Joseph Ojonugwa Obaje

Miscanthus is a leading lignocellulosic crop for low‐carbon bioenergy systems, yet its deployment is limited by establishment challenges, early‐stage growth variability and performance constraints on marginal or contaminated soils. Plant growth regulators (PGRs), biostimulants (BS), and growth‐promoting microorganisms (GPMs) have been proposed to enhance establishment and stress tolerance, but evidence remains fragmented across species, environments, and application strategies. This scoping review systematically mapped peer‐reviewed experimental studies published between 2010 and 2025, following PRISMA‐ScR guidelines. Searches across Scopus, Web of Science and PubMed identified 252 records, of which 29 met the inclusion criteria after screening and deduplication. Data extraction captured species, planting material, growth environment, soil context, intervention class, application strategy, outcome domains and effect direction. The evidence base was dominated by Miscanthus × giganteus (52% of studies), rhizome‐based planting material, controlled environments and short‐duration experiments. GPMs and BS were the most frequently tested interventions, occurring in approximately 93% of studies. Growth outcomes were assessed in 26 of the 29 studies and were predominantly positive. Across studies reporting comparable data, the best‐performing treatments produced increases in above‐ground biomass ranging from approximately 15% to 200% relative to controls, while shoot‐height responses ranged from negligible effects to increases exceeding 100%. Photosynthesis‐related parameters, including photosynthetic rate and chlorophyll, also showed variable but generally positive responses. However, physiological and remediation outcomes were less consistently assessed and exhibited greater heterogeneity. The review highlights substantial methodological clustering and identifies critical gaps in long‐term field studies, seed‐ and plug‐based systems, and integrated physiological–remediation assessments needed to support scalable, net‐zero‐aligned Miscanthus deployment.

Seed‐based propagation of Miscanthus offers scalable potential for expanding bioenergy production; however, early establishment remains a major limitation due to poor plug vigour and variable field performance. This study evaluated the influence of selected biostimulants and phytohormones on germination, growth, biomass allocation, and photosynthetic efficiency in three Miscanthus seed‐based hybrids (GNT3, GNT14, and GNT43) grown under controlled glasshouse conditions. Five treatments were applied—Liquid Ice, MicroPull, indole‐3‐acetic acid (IAA), 1‐naphthaleneacetic acid (NAA), and an untreated control—during the plug phase. ANOVA revealed strong hybrid‐dependent responses. Liquid Ice and IAA significantly enhanced stem elongation, total biomass, and photosynthetic capacity (rETR _max , I _k ), while also shifting biomass allocation toward above‐ground structures. MicroPull, in contrast, delayed germination and reduced photosynthetic parameters in certain hybrids, though it improved initial quantum yield (α) at low light intensities. Enhanced root and bud development under Liquid Ice and NAA treatments suggests improved plug vigour and potential for stronger field establishment. The observed morphological and physiological modifications indicate that targeted PGR use can simultaneously enhance early growth, resource allocation, and photosynthetic performance in Miscanthus . Additionally, the findings highlight the importance of hybrid‐specific optimization of PGR regimes to improve plug quality and establishment success, advancing the scalability of seed‐based Miscanthus systems for sustainable bioenergy production and net‐zero carbon targets.

Elevated atmospheric CO₂ is known to alter plant physiology, yet its specific effects on nutrient-rich leafy vegetables remain insufficiently quantified. This study aimed to examine how eCO₂ influences yield and nutritional quality in kale (Brassica oleracea) and spinach (Spinacia oleracea) through the first meta-analysis focused exclusively on these crops. Following the Collaboration for Environmental Evidence (CEE) guidelines, we systematically reviewed eligible studies and conducted a random-effects meta-analysis to evaluate overall and subgroup responses based on CO₂ concentration, crop type and exposure duration. Effect sizes were calculated using Hedges’ g with 95% confidence intervals. The analysis showed that eCO₂ significantly increased biomass in spinach (g = 1.21) and kale (g = 0.97). However, protein content declined in both crops (spinach: g = −0.76; kale: g = −0.61), and mineral concentrations, particularly calcium and magnesium, were reduced, with spinach exhibiting stronger nutrient losses overall. The variability in response across different CO₂ concentrations and exposure times further underscores the complexity of eCO₂ effects. These results highlight a trade-off between productivity and nutritional quality under future CO₂ conditions. Addressing this challenge will require strategies such as targeted breeding programmes, biofortification, precision agriculture and improved sustainable agricultural practices to maintain nutrient density. This research provides critical evidence for policymakers and scientists to design sustainable food systems that safeguard public health in a changing climate.

The meta-analysis examines the effects of eCO₂ on the growth, yield, and nutritional composition of two widely consumed leafy vegetables: kale (Brassica oleracea) and spinach (Spinacia oleracea). Following the Collaboration for Environmental Evidence (CEE) guidelines, we systematically reviewed studies that reported on the impacts of eCO₂ on these crops and conducted a meta-analysis to quantify the overall as well as sub-group responses via moderator analyses. A random-effects model was used to calculate effect sizes (Hedges' g), and confidence intervals (CI) were set at 95%. Our results reveal that eCO₂ significantly increased the biomass of spinach (g = 1.21, p < 0.01, CI [0.88, 1.54]) and kale (g = 0.97, p < 0.05, CI [0.65, 1.29]). However, the analysis also detected a significant decrease in protein content in both crops under eCO₂ conditions (spinach: g = -0.76, p = 0.03, CI [-1.10, -0.42]; kale: g = -0.61, p = 0.04, CI [-0.95, -0.27]). Additionally, calcium and magnesium concentrations declined in kale (g = -0.55, p = 0.05, CI [-0.89, -0.21]), and spinach showed a stronger reduction in nutrient content overall. The variability in response across different CO2 concentrations and exposure times further underscores the complexity of eCO2 effects. These findings suggest that while eCO₂ may enhance crop yields, it also leads to a dilution of essential nutrients, raising concerns about the trade-offs between productivity and nutritional quality. The study concludes that targeted breeding programmes, strategic precision agriculture, sustainable agricultural practices and policy interventions will be critical in mitigating the negative nutritional effects of eCO₂ to ensure food security in a changing climate.

: Plants exploit developmental plasticity to adapt their growth and development to prevailing environmental cues. This developmental plasticity provides a selective and competitive advantage in nature but is obstructive during large-scale, intensive agricultural practices since economically important traits (including vegetative growth and flowering time) can widely vary depending on local environmental conditions. This prevents accurate prediction of harvesting times and produces a variable crop. We sought to restrict developmental plasticity by manipulating signalling systems that govern plants’ responses to environmental signals. Mathematical modelling of plant growth and development predicted a reduction in plant responses to changing environments when circadian and light signaling pathways were manipulated. We tested this hypothesis by utilising a constitutively-active allele of the plant photoreceptor phytochromeB, along with disruption of the circadian system via mutation of EARLY FLOWERING3. We found that the combination of these manipulations produced plants that are less responsive to light and temperature cues. These engineered plants have uniform vegetative growth and flowering time and demonstrate how developmental plasticity can be limited whilst maintaining plant productivity. This has significant implications for future agriculture in both open fields and controlled environments.

Seed dormancy is a phenomenon that prevents seeds from growing during adverse conditions. A number of factors may be responsible for this phenomenon, but one very common reason is the hardness of the seed coat as in the case of Date palm. This research was conducted to determine the effect of different priming methods on the rate of germination of date palm seeds. The treatments include cold water, hot water, H2SO4 and control in a cross randomized design. For the cold water treatment seeds were soaked for either 24, 48 or 72 hours; for the hot water treatment they were soaked for either 5, 10, or 15 minutes; and for the acid treatment they were soaked in 25 %, 50 % or 100 % of H2SO4 for 5 minutes. Twenty (20) seeds were selected for each treatment to carry out the germination experiment using moist absorbent paper. Data for germination rate was collected at 1, 2 and 3 weeks after planting (WAP). An optimal germination rate of 83% was observed at 3 WAP for the hot water treatment for 5 minutes. From this research, it can be concluded that priming generally increased the rate of germination of date palm seeds.