Biology Reference
In-Depth Information
V. CONCLUDING REMARKS
The results of many studies clearly show that abiotic stresses modulate both
the phenylpropanoid and lignin pathways. However, conclusive proof of
lignin synthesis is less often reported and in many cases is absent. Moreover,
the tissue and cellular localization/characterization of lignified cells is almost
inexistent even though such knowledge could greatly contribute to a better
understanding of the role that lignin plays in tolerance to abiotic stresses.
Examples of increased lignin synthesis were found for almost all abiotic
stresses without being able to confirm whether it is a general feature or
whether it is highly species dependent. Indeed, stress-induced lignification
also appears to vary depending upon the organ/tissue examined. Although it
is likely that stress-induced lignins play different role such as signalling,
defence and adjustment during the stress response, direct evidence of these
roles are still necessary.
The regulation of the stress response should be investigated in order to
assess whether it overlaps with the better characterized regulation pathways
for constitutive lignin and whether different abiotic stresses share common
regulation mechanisms. This knowledge is essential in a perspective of lignin
manipulation for industrial purposes without compromising the plant's
ability to respond to stress.
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