LETTUCE COMPOSITION AS AFFECTED BY GENOTYPE AND LEAF POSITION

Three lettuce (Lactuca sativa L.) cultivars (‘Parris Island’, a romaine type, ‘Atraxion’, a leaf type and ‘C/S L 16’, a crisphead type) were grown in an unheated glasshouse from December 1999 to April 2000. At harvest (123 days after transplanting), the leaves of each plant were separated into outer, middle and inner ones, each group representing about 1/3 of the total leaf number (37±5, 29±3 and 36±4 for ‘Parris Island’, ‘Atraxion’ and ‘C/S L 16’, respectively) and their dry matter, soluble solids, ascorbic acid, nitrates, pH and titratable acidity were determined.
The whole plant composition was calculated from the above measurements taking into account the weight of the outer, middle and inner leaves as a percentage of the total plant weight.
Dry matter and soluble solids were higher in plants of the leaf type and lower in plants of the romaine and head types.
The highest nitrate content on a fresh and dry weight basis was found in plants of the head type and the lowest in plants of the leaf type.
Plants of the romaine and head types had a higher ascorbic acid content than those of the leaf type.
The highest and lowest pH was found in plants of the head and leaf type, respectively.
Plants of the leaf type had the highest titratable acidity and plants of the head type the lowest.
In all lettuce types, the inner leaves had the highest dry matter, soluble solids, pH and titratable acidity; the outer leaves had the highest nitrates, while the middle leaves had the highest ascorbic acid, with the exception of plants of the leaf type, in which no significant difference in ascorbic acid relative to leaf position, was observed.

II Balkan Symposium on Vegetables and Potatoes

A.S. Siomos, P.P. Papadopoulou, C.C. Dogras, E. Vasiliadis, A. Dosas, N. Georgiou

Nutritional value, flavour, nitrates, ascorbic acid, lettuce type, Lactuca sativa L.

https://doi.org/10.17660/ActaHortic.2002.579.112