EFFECTS OF DIFFERENT CONCENTRATIONS NUTRIENT SOLUTION ON THE GROWTH, QUALITY AND ABSORPTION OF MAIN MINERAL MACRO-ELEMENTS OF BRASSICA CAMPESTRIS SSP. CHINENSIS IN SUBSTRATE CULTURE

Abstract

The China-originated non-heading Chinese cabbage cultivar 'Aijiao Huang' was used as the material. Effects of three different nutrient solution concentration levels (0.5, 1.0 and 2.0 strength of the nutrient solution formula, taking water as control) on the dry weight accumulation, nutrition quality, nitrate content and the absorption and distribution property of main mineral macro-elements of non-heading Chinese cabbage plant were studied, given the nutrient solution formula special for leaf vegetables by South China Agricultural University and the compound substrate (50% reed residue, 25% vermiculite and 25% perlite). Results showed that, both the fresh weight and dry weight of the plants increased with the increase of the nutrient level, but no significant difference showed between 1.0 and 2.0 strength nutrient solution treatments. As the nutrient level increased, the content of Vitamin C (Vc) and soluble sugars reduced, while soluble protein and nitrate accumulated, which showed a decrease in the nutrition quality of non-heading Chinese cabbage. At a concentration of 2.0 strength concentration of nutrient solution, the nitrate content in the plant leaves achieved 2735.3 mg/kg Fw. The mineral elements analysis indicated that, the non-heading Chinese cabbage was a nitrophile, and the nitrogen accumulated most in leaf, petiole and root. At a concentration of lower nutritive solution level (0 to 1 strength), the absorption amount of mineral macro-elements in various parts of non-heading Chinese cabbage plant increased with nutrient level rising. However, at 2.0 strength concentration of nutritive solution, the absorption amount of all mineral elements declined excepted N, Mg. The most of N, P, Ca, and Mg distributed in leaf, while most of K distributed in petiole. In addition, the effect of nutrient level on distribution percentage of all mineral macro-elements in different parts of the plant was not remarkable. Within the tested range of nutrient levels, the ratio of N, P, K, Ca and Mg which the plant absorbs was 6.1-7.7:1.0:3.5-3.8:1.7-2.2:0.8-1.2.