Seed quality, chlorophyll content index and leaf nitrogen levels in maize inoculated withAzospirillum brasilense

Lívia De Matos Pereira,Elise De Matos Pereira,Gustavo Vitti Môro,Lucas Tadeu Mazza Revolti,Sonia Marli Zingaretti

doi:10.5935/1806-6690.20150047

Lívia De Matos Pereira, Elise De Matos Pereira + Show 3 more

Open Access

https://doi.org/10.5935/1806-6690.20150047

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Abstract

The aim of this study was to evaluate differences between maize genotypes in relation to the germination response of the seeds and the growth of seedlings inoculated with Azospirillum brasilense, as well as the effect of inoculation on nitrogen levels and the chlorophyll content index of the leaves. The physiological seeds quality from the single-cross hybrids AG7098 and 2B707, and from the experimental synthetic varieties V2 and V4, inoculated with A. brasilense, was tested for germination, percentage and rate of emergence, and dry matter weight of the shoots and roots. Nitrogen levels and chlorophyll content index were evaluated in leaves of the same four genotypes grown in a greenhouse under different nitrogen supply systems and methods of inoculation with A. brasilense. The genotypes differ with regard to inoculation with A. brasilense. The hybrids were responsive to inoculation with A. brasilense for root dry matter weight. The V2 variety had a lower performance as regards root dry matter weight, with the opposite being seen for the dry matter weight of the shoots. V4 displayed no significant differences when inoculated. The results of the chlorophyll content index were not significant. Each genotype under evaluation displayed a different response for leaf nitrogen levels. It is possible to infer that the hybrids responded better to inoculation with the bacteria, with the greater root development leading to a better utilisation of water and nutrients.

Highlights

In maize (Zea mays L.), the increases in productivity from genetic improvement are evident; but the low average national productivity is directly linked to factors such as soil fertility and the low level of technology adopted when adding to the soil
Standing out in this context is nitrogen fertilisation, which supplies the macronutrient most required and absorbed by the maize plants, and the most limiting to production. This element plays a part in the composition of vital molecules such as amino acids, proteins, enzymes and chlorophyll, which are related to leaf expansion, the increase in the photosynthetic rate, increased growth, development and plant production (OKUMURA et al, 2011)
Inoculation with Azospirillum brasilense was carried out using a commercial product containing the AbV5 AbV6 strains in a liquid formulation at the minimum concentration of 5Â108 cells mL-1 (Qualyfix Gramínea, Brasilquímica) at dosages suggested by the manufacturer, corresponding to 4 mL kg-1 for inoculation via the seeds, as used in both experiments and 600 mL h-1 for inoculation via the soil

Summary

Introduction

In maize (Zea mays L.), the increases in productivity from genetic improvement are evident; but the low average national productivity is directly linked to factors such as soil fertility and the low level of technology adopted when adding to the soil. Standing out in this context is nitrogen fertilisation, which supplies the macronutrient most required and absorbed by the maize plants, and the most limiting to production. The use of microorganisms which are beneficial to plants is recognised in species of the Fabaceae family, in the model of symbiosis which involves bacteria of the genus Rhizobium

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