Plant growth promotion by Azospirillum sp. in sugarcane is influenced by genotype and drought stress

• Published in: Plant and soil Vol. 337; no. 1-2; pp. 233 - 242
• Main Authors: Moutia, Jean-Francois Yvan, Saumtally, Salem, Spaepen, Stijn, Vanderleyden, Jos
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-12-2010; Springer; Springer Netherlands; Springer Nature B.V
• Subjects: Agricultural soils; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Auxin; auxins; Azospirillum; Bacterial inoculation; Biological and medical sciences; Biomedical and Life Sciences; Cultivars; Drought; Droughts; Ecology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Genotype & phenotype; Gibberellins; Growth; Hormones; Indigenous plants; Inoculation; Irrigation; Life Sciences; Mauritius; Nutrient uptake; Plant growth; Plant Physiology; Plant roots; Plant Sciences; Plants; Regular Article; Root development; Soil inoculation; Soil microorganisms; Soil Science & Conservation; Soil water; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Sugar cane; Sugarcane; Mauritius; Auxins; Bacterial inoculation; Root development; Monocotyledones; Auxin; Growth; Rhizogenesis; Spirillaceae; C4-Type; Stimulation; Water stress; Inoculation; Gramineae; Water regime; Angiospermae; Bacteria; Plant growth substance; Drought; Vegetals; Spirillales; Azospirillum; Tropical crop; Genotype; Sugar plant; Organogenesis; Saccharum officinarum; Spermatophyta; Sugar cane; Soil plant relation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-010-0519-7

Azospirillum influences growth and development of several crops by producing phytohormones such as auxins which have a major impact on root development. An improved root system leads to better water and nutrient uptake that in turn may influence yield positively. In this study, two agronomically contrasting sugarcane cvs R 570 and M 1176/77 adapted to different agroclimatic zones were inoculated with Azospirillum sp., with and without drought stress, to gauge how far they could benefit from this bacterial association. As early as 103 days after planting, cv M 1176/77 responded positively to inoculation with 15% improved growth (shoot height) and 75% more root dry mass when subjected to drought stress, whereas cv R 570 responded negatively particularly in the absence of drought stress. The significant interaction of cultivar x water regime x Azospirillum inoculation suggests a complex interplay of these factors, possibly involving the indigenous plant auxin pool. Therefore, plant genotype needs to be taken into account when recommending bacterial inoculation for direct plant growth promotion. Furthermore, enhanced growth under sub-optimal water conditions shows clearly the benefits that could be obtained in semi-arid conditions where water deficits frequently occur.