25 Correlations between Leaf Nitrogen, Phosphorus and Potassium and Leaf .......... Journal of Tropical Crop Science Vol. 5 No. 1, February 2018 www.j-tropical-crops.com Correlations between Leaf Nitrogen, Phosphorus and Potassium and Leaf Chlorophyll, Anthocyanins and Carotenoids Content at Vegetative and Generative Stage of Bitter Leaf (Vernonia amygealina Del.) Abstract Vernonia amygdalina Del. (Asteraceae) is a nutritional and medicinal plant that is used widely throughout tropical Africa and other countries. The leaves are proved to have strong antioxidant property. The concentration of chlorophyll a, chlorophyll b, anthocyanins and carotenoids in fve different leaf positions of vegetative and generative phases were studied. The aim of the study is to understand and to correlate the content of the three nutrients and the bioactive compounds along the fve leaf positions at vegetative and generative stage of the crop growth. The study showed that the concentration of chlorophyll a and b was higher, and anthocyanin concentration was almost zero in the generative than in the vegetative stage. The leaf concentration of N, P, and K were higher in vegetative than in generative stage. At vegetative stage, N positively correlated with chlorophyll a at the 1 st leaf; K had strong correlations with anthocyanins at the 2 nd and 3 rd leaf and with chlorophyll a at the 2 nd and 5 th , and with chlorophyll b and carotenoids at the 5 th leaf. At the generative stage, P had a strong positive correlation with carotenoids at 4 th and 5 th leaves, and K positively correlated with chlorophyll a and b at 5 th leaf. The fndings suggest that bitter leaf is better to be harvested at vegetative stage, and that potassium level is important to increase anthocyanins and carotenoids content. Keywords: bitter leaf, nutrient level¸ pigments, vegetables, vegetative and generative phases Introduction Bitter leaf, Vernonia amygdalina, belongings to the family Asteraceae, is perennial shrub or tree up to 10 m. In cultivation, it is often pruned to a shrub or hedge. Leaves blade is dark green, ovate-elliptical to lanceolate, cuneate or rounded at base, acuminate at apex, margin minutely toothed to coarsely serrate and fnely pubescent. It can grow up to 2000 m altitude and on almost all types of soil (Grubben and Denton, 2004). Figure 1. Vernonia amygdalina plant (left), fowers (a, top right) and leaves (b, bottom right) Bitter leaf is commonly used in traditional medicinal plant in Africa and other countries around the world. The leaves is also well known and consumed as a vegetable. Bitter leaf is traditionally used to treat gastroenteritis, diarrhea, fever, parasite infections, dysentery, diabetes and hepatitis (Challand and Willcox, 2009; Vlietinck et al., 1995). Several research have shown that V. amygdalina Betty Tjhia A) , Sandra Arifn Aziz B) , Ketty Suketi B) A Postgraduate School, Bogor Agriculture University, Bogor, 16680, Indonesia. B Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, Kampus IPB Darmaga, Bogor, 16680, Indonesia *Corresponding author: sandra.a.aziz@gmail.com