Italian ryegrass (Lolium multiflorum Lam.) is a major winter forage crop requiring improved drought tolerance under climate change. This study evaluated 42 accessions, consisting of 20 Korean cultivars and 22 exotic germplasm under four polyethylene glycol (PEG) concentrations (0, 10, 15, and 20%) to assess germination and early seedling responses to drought stress. Increasing PEG levels significantly reduced germination percentage (GP), germination energy (GE), germination index (GI), and seedling vigor index (SVI), while mean germination time (MGT) increased. At 20% PEG, GP decreased by approximately 74% compared with the control. Early seedling vigor, expressed as SVI (integrating fresh weight, shoot length, and root length) also declined depending on concentration. Germination traits (GE and GI) showed strong positive correlations with SVI, indicating that early germination performance was closely associated with subsequent growth under drought stress. Fuzzy comprehensive evaluation and principal component analysis consistently identified several accessions (Earlybird, IR602, IR901, Florida 98, Maximus, Orlando, and Moscovsky 74) as relatively drought tolerant. Overall, the integration of germination and seedling vigor index provides a reliable phenotypic screening approach for identifying drought-tolerant Italian ryegrass.

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.

에탄올의 외생적 처리는 다양한 비생물적 스트레스에 대한 식물의 내성을 향상시키는 것으로 보고되어 왔 으나, 이러한 결과의 대부분은 엽체류나 타 모델식물에 한정되어 있었으며, 과실을 맺는 원예작물에 대한 연구는 상대적으로 부족하다. 특히 주요 과채류인 멜론(Cucumis melo L.)에서의 애탄올 효과는 아직 충분히 규명되지 않 았다. 본 연구에서는 멜론에 가뭄 스트레스를 부여하기 전에 에탄올이 각각 0, 25, 50, 100mM 농도로 첨가된 양액 을 관주 처리하고, 봄과 여름 두 생육시기에 걸쳐 형태적 특성, 잎의 생리 반응 및 과실 특성을 평가하였다. 그 결과, 광합성률, 가공전도도, 증산률 등 가스 교환 생리 지표는 가뭄 스트레스 개시 6시간 이내에 에탄올 농도 증가에 따라 일시적으로 감소하였으나 24시간 내 회복되어 계절 간 유사한 경향을 보였다. 과실 특성에서는 계절적 변이가 뚜렸 하였으며, 봄에는 에탄올 농도 증가에 따라 가용성 고형물 함량 (°Brix)과 항산화 물질 함량이 지속적으로 증가한 반면, 여름에는 50mM 처리구에서 가장 높은 °Brix가 나타났고 총 페놀 함량과 DPPH 라디칼 소거 활성은 대조구 를 제외한 처리 간 유의한 차이가 없었다. 이러한 결과는 에탄올 처리가 식물의 스트레스 인지를 강화하고 멜론 과 실의 당 축적 및 항산화 능력을 증진시켜 가뭄 조건에서 과실 품질 향상을 위한 잠재적 전략이 될 수 있음을 시사한다.