Assessment of the carbon dissimilation methodology in the in vitro growth of the 'Paulsen 1103' grapevine

A simple and non-destructive carbon dissimilation method to assess plant cell growth was tested for its in vitro suitability for grape vines. In vitro culture plants can either use atmospheric CO 2 or the sugars present in the culture medium as carbon source. Carbon dissimilation predicts that the sugar metabolism of the culture medium results in a net weight loss of the culture flask contents and may thus be used to follow culture growth. The ‘Paulsen 1103’ grapevine rootstock was introduced and multiplied in vitro by the auxiliary shoot methodology. Tubes with and without plants were weighed daily throughout an experimental growth period of 60 days. Results from the in vitro plants showed that the variety studied presented dissimilation and assimilation activity over the culture period and therefore presented in vitro fotomixotrophy. There were three distinct growth phases: an initial phase, during the first 10 days of culture, where there was intense weight loss by dissimilation; a second stationary phase, which lasted approximately 10 days, and a final phase of 40 days, where an important weight gain was observed (37.68 mg). Thus carbon use and micropropagated plant growth could be assessed quickly and efficiently.