AN IMPROVEMENT OF THE ZIEMAN LEAF MARKING TECHNIQUE FOR ZOSTERA-MARINA GROWTH AND PRODUCTION ASSESSMENT

We present a modification of Zieman's leaf marking technique that uses the meristem as reference level. This technique allows both a detaile d description of eelgrass (Zostera marina L.) shoot dynamics by dissec tion and a rapid estimation of shoot growth from field data. The avera ge number of leaves per shoot, and the average number of new leaves pe r shoot were compared between a traditional technique, analyzing only the visible portion of leaves, and the long version of the proposed te chnique (previous growth analytical technique); significantly higher v alues were found with the latter technique. Higher correlation coeffic ients with environmental variables such as light and temperature were also found, indicating an improvement in the data quality. The rapid a pproach had a 0.8 correlation coefficient with shoot growth and produc tion, making it evident that the distance we call the previous growth can be used as a morphological index to assess these shoot variables.