Environmental Engineering Reference
In-Depth Information
Figure 4(D). The situation of ion fluxes in mature seedling under salt stress.
In this study, we adopted a series of NaCl treatments ranging from 0 to 300 mM. The
results suggested that both the water potential and RWC were decreased with the increase in
NaCl concentration in two types of soybean (Figure 3.1A, B). By comparison, the decline was
more serious in leaves. For the mature seedling of cultivated soybean---
Glycine max
, the
water potential was reduced 11.2 times and the RWC dropped to 64.2% under 300 mM
treatment, demonstrating that they have suffered serious osmotic stress. In addition, all the
plants under this stress displayed the symptom of water loss and what is more 30% percent of
the plants died after the stress. With regard to the mature seedling of wild soybean---
Glycine
soja
, though the water potential and RWC were also declined, the extent was small and few
plants turned into the state of water loss.
The young seedlings were also influenced by salt stress, thus the water potential and
RWC were lessoned as well, yet the effect was a lesser extent (Figure 3.1A, B). There is no
distinct difference in roots between two species, yet the wild soybean maintained higher water
potential in leaves relatively. The young seedlings did not turn into dehydration and wilting,
but their growth rates were stunted significantly by high concentration of NaCl. We
speculated that the plants can manage to regain the original volume and turgor by adjustment
after a period time of the stress, although the growth and elongation rate of the cells were
slowed down (Cramer, 2002;W. Fricke and Peters, 2002). These reductions may due to the
decreased stomatal conductance, the reduced transpiration and the enhanced efficiency of
water application (Munns and Tester, 2008). In short, the outcome revealed that the wild
soybean may own stronger capabilities to maintain water potential, keep water in balance and
a normal RWC.
