Drought stress is a significant environmental factor that can impede plant growth and ornamental quality. Hemerocallis middendorffii, a drought-tolerant garden plant, has attracted attention for its ornamental value and application prospects. To investigate the molecular mechanism of drought stress resistance of H. middendorffii, this study employed 20% polyethylene glycol (PEG) 6000 to simulate drought stress. Leaves and roots of H. middendorfii were subjected to 24 h treatment and followed by transcriptome sequencing. Analysis revealed 8796 and 3401 differentially expressed genes (DEGs) in leaves and roots. The major biological processes and key molecular pathways activated under drought stress in H. middendorffii were revealed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The focus of this analysis was on the gene expression changes within plant hormone signal transduction pathway. Additionally, drought-associated transcription factor families such as AP2/ERF, WRKY, MYB, bHLH, NAC, and bZIP were identified among DEGs. Furthermore, potential regulatory relationships of the above transcription factors (TFs) with functional genes in the abscisic acid (ABA) and jasmonic acid (JA) signalling pathways were analysed using correlation network prediction. This research establishes the groundwork for subsequent exploration of drought-responsive gene expression and regulatory patterns in H. middendorfii and provides an importance for the systematic study of its drought-resistant molecular mechanism.

Hosta ‘So Sweet’, a shade-tolerant Asparagaceae species, displays remarkable high-light tolerance in open-field full-sun cultivation without photoinhibition symptoms. To clarify its growing-season photosynthetic dynamics and adaptive strategies, this study measured diurnal photosynthetic variations from May to September, determined chlorophyll fluorescence parameters and pigment contents in May, July and September, and analyzed the data alongside the light and CO₂ response curves for July. The results showed that the high temperatures combined with high-light conditions in July lowered P_n relative to May and September, but the light saturation point (LSP) reached 1508.99 μmol m⁻² s⁻¹, and the CO₂ compensation point (CCP) was 75.46 μmol mol⁻¹, highlighting the robust light energy utilization and carbon assimilation potential. Meanwhile, PSII maximum photochemical efficiency (Fv/Fm) remained stable under these conditions, indicating undamaged photosystems. Mechanistically, its photosynthetic limitation strategies showed seasonal plasticity: a tight coupling between P_n, stomatal conductance, and humidity in May shifted to a strong association between P_n and photoprotective dissipation (qN) in July, followed by an optimization of light capture linked to increased chlorophyll content and adjusted Chl a/b ratios in September. Taken together, H. ‘So Sweet’ synergistically adapts to growing-season light and temperature fluctuations by integrating light utilization potential, photosystem stability and pigment adjustment strategies. This study preliminarily delineated its photosynthetic physiological profile, revealed core light-adaptive strategies, and provided a theoretical basis for the ecological application of this excellent ornamental cultivar.

Iris setosa is a characteristic perennial wild herbaceous flower in the Changbai Mountain region of China, boasting significant ornamental and medicinal values. Given the increasing scarcity of its wild resources, this study developed an efficient in vitro regeneration system using shoot tips as explants via the direct organogenesis pathway. The optimal surface sterilization protocol was achieved with a treatment of 0.1% HgCl₂ for 8 min, resulting in an explant survival rate of 57.78%. The highest multiple shoot induction rate (88.89%) of shoot tips was achieved on MS medium supplemented with 2.0 mg·L⁻¹ 6-benzylaminopurine (6-BA), 0.5 mg·L⁻¹ naphthalene acetic acid (NAA), and 1.0 mg·L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D). The optimal shoot differentiation and proliferation medium was MS + 2.0 mg·L⁻¹ 6-BA + 0.3 mg·L⁻¹ NAA, achieving a proliferation coefficient of 3.37. The optimal medium for rooting was confirmed to be 1/2 MS + 0.5 mg·L⁻¹ indole-3-butyric acid (IBA), exhibiting a high rooting rate reached 98.33%. During transplantation, plantlets exhibited high survival rates (over 90%) and vigorous growth across all three tested substrates, with no significant differences in survival rates among substrates. The key advance of this study lies in the development of a highly efficient and stable regeneration protocol for I. setosa derived from shoot tip explants, providing critical technical backing for the conservation and sustainable exploitation of its wild-type germplasm.