Z. Lamrani et al., INFLUENCE OF NITROGEN, PHOSPHORUS, AND POTASSIUM ON PIGMENT CONCENTRATION IN CUCUMBER LEAVES, Communications in soil science and plant analysis, 27(5-8), 1996, pp. 1001-1012
Cucumber plants (Cucumis sativus cv. Brunex) were grown under controll
ed conditions and submitted to an individual fertilization with differ
ent doses of N (N1 = 5 g/m(2); N2 = 10 g/m(2); N3 = 20 g/m(2); N4 = 40
g/m(2)) as NH4NO3, P (P1 = 7 g/m(2); P2 = 14 g/m(2)) as H3PO4, and K
(K1 = 20 g/m(2); K2 = 40 g/m(2)) as K2SO4. This fertilization was appl
ied together with organic matter and a micronutrients solution, with d
oses standard throughtout the plant's biological cycle. Control plants
were included in the experimental design. Cucumber leaves were collec
ted every 15 days during the plant life cycle, bing assayed for their
chlorophyll a and b (Chi a and Chl b), carotene, and licopene contents
. Our results showed that N fertilization induced an increase of 15% i
n Chll a respect to the control plants for the N3 treatment, whereas t
he N4 treatment resulted in a decrease in Chi a. Chlorophyll b present
ed a similar behaviour as that for Chll a, with a 10% increase occurri
ng with the N3 treatment. Carotenes behaved in a same manner as that f
or chlorophyll, while the licopenes did not show any significant varia
tion among treatments. Inversely, P fertilization induced a decrease o
f both chlorophyll a and b with the P2 treatment, whereas P did not af
fect accessory pigments concentration. The K2 treatment acted positive
ly on the chll a and carotene levels with an 1.1% and 7% increase as c
ompared with the control plants, respectively. Chlorophyll b did not v
ary significantly due to the K doses. In summary, our results showed t
hat N affected the pigment content, specially the photosynthetic pigme
nts, while high doses of P acted negatively on all the pigments studie
d.