Book ChapterDOI
Development and function of Azospirillum -inoculated roots
Yaacov Okon,Yoram Kapulnik +1 more
TLDR
Inoculation of several cultivars of wheat, corn, sorghum and setaria with several strains of Azospirillum caused morphological changes in root starting immediately after germination, which lead in many cases to higher crop yield.Abstract:
The surface distribution of Azospirillum on inoculated roots of maize and wheat is generally similar to that of other members of the rhizoplane microflora. During the first three days, colonization takes place mainly on the root elongation zone, on the base of root hairs and, to a lesser extent, on the surface of young root hairs. Azospirillum has been found in cortical tissues, in regions of lateral root emergence, along the inner cortex, inside xylem vessels and between pith cells. Inoculation of several cultivars of wheat, corn, sorghum and setaria with several strains of Azospirillum caused morphological changes in root starting immediately after germination. Root length and surface area were differentially affected according to bacterial age and inoculum level. During the first three weeks after germination, the number of root hairs, root hair branches and lateral roots was increased by inoculation, but there was no change in root weight. Root biomass increased at later stages. Cross-sections of inoculated corn and wheat root showed an irregular arrangement of cells in the outer layers of the cortex. These effects on plant morphology may be due to the production of plant growth-promoting substances by the colonizing bacteria or by the plant as a reaction to colonization. Pectic enzymes may also be involved. Morphological changes had a physiological effect on inoculated roots. Specific activities of oxidative enzymes, and lipid and suberin content, were lower in extracts of inoculated roots than in uninoculated controls. This suggests that inoculated roots have a larger proportion of younger roots. The rate of NO 3 - , K+ and H2PO 4 - uptake was greater in inoculated seedlinds. In the field, dry matter, N, P and K accumulated at faster rates, and water content was higher in Azospirillum-inoculated corn, sorghum, wheat and setaria. The above improvements in root development and function lead in many cases to higher crop yield.read more
Citations
More filters
Journal ArticleDOI
Inhibition of biosynthesis and activity of nitrogenase in Azospirillum brasilense Sp7 under salinity stress.
TL;DR: Assays indicated that movement of the pellicle to the anaerobic zone and inhibition of DRAT might be adaptive responses of A. brasilense to salinity stress under diazotrophic conditions.
Journal ArticleDOI
An optimized process for manufacturing an Azospirillum inoculant for crops
TL;DR: An optimized process for manufacturing a crop moculant was developed with anAzospirillum lipoferum strain, containing more than 10 billion cells/g, easy to store and to handle, which can be used in the field as a microgranule or as a seed coating.
Journal ArticleDOI
Improved nutrient use efficiency increases plant growth of rice with the use of IAA-overproducing strains of endophytic Burkholderia cepacia strain RRE25.
TL;DR: It was concluded that one of the possible mechanisms of growth promotion of rice plants inoculated with bacterial endophytes is their effects on an increase in the capability of nutritional uptake possible through the effect of IAA production which results in proliferation of root system that could mine more nutrients from the soil.
Journal ArticleDOI
Changes in root morphological traits in soybean co-inoculated with Bradyrhizobium spp. and Azospirillum brasilense or treated with A. brasilense exudates
Artur Berbel Lirio Rondina,Artur Berbel Lirio Rondina,Alisson Wilson dos Santos Sanzovo,Gabriel Silva Guimarães,Jhonatan Rafael Wendling,Jhonatan Rafael Wendling,Marco Antonio Nogueira,Marco Antonio Nogueira,Mariangela Hungria,Mariangela Hungria +9 more
TL;DR: Co-inoculation of soybean with Bradyrhizobium and A. brasilense improved several root morphological traits, increasing the plant capacity to overcome moderate drought stress episodes in sandy soils, allowing to reach higher yields.
Journal ArticleDOI
Isolement de bactéries rhizosphériques et effet de leur inoculation en pots chez Zea mays
Jacques Fages,Daniel Mulard +1 more
TL;DR: Cette approche globale incluant l’isolement etl’inoculation apparait comme une voie interessante pour obtenir une promotion de the croissance vegetale.
References
More filters
Journal ArticleDOI
Plant Growth Substances Produced by Azospirillum brasilense and Their Effect on the Growth of Pearl Millet (Pennisetum americanum L.)
TL;DR: Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots, andIndole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan, and combinations of these substances produced changes in root morphology of pearl millet similar to those produced by inoculated plants.
Journal ArticleDOI
Methods for Growing Spirillum lipoferum and for Counting It in Pure Culture and in Association with Plants.
TL;DR: Methods are described for growing Spirillum lipoferum in quantities sufficient to serve as inoculant in field trials of its associative N(2)-fixing ability with higher plants and as a source of cells for the preparation of nitrogenase, cytochromes, respiratory enzymes, etc.
Journal ArticleDOI
Enhanced Mineral Uptake by Zea mays and Sorghum bicolor Roots Inoculated with Azospirillum brasilense.
TL;DR: Corn and sorghum plants grown to maturity on limiting nutrients in the greenhouse showed improved growth from inoculation approaching that of plants grown on normal nutrient concentrations.
Journal ArticleDOI
Microbial Colonization of Plant Roots
and G D Bowen,A D Rovira +1 more
TL;DR: After a long period devoted largely to isolation of organisms from roots, there is new impetus into finding mechanisms of colonization of the root; also, ex perimental approaches to the population dynamics of microorganisms on roots are emerging.