Dealing with Environmental Stresses: Role of Polyamines in Stress Responses - Crop Improvement: New Approaches and Modern Techniques - page 470

Conclusion and Future Perspective
Plant growth is highly affected by the adverse environmental conditions such as
drought, high salinity, extreme temperature regimes, mineral deficiencies and metal
toxicity causing decreased crop yields. The dynamic climate changes have great im-
pacts on global food security, emphasising vital solution for the crop improvement
by enhancing the stress tolerance. Despite the improvement of conventional meth-
ods, considerable attention has been paid to the utilization of recent advancements
such as transgenic approach, marker assisted screening methods and breeding in
enhancing plant performance under stress conditions.
Apart from essential growth regulatory functions, plant PAs are known to play
important role in stress tolerance by modulating the PA levels. Considerable evi-
dences exist for the natural variations of PAs in different cultivars/accessions cor-
relating with stress situations (Bouchereau et al. 1999 ). As described in this article,
PA biosynthesis and catabolism are genetically manipulated in some plant species
especially in model plants for enhanced environmental stress tolerance ranging
from drought, salinity, temperature extremes, mineral deficiency to wounding. Fur-
ther investigations are necessary in understanding the molecular mechanisms of
PA action in response to multiple stress situations. Broader insight is also required
on the interacting components and signalling pathways in the PA metabolism and
catabolism to fully uncover the protective function of PAs for subsequent successful
utilization in enhanced crop performance. Advanced techniques including microar-
ray, proteomics and metabolomics will be helpful in gaining detailed understanding.
Future challenge is to transfer knowledge obtained especially from model plants to
a variety of important crop species for enhanced tolerance to adverse environmental
stresses finally aiming at increased crop yields.
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