9 Phosphate Solubilization by Endophytes from the Tropical Plants
215
Fig. 9.2 Average root
system length (RL) in
millimeters (mm) of 8 plants
per treatment (T1 to T10),
measured 180 days after the
first inoculation of bacteria
with the potential for plant
growth promotion
inoculation, the following variables were evaluated: aerial height (AH), root length
(RL), stem diameter (SD), aerial dry weight (ADW), and dry weight of the root
system (DWRS). All treatments of plants inoculated, except for the T3 treatment,
all caused a reduction in AH corresponding to the plants of a control group. For RL,
all treatments differed significantly from the control, showing an increase in root
system length of 77.76%, on an average. For the variables SD, ADW, and DWRS,
and the analysis of macro- and micronutrients in the leaf tissue, it was possible to
observe that none of the treatments differed significantly from the control. All statistical analyses were performed considering p ≤ 0.05. A principal component analysis
showed that RL explained 99% of the total variation in the observed morphological
characteristics; that is, the tested bacterial strains were able to promote the growth
of the coffee seedlings (Fig. 9.2).
9.4.2 Endophytic Bacteria from Jatropha curcas
Jatropha (Jatropha curcas L.), which belongs to the Euphorbiaceae family, is a plant
that is genetically close to the castor plant (Ricinus communis L.); it originates from
Central America and is currently distributed in all tropical regions of the globe
(Kumar and Tewari 2015; Kumar et al. 2016). Jatropha cultivation has received more
attention in the last few decades due to its role in biodiesel production. Jatropha is also
recommended for cultivation for soil health improvement, climate change mitigation,
carbon sequestration, and socio-economic development (Islam et al. 2014). The yield
of jatropha varies from 0.2 kg to >2 kg seeds from a single plant or 2–12 t ha
−1 (Tikkoo
et al. 2013; Singh et al. 2014). In Brazil, jatropha has received special attention as
an alternative supply of vegetable oil as a raw material for biodiesel manufacturing
due to the biotechnological potential of its seeds (Laviola et al. 2011; 2015). Several
studies on climatic adaptation and productivity have been developed on the genetic
variability of jatropha (Reddy et al. 2008; Behera et al. 2010; Laviola et al. 2010;
215
Fig. 9.2 Average root
system length (RL) in
millimeters (mm) of 8 plants
per treatment (T1 to T10),
measured 180 days after the
first inoculation of bacteria
with the potential for plant
growth promotion
inoculation, the following variables were evaluated: aerial height (AH), root length
(RL), stem diameter (SD), aerial dry weight (ADW), and dry weight of the root
system (DWRS). All treatments of plants inoculated, except for the T3 treatment,
all caused a reduction in AH corresponding to the plants of a control group. For RL,
all treatments differed significantly from the control, showing an increase in root
system length of 77.76%, on an average. For the variables SD, ADW, and DWRS,
and the analysis of macro- and micronutrients in the leaf tissue, it was possible to
observe that none of the treatments differed significantly from the control. All statistical analyses were performed considering p ≤ 0.05. A principal component analysis
showed that RL explained 99% of the total variation in the observed morphological
characteristics; that is, the tested bacterial strains were able to promote the growth
of the coffee seedlings (Fig. 9.2).
9.4.2 Endophytic Bacteria from Jatropha curcas
Jatropha (Jatropha curcas L.), which belongs to the Euphorbiaceae family, is a plant
that is genetically close to the castor plant (Ricinus communis L.); it originates from
Central America and is currently distributed in all tropical regions of the globe
(Kumar and Tewari 2015; Kumar et al. 2016). Jatropha cultivation has received more
attention in the last few decades due to its role in biodiesel production. Jatropha is also
recommended for cultivation for soil health improvement, climate change mitigation,
carbon sequestration, and socio-economic development (Islam et al. 2014). The yield
of jatropha varies from 0.2 kg to >2 kg seeds from a single plant or 2–12 t ha
−1 (Tikkoo
et al. 2013; Singh et al. 2014). In Brazil, jatropha has received special attention as
an alternative supply of vegetable oil as a raw material for biodiesel manufacturing
due to the biotechnological potential of its seeds (Laviola et al. 2011; 2015). Several
studies on climatic adaptation and productivity have been developed on the genetic
variability of jatropha (Reddy et al. 2008; Behera et al. 2010; Laviola et al. 2010;