Agriculture Reference
In-Depth Information
microbial cultures: a wild-type (WT)
R. meliloti
strain, its genetically modified
(GM) derivative, the AM fungus
G. mosseae
(Nicol and Gerd) Gerd and Trappe,
and a PSB
Enterobacter
sp. and rock phosphate (RP), on N and P accumulation in
alfalfa plants. Microbial cultures, in general, survived well inside root tissues and
colonized alfalfa rhizosphere and did not show any antagonism toward each other.
The population of PSB is stimulated due to both AM colonization, RP application,
and GM
Rhizobium
inoculation leading to a substantial increase in N and P
acquisition by alfalfa plants. Even though the
Enterobacter
application showed
no observable effects on N or P accumulation in soil treated with RP, it had an
obvious effect on N and P in the non-RP-amended control. In addition,
15
N:
14
N
ratio in plant shoots indicated enhanced N
2
fixation rates in
Rhizobium
-inoculated
AM plants, compared to those obtained by the same
Rhizobium
strain in
non-mycorrhizal plants. Regardless of the
Rhizobium
strain and of whether or not
RP was added, AM-inoculated plants showed a lower specific activity (
32
P:
31
P)
than did their comparable non-mycorrhizal controls suggesting that the plant was
using otherwise unavailable P sources. The P-solubilizing, AM-associated,
microbiota could in fact release P ions, either from the added RP or from the
indigenous “less-available” P. Additionally, the proportion of plant P derived either
from the labeled soil P (labile P pool) or from RP was similar for AM-inoculated
and non-mycorrhizal controls (without
Enterobacter
inoculation) for each
Rhizo-
bium
strain, but the total P uptake, regardless of the P source, was far higher in AM
plants which could probably be due to P mobilization by AM fungi. In other
investigation, Mehdi et al. (
2006
) assessed the responses of lentil to co-culture of
P-solubilizing rhizobia and AM fungi in a calcareous soil with high-pH and low
available P and N. The effects of AM fungi (
Glomus mosseae
and
G. intraradices
),
rhizobial strain (
R. leguminosarum
bv. Viciae) and mixture of rhizobial inoculant
and PS
M. ciceri
, and P fertilizers (superphosphate and RP) were highly significant
and enhanced the dry matter accumulation in shoots, seed yield, P and N contents,
and AM colonization. The PS rhizobial strain had a more pronounced favorable
effect on lentil growth and nutrient uptake than the strain without this ability. The
P-uptake efficiency was increased when P fertilizers were applied along with AM
fungi and/or P-solubilizing rhizobial strains.
8.4.2 Cereal Production and Its Nutritive Value
Cereal crops are grown largely for the edible components of its grain which
contains the endosperm, germ, and bran. Cereal is grown in many parts of the
world (Table
8.5
) and serves as a major energy source worldwide than any other
type of crops and hence are called staple crops. They also provide some useful and
valuable food nutrients even in their natural form as in the form of whole grain and
have been found as a rich source of vitamins, minerals, carbohydrates, fats, oils, and
protein (Table
8.6
). In some developing countries, rice, wheat, millet, or maize
form an important component of dietary system and a sound means of daily
