Tipburn is recognized as one of the most important physiological disorders of lettuce and other leafy vegetables. More specifically, tipburn is a great threat for the development of innovative soilless cultivation techniques, since the production losses in these systems due to tipburn have been estimated at 50%.
Tipburn has been related to a lack of calcium in the developing leaves associated with a high growth rate or an insufficient transpiration flow. However, many scientific studies in the past are not clear or even contradictive concerning the cause of tipburn and the measures to prevent it. For a good understanding, the ecophysiological response of a lettuce plant to its entire environment should be examined. Therefore, recently developed techniques might bring new insights.
In this research program, the symptoms of tipburn will be examined by using both anatomical and biochemical techniques as a first step to uncover its causes. Next, in several experiments both growth and transpiration will be continuously monitored based on stem diameter and crop temperature measurements, respectively. Leaf thickness will be measured to record sudden changes in leaf turgor. Based on these plant responses, different hypotheses are to be tested: i) plant tissue sensitive to tipburn has weak cell walls caused by a lack of incorporated calcium, which may result from an excessive growth combined with a lack of transpiration, or ii) sensitivity to tipburn is caused by development of dysfunctional stomata under humid conditions; iii) tipburn symptoms are induced by a strong fluctuating turgor pressure in the cells, and/or iv) tipburn symptoms are the direct result of a phytotoxic effect of latex release within the leaf.
This research program aims to reveal the mystery of tipburn in lettuce and to propose rational measures to prevent it.
The TIPRELET-project is an Agricultural Research project (IWT-080499) coordinated by inagro and in collaboration with Ghent University – Faculty of Bioscience Engineering, the Research Station for Vegetable Production at Sint-Katelijne-Waver and the Research Centre Kruishoutem.