DAILY VARIATION IN LEAF NITRATE CONTENT OF TWO CULTIVARS OF HYDROPONICALLY GROWN BASIL

We studied the effects of cultivar, nutrient solution strength and light intensity on daily variation of nitrate content in basil (Ocimum basilicum L.) leaves.
A glasshouse experiment was carried out in Naples (Portici, Italy) from the 26^th of May to the 5^th of July 2005. Plants of two basil cultivars (‘Napoletano’ and ‘Genovese’) were cultivated on floating system with aerated nutrient solution replaced every week.
Two nutrient solutions were compared: single strength Hoagland (H) and double strength Hoagland (2H). Thirty days after transplanting (DAT), the plants grown in the 2H solution were divided into two different shading treatments: 0% (control) and 50% shading obtained by using a 50% cut-off screen.
On the 29^th of June (34 DAT), leaf nitrate content was measured five times during the day (at 6:30am, 10:30am, 1:00pm, 4:00pm and 6:30pm) on ‘Genovese’ and ‘Napoletano’ plants grown in H and 2H solution.
On the 5^th of July (40 DAT), the leaf nitrate content was measured on plants grown at full sun light and 50% shading, only in 2H solution.
Nutrient solution strength affected leaf nitrate content, which was higher in leaves of plants grown in the 2H solution.
Plants at 50% shading showed higher leaf nitrate content compared to the control.
Leaf nitrate content decreased during the day in response to light intensity.
Plants of the cultivar ‘Napoletano’ showed the largest leaf area and the lowest leaf dry matter percentage, nevertheless no significant differences were observed in terms of nitrate contents between the two cultivars.

VIII International Symposium on Protected Cultivation in Mild Winter Climates: Advances in Soil and Soilless Cultivation under Protected Environment

F. Orsini, S. De Pascale

floating system, light intensity, nutrient solution strength, Ocinum basilicum L.

https://doi.org/10.17660/ActaHortic.2007.747.23