Authors:
Faridah, M.1, Roslan, I.
, Arina Shairah, A.S.
, Razali, M. ,Malaysia |
Abstract:
One of the main reasons for the preferences toward organically produced food is due to health
awareness, especially the nutritional values (antioxidant) provided by organic produce. Based on
the previous study, antioxidant level is reported to have an association with nitrogen (N) uptake
by plants. However, the information on the effect of different level of N input (%) on antioxidant
activity in vegetable is still limited, especially in organic vegetables. Therefore, glasshouse
experiments were conducted to determine the effect of different treatment of N level (%) namely
T1: Control (0% N), T2: 2% N, T3: 4% N, T4: 6% N, T5: 10% N, T6:
15% N, T7: 20% N on antioxidant characteristics in organic spinach as test crop. The results
revealed that antioxidant activity in spinach was enhanced under lower level (%) of N.
Statistically, treatment with 4% N (T3) was found to be significantly (P<0.05) highest activity of
antioxidant with 61.89 mg AA/ g DW sample compared to spinach grown under 10 – 20% N.
The yield obtained under 4% N (T3) was also comparable with spinach treated under 15% N
(T6). The negative correlation (r = -0.192) between antioxidant activity and N uptake implies
that a lower uptake of N can induce plant antioxidant activity. These findings bring to the
conclusion that 4-6% of N from organic sources, was identified as an effective amount to
increase the antioxidant characteristic of spinach farmed under the organic system, and other
similar leafy vegetables with no significant loss in plant growth and yield |
