Agriculture Reference
In-Depth Information
Fig. 3.4
Methane transport
capacity of rice plants of cul-
tivar IR72 at seedling, early
tillering, maximum tillering,
panicle initiation, flowering
and maturity. Data shown is
means ± SD of three replicate
plants each measured in
triplicate. Different letters
indicate significant differ-
ences (
p
> 0.05). (Source:
Aulakh et al.
2000a
)
the MTC of four high-yielding varieties (IR72 > IR52 > IR64 > PSBRc 20) by using
automated system.
Aulakh et al. (
2002
) studied the MTC of 18 inbred varieties and four hybrids at
various growth stages. MTC of different varieties varied from 62 to 445 % of IR72-
MTC. The study showed that tiller numbers were linearly co-related to MTC i.e.,
number of tillers directly determines CH
4
transport. Their study proved that the use
of high-yielding cultivars with low MTC (e.g., KDML 105, IR65598 and PR 108)
could be a viable option for reducing CH
4
emissions from rice fields
(
Fig.
3.4
).
Nouchi et al. (
1994
) used modified diffusion model for quantitative estimation
of methane transport through the micropores in the leaf sheath and the gaps at the
joint of nodal plate and leaf sheath of the rice plants (Nouchi et al.
1990
). Methane
emission is mainly driven by CH
4
concentration gradient between atmosphere and
soil pore water, molecular diffusion (Denier Van der Gon and Breemen
1993
) and
thermo-osmosis (Schröder et al.
1996
).
Yao et al. (
2000
) reported that CH
4
emissions through rice plants are influenced
by many factors like growth stage, rice cultivars, stem inter-cellar volume, length of
root bundle and total root volume at matured stage. They studied CH
4
conductance
among 11 different rice cultivars and reported that the CH
4
conductance is posi-
tively correlated with inter-cellar volume at tillering stage and root volume at the
reproduction stage. They have also done regression analysis to prove that in both
the stage of growth considered together, CH
4
conductance is significantly correlated
