Salt-affected soils severely decrease agricultural productivity by reducing the uptake of water and nutrients by plants, toxic ions accumulation and soil structure degradation. The sustainable synthesis of hybrid nanospheres through green approaches has emerged as an effective strategy to enhance crop productivity and improve tolerance to abiotic stress. However, the defensive functions and fundamental mechanisms of green synthesized calcium-doped carbon nano-spheres in protecting maize against salt stress remain elusive. Thus, calcium-doped carbon nanospheres were innovatively synthesized by doping calcium oxide nanoparticles (CaO NPs) with lignin nanoparticles (LNPs) which were further analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), Energy Dispersive X-Ray Spectroscopy (EDX), Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). These analyses validated the successful doping of Ca@CNs, elucidating the purity and morphology of the hybrid nanospheres. More importantly, the effect of Ca@CNs on maize plants under NaCl stress, unreported so far, was examined. Results of the current study showed that treating salt-stressed plants with Ca@CNs significantly improved maize growth and biomass accumulation by enhanced absorption of minerals and improved photosynthetic efficiency. Furthermore, Ca@CNs application has also reduced NaCl-induced oxidative damage by enhancing antioxidant defense mechanisms and maintaining cellular integrity, resulting in improved resistance to salt stress. Moreover, Ca@CNs substantially up-regulated the expression of salt-tolerant genes ZmNHX3, CBL, ZmHKT1, and MAPK1, as well as genes involved in lignin biosynthesis such as 4CL2, PAL1, CCR, and COMT, in both shoot and root tissues. Conversely, the expression levels of genes Zm00001d003114, Zm0001d026638, Zm00001d028582 and Zm00001d051069 associated with Ca2 +-responsive SOS3 pathway were all down-regulated under NaCl treatment, while up-regulated in the presence of Ca@CNs along with NaCl. The observed changes in transcript levels of these genes highlight the potential of Ca@CNs in alleviating NaCl toxicity. These results demonstrated that the green synthetic Ca@CNs can significantly alleviate salt stress and promote plant growth in saline environments, which will provide a new strategy for the utilization of nanoparticles in agriculture to maintain sustainable agriculture and improve crop yield.

Seed priming and plant growth-promoting bacteria (PGPB) may alleviate salt stress effects. We exposed a salt-sensitive variety of melon to salinity following seed priming with NaCl and inoculation with Bacillus. Given the sensitivity of photosystem II (PSII) to salt stress, we utilized dark- and light-adapted chlorophyll fluorescence alongside analysis of leaf stomatal conductance of water vapour (Gsw). Priming increased total seed germination by 15.5% under salt-stress. NaCl priming with Bacillus inoculation (PB) increased total leaf area (LA) by 45% under control and 15% under stress. Under the control condition, priming (P) reduced membrane permeability (RMP) by 36% and PB by 55%, while under stress Bacillus (BS) reduced RMP by 10%. Although Bacillus inoculation (B) and priming (P) treatments did not show significant effects on some PSII efficiency parameters (FV/FM, ABS/RC, PIABS, FM), the BS treatment induced a significantly higher quantum efficiency of PSII (Phi PSII) and increased Gsw by 159% in the final week of the experiment. The BS treatment reduced electron transport rate per reaction center (ETO/RC) by 10% in comparison to the salt treatment, which showed less reaction centre damage. Bacillus inoculation and seed priming treatment under the stressed condition (PBS) induced an increase in electron transport rate of 40%. Salt stress started to show significant effects on PSII after 12 days, and adversely impacted all morphological and photosynthetic parameters after 22 days. Salt priming and PGPB mitigated the negative impacts of salt stress and may serve as effective tools in future-proofing saline agriculture.

To thrive as a successful weed in natural pastures, a plant must have not only highly competitive ability, but also the resilience to endure environmental stress and rapidly reclaim space once those stressors diminish and the other non-stress-tolerant plants die. Acanthostyles buniifolius [(Hook. ex Hook. & Arn.) R.M.King & H.Rob.], known as chirca, is a widely spread weed in South American natural pastures. It is known for its remarkable ability to withstand environmental stress and flourish in environments with prevalent stressors. The study evaluated the memory effect of water stress (drought) in chirca plants. The experiment was conducted in a greenhouse in a randomized block design with three replications. Treatments included Control = control plants without water deficit kept at 100% of the soil water-holding capacity (WHC); Primed plants = plants that were primed with water stress at 141 days after emergence (DAE) and received recurrent stress at 164 DAE; Na & iuml;ve plants: plants that only experienced water stress at 164 DAE. To reach water stress, plants were not watered until the soil reached 15% of the soil's WHC, which occurred ten days after water suppression in the priming stress and nine days after water suppression in the second stress. During periods without restriction, the pots were watered daily at 100% of the WHC. Primed plants exposed to water deficit better-maintained water status compared to the na & iuml;ve plants; glycine betaine is an important defense mechanism against water deficit in chirca; na & iuml;ve plants have a higher concentration of proline than plants under recurrent stress, demonstrating the greater need for protection against oxidative damage and needs greater osmotic regulation. Recurrent water deficits can prepare chirca plants for future drought events. These results show that chirca is a very adaptative weed and may become a greater threat to pastures in South America due to climate change, especially if drought becomes more frequent and severe.

Hydropriming rice seeds effectively improve the germination percentage, shortens the germination period, and promotes seedling growth. The impact of seed hydropriming is to speed up growth under dry soil conditions, thereby avoiding drought damage. This study analyzes the effect of hydropriming on morpho-physiological changes in the water uptake of rice seeds using Kasalath and Nipponbare under water-deficit conditions. Upon exposure to osmotic stress, both varieties showed delays in the time to reach germination. In addition, all germination phases exhibited reductions in the activity of alpha-amylase and total soluble sugar by osmotic stress; however, in all germination phases of the hydroprimed seeds, the activity and contents of those were significantly increased, resulting in increased size of the coleoptile, plumule, and radicle. In hydroprimed seeds, Kasalath was superior to Nipponbare in the ratio of the water-deficit-to-well-watered conditions for all traits related to germination, which may have been attributable to hydropriming having a greater effect on Kasalath. Interestingly, Primed Kasalath had a lower level of alpha-amylase, despite the having a higher content of total soluble sugars than primed Nipponbare.

Rising soil salinity hinders global crop yields by damaging plants, threatening food security. This study assessed glycine betaine (GB) application methods (foliar, seed priming) and salinity levels (0, 60, 120, 180 mM NaCl) on quinoa over two seasons. For ionic homeostasis, seed priming improved K+/Na+ ratio by 10-15 % at low salinity, while foliar was 12-18 % more effective at high salinity. Seed priming remained 10-15 % superior for roots. Foliar enhanced osmolytes by 12-16 % at low salinity, but seed priming had 16-20 % stronger effects at high salinity. Under low salinity, seed priming provided 8-12 % better protection for chlorophyll and photosynthetic efficiency. At high salinity, foliar GB was 10-15 % best for chlorophyll, seed priming 12-16 % more effective for photosynthetic rate, and foliar GB had an 8-10 % edge for Fv/Fm. GB reduced MDA by 8-12 % at low salinity, 12-16 % with seed priming at medium salinity in 2023, and 16-20 % with foliar in 2024. At high salinity, seed priming decreased MDA by 20-25 % in 2023, while foliar showed a 24-28 % reduction. GB moderately enhanced antioxidants by 8-12 % under mild stress, but seed priming and foliar differed 16-20 % in effectiveness under severe stress. For nutrients, seed priming had a 12-16 % advantage for nitrogen at medium salinity in 2023, while foliar excelled with a 16-20 % increase under high stress in 2024. Seed priming was 16-20 % better for phosphorus at high salinity in 2023, but foliar had 20-25 % superior results in 2024. These findings highlight complex plant responses to GB-salinity interactions, with optimal methods varying by trait, stress level, and environmental conditions. (c) 2024 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Soil organic carbon (SOC) rapidly accumulates during ecosystem primary succession in glacier foreland. This makes it an ideal model for studying soil carbon sequestration and stabilization, which are urgently needed to mitigate climate change. Here, we investigated SOC dynamics in the Kuoqionggangri glacier foreland on the Tibetan Plateau. The study area along a deglaciation chronosequence of 170-year comprising three ecosystem succession stages, including barren ground, herb steppe, and legume steppe. We quantified amino sugars, lignin phenols, and relative expression of genes associated with carbon degradation to assess the contributions of microbial and plant residues to SOC, and used FT-ICR mass spectroscopy to analyze the composition of dissolved organic matter. We found that herbal plant colonization increased SOC by enhancing ecosystem gross primary productivity, while subsequent legumes development decreased SOC, due to increased ecosystem respiration from labile organic carbon inputs. Plant residues were a greater contributor to SOC than microbial residues in the vegetated soils, but they were susceptible to microbial degradation compared to the more persistent and continuously accumulating microbial residues. Our findings revealed the organic carbon accumulation and stabilization process in early soil development, which provides mechanism insights into carbon sequestration during ecosystem restoration under climate change.

Soil salinity is a big environmental issue affecting crop production. Although seed nanopriming has been widely used to improve seed germination and seedling growth under salinity, our knowledge about the underlying mechanisms is still insufficient. Herein, we newly synthesized selenium-doped carbon dots nanoparticles coated with poly acrylic acid (poly acrylic acid coated selenium doped carbon dots, PAA@Se-CDs) and used it to prime seeds of rapeseeds. The TEM (transmission electron microscope) size and zeta potential of PAA@Se-CDs are 3.8 +/- 0.2 nm and- 30 mV, respectively. After 8 h priming, the PAA@Se-CDs nanoparticles were detected in the seed compartments (seed coat, cotyledon, and radicle), while no such signals were detected in the NNP (no nanoparticle control) group (SeO2 was used as the NNP). Nanopriming with PAA@Se-CDs nanoparticles increased rapeseeds germination (20%) and seedling fresh weight (161%) under saline conditions compared to NNP control. PAA@Se-CDs nanopriming significantly enhanced endo-b-mannanase activities (255% increase, 21.55 mu mol h- 1 g-1 vs. 6.06 mu mol h-1 g-1, at DAS 1 (DAS, days after sowing)), total soluble sugar (33.63 mg g-1 FW (fresh weight) vs. 20.23 mg g-1 FW) and protein contents (1.96 mu g g-1 FW vs. 1.0 mu g g-1 FW) to support the growth of germinating seedlings of rapeseeds under salt stress, in comparison with NNP control. The respiration rate and ATP content were increased by 76% and 607%, respectively. The oxidative damage of salinity due to the over- accumulation of reactive oxygen species (ROS) was alleviated by PAA@Se-CDs nanopriming by increasing the antioxidant enzyme activities (SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase)). Another mechanism behind PAA@Se-CDs nanopriming improving rapeseeds salt tolerance at seedling stage was reducing sodium (Na*) accumulation and improving potassium (K*) retention, hence increasing the K*/Na* ratio under saline conditions. Overall, our results not only showed that seed nanopriming with PAA@Se-CDs could be a good approach to improve salt tolerance, but also add more knowledge to the mechanism behind nanopriming-improved plant salt tolerance at germination and early seedling growth stage. (c) 2024 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC- ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Soil salinization poses a serious threat to sustainable ecological agricultural development. Most crops are susceptible to salt stress during the growth phase of seed germination and seedling emergence. Seed priming could activate the pre-germination metabolic processes, thereby improving seed germination and seedling growth under abiotic stress conditions. Moreover, multi-walled carbon nanotube (MWCNT), as an important class of carbon nanotubes, has been applied to promote plant growth by enhancing antioxidant defense systems and photosynthetic performance during the seedling stage. In this way, it is worth exploring the combination of pre-germination and post-germination treatments to reduce the damage of salt stress to crops. Therefore, in this study, rice seeds were firstly exposed to UV-B tube in a UV irradiation box for priming treatment (90 min). After emergence, the seedlings were transplanted into pots containing 150 mg L-1 MWCNT and 200 mM NaCl to evaluate the positive effects of nanomaterial on the growth of rice. The results demonstrated that after 28 days of salt stress exposure, the combination of UV-B priming and MWCNT significantly improved the growth performance of rice and minimized the adverse effects of salt stress, as compared with the single UV-B priming or MWCNT treatment, increasing biomass accumulation and the contents of osmoregulation substances, modulating antioxidant enzyme system, improving photosynthetic performance. This study suggested that the integration of seed priming with UV-B and soil application of MWCNT enhanced antioxidant capacity, which might increase photosynthesis and biomass accumulation, thereby improving the salt tolerance of rice.

Plants respond to complex blends of above- and below-ground volatile organic compounds (VOCs) emitted by neighboring plants. These responses often involve priming (i.e., preparation) or induction (i.e., increase) of defenses by receiver plants upon exposure to VOCs released by herbivore-damaged neighboring emitters. However, recent work has shown that induction of VOC emissions by herbivory is modulated by abiotic factors, potentially affecting plant-plant signaling. We tested the effect of soil salinization on the induction of VOC emissions in wild cotton (Gossypium hirsutum) due to leaf damage and its consequences for the induction of defenses in neighboring plants. To this end, we performed a greenhouse factorial experiment where emitter plants were subjected to augmented soil salinity (vs. ambient salinity) and within each group emitter plants were subsequently exposed to simulated caterpillar damage (mechanical leaf damage treated with Spodoptera frugiperda oral secretion) or no damage (control). After 48 h of exposure, we collected VOCs released by emitter plants and then damaged the receivers and collected their leaves to measure levels of chemical defenses (terpenoid aldehydes of known insecticidal effects). We found an interaction between leaf damage and salinization for two groups of VOCs released by emitters (sesquiterpenes and other aromatic compounds), whereby damaged receivers had higher emissions than control plants under ambient but not salinized soil conditions. We also found that, upon being damaged, receiver plants exposed to damaged emitters exhibited a significantly higher concentration of heliocides (but not gossypol) than control plants. However, salinization did not alter this VOC exposure effect on receiver induced responses to damage. Overall, we show that exposure to induced VOC emissions from damaged plants magnifies the induction of chemical defenses due to leaf damage in neighboring individuals and that this is not contingent on the level of soil salinity despite the latter's effect on VOC induction.

Plant-parasitic nematodes pose a significant threat to finger millet crops, potentially causing yield reduction of up to 70%. Extracts derived from finger millet varieties contain potent bioactive compounds that can mitigate nematode damage and promote plant growth. This study aimed at isolating and characterizing bioactive compounds from the finger millet varieties Ikhulule, Okhale-1, and U-15; evaluating the impact of Ikhulule and U-15 extracts on the mortality of the root lesion nematode Pratylenchus vandenbergae; assessing the growth promotion effects of Ikhulule and U-15 extracts on the finger millet variety Okhale-1; and determining the efficacy of these extracts in managing plant-parasitic nematodes under greenhouse conditions. Extracts were obtained from both leaves and roots and tested in vitro for nematode mortality and in vivo for growth promotion and nematode control. The results showed that finger millet extracts exhibited strong nematicidal properties in vitro, achieving a mortality rate of up to 98% against P. vandenbergae nematodes. Applying these extracts to finger millet shoots significantly reduced nematode populations in both soil and roots and decreased the reproductive factor to below one (1), indicating an effective nematode control. The study attributes the enhanced nematicidal effects of finger millet extracts to their bioactive compounds, particularly dodecanoic acid, phytol, 1,1,4a-trimethyl-6-decahydro naphthalene, 2,3-dihydro-benzofuran, 2-methoxy-4-vinylphenol and ethyl ester, and hexadecanoic acid. These findings suggest that finger millet-derived extracts offer a natural solution for nematode management and broader agronomic benefits, ultimately contributing to overall plant health and productivity.