Botany Department, Faculty of Science, Ain Shams University, P.O.11566, Abbassyia, Cairo, Egypt.
Botany Department, Agricultural and Biological Research Institute, National Research Centre, P. O. 12622, 33 El-Buhouth Street, Dokki, Giza, Egypt.
BMC Plant Biol. 2024 Oct 15;24(1):963. doi: 10.1186/s12870-024-05626-z.
Secondary metabolites of several plants, including esculin and digitoxin, which are cardiac glycosides, were previously employed for their therapeutic effects. The current study aims to investigate the functions of the main Na /K transport inhibitor digitoxin and the antioxidant esculin for enhancing flax plant growth and production under salinity.
Flax plants were irrigated with distilled water supplemented with 0.0 and 5000 mg/L salt solution starting from 15 DAS from sowing. Then exogenous treatment with digitoxin and esculin with 50 mg L and 100 mg L were used for this work.
According to the results of this work, foliar spraying of esculin or digitoxin increased the salinity tolerance of flax plants.The foliar application of either esculin or digitoxin induced an elevation in the contents of photosynthetic pigments, osmolytes including soluble sugar and proline as well as the total phenols in salt-stressed flax plants. Moreover, esculin and digitoxin in particular counteract oxidative stress by increasing the activity of antioxidant enzymes including superoxide dismutase, catalase, peroxidase, phenylalanine ammonia-lyase, and tyrosine ammonia lyase, leading to a decrease in reactive oxygen species and lipid peroxidation levels and electrolyte leakage. The efficiency of esculin and digitoxin to sustain ion homeostasis by inhibiting Na absorption and increasing potassium, calcium, and phosphorus in flax plants may be the reason for their protective actions towards salinity.As a consequence, esculin and digitoxin increased yield quantity and quality as shown by increases in all investigated yield criteriaas shoot height, root length, their fresh and dry weights as well asseed yield/plant (g), and 1000 seeds weight, especially those that improved the desired oil properties.
In conclusion, this study concluded that digitoxin was more effective in inhibiting Na build-up and increasing flax salinity tolerance, particularly at the high investigated dose as compared to esculin. In this study, we reported the recent findings of exogenousapplication of either digitoxin or esculin glycosides which are new investigated salt alleviators never used before for improving the salt tolerance in flax plants.
几种植物的次生代谢产物，包括地锦草苷和洋地黄毒苷，它们是强心苷，以前曾因其治疗作用而被使用。本研究旨在探讨主要的 Na+/K+运输抑制剂洋地黄毒苷和抗氧化剂地锦草苷在盐胁迫下增强亚麻植物生长和产量的功能。
从播种后 15 天开始，用蒸馏水和 0.0 和 5000mg/L 盐溶液灌溉亚麻植物。然后用 50mg/L 和 100mg/L 的地锦草苷和洋地黄毒苷进行外源处理。
根据本研究的结果，地锦草苷或洋地黄毒苷的叶面喷施提高了亚麻植物的耐盐性。叶面喷施地锦草苷或洋地黄毒苷均可提高盐胁迫下亚麻植物的光合色素、渗透调节剂（包括可溶性糖和脯氨酸）和总酚含量。此外，地锦草苷和洋地黄毒苷尤其通过增加抗氧化酶（包括超氧化物歧化酶、过氧化氢酶、过氧化物酶、苯丙氨酸解氨酶和酪氨酸解氨酶）的活性来对抗氧化应激，从而降低活性氧和脂质过氧化水平和电解质渗漏。地锦草苷和洋地黄毒苷通过抑制 Na+吸收和增加亚麻植物中的钾、钙和磷来维持离子稳态的效率可能是它们对盐胁迫具有保护作用的原因。因此，地锦草苷和洋地黄毒苷增加了产量的数量和质量，如增加了所有调查的产量指标，包括株高、根长、鲜重和干重以及种子产量/株（g）和 1000 粒种子重量，特别是那些改善了所需油的特性。
总之，本研究得出结论，与地锦草苷相比，洋地黄毒苷在抑制 Na+积累和提高亚麻耐盐性方面更有效，特别是在高剂量下。在本研究中，我们报告了外源应用洋地黄毒苷或地锦草苷糖苷的最新发现，这些糖苷是以前从未用于提高亚麻植物耐盐性的新研究的盐缓解剂。
