De novo hydroponics system efficiency for the cuttings of alfalfa (Medicago sativa L.)

The legume plant alfalfa (Medicago sativa L.) is a widely cultivated perennial forage due to its high protein content, palatability, and strong adaptability to diverse agro-ecological zones. Alfalfa is a self-incompatible cross-pollinated autotetraploid species with tetrasomic inheritance. Therefore, maintaining excellent traits through seed reproduction is a prime challenge in alfalfa. However, the cutting propagation technology could enable consistent multiplication of quality plants that are genetically identical to the parent plant. The current study aimed to develop a simple, cost-effective, reproducible, and efficient hydroponic cutting method to preserve alfalfa plants and for molecular research. In this study, alfalfa landrace ‘Wudi’ was grown in hydroponics for 30 days and used as source material for cuttings. The top, middle and bottom sections of its stem were used as cuttings. The rooting rate, root length, and stem height of the different stem sections were compared to determine the best segment for alfalfa propagation in four nutrient treatments (HM, HM + 1/500H, HM + 1/1000H and d HM + 1/2000H). After 21 days of culture, the rooting rates of all the three stem types under four cutting nutrient solutions were above 78%. The rooting rate of the middle and bottom parts in HM + 1/1000 H and HM + 1/2000 H nutrient solutions reached more than 93%, with a higher health survey score (> 4.70). In conclusion, this study developed a de novo cutting propagation method that can be used to conserve and propagate germplasm in breeding programs and research. This method is a new report on the cutting propagation of alfalfa by hydroponics, which could supplement the existing cutting propagation methods.

Effects of Node Position and Electric Conductivity of Nutrient Solution on Adventitious Rooting of Nasturtium (Tropaeolum majus L.) Cuttings

Nasturtium is a popular herbal plant, widely cultivated as culinary and medicinal plants all over the world. However, the seed propagation of nasturtium is inefficient, and in-vitro propagation is sophisticated and high-cost. In this study, the cutting propagation method was employed to produce nasturtium seedlings. We aimed to determine the optimal conditions for cutting propagation of nasturtium seedlings by investigating the effects of node position and electric conductivity (EC) of nutrient solution on the root formation of the cuttings. Cuttings from five node positions (apical bud, 2nd node, 3rd node, 4th node, and 5th node) were subjected to water and five EC (1.0, 2.0, 3.0, 4.0, and 5.0 dS m−1) treatments with a hydroponic cultivation system in a plant factory. Results showed that all cuttings rooted successfully within two weeks. The cuttings from the apical bud position rooted earliest and produced the most roots regardless of EC level. Cuttings from other node positions produced longer roots and heavier root fresh and dry weights than those from the apical bud position. The cuttings under EC of 1.0 dS m−1 had the greatest root number, the longest root length, and the heaviest root fresh and dry weights regardless of node positions. The EC of 1.0 dS m−1 is considered the best condition for nasturtium cuttings for the range of EC tested in this study, and the cuttings from all the five node positions can be used as seedling materials.

Method of Silicon Application Affects Quality of Strawberry Daughter Plants during Cutting Propagation in Hydroponic Substrate System

The beneficial effects that silicon (Si) has on plant growth as well as resistance to biotic and abiotic stresses have been well documented for many crops in recent years. However, few studies focus on the effects of Si on plant growth during the propagation stage of strawberry (Fragaria × ananassa, Duchesne). This study was conducted to investigate the optimal method for Si application during the cutting propagation of strawberry in soilless cultivation. Strawberry mother plants were supplied with Si through foliar spray, runner spray, or root drench before the cutting propagation, then half of the daughter plants in each treatment received continued Si supply through foliar spray or through root drench after the cutting propagation. The results showed that the plant height, petiole length and diameter, leaf length and width, shoot fresh and dry weights, and root fresh and dry weights were significantly increased by Si root drench both before and after the cutting propagation. Moreover, plants absorbed more Si by drench than by spray, and the absorbed Si was only able to be transported from the root to the shoot, and from the mother plant to the daughter plant. Further research found that the chlorophyll fluorescence parameter of the maximum quantum efficiency of the photosystem II (Fv/Fm) and the activities of superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase were also enhanced while catalase did not change under a high temperature stress in strawberry treated with Si before and after cutting propagation by root drench. Thus, Si application by drenching the roots during the whole propagation period is recommended to increase the quality of the strawberry daughter plants in soilless cultivation.

De novo Propagation of Alfalfa Under Hydroponics

Background: The legume plant alfalfa (Medicago sativa L.) is a widely cultivated perennial forage due to its high protein levels, palatability, and strong adaptability to diverse soil types and agro-ecological zones. This forage plant is a self-incompatible, cross-pollinated autotetraploid with tetrasomic inheritance. Therefore, maintaining excellent traits through seed reproduction is challenging in alfalfa. However, the cutting propagation technology could enable consistent multiplication of quality plants that are genetically identical to the parent plant, for use in breeding and other research applications. Most of previous alfalfa omics researches used varieties as material on omics and gene mining experiment due to poor growth consistency of cuttings by existing cutting methods, which generate genetically un-identical cuttings and thus compromise on the reliability of the results. Therefore, this study aimed to develop a simple, cost-effective, reproducible, and efficient hydroponic cutting method for the preservation of alfalfa plants and molecular research applications such as genomic, transcriptomic, and proteomic analyses. Results: Alfalfa cultivar ‘Wudi’ grown under hydroponics for 30 days was used as source material for cuttings. The top, middle and bottom sections of its stem were used as cuttings. The rooting rate, root length, and stem height of the different stem sections were compared to determine the best segment for alfalfa propagation in four nutrient solutions (HM, HM+1/500H, HM+1/1000H and d HM+1/2000H). After 21 days of culture, the rooting rates of all the three stem types under four cutting nutrient solutions were above 78%, The rooting rate of the middle and bottom parts in HM +1/1000 H and HM +1/2000 H nutrient solutions reached more than 93% with higher health survey score (>4.70). Besides, root length and stem height in these two sections was exemplary. Conclusions: This study developed a de novo cutting propagation method that can be used to conserve and propagate germplasm in breeding programs and research. This article is the first report on the cutting propagation of alfalfa by hydroponics, which could supplement the existing cutting propagation methods.