College of Landscape Architecture and Art, Henan Agricultural University, Zhengzhou, 450002, Henan, China; College of Horticulture, Henan Agricultural University, Zhengzhou, 450046, Henan, China; Henan Research Center of Protected Horticulture Engineering Technology, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
College of Horticulture, Henan Agricultural University, Zhengzhou, 450046, Henan, China; Henan Research Center of Protected Horticulture Engineering Technology, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
Plant Physiol Biochem. 2024 Dec;217:109214. doi: 10.1016/j.plaphy.2024.109214. Epub 2024 Oct 19.
Melon (Cucumis melo L.) is an important economic crop and widely planted around the world. Cold stress severely limits its development and yield. Carbohydrates play multiple roles in plant cold tolerance. However, little is known in melon. Based on the metabolome analysis, a total of 635 metabolites were identified upon cold stress in melon seedlings. KEGG analysis shows that differential metabolites were mainly enriched in the glycolysis/gluconeogenesis pathway and pentose phosphate pathway, with glucose being one of the most prominent metabolites. To further investigate the role of glucose in cold tolerance of melon seedlings. We found that root irrigation was more effective than foliar spraying for exogenous glucose application, with optimal concentrations of 0.5% and 1% for cold-tolerant and cold-sensitive genotypes, respectively. Glucose irrigation mainly promoted soluble sugar accumulation to reduce cold damage in melon seedlings. For cold-sensitive genotype, only the sucrose content could be increased, while for cold-tolerant genotype, sucrose, fructose and glucose content could be simultaneously increased. Meanwhile, glucose irrigation recruited ABA not antioxidant enzyme system to cope with cold stress. Hence, glucose watering could improve the maximum photochemical efficiency of seedling photosystem II (Fv/Fm), alleviate physiological drought, reduce the accumulation of malondialdehyde, and accelerated the photosynthetic efficiency of melon seedlings. Based on coefficient of variation and principal component analysis, it was confirmed again that glucose irrigation did alter the strategies for withstanding cold stress and enhance the cold tolerance of melon seedlings. Thus, the results would provide a theoretical basis and feasible measures to protect melon seedings from cold damage.
甜瓜（Cucumis melo L.）是一种重要的经济作物，在世界各地广泛种植。低温胁迫严重限制了其发展和产量。碳水化合物在植物的耐寒性中发挥着多种作用。然而，人们对甜瓜中的碳水化合物知之甚少。基于代谢组学分析，在甜瓜幼苗受到冷胁迫时，共鉴定出 635 种差异代谢物。KEGG 分析表明，差异代谢物主要富集在糖酵解/糖异生途径和戊糖磷酸途径，葡萄糖是最显著的代谢物之一。为了进一步研究葡萄糖在甜瓜幼苗耐寒性中的作用。我们发现，根灌比叶喷更有利于外源葡萄糖的应用，对于耐寒和敏感基因型，最佳浓度分别为 0.5%和 1%。葡萄糖灌溉主要促进可溶性糖的积累，以减轻甜瓜幼苗的冷害。对于敏感基因型，只有蔗糖含量可以增加，而对于耐寒基因型，蔗糖、果糖和葡萄糖含量可以同时增加。同时，葡萄糖灌溉招募了 ABA 而不是抗氧化酶系统来应对冷胁迫。因此，葡萄糖浇水可以提高幼苗光合作用系统 II 的最大光化学效率（Fv/Fm），缓解生理干旱，减少丙二醛的积累，并加速甜瓜幼苗的光合作用效率。基于变异系数和主成分分析，再次证实了葡萄糖灌溉确实改变了抵御冷胁迫的策略，增强了甜瓜幼苗的耐寒性。因此，这些结果将为保护甜瓜幼苗免受冷害提供理论依据和可行措施。
