An enhanced drought-tolerant method using SA-loaded PAMPS polymer materials applied on tobacco pelleted seeds

Seed enhancement technologies for sustainable dryland restoration: Coating and scarification

High temperatures, soil salinity, a lack of available water, loose soils with reduced water holding, and low soil fertility are obstacles to restoration efforts in degraded drylands and desert ecosystems. Improved soil physical and chemical properties, seed germination and seedling recruitment, and plant growth are all proposed as outcomes of seed enhancement technologies (SETs). Seed priming, seed coating, and seed scarification are three SETs' methods for promoting seed germination and subsequent plant development under unfavorable environmental conditions. Various subtypes can be further classified within these three broad groups. The goals of this review are to (1) develop a general classification of coating and scarification SETs, (2) facilitate the decision-making process to adopt suitable SETs for arid lands environments, and (3) highlight the benefits of coating and scarification SETs in overcoming biotic and abiotic challenges in ecological restoring degraded dryland. For rehabilitating degraded lands and restoring drylands, it is recommended to 1) optimize SETs that have been used effectively for a long time, particularly those associated with seed physiological enhancement and seed microenvironment, 2) integrate coating and scarification to overcome different biotic and abiotic constraints, and 3) apply SET(s) to a mixture of seeds from various species and sizes. However, more research should be conducted on developing SETs for large-scale use to provide the required seed tonnages for dryland restoration.

Modular stimuli-responsive hydrogel sealants for early gastrointestinal leak detection and containment

Millions of patients every year undergo gastrointestinal surgery. While often lifesaving, sutured and stapled reconnections leak in around 10% of cases. Currently, surgeons rely on the monitoring of surrogate markers and clinical symptoms, which often lack sensitivity and specificity, hence only offering late-stage detection of fully developed leaks. Here, we present a holistic solution in the form of a modular, intelligent suture support sealant patch capable of containing and detecting leaks early. The pH and/or enzyme-responsive triggerable sensing elements can be read out by point-of-need ultrasound imaging. We demonstrate reliable detection of the breaching of sutures, in as little as 3 hours in intestinal leak scenarios and 15 minutes in gastric leak conditions. This technology paves the way for next-generation suture support materials that seal and offer disambiguation in cases of anastomotic leaks based on point-of-need monitoring, without reliance on complex electronics or bulky (bio)electronic implantables.

Superabsorbent Polymer Seed Coating Reduces Leaching of Fungicide but Does Not Alter Their Effectiveness in Suppressing Pathogen Infestation

Superabsorbent polymers (SAPs) applied to soil have been recognized as water reservoirs that allow plants to cope with periods of drought. Their application as a seed coat makes water available directly to the seeds during their germination and early growth phase, but on the other hand, it can affect the efficiency of plant protection substances used in seed dressing. In our experiments, we evaluated the effect of seed coating with SAP on fungicide leaching and changes in their effectiveness in suppressing Fusarium culmorum infestation. Leaching of fungicide from wheat seeds coated with SAP after fungicide dressing, as measured by the inhibition test of mycelium growth under in vitro conditions, was reduced by 14.2-15.8% compared to seeds without SAP coating. Germination of maize seeds and growth of juvenile plants in artificially infected soil did not differ significantly between seeds dressed with fungicide alone and seeds treated with SAP and fungicide. In addition, plants from the seeds coated with SAP alone grew significantly better compared to untreated seeds. Real-time PCR also confirmed this trend by measuring the amount of pathogen DNA in plant tissue. Winter wheat was less tolerant to F. culmorum infection and without fungicide dressing, the seeds were unable to germinate under strong pathogen attack. In the case of milder infection, similar results were observed as in the case of maize seeds.

Seed encrusting with salicylic acid: A novel approach to improve establishment of grass species in ecological restoration

To achieve global ambitions in large scale ecological restoration, there is a need for approaches that improve the efficiency of seed-based interventions, particularly in overcoming the bottleneck in the transition from germination to seedling establishment. In this study, we tested a novel seed-based application of the plant stress modulator compound salicylic acid as a means to reduce seedling losses in the seed-to-seedling phase. Seed coating technology (encrusting) was developed as a precursor for optimising field sowing for three grass species commonly used in restoration programs, Austrostipa scabra, Microlaena stipoides, and Rytidosperma geniculatum. Salicylic acid (SA, 0.1mM) was delivered to seeds via imbibition and seed encrusting. The effects of SA on seed germination were examined under controlled water-limited conditions (drought resilience) in laboratory setting and on seed germination, seedling emergence, seedling growth and plant survival in field conditions. Salicylic acid did not impact germination under water stress in controlled laboratory conditions and did not affect seedling emergence in the field. However, seedling survival and growth were improved in plants grown from SA treated seeds (imbibed and encrusted) under field conditions. When SA delivery methods of imbibing and coating were compared, there was no significant difference in survival and growth, showing that seed coating has potential to deliver SA. Effect of intraspecific competition as a result of seedling density was also considered. Seedling survival over the dry summer season was more than double at low seedling density (40 plants/m²) compared to high seedling density (380 plants/m²). Overall, adjustment of seeding rate according to expected emergence combined with the use of salicylic acid via coating could improve seed use efficiency in seed-based restoration.

Optimising seed processing techniques to improve germination and sowability of native grasses for ecological restoration

Grasslands across the globe are undergoing expansive degradation due to human impacts and climate change. If restoration of degraded native grassland is to be achieved at the scale now required, cost-effective means for seed-based establishment of grass species is crucial. However, grass seeds present numerous challenges associated with handling and germination performance that must be overcome to improve the efficiency of seeding. Previous research has demonstrated that complete removal of the palea and lemma (husk) maximises germination performance, hence we investigated the effects of complete husk removal on seed handling and germination of four temperate Australian grass species. Three techniques were tested to remove the husk - manual cleaning, flaming or acid digestion (the latter two followed by a manual cleaning step); these techniques were refined and adapted to the selected species, and germination responses were compared. The complete removal of the husk improved seed handling and sowability for all species. Germination was improved in Microlaena stipoides by 19% and in Rytidosperma geniculatum by 11%. Of the husk removal methods tested, flaming was detrimental to seed germination and fatal for one species (R. geniculatum). Compared to manual cleaning, sulphuric acid improved the overall efficacy of the cleaning procedure and increased germination speed (T50) in Austrostipa scabra, Chloris truncata and M. stipoides, and improved final germination in R. geniculatum by 13%. The seed processing methods developed and tested in the present study can be applied to grass species that present similar handling and germination performance impediments. These and other technological developments (seed coating and precision sowing) will facilitate more efficient grassland restoration at large scale.

Seed Pelleting with Calcium Peroxide Improves Crop Establishment of Direct-seeded Rice under Waterlogging Conditions

Poor crop establishment of direct-seeded rice (DSR) is one of the major constraints to wide adoption of DSR, particularly in areas prone to flooding after sowing or where fields are not level. Seed pelleting is an effective, practical and facile technique to enhance crop establishment under unfavorable environmental conditions. To evaluate the effects of seed pelleting on rice germination, seedling growth and associated metabolic events under waterlogging stress, various seed pelleting treatments including formulae, pelleting times (the weight ratio of pelleting agents: rice seeds = 1:1~7:1 (w/w) and CaO₂ contents were tested in series of experiments. Naked seeds were maintained for comparison as a control. Pelleting treatments with CaO₂ significantly increased seed germination and seedling growth of DSR under waterlogging conditions compared with pelleted seeds without CaO₂ and naked seeds. The optimum weight ratios of CaO₂ to dry seeds were found to be in the range of 0.6:1–1:1 based on seed germination and seedling growth performance under waterlogging conditions. Under waterlogging conditions, high seed germination percentage and vigorous seedling growth of DSR due to seed pelleting with CaO₂ was associated with an increase in α-amylase activity, but decrease in alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) activities in pelleted seeds.