This investigation explores the physiological modulation in Brassica oleracea var. italica (broccoli) in response to treatments with distinct nanoparticles and biochemical elicitors, including copper oxide (CuO), zinc oxide (ZnO), silver nitrate (AgNO3), chitosan, methyl jasmonate (MeJA), and salicylic acid (SA). The study evaluated parameters indicative of plant vitality and stress adaptability, namely chlorophyll a and b concentrations, carotenoid content, relative water content (RWC), and relative stress injury (RSI). The application of chitosan elicited the highest RWC (95.38%), demonstrating its efficacy in preserving cellular hydration under stress, with SA (92.45%) and MeJA (90.53%) closely following. Notably, SA minimized RSI (28.95%), highlighting its superior capacity for mitigating cellular damage under adverse conditions. Comparable stress-ameliorative effects were observed for ZnO and chitosan treatments, suggesting their roles in fortifying membrane integrity. In the context of photosynthetic pigment accumulation, MeJA exhibited the most pronounced effect, achieving maximal chlorophyll a (7.13 mg/g fresh weight) and chlorophyll b (2.67 mg/g fresh weight) concentrations, with SA and ZnO displaying substantial supportive effects. Conversely, AgNO3 treatment was largely ineffective, manifesting the lowest recorded chlorophyll and carotenoid levels across all experimental conditions. Collectively, the findings underscore the potential of MeJA, SA, and chitosan nanoparticles as potent modulators of broccoli's physiological processes, particularly in enhancing photosynthetic efficiency, maintaining water balance, and mitigating oxidative damage under stress conditions. However, before field application, limitations such as the uncertain long-term effects of nanoparticles on plant genomic stability and soil ecosystems, the need for field validation under variable environmental stresses, and the economic feasibility for small-scale farmers must be addressed. Future research should focus on elucidating the molecular mechanisms behind nanoparticle-mediated stress tolerance, conducting eco-toxicity assessments of nanomaterials in agricultural systems, and optimizing cost-effective delivery methods.

Introduction: Toxicity due to excess soil iron (Fe) is a significant concern for rice cultivation in lowland areas with acidic soils. Toxic levels of Fe adversely affect plant growth by disrupting the absorption of essential macronutrients, and by causing cellular damage. To understand the responses to excess Fe, particularly on seedling root system, this study evaluated rice genotypes under varying Fe levels. Methods: Sixteen diverse rice genotypes were hydroponically screened under induced Fe levels, ranging from normal to excess. Morphological and root system characteristics were observed. The onset of leaf bronzing was monitored to identify the toxic response to the excess Fe. Additionally, agronomic and root characteristics were measured to classify genotypes into tolerant and sensitive categories by computing a response stability index. Results: Our results revealed that 460 ppm of Fe in the nutrient solution served as a critical threshold for screening genotypes during the seedling stage. Fe toxicity significantly affected root system traits, emphasizing the consequential impact on aerial biomass and nutrient deprivation. To classify genotypes into tolerant and sensitive categories, leaf bronzing score was used as a major indicator of Fe stress. However, the response stability index provided a robust basis for classification for the growth performance. Apart from the established tolerant varieties, we could identify a previously unrecognized tolerant variety, ILS 12-5 in this study. Some of the popular mega varieties, including BPT 5204 and Pusa 44, were found to be highly sensitive. Discussion: Our findings suggest that root system damage, particularly in root length, surface area, and root volume, is the key factor contributing to the sensitivity responses under Fe toxicity. Tolerant genotypes were found to retain more healthy roots than the sensitive ones. Fe exclusion, by reducing Fe(2+ )uptake, may be a major mechanism for tolerance among these genotypes. Further field evaluations are necessary to confirm the behavior of identified tolerant and sensitive lines under natural conditions. Insights from the study provide potential scope for enhancement of tolerance through breeding programs as well as throw light on the role root system in conferring tolerance.

Finding practical solutions for utilizing agricultural organic wastes has always been a challenge. To address this, our study investigated the effects and mechanisms of different exogenous organic waste fermentation solutions on alleviating Cd stress in plants using hydroponic experiments. Out of the seven fermentation solutions examined, pea fermentation liquid (T3), chicken manure (T5), molasses (T6), and chitosan oligosaccharide broth (T9) exhibited positive effects. They increased shoot fresh weight by 1.17%, 26.83%, 7.94%, and 15.59%, and root fresh weight by 50.00%, 12.21%, 81.19%, and 19.47%, respectively. Conversely, amino acid mother liquid (T7) and potassium polyaspartate liquid (T8) reduced shoot fresh weight by 34.21% and 24.74%, and root fresh weight by 27.06% and 7.10%, respectively. All organic waste liquids reduced Cd concentration in shoots and roots. Corn fermentation liquid (T4) reduced Cd in shoots from 87.91 to 19.20 mg/kg, while molasses (T6) reduced Cd in roots from 980.94 to 260.47 mg/kg. SEM-EDX results revealed that molasses (T6) effectively repaired Cd damage on root surfaces. In addition, several waste liquids mitigated microelement absorption disturbances. All waste liquids reduced MDA, corn fermentation liquid (T4), chicken manure (T5), molasses (T6), potassium polyaspartate liquid (T8), and chitosan oligosaccharide liquid (T9) significantly decreased H2O2 by 21.6-38.3%. Structural equation model (SEM) and correlation analysis highlighted the importance of root Mg, Cu, and Zn content and CAT activity in relieving Cd stress and promoting plant growth. Overall, molasses (T6) and chicken manure (T5) demonstrated the most beneficial combined effects, while amino acid mother liquid (T7) and chitosan oligosaccharide liquid (T9) should be exercised with caution due to their weaker effects.