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

Iron (Fe) plays an important role in the growth and development of the human body and 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 content of vitamin C (Vc), 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. Meanwhile, Fe deficiency stress obviously reduced the net photosynthetic rate and nitrate reductase (NR) activity of leaves. The balance system of active oxygen metabolism was destroyed due to Fe deficiency, resulting in the decrease of catalase (CAT) activity, superoxide dismutase (SOD) activity of roots and leaves, and peroxidase (POD) activity of leaves, while POD activity in roots and malonaldehyde (MDA) content were significantly increased. The treatments of Fe deficiency and ACC significantly reduced pH value of the root medium, promoted release of ethylene, and increased Fe3+ reductase activity, while Co2+ treatment showed the results opposite to those of Fe deficiency and ACC treatments. Thus, Fe deficiency stress could induce nitrogen metabolism, photosynthesis, reactive oxygen metabolism, pH of root medium, and Fe3+ reductase activity that was related to physiological adaptive response and tolerance mechanisms. We also found that ethylene could involve in regulating the adaptive response to Fe deficiency stress and improve the availability of Fe in flowering Chinese cabbage.Main ConclusionFe deficiency stress could induce nitrogen metabolism, photosynthesis, reactive oxygen metabolism, pH of root medium, and Fe3+ reductase activity that was related to physiological adaptive response and tolerance mechanisms.

About the influence of solutions of fulvic acids from sapropel on lettuce plants in various types of its processing

The purpose of our research was to assess the influence of treatment with fulvic acid (FA) solutions (obtained from sapropel) on the physiological state, production process, and quality of salad crops under intensive controlled conditions. Research method. Treatment of plants with solutions of FA in various concentrations was carried out under controlled conditions using three different methods: soaking cress seeds (0.03-300mg/l); non-root treatment of vegetative plants (90–150 mg/l), when growing lettuce by a low – volume method with drip fertigation with Knop nutrient solution; adding a nutrient solution to the root medium (0.03-150 mg/l), when growing lettuce under nutrient film technique. Results. The most pronounced stimulating effect on plant growth was obtained after seeds treatment with FA solutions in concentrations of 0.3-150.0 mg/l, during non-root treatment of lettuce in concentrations of 0.3 and 150.0 mg/l, and when FA was introduced into the root medium at a concentration of 90.0 mg/l. It was suggested the lettuce growth under the action of FA was conditioned by enhancing plants metabolism and increased entry of nutrients to the aboveground organs of plants (during non – root processing)- and by nutrient uptake increasingas well as activation of the synthesis of photosynthetic pigments-chlorophylls and carotenoids (when a nutrient solution was add to the root medium. Scientific innovation. Under controlled conditions, a comprehensive assessment of the effect of FA solutions obtained from sapropel on the physiological state, production process, and quality of salad crops was carried out. The concentrations of fulvic acid solutions that had the most pronounced stimulating effect on the growth and development of lettuce plants in various types of treatment were determined. The specificity of the responses of lettuce plants to various types of treatment with FA solutions was revealed.

Distribution and Redistribution of 109Cd and 65Zn in the Heavy Metal Hyperaccumulator Solanum nigrum L.: Influence of Cadmium and Zinc Concentrations in the Root Medium

Heavy metal redistribution is relevant for the quality of edible crops and the suitability of hyperaccumulators for bioremediation. Root-to-shoot transfer via the xylem and redistribution in the aerial parts via the phloem differ between various heavy metals. In general, cadmium is more slowly released to the shoot than zinc (e.g., in wheat, bean, and lupin). However, rapid cadmium transport to the shoot was detected in the hyperaccumulator Solanum nigrum L. This is a key aspect in this article and might be important for bioremediation. The radionuclides 109Cd and 65Zn were used to investigate the respective influence of elevated cadmium or zinc in the root medium on the dynamics of the two heavy metals in S. nigrum. Although transport via the xylem to the leaves was similar for 109Cd and 65Zn, the further redistribution from older leaves to younger leaves, flowers, and fruits via the phloem was far less efficient for 109Cd than for 65Zn. Furthermore, the redistribution of 109Cd within the shoot was negatively influenced by increased cadmium (but not by increased zinc) concentrations in the nutrient medium. The redistribution of 65Zn in the shoot was selectively decreased by increased zinc concentrations (but generally not by cadmium).