Abstract:

Dwarf phenomenon, chlorosis, low quality often occur in hydroponics kale because of iron deficiency, while the plant growth would be easily inhibited by high iron concentration due to the physiological obstacle brought about iron toxicity. In this study, the effects of iron concentrations (2.8 mg/L, 5.6 mg/L, 8.4 mg/L, 11.2 mg/L and 14 mg/L, with EDTA-Fe as a source) on the growth, quality and some physiological characteristics of hydroponic Chinese kale was investigated. Results showed that the plant fresh weight and plant height increased significantly as the iron concentration went up to 8.4 mg/L. But when the iron concentration went over 8.4 mg/L, the plant fresh weight did not increase and plant height even dropped down. It was conducive to improve nutrient contents of Chinese kale, to increase iron concentration within a certain range. The contents of soluble protein, soluble sugar and vitamin C in leaf and bolting stem would increase significantly along with the increase of iron concentration. But, the soluble protein content in leaf did not increase when the iron concentration was higher than 8.4 mg/L. The soluble protein content in bolting stem, and soluble sugar contents in leaf and bolting stem would not increase when the iron concentration was over 11.2 mg/L. Chlorophyll content, CAT and POD activities of leaf showed the tendency of first raising then dropping with the adding of iron concentration, and then reached the peak when iron concentration was 8.4 mg/L. The vitality of root system was in the same situation. Total plant iron content also increased at first and then decreased with the increase of iron concentration. The peak of total iron content in leaf was at the iron concentration of 8.4 mg/L, and the peak of total iron contents in bolting stem and root was at 11.2 mg/L. So 8.4 mg/L was considered the most appropriate iron concentration of the nutrient solution for hydroponic Chinese kale under this experimental condition.

Key words: Chinese kale, iron concentration, hydroponics, growth, quality

摘要：

水培芥蓝时常遇到缺铁造成植株矮小、品质降低的现象，但高铁浓度培养易引起铁中毒产生生理障碍而抑制芥蓝生长。以EDTA-Fe为铁源，研究了不同铁浓度水平（2.8 mg/L、5.6 mg/L、8.4 mg/L、11.2 mg/L和14.0 mg/L）对水培芥蓝生长、品质及生理特性的影响。结果表明：芥蓝植株鲜重和株高随营养液供铁浓度的增加而增加，但铁浓度超过8.4 mg/L后植株鲜重无显著增加，株高则下降。芥蓝薹叶与薹茎的可溶性蛋白、可溶性糖和维生素Ｃ含量都随铁浓度的增加而显著增加，超过8.4 mg/L后薹叶的可溶性蛋白含量不再显著增加，超过11.2 mg/L时薹茎的可溶性蛋白、薹叶与薹茎的可溶性糖含量都不再显著增加。叶片叶绿素含量、薹叶CAT和POD活性均随铁浓度增加呈先增加后下降的趋势，至8.4 mg/L时达到最高。根系活力随着铁浓度的增加呈先增加后下降的趋势，至8.4 mg/L时达到最高。植株全铁含量也随着铁浓度增加而先升高后下降，薹叶全铁含量至8.4 mg/L处理达到最高，薹茎与根全铁含量11.2 mg/L时最高。本试验条件下水培芥蓝最适合的铁浓度是8.4 mg/L，可获得最佳的生物量和经济性状。

关键词: 芥蓝, 铁浓度, 水培, 生长, 品质