Handling Soybean ( Glycine max L.) Under Stress - Crop Improvement: New Approaches and Modern Techniques - page 429

It has been suggested and tested that plants be modified genetically for nitrate
tolerant; however such a method has not been appropriate, because it resulted in the
reduction of crop yield (Salvagiotti et al. 2008 ). Although the physiological altera-
tions in plant metabolism is one of the main reasons for decreased N-fixation at the
time of N-fertilization, however the other important reason is that the process of
N-fixation is demanding and requires high rate of energy spent by the host plant;
when N-fertilization provides mineral N for plan use, the plant will not be willing
to develop a symbiotic association with the bacteria, adversely affecting the process
of N fixation.
Conclusions and Future Perspectives
Handling crop plants under stress is among the most important research issues. Soy-
bean is a leguminous crop plant most used by human. Although it is not considered
a tolerant crop plant to stress, research has indicated that it is likely to alleviate the
effects of different stresses such as acidity, salinity, sub optimal roots zone tempera-
ture and N-fertilization on soybean growth and yield using molecular and breeding
methods. Researchers have tested and proved that use of the plant to bacteria signal,
genistein, for the pre incubation of soybean symbiotic bacteria, Bradyrhizobium
japonicum can be useful to alleviate the unfavorable effects of stress on soybean
growth and yield. Identification of tolerant genes in different plant species and in-
serting them in soybean may also be effective to alleviate stress.
Although research work has indicated much detail related to the handling of
soybean under stress, there are more, which must be elucidated. For example, us-
ing proteomic analysis, the production of different proteins under stress must be
indicated and accordingly the related genes be recognized and inserted to produce
tolerant varieties. The other important point is the production of tolerant rhizobium
under stress, which may also be similarly recognized and produced.
References
Abd-Alla MH, Vuong TD, Harper JE (1998) Genotypic differences in dinitrogen fixation response
to NaCl stress in intact and grafted soybean. Crop Sci 38:72-77
Aguilar JM, Ashby AM, Richards JM, Loake GJ, Watson MD, Shaw CH (1988) Chemotaxis of
Rhizobium leguminosarum biovar phaseoli towards flavonoid inducers of the symbiotic nodu-
lation genes. J Genetical Microbiol 134:2741-2746
Akaya M, Takenaka C (2001) Effects of aluminum stress on photosynthesis of Quercus glauca
Thumb. Plant Soil 237:137-146
Appunu C, Dhar B (2006) Symbiotic effectiveness of acid-tolerant Bradyrhizobium strains with
soybean in low pH soil. Afric J Biotechnol 5:842-845
Asbjornsen H, Alvardo-Barrientos MS, Rebel K, Van Osch FP, Rietkerk M, Chen J, Gotsch S, To-
bon C, Geissert DR, Gomez-Tagle A, Kellie V, Dawson TE (2011) Ecohydrological advances
and applications in plant-water relations research: a review. J Plant Ecol 4:3-22