Shaimaa Mahmoud Heider

Cryopreservation offers a valuable approach for the long-term conservation of plant genetic resources, but its influence on seed viability and plant development remains underexplored. This study investigates the physiological and biochemical effects of different pre-cryopreservation drying treatments on Catharanthus roseus seeds. Seeds were subjected to silica gel desiccation and oven drying before immersion in liquid nitrogen (-196°C). Results showed that a moderate oven drying period (10 minutes) preserved high seed viability and led to optimal plantlet growth, mirroring untreated controls. In contrast, prolonged silica gel drying (3, and 9 hours) as well as drying for 20 min in oven significantly reduced germination rates, plantlet height, biomass, and levels of carbohydrates and alkaloids. Anatomical evaluations revealed improved vascular and mesophyll structures in plantlet leaves derived from oven-dried seeds, while moderate silica gel exposure increased epidermal thickness, indicating enhanced stress resilience. Hormonal analyses showed higher gibberellic acid (GA₃) and lower abscisic acid (ABA) levels in successfully germinated seeds. In conclusion, the study emphasizes the importance of pre-cryopreservation drying for optimizing plantlet performance and plant development with implications for pharmaceuticals. Thus, this research contributes to refining cryopreservation strategies for sustainable conservation of medicinal plants like Catharanthus roseus plants.

Background: Peace lily (Spathiphyllum wallisii Regel) is an ornamental indoor plant with promising cut flower market, as well as antiviral, pharmacological and ecological potentials. Water deficiency can have sound effects on the growth performance and aesthetic quality of such plant. The aim of this study was to investigate the consequences of zeolite, biochar, and zeo-char loaded nano-nitrogen application on the growth performance and biochemical components of peace lily under water shortage conditions. An experiment was conducted over two consecutive seasons (2021–2022) at the experimental nursery of Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, Egypt. Soil amendments; zeolite, biochar, and zeo-char loaded nano-nitrogen were prepared and applied to soil before cultivation. Results: Our results revealed that the new combination treatment (zeo-char loaded nano-N) had an exceeding significant effect on most of the studied parameters. Vegetative traits such as plant height (35.7 and 35.9%), leaf number per plant (73.3 and 52.6%), leaf area (40.2 and 36.4%), stem diameter (28.7 and 27.1%), root number (100 and 43.5%) and length (105.7 and 101.9%) per plant, and fresh weight of leaves (23.2 and 21.6%) were significantly higher than control (commercially recommended dose of NPK) with the application of zeo-char loaded nano-N during the two growing seasons, respectively. Similar significant increments were obtained for some macro- (N, P, K, Mg, Ca) and micro- (Fe, Zn, Mn) elements with the same treatment relative to control. Chlorophyll (18.4%) and total carotenoids (82.9 and 32.6%), total carbohydrates (53.3 and 37.4%), phenolics (54.4 and 86.9%), flavonoids (31.7% and 41.8%) and tannins (69.2 and 50%), in addition to the phytohormone gibberellic acid (GA₃) followed the same trend with the application of zeo-char loaded nano-N, increasing significantly over control. Leaf histological parameters and anatomical structure were enhanced with the new combination treatment in comparison with control. Antioxidant enzymes (catalase and peroxidase), proline and abscisic acid (ABA) exhibited significant declines with zeo-char loaded nano-N treatment relative to control. Conclusion: These findings suggest that incorporating soil amendments with nano- nutrients could provide a promising approach towards improving growth performance and quality of ornamental, medicinal and aromatic species under water deficiency conditions.

Salinity is one of abiotic stress that affects plant growth and production. The objective of this study was to investigate the effect of salinity and vermicompost on morphology and physiology parameters of Calliandra haematocephala. The experiment was carried out with salinity treatments at 1000, 2000 3000 ppm in addition to the control (tap water, 280 ppm), vermicompost treatments at 5%, 10%, 15%, and 20% in addition to the control. The results indicated that increasing level of salinity resulted in reduction in vegetative growth and flowering parameters (plant height, number of branches/plant, stem diameter, root length, fresh and dry weights of leaves and roots/plant, number of flowers /plant, as well as fresh and dry weights of flowers /plant), total chlorophylls, total carbohydrates, K⁺%, Ca²⁺%, and K⁺/Na⁺ ratio, while increased proline, Na⁺ and Cl⁻% in the plants. Catalase (CAT), superoxide dismutase (SOD), Ascorbate peroxidase (APX) enzyme activities significantly increased with elevating salinity level from 0 to 3000 ppm. Application of vermicompost with any concentration had a positive effect on vegetative growth and flowering parameters, total chlorophylls, total carbohydrates, nutrient uptake, K⁺/Na⁺ ratio, proline content, enzyme activities and reducing accumulation of Na⁺ and Cl⁻% toxic ions in leaves. Based on the results, application of vermicompost at 20% recommended for alleviating the harmful efects of salinity on Calliandra haematocephala plants irrigated with saline water at concentration up to 3000 ppm.