW-234, obtained from Department of Genetics and Plant Breed- ing, Institute of Agricultural Sciences, BHU, were sur- face sterilized with 1% NaOCl for 3–5 minutes and sub- sequently washed in distilled water 3–4 times and air dried. The seeds were subjected to seed treatment by the plant growth promoting rhizobacteria, Pseudomonas aeruginosa (strain 2CpS1) following the method in which the population of the rhizobacterial strain to be obtained was 107 cfu ml–1. Surface-sterilized wheat seeds of uniform size were then bacterized by dipping for 2 h into the bacterial suspension followed by air drying at room temperature under aseptic conditions.( Abbasi et al. 2011).

The soil to be used for pot !lling was collected from the experimental farm and was cleaned, dried, powdered and mixed thoroughly. Soil, sand and FYM were mixed in the ratio of 1:3:1 and then sterilized by using 4% for- maldehyde. The pots (20 × 20 cm), after being sterilized by 70% methanol, were subjected to pot-!lling after 5–6 days of soil and pot sterilization. Fertilizer was applied in the ratio of 120:60:60 ppm of N, P, K respectively to the pots two days prior to sowing. Half of the pot comprising T2 and T4 were sown with Pseudomonas aeruginosa treated seeds, whereas, T1 and T3 were sown with non-treated seeds. After 21 days of sowing, plants were imposed with temperature stress. Nine pots sown with seeds treated with Pseudomonas aeruginosa and

equal number of pots sown with non treated seeds were transferred to a plant growth chamber having 30°C/ 25°C day/ night temperatures. The relative humidity was maintained at 90% with 12 hours of light and dark peri- ods. The control pots were maintained in the net house of Department of Plant Physiology. Observations on different morphological, physiological and biochemical parameters were recorded at 24 days after temperature treatment imposition. Each pot containing four plants were taken as one replication for determination of mor- phological and growth parameters. Samples for physi- ological parameters and chlorophyll content were col- lected between 9.00 to 10.00 AM. from fully expanded leaf and was brought to the laboratory in ice buckets.

RESULTS AND DISCUSSION

Seed treatment with Pseudomonas aeruginosa (strain 2CpS1) resulted in an overall increase in the morpho- logical, physiological and biochemical parameters in wheat plant during elevated temperature as well as nor- mal temperature condition as indicated in Table 1. The parameters such as plant height, root length, leaf area, total dry matter, relative water content and chlorophyll content were observed to have the maximum value for the treatment T2 [Pseudomonas aeruginosa (2CpS1) treatment + No elevated temperature treatment] and the least value was observed for T3 [No Pseudomonas aeru- ginosa (2CpS1) treatment + elevated temperature treat- ment], at 24 days after temperature treatment. Pseu- domonas aeruginosa, strain 2CpS1 has been found to show ACC-deaminase activity. Increased root elongation might be due to ACC deaminase which break down eth- ylene, that inhibits root elongation. Improved morpho- logical and physiological parameters in Pseudomonas aeruginosa treated seeds could also be due to better nitrogen !xation, facilitation of nutrient uptake, solubi-

lization of phosphorus and phytohormone production,( Tahir et al.2009).

The value for cell membrane injury was recorded to be the maximum for T3 [No Pseudomonas aeruginosa (2CpS1) treatment + elevated temperature treatment] and minimum for T2 [Pseudomonas aeruginosa (2CpS1) treatment + no elevated temperature treatment] ,while the treatments T4 [Pseudomonas aeruginosa (2CpS1)

+elevated temperature treatment] was found to have reduced damage to its membrane, as there is the amel- iorative effect of PGPR treatment on the elevated tem- perature stress, ( Mator et al. 2005, Gupta et al. 2006).

The treatment T3 [No Pseudomonas aeruginosa (2CpS1) treatment + elevated temperature treatment] was recorded to have the minimum value for yield and yield related attributes while the maximum value was observed for the treatment T2 [Pseudomonas aeruginosa (2CpS1) treatment + No elevated temperature treatment] and this was followed by T4 and T1.

Our observations in Table 1 and Table 2 indicate that percent increase in morphological, physiological and biochemical parameters due to Pseudomonas aeruginosa treatment had better effect under stress (elevated tem- perature treatment) conditions as compared to normal condition. Pseudomonas aeruginosa, strain 2CpS1 has been reported to show ACC deaminase activity and has been found to survive and grow well at optimum tem- perature of 37°C, and it is able to grow at temperatures as high as 42°C ( Bano, 2008).

Thus, it affects morphological, physiological, bio- chemical parameters in wheat under both control and elevated temperature situation. The present study sug- gests that Pseudomonas aeruginosa strain 2CpS1 seed treatment can ameliorate the deleterious effects of tem- perature stress by increasing plant height, root length, leaf area, chlorophyll content, relative water content and decreasing cell membrane injury in wheat plant.

(Bhatti et al. 2005) There is amelioration of elevated temperature stress in wheat on the basis of which it can be concluded that the application of isolated, character- ized and tested stress tolerant PGPR strains can enhance stress tolerance in crop plants and could be used as a feasible strategy for improving crop production under the conditions of high temperature stress.

REFERENCES

Abbasi, M. K., Sharif, S., Kazmi, M., Sultan, T. and Aslam, M. (2011). Isolation of plant growth promoting rhizobacteria from wheat rhizosphere and their effect on improving growth, yield and nutrient uptake of plants. Plant Biosystems. 145(1):159- 168

Awad, N. M., Turky, A. S.(2007). Effect of organic manures forti!ed with plant growth- promoting rhizobacteria on con- trolling some soil-borne diseases and growth of wheat plants. Egyptian Journal of Soil Science. 47( 1): 22-36.

Bhatti A.R, Kumar, K., Stobo, C., Chaudhry, G.R and Ingram, J.M.(2005). High temperature induced antibiotic sensitivity changes in Pseudomonas aeruginosa. Laboratory of Microbial Ecology, Faculty or Agricultural Sciences

Balla, K. and Veisz, O. (2008). Temperature dependence of wheat development. Acta Agronomica Hungarica. 56(3): 313- 320.

Bano, A. A. A.(2008). Rhizobium and phosphate solubilizing bacteria improve the yield and phosphorus uptake in wheat (Triticum aestivum). International Journal of Agriculture and Biology. 10(1): 85-88.

Chakraborty U, Chakraborty BN, Chakraborty AP, Dey PL (2013) Water stress amelioration and plant growth promotion in wheat plants by osmotic stress tolerant bacteria. World J Microbiol Biotechnol 29:789–803

Farooq, M., Bramley, H., Palta, J. A. and Siddique, K. H. M. (2011). Heat stress in wheat during reproductive and grain-!ll- ing phases. Critical Reviews in Plant Sciences. 30(6): 491-507.

Meena, Ahmed and Prakash

Gupta, N. K., Gupta S., Shukla, D. S. and Deshmukh, P. S.(2006). Post anthesis high temperature in"uences photosyn- thesis, grain growth and dry matter accumulation in contrast- ing wheat genotypes. Physiology and Molecular Biology of Plants.12(2): 151-156.

Kasim WA, Osman ME, Omar MN, Abd El-Daim IA, Bejai S, Meijer J (2013) Control of drought stress in wheat using plant- growthpromoting bacteria. J Plant Growth Regul 32:122–130

Matos, A., Kerkhof, L. and Garland, J. L.(2005). Effects of microbial community diversity on the survival of Pseudomonas

aeruginosa in the wheat rhizosphere. Microbial Ecology. 49( 2): 257-264.

Sikder, S. and Paul, N. K.(2010). Evaluation of heat tolerance of wheat cultivars through physiological approaches. Thai Jour- nal of Agricultural Science. 43(4): 251-258.

Tahir, I. S. A., Nakata, N., Yamaguchi, T., Nakano, J. and Ali, A. M.(2009). Physiological response of three wheat cultivars to high shoot and root temperatures during early growth stages. Plant Production Science. 12(4): 409-419.