Length/diameter allometric variation of the stipe for three "Laminaria" species

Resumen

This paper reports the allornetric variation between the stipe length and the stipe diame(er for three species of the kelp Larninaria, L. ochrolettea. L. cligitaia and L. hyperborea. The allometry of stipe length with respect to the stipe diameter, provides a quantitative means to compare the morphologic adaptation of the stipe to the environment. The regression curve slope characterizes the relation between stipe length and stipe diameter that influence the mechanical stability of the stipes, and therefore their flexibility. Traditionally, one of the field characters used to identify L. digitata has been its stipe flexibility. It bends during the low tide while L. ochroleilea and L. hyperborea stipes usually stand up. Scaling exponents show a positive allometry (a >1) for the three species. Slope values greater than one indicate that taller stipes are proportionately thinner than their shorter counterparts. Slope values in L. hyperborea and L. ochroleuca are greater than in L. digilata, indicating that stipes taller are proportionately thinner in L. hyperborea and L. ochroieuca than in L. digitata. Scaling exponents suggest that shape stipe and habitat are related, especially with the hidrodynamic conditions.