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1. Emerging investigator series: molecular mechanisms of plant salinity stress tolerance improvement by seed priming with cerium oxide nanoparticles

   https://doi.org/10.1039/D0EN00387E  

   An, Jing; Hu, Peiguang; Li, Fangjun; Wu, Honghong; Shen, Yu; White, Jason C.; Tian, Xiaoli; Li, Zhaohu; Giraldo, Juan Pablo (January 2020, Environmental Science: Nano)

   Engineered nanomaterials interfaced with plant seeds can improve stress tolerance during the vulnerable seedling stage. Herein, we investigated how priming seeds with antioxidant poly(acrylic acid)-coated cerium oxide nanoparticles (PNC) impacts cotton ( Gossypium hirsutum L.) seedling morphological, physiological, biochemical, and transcriptomic traits under salinity stress. Seeds primed with 500 mg L −1 PNC in water (24 h) and germinated under salinity stress (200 mM NaCl) retained nanoparticles in the seed coat inner tegmen, cotyledon, and root apical meristem. Seed priming with PNC significantly ( P < 0.05) increased seedling root length (56%), fresh weight (41%), and dry weight (38%), modified root anatomical structure, and increased root vitality (114%) under salt stress compared with controls (water). PNC seed priming led to a decrease in reactive oxygen species (ROS) accumulation in seedling roots (46%) and alleviated root morphological and physiological changes induced by salinity stress. Roots from exposed seeds exhibited similar Na content, significantly decreased K (6%), greater Ca (22%) and Mg content (60%) compared to controls. A total of 4779 root transcripts were differentially expressed by PNC seed priming alone relative to controls with no nanoparticles under non-saline conditions. Under salinity stress, differentially expressed genes (DEGs) in PNC seed priming treatments relative to non-nanoparticle controls were associated with ROS pathways (13) and ion homeostasis (10), indicating that ROS and conserved Ca 2+ plant signaling pathways likely play pivotal roles in PNC-induced improvement of salinity tolerance. These results provide potential unifying molecular mechanisms of nanoparticle-seed priming enhancement of plant salinity tolerance. 

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2. Growth and transcriptional response of wheat and rice to the tertiary amine BMVE

   https://doi.org/10.3389/fpls.2023.1273620  

   Dharni, Jaspinder Singh; Shi, Yu; Zhang, Chi; Petersen, Chris; Walia, Harkamal; Staswick, Paul (January 2024, Frontiers in Plant Science)

   IntroductionSeed vigor is largely a product of sound seed development, maturation processes, genetics, and storage conditions. It is a crucial factor impacting plant growth and crop yield and is negatively affected by unfavorable environmental conditions, which can include drought and heat as well as cold wet conditions. The latter leads to slow germination and increased seedling susceptibility to pathogens. Prior research has shown that a class of plant growth regulators called substituted tertiary amines (STAs) can enhance seed germination, seedling growth, and crop productivity. However, inconsistent benefits have limited STA adoption on a commercial scale MethodsWe developed a novel seed treatment protocol to evaluate the efficacy of 2-(N-methyl benzyl aminoethyl)-3-methyl butanoate (BMVE), which has shown promise as a crop seed treatment in field trials. Transcriptomic analysis of rice seedlings 24 h after BMVE treatment was done to identify the molecular basis for the improved seedling growth. The impact of BMVE on seed development was also evaluated by spraying rice panicles shortly after flower fertilization and subsequently monitoring the impact on seed traits. ResultsBMVE treatment of seeds 24 h after imbibition consistently improved wheat and rice seedling shoot and root growth in lab conditions. Treated wheat seedlings grown to maturity in a greenhouse also resulted in higher biomass than controls, though only under drought conditions. Treated seedlings had increased levels of transcripts involved in reactive oxygen species scavenging and auxin and gibberellic acid signaling. Conversely, several genes associated with increased reactive oxygen species/ROS load, abiotic stress responses, and germination hindering processes were reduced. BMVE spray increased both fresh and mature seed weights relative to the control for plants exposed to 96 h of heat stress. BMVE treatment during seed development also benefited germination and seedling growth in the next generation, under both ambient and heat stress conditions. DiscussionThe optimized experimental conditions we developed provide convincing evidence that BMVE does indeed have efficacy in plant growth enhancement. The results advance our understanding of how STAs work at the molecular level and provide insights for their practical application to improve crop growth. 

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3. Investigations into Selected Pollinator-Friendly Plant Species: Seed Lot Germination, Breaking Dormancy with Plant Hormone Priming and the Influence of Water Stress on Germination

   https://doi.org/10.3390/horticulturae12010032  

   Ermiş, Sıtkı; Amirkhani, Masoume; Loos, Michael T; Taylor, Alan G (January 2026, Horticulturae)

   Valeria, Cafaro; Cristina, Patane (Ed.)

   The lack of protocols for breaking seed dormancy, inconsistent seed quality, and abiotic stress factors such as drought impede large-scale restoration efforts of pollinator-friendly native plant species. This research explores the germination response, dormancy-breaking techniques, and water stress tolerance in selected pollinator-friendly plant species with characteristics facilitating mechanized rehabilitation protocols and biodiversity enhancement. Forty-two commercial seed lots representing seven plant families with 28 species were evaluated under two alternating temperature regimes (15/25 °C and 20/30 °C) with and without gibberellic acid (GA3) priming treatments. Six of the twenty-eight species were selected based on pollinator requirements for the monarch butterfly (Danaus plexippus L.) and further examined by priming seeds for 24 h in solutions containing GA3, kinetin (KIN), and hydrogen peroxide (H2O2), or their combinations, to evaluate their dormancy-breaking responses. The effect of water stress on seed germination was assessed in controlled chambers at soil water potentials of −1.08, −0.75, −0.13, and 0 MPa. Initial seed quality of the 42 seed lots revealed that only 62% had greater than 50% germination, while of the same 42 lots, 98% had greater than 50% viability based on the commercial seed label. The difference was largely attributed to seed dormancy. In laboratory studies of the 42 seed lots, GA3 significantly enhanced germination percentage, and reduced T50 (time to 50% germination) across most seed lots. Overall, germination was higher and faster at 20/30 °C than 15/25 °C. Priming the six selected species with 1.0 mM GA3 in 0.3% H2O2 consistently improved germination compared to the non-primed control after 14 days. Asclepias species (A. incarnata, A. syriaca, and A. tuberosa) exhibited consistently high germination across a broad moisture range of −0.75 to 0 MPa. In contrast, Echinacea purpurea required high moisture levels (−0.13 to 0 MPa) for optimal germination. Monarda fistulosa and Rudbeckia hirta showed their best performance under moderate moisture conditions (−0.13 MPa). Collectively, the use of GA3 priming to break physiological seed dormancy offers a promising approach to enhance germination and improving the establishment potential of native pollinator species in restoration programs. 

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4. Seed Cryopreservation, Germination, and Micropropagation of Eastern Turkeybeard, Xerophyllum asphodeloides (L.) Nutt.: A Threatened Species from the Southeastern United States

   https://doi.org/10.3390/plants10071462  

   Issac, Michelle; Kuriakose, Princy; Leung, Stacie; Costa, Alex B.; Johnson, Shannon; Bucalo, Kylie; Stober, Jonathan M.; Determann, Ron O.; Rogers, Will L.; Cruse-Sanders, Jenifer M.; et al (July 2021, Plants)

   null (Ed.)

   Xerophyllum asphodeloides (Xerophyllaceae), known as eastern turkeybeard, is an herbaceous perennial found in eastern North America. Due to decline and destruction of its habitat, several states rank X. asphodeloides as “Imperiled” to “Critically Imperiled”. Protocols for seed cryopreservation, in vitro germination, sustainable shoot micropropagation, shoot establishment in soil, and seed germination are presented. Seeds from two tested sources were viable after 20 months of cryopreservation. Germination of isolated embryos in vitro was necessary to overcome strong seed dormancy. Shoot multiplication and elongation occurred on ½ MS medium without PGRs. Shoots rooted in vitro without PGRs or with 0.5 mg/L NAA or after NAA rooting powder treatment and placement in potting mix. When planted in wet, peaty soil mixes, shoots grew for two months and then declined. When planted in a drier planting mix containing aged bark, most plants continued growth. In the field, plant survival was 73% after three growing seasons. Safeguarding this species both ex situ and in situ is possible and offers a successful approach to conservation. Whole seeds germinated after double dormancy was overcome by incubation under warm moist conditions for 12 weeks followed by 12 weeks cold at 4 °C and then warm. 

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5. Switchgrass-associated soil microbes have subtle but distinct effects on germination vs. growth under drought

   https://doi.org/10.1016/j.rhisph.2026.101301  

   Ulbrich, Tayler C; Bell-Dereske, Lukas; Ervin, Harry; Hilborn, Shanna; Evans, Sarah E (June 2026, Rhizosphere)

   Soil microbial communities can play a large role in plant fitness, including plants' response to drought. How microbes mediate drought response may also differ across the plants' life stage, but studies rarely study causal effects of microbes on plant fitness at multiple stages. We conducted a greenhouse experiment on switchgrass (Panicum virgatum L.) to investigate how microbial presence (sterile bulk vs. live bulk soils) and microbial source (communities from bulk vs. rhizosphere soil) affect germination and seedling growth (life-stage) during drought. We also investigated how drought and life-stage alter the assembly of the inoculated communities. Both drought conditions and the absence of microbes reduced germination (49% and 50% fewer seedlings, respectively, p < 0.05), but there were few effects of microbial presence on older seedlings. In addition, microbial source had no effect on the evaluated plant traits, but interestingly, the initially similar bulk and rhizosphere communities became compositionally distinct after 34 days with germinating seeds, but not with seedlings. Therefore, it may be that the plants did respond to microbial source through changes in seed or root exudates, and calls for further study. Finally, while sometimes microbes did benefit plants under drought, we did not find evidence that they are especially beneficial in this condition. We suggest that microbes’ effects differ across plant life stage, and may be both positive and negative. Further research should advance understanding of plant stress tolerance within a framework of plant-microbiome co-development. 

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