Climate change is increasing the frequency and severity of abiotic stresses, including drought, salinity, heat, cold, and fluctuating light intensity, posing significant challenges to ornamental plant growth, market quality, and postharvest performance. Nitric oxide (NO) has emerged as a key gaseous signaling molecule involved in plant adaptive responses to such stress conditions. Although extensive research in model plants, particularly Arabidopsis thaliana, has elucidated NO biosynthesis pathways, redox signaling networks, hormone crosstalk, and S-nitrosylation-based regulation, comparable mechanistic studies in ornamental species remain limited. Existing evidence from Rosa, Tagetes, Gazania, Gerbera, Lilium, Chrysanthemum, Petunia, Zinnia, and other floricultural crops suggests that NO enhances stress resilience by regulating antioxidant activity, maintaining photosynthetic efficiency, stabilizing cellular membranes, modulating stomatal behavior, and extending vase life through delayed senescence. This review synthesizes the current state of knowledge on NO-mediated abiotic stress tolerance in ornamental plants within the context of climate change impacts and compares these findings with well-characterized NO functions in model systems. By identifying parallel mechanisms, knowledge gaps, and translational opportunities, we highlight experimental directions that may accelerate the application of NO-based approaches in floriculture. Finally, the review discusses practical implications, including the use of exogenous NO donors, priming strategies, and advanced delivery systems,

Humic acid (HA), a key component of soil organic matter, has emerged as a multifunctional biostimulant that enhances soil quality, nutrient availability, plant growth, and stress resilience. The complex supramolecular structure of HA influences soil physicochemical properties by improving aggregation, increasing cation exchange capacity, and enhancing water and nutrient retention. These changes facilitate greater uptake of essential macro- and micronutrients, supporting improved photosynthesis, root development, and biomass accumulation. At the physiological and molecular levels, HA modulates hormone signaling, activates antioxidant defenses, and primes stress-responsive pathways that enhance tolerance to drought, salinity, and other abiotic stresses. HA’s ability to regulate reactive oxygen species (ROS) homeostasis, maintain ion balance, promote osmolyte accumulation, and activate pathways such as Salt-Overly-Sensitive (SOS) or other stress-regulatory networks has been demonstrated across diverse crop species. Despite these benefits, variability arising from differences in HA source materials and extraction methods remains a major challenge for consistent application. Future research integrating multi-omics approaches, improved formulation strategies, and large-scale field validation will be essential for elucidating unknown HA’s regulatory mechanisms and maximizing its agricultural potential. Collectively, current evidence positions HA as a promising biostimulant capable of enhancing crop productivity and resilience within sustainable agricultural systems.

To study the effects of external ethanol pretreatment on growth and drought tolerance in alfalfa, 21-day-old plants were pretreated with ethanol at 0-1000 mM for 4 days and then subjected to drought stress for 9 days. Ethanol pretreatment significantly enhanced plant survival under drought conditions, with the highest survival rate observed in the 250 mM treatment. In contrast, fresh weight and dry weight were not significantly affected by ethanol pretreatment. Relative water content was increased 7.15% at 250 mM ethanol treatment compared to 0 mM ethanol treatment. Chlorophyll content decreased compared to the control, while carotenoid content remained unchanged. total soluble carbohydrate content was reduced by ethanol pretreatment. Hydrogen peroxide (H2O2) levels were maintained only in plants treated with 250 mM ethanol, whereas lower and higher concentrations resulted in significantly decreased H2O2 content. These results suggest that ethanol pretreatment does not affect alfalfa growth, but significantly improves survival rate under drought conditions by maintenance of relative water content. Furthermore, it suggests that chemical priming using ethanol pretreatment could be applied as a method to improve drought tolerance of alfalfa plants.

Humic acids (HA), with their irregular polymeric structures and largely existing in grassland, present challenges in quality control due to significant variations in biological activities depending on extraction sources. To address this, we explored industrial byproducts as potential alternatives mimicking HA-like bioactivities. This study evaluates sulfite lignin, a byproduct of the pulp industry, as an eco-friendly biostimulant for enhancing plant growth and stress tolerance. Sulfite lignin demonstrated HA-like bioactivities, promoting seed germination and salt stress tolerance in Arabidopsis thaliana. Germination assays revealed that sulfite lignin significantly improved radicle and cotyledon emergence, particularly at low concentrations (8.6 mg L⁻¹), outperforming HA and kraft lignin. Additionally, under salt stress conditions, sulfite lignin-treated plants exhibited healthier phenotypes and maintained higher chlorophyll content compared to control treatments, similar to HA and kraft lignin. The findings highlight sulfite lignin as a promising, sustainable, and cost-effective biofertilizer, effectively replicating HA's biological functions while leveraging industrial byproducts.

본 연구는 페튜니아(Petunia×hybrida)의 내건성 증진을 위 해 스트레스 메모리 기작을 활용한 프라이밍 처리의 효과를 구명 하고자 하였다. 건조-회복 과정을 통한 프라이밍 처리를 4회 반복 수행하였고, 두 가지 프라이밍 강도(Priming1:물 100mL, Priming2: 물 50mL 관수 후 건조)를 적용한 후 5일 동안 건조스 트레스 조건에서 내성 증진 효과를 관찰하였다. 프라이밍 강도가 높은 Priming2 처리구에서 대조군에 비해 수명이 약 25시간 연장되었다. 이는 페튜니아가 스트레스 메모리 기작을 통해 건조 스트레스에 대한 내성을 높일 수 있음을 보여준다. 본 연구는 정원 식물의 환경 스트레스 내성을 증진시키기 위한 프라이밍 기술의 유용성을 확인하였으며, 향후 다양한 환경 스트레스 조건 에서의 프라이밍 효과를 평가함으로써 화훼식물의 내건성 증진 에 대한 실용적 기술 개발에 기여할 수 있을 것으로 기대된다.

Drought is one of the environmental factors inhibiting plant productivity and growth, leading to oxidative damage. This study aims to identify the role of sodium hydrosulfide (NaHS) as a hydrogen sulfide (H2S) donor in drought stress tolerance in Brassica napus. Drought-induced stress symptoms appeared eight days after treatment, showing wilted leaves and a significant reduction of leaf water potential. Drought-induced increase of lipid peroxidation was significantly reduced by NaHS application. NaHS-treated plants mitigated stress symptoms under drought conditions by reducing hydrogen peroxide (H2O2) content, confirmed with H2O2 localization in situ. Furthermore, NaHS promotes photosynthetic activity by maintaining chlorophyll and carotenoid content, thereby supporting plant growth under drought conditions. Pyrroline-5-carboxylate and proline contents were significantly increased by drought but further enhanced by NaHS treatment, indicating the important roles of proline accumulation in drought stress tolerance. In conclusion, this study provides valuable insight into the roles of NaHS in alleviating drought stress by reducing oxidative stress and promoting proline accumulation. Therefore, NaHS may serve as an effective strategy to enhance crop production under drought-stress conditions.

Ethylene-responsive factors (ERFs) are important plant transcription factors (TFs) that regulate plant responses against various abiotic stresses. However, little information of ERF genes involved in abiotic stress is available in petunia (Petunia ×hybrida). In this study, a petunia ERF gene, PhERF039, was cloned and functional analysis was performed. The quantitative PCR analysis revealed that PhERF039 was induced at the early stage of water deficit stress. Under-expression of PhERF039 (UE) exhibited rosette growth habit, higher number of branches, and delayed flowering compared to the wild type (WT). The UE petunia was evaluated under various volumetric water contents (θ): 0.25, 0.15, 0.10, or 0.05 m3·m-3 using an automated irrigation system. Transgenic plants did not delay plant wilting, but the θ for UE reached to the set point later than that for WT. A lower stomatal conductance was observed in UE than WT under all treatments. These results suggested that PhERF039 could be involved in plant responses under water deficit by regulating stomatal movements as well as branching pattern and flower development.

This study was carried out to establish various physiological changes according to soil water stress and to compare the degree of water stress between two species of grapevines (‘Jinok’ as a new breeding cultivar and ‘Campbell Early’ as a control) using thermography. Soil water potentials were treated at -70, -30, and -5 kPa with waterlogging for 7 days. Regarding the photosynthetic rates (A) of the two cultivars, they showed an order of –30 kPA > -5 kPa > -70 kPa in order. With -70 kPa and waterlogging treatments, a decrease of photosynthetic rate was observed at 3 days after treatment, with a more significant decrease accumulating over time. At 7 days after treatment, photosynthetic rates of ‘Campbell Early’ (33.3, 45.6%) and ‘Jinok’ (56.6, 57.3%) grapes decreased compared to those with -30 kPa treatment. H2O2 and proline synthesis were the highest with the waterlogging treatment. In terms of proline synthesis, ‘Campbell Early’ had a relatively higher rate than ‘Jinok’. Leaf and stem water potential were the lowest with the -70 kPa treatment and the highest with the - 30 kPa treatment f or both cultivars. Crop water stress index (CWSI) showed the following order: waterlogging > -70 kPa > -5 kPa > -30 kPa, which was the opposite result of water vapor transfer (IG). As a result of correlation analysis between factors, photosynthetic rate showed negative correlations with the water potential of leaf and stem and crop water stress index but a positive correlation with the relative water content of leaves. Thus, tolerance to water stress of ‘Campbell Early’ was relatively stronger than that of ‘Jinok’ grape. It is possible to compare water stress using infrared imaging.

Drought stress is a condition that occurs frequently in the field, it reduces of the agricultural yield of field crops. The aim of the study was to screen drought-adapted genotype of Italian rye grass. The experiments were conducted between the two Italian ryegrass (Lolium multiflorum L.) cultivars viz. Hwasan (H) and Kowinearly (KE). The plants were exposed to drought for 14 days. The results suggest that the morphological traits and biomass yield of KE significantly affected by drought stress-induced oxidative stress as the hydrogen peroxide (H2O2) level was induced, while these parameters were unchanged or less affected in H. Furthermore, the cultivar H showed better adaptation by maintaining several physiological parameter including photosystem-II (Fv/Fm), water use efficiency (WUE) and relative water content (RWC%) level in response to drought stress. These results indicate that the cultivar H shows improved drought tolerance by generic variation, improving photosynthetic efficiency and reducing oxidative stress damages under drought stress. These findings can be useful to the breeder and farmer for improving drought tolerance in Italian rye grass through breeding programs.

The objective of this study was to determine effects of phosphorus on lignification and carbohydrate metabolism in Kentucky bluegrass under drought stress. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (PO4 3-; P) or potassium phosphonate (PO3 3-; PA) in drought-stressed plants. Drought had significant negative effects on plant growth, as revealed by reduced biomass of shoot. Drought-induced increase of lignin content was concomitant with the increase of phenylalanine ammonia-lyase (PAL). Soluble sugar content was highly increased but fructan content was largely decreased by drought stress. However, the application of phosphorus was efficient to ameliorate the adverse effects of drought. PA application improved reduced shoot growth and relative water content, and inhibited lignification synthesis with a reduction of PAL activity. P or PA application maintained soluble sugar and fructan content at similar levels to controls under drought stress. These results indicate that phosphorus application may mitigate the drought stress by inhibiting the lignification and promoting the fructan assimilation.