MATERIALS AND METHODS

1
CONTAMINATED IRRIGATION WATER INFLUENCES ON
LENTIL SOIL-PLANT-MICROBE INTERACTIONS
F.R SADEQUE AHMED, KEN KILLHAM and IAN
ALEXANDER School of Biological Sciences (Plant
and Soil Science), University of Aberdeen,
Aberdeen, AB24 3UU,UK.
Introduction
Arsenic (As) contaminated irrigation water is a
major constraint to Bangladesh agriculture.
Arbuscular Mycorrhizal (AM) fungi have their most
significant effect on phosphorus (P) uptake . AM
fungi often protected plants against high
accumulation of toxic elements in the shoots, as
it was reported for Al (Rufyikiri et al., 2000),
Pb (Malcova et al., 2003). Chemically, As and P
are analogues. This study examined the single and
interactive effect of As and the AM fungi Glomus
mosseae in respect of growth, nitrogenase
activity As/P concentration/offtake and AM fungi
mediated effect on As toxicity with compatible
rhizobial symbionts on lentil.
MATERIALS AND METHODS
Three plants were grown in a controlled green
house for 9 weeks in potted, 1.2 kg autoclaved
soil (sand and terra Green mixture 5050 v/v)
with As contaminated irrigation water. 5 levels
of As (0, 1ppm, 2ppm, 5ppm, 10ppm arsenate) and 2
levels of G. mosseae (/-) were used. Modified
Hoaglands solution (1/10th N and without P) was
applied. Nitrogen fixation was measured by using
the acetylene reduction assay. The experiment was
carried out in a randomized block design with 5
replicates per treatment. Treatments effects were
determined by ANOVA. Differences among the
treatment means were determined by LSD.
RESULT AND DISCUSSION
Mycorrhiza increased shoot P concentration
(Plt0.01) and offtake (Plt0.01), but decreased
shoot As Concentration (Plt0.01). Increasing As
load increased shoot As concentration (Plt0.001),
offtake (Plt0.001) and decreased shoot P
concentration (Plt0.001) and offtake (Plt0.001). AM
fungi and As increased and decreased plant
biomass respectively (Plt0.001).
Arsenic affected plants
Control plants
AM infected root with vesicle
Uninfected root
As load significantly decreased plant height,
flower number, nitrogenase activity, N
concentration/offtake, root length and biomass
(Plt0.001). Chemically, P and As are analogues,
but the AM acts as a barrier to uptake of As in
lentil shoot.
CONCLUSION
Spore of Glomus mosseae
Growing leguminous crops (lentil) with compatible
symbionts minimized As toxicity and increased P
concentration and offtake. As was found to be
harmful (down to 1 ppm) for plant growth,
nutrient uptake, nitrogenase activity and
mycorrhizal infection.
REFERENCES
1.Malcova, R., Vosatka, M., Gryndler, M., 2003.
Effects of inoculation with Glomus intraradices
on lead uptake by Zea mays L. and Agrostis
capilaris L. Applied Soil Ecology 23(1),
255-267. 2.Rufyikiri, G., Declerck, S., Dufey,
J.E., Delvaux, B., 2000. Arbuscular mycorrhizal
fungi might alleviate aluminium toxicity in
banana plants. New Phytologist 148(2), 343-352.