Cotton Genomics and Genetics 2015, Vol.6, No.3, 1-5
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The cotton seeds were soaked during 6 hours and
inoculated AMF Glomus mosseae hyphae/spores
before planting them on experimental plot. For the
inoculation with mycorrhiza ~50 g of Glomus
mosseae inoculum (BEG 12; International Bank of
Glomeromycota;
was
added to 1 kg cotton seeds and planted.
The criteria for growth promotion were studied in root
and shoot dry matter, N and P content of plants were
analysed. After 4~8 weeks, shoots and roots were
separated and dried. The total N content in plant
tissues was determined following the semi-micro
Kjedahl procedure. The P content was determined
spectrophotometrically using classic methods of P
measurement. The roots were carefully washed free of
soil and the mycorrhizal colonisation of the roots was
assessed using the methods of Vierheiling et al. (1998).
Plant samples from field were also collected for
mycorrhizal assessment and to compare with root box
data. At the end of growing season the two center
rows of each plot were harvested, weighed and ginned
and lint yield and percent lint were determined.
Statistical analysis
Data were tested for statistical significance using the
analysis of variance package included in Microsoft
Excel 98 and comparison was done using a Student’s
t-test. Mean comparisons were conducted using a least
significant difference (LSD) test (P=0,05). Standard
error and a LSD result were calculated.
Results and Discussion
Salinity decreases shoot/root ratio of plant because
shoots are sensitive than roots to salts stress (Nazarov,
2007). In another study Lin et al. (1997) observed that
increasing salinity (NaCl) decreased the protein
content in the seedlings and increased the enzyme
activity in both salt tolerant and salt sensitive cotton
cultivars. Growth and biomass inhibition of cotton
varieties under salt stress are caused due to high
accumulation of NaCl salt.
Cotton is a mycotrophic plant in which growth and
nutrient uptake is usually increased by AM
colonisation. It is known that most terrestrial plants
live in symbiosis with AMF (Hoffmann, 2009), and in
most cases AMF symbiosis improves the nutritional
status of the host plant and thus, its overall fitness
(Read 1998). However, it is uncertain whether slow
AM colonisation in the cotton growth disorder is a
symptom or the cause of reduced plant growth (Nehl
et al. 1998). Some authors declared that the highest
growth stimulation of plant by beneficial bacteria and
fungi occurred when plant have encountered stressful
conditions, whereas non-treated plants by comparison
performed
poorly
under
such
conditions
(Egamberdieva, 2013; Nehlet al. 1998).
In our experiments inoculation of cotton varieties with
AMF caused increase in plant height, number of bolls
per plant, and overall cotton yield compared
uninoculated plants in saline soil condition.
In AN-Bayaut-2 variety, inoculation with AMF
resulted in increased shoot and root development, the
fresh and the dry weight of the shoot and root (Table
1), the number of capsules, and the shoot P and N
content (Table 2). Also, in S-6524 variety were
observed the significant increase of above indicated
parameters of growth but slightly lower than
AN-Bayaut-2 (Table 3).
At 8 weeks, root and shoot dry weights were
significantly greater at the AMF symbioses cotton
plants (Table 1). Also, significant differences
determined between cotton varieties in root and shoot
weight at this stage. Also, shoot and root fresh weights
(Table 1) were significantly increased by the
mycorrhizal associations, although no major effects on
shoot:root ratios were apparent.
Table 1 The effect of AMF on plant growth of cotton at soil salinity conditions
Cotton varieties
In 4 weeks
In 8 weeks
Shoot
Root
Shoot
Root
AN-Bayaut-2 (control)
0,461±0.02
0,591±0.02
1,402±0.03
1,501±0.03
AN-Bayaut-2+AMF
0,513±0.01
0,656±0.008
1,739±0.018
1,852±0.01
S-6524(control)
0,441±0.01
0,572±0.02
1,389±0.04
1,488±0.04
S-6524+AMF
0,492±0.012
0,623±0.03
1,604±0.03
1,789±0.02
Note: 1 g/plant, plants grown for 4 week; 2 g/plant, plants grown for 8 week
