Abstract:

To further optimize the application of nitrogen and potassium fertilizers in Momordica charantia cultivation and increase the saponin content, the low- (‘206’) and high- (‘Youjia 4’) saponin varieties were selected as the test materials, and the medium-saponin variety ‘Gedalv’ was used as the control. The root tip non-invasive detection method was used to detect root absorption of nitrogen and potassium ions. The results showed that the absorption of nitrogen ions by ‘Youjia 4’ roots was significantly higher than that by ‘Gedalv’ and ‘206’ at young fruit stage, while the release of potassium ions was 40% and 63.5% lower than that by ‘206’ at the seedling and young fruit stage, respectively. In the field cultivation, three levels (low, medium and high) of nitrogen and potassium were used as variables to carry out the orthogonal design, and the fertilization verification was carried out. The results indicated that ‘Youjia 4’ had stronger ability to absorb nitrogen and retain potassium and could also produce high saponin under low nitrogen and potassium conditions. The high content of nitrogen and potassium could significantly increase the saponin content of low saponin varieties. To obtain high saponin in Momordica charantia cultivation and production, low nitrogen and potassium fertilization can be applied to high-saponin varieties, and fertilization with high nitrogen and potassium should be selected for low-saponin varieties.

Key words: Momordica charantia, saponin, nitrogen, potassium, non-invasive micro-test technology