Background: Several plants are facing drought stress due to climate change in recent years. In this study, we aimed to explore the effect of varying watering frequency on the growth and photosynthetic characteristics of Hosta ‘Guacamole’. Moreover, we investigated the effect of high-nitrogen and -potassium fertilizers on alleviating the impacts of drought stress on the morphology, photosynthetic characteristics, chlorophyll fluorescence, fast chlorophyll a fluorescence transient, JIP-test parameters, and enzymatic and non-enzymatic scavenging system for reactive oxygen species (ROS) in this species. Results: Leaf senescence, decreased chlorophyll contents, limited leaf area, and reduced photosynthetic characteristics and oxygen-evolving complex (OEC) activity were observed in Hosta ‘Guacamole’ under drought stress. However, high-nitrogen fertilizer (30-10-10) could efficiently alleviate and prevent the adverse effects of drought stress. High-nitrogen fertilizer significantly increased chlorophyll contents, which was higher by 106% than drought stress. Additionally, high-nitrogen fertilizer significantly improved net photosynthetic rate and water use efficiency, which were higher by 467% and 2900% than those under drought stress. It attributes that high-nitrogen fertilizer could reduce transpiration rate of leaf cells and stomatal opening size in drought stress. On the other hand, high-nitrogen fertilizer enhanced actual photochemical efficiency of PS II and photochemical quenching coefficient, and actual photochemical efficiency of PS II significantly higher by 177% than that under drought stress. Furthermore, high-nitrogen fertilizer significantly activated OEC and ascorbate peroxidase activities, and enhanced the performance of photosystem II and photosynthetic capacity compared with high-potassium fertilizers (15-10-30). Conclusions: High-nitrogen fertilizer (30-10-10) could efficiently alleviate the adverse effects of drought stress in Hosta ‘Guacamole’ via enhancing OEC activity and photosynthetic performance and stimulating enzymatic ROS scavenging system.

The effects of different light-emitting diode (LED) lights on saffron growth and photosynthetic characteristic were explored. Physiological mechanisms were explained by chlorophyll a fluorescence transient curves (OJIP) and JIP-test parameters...

Saffron (Crocus sativus L.) is an important medicinal crop with high economic value in the world. Due to its growth patterns and environmental requirements, Chinese enterprises employ two-stage cultivation for saffron. However, the relationship between corm size and flowering characteristics in this cultivation remains understudied. This study investigated the correlation between corm size and flowering characteristics, including flower count, stigma yield, and mass concentration percentage of crocin and picrocrocin, as well as physiological differences in corm of different sizes indoors. Results indicated that there was a significantly positive correlation with corm size and flower number (r = 0.98) and stigma yield (r = 0.98). Additionally, a positive correlation was observed between corm size and mass concentration percentage of crocin (r = 0.54), whereas no correlation existed between corm size and mass concentration percentage of picrocrocin (r = 0.19). Significant variations in soluble protein, soluble sugar, starch, and hormone (ZR, IAA, GA₃, ABA) contents were noted in this study. Larger corm sizes had higher contents of soluble protein, soluble sugar, and starch. Meanwhile, starch content mostly had a decreasing trend indoors, which provides sufficient energy and nutrients for flower bud differentiation. ZR and IAA showed greater responsiveness, and increased levels of ZR and IAA potentially promote flower bud differentiation. This study provides theoretical guidance for field management optimization, yield improvement, and quality control of saffron in Chinese two-stage cultivation.

This study evaluated the effects of three storage temperatures (4 °C, −20 °C, −80 °C) on metabolites in saffron stigmas after one year of storage using non-targeted metabolomics based on LC-MS and GC-TOF-MS. Lower storage temperatures better preserved chemical activity, and different metabolites markedly included capsiate, sarmentine, sesamolinol, nobiletin, prostaglandin F1α, vanillin, and α-ketoglutaric acid. Amino acid-centered pathways, including alanine, aspartate, glutamate, and phenylalanine metabolism, constitute core temperature-responsive modules. Aspartic acid and alpha-ketoisovaleric acid exhibited strong correlations with key quality indicators crocin and picrocrocin. The −80 °C treatment significantly yielded the highest retention of crocin and picrocrocin, with their contents being 21.46% and 31.25% higher, respectively, than at 4 °C. −80 °C is recommended for long-term storage, whereas −20 °C is suitable for household use. This study provides a theoretical foundation and practical guidance for saffron preservation for producers and consumers.