DOES N DIRECTLY INFLUENCE CARBOHYDRATES AND PIGMENTS IN TOMATO AND CUCUMBER?

Tomato and cucumber plants were given different N-based fertilizers under controlled greenhouse conditions.
Leaves were sampled from the middle third of the plants at 15-day intervals throughout the biological cycle, and used to determine the concentrations of both of chlorophyll and the main carbohydrates.
Carbohydrate contents, in contrast to other parameters, differed between the two species.
Highest foliar concentrations of glucose, fructose saccharose and starch appeared in tomato plants treated with the fertilizer containing the lowest exogenous and endogenous N, but in cucumber, maximum levels were recorded in plants treated with the highest amount of N. In tomato, the different treatments led to no highly significant differences in chlorophyll levels (a, b and total), while in cucumber, only chlorophyll a remained unchanged with the different treatments.
Changes in concentrations of pigments and carbohydrates provided only an aproximate reflection of the nutritional status of the plants.

II International Symposium on Protected Cultivation of Vegetables in Mild Winter Climates

J.L. Valenzuela, A. Sánchez, F.A. Lorente, A. del Río, L. Romero

https://doi.org/10.17660/ActaHortic.1991.287.58