Effects of Iron Deficiency Stress on Plant Growth and Quality in Flowering Chinese Cabbage and Its Adaptive Response

Abstract

Iron (Fe) plays an important role in the growth and development of plants. The effects of different Fe concentrations, 1-aminocyclopropane-1-carboxylic acid (ACC), and cobalt chloride (Co2+) treatments on plant growth, quality and the adaptive response to Fe deficiency stress were investigated in flowering Chinese cabbage. The results revealed that Fe deficiency stress inhibited plant growth. The contents of vitamin C, soluble protein, and soluble sugar in leaves and stalks were significantly reduced under Fe deficiency stress, while the content of cellulose and nitrate was increased. Fe deficiency stress clearly reduced the net photosynthetic rate and nitrate reductase activity in the leaves. The balance system of active oxygen metabolism was destroyed due to Fe deficiency, resulting in the decrease in catalase activity, superoxide dismutase activity of roots and leaves, and peroxidase (POD) activity of leaves, while POD activity in roots and malonaldehyde content in roots and leaves were significantly increased. The treatments of Fe deficiency and ACC significantly reduced the pH value of the root medium, promoted the release of ethylene, and increased Fe3+ reductase activity, while Co2+ treatment showed results that were the opposite to those of Fe deficiency and ACC treatments. Thus, Fe deficiency stress affected nitrogen metabolism, photosynthesis, reactive oxygen metabolism, pH of root medium, and Fe3+ reductase activity, which was related to physiological adaptive response and tolerance mechanisms. We also found that ethylene could be involved in regulating the adaptive response to Fe deficiency stress in flowering Chinese cabbage.