BackgroundLow soil temperature and its fluctuation can negatively impact the growth of seedlings. The district of Cooch Behar (India), belonging to the Cwa zone (according to Koppen's classification), receives several cold waves during winter. Our previous study demonstrated that a constant temperature of 20 degrees C (chilling but not freezing) can cause a loss in the vigor of tomatoes. Since the temperature of the soil is not uniform throughout the day, we hypothesized that the duration of cold exposure can have variable effects on seed vigor.ResultsIt was observed that increasing the duration of cold stress can slow down the germination process and reduce vigor. This was due to the cold-mediated damage to cell membranes (due to dehydration) which caused electrolyte leakage and reduced levels of glutathione reductase. In this regard, biopriming seeds with microbes that produce exopolysaccharide (EPS) can be useful as it can form a protective layer on the seeds. Indigenous EPS-producing bacteria, Bacillus, Phytobacter and Priestia sp., were used for biopriming. Priestia and Phytobacter sp. not only reduced the electrolyte leakage but also increased the levels of antioxidant genes. This improved the germination speed and vigor. In a field trial, the rhizosphere of the seedlings pretreated with bioinoculants displayed a reduced thermal fluctuation compared with the untreated seeds.ConclusionThe seedlings treated with bioinoculants grew faster in soil in spite of low soil temperature. This can reduce the nursery time of seedlings. (c) 2025 Society of Chemical Industry.

Biochar (BC), a charred organic material produced through pyrolysis, has emerged as a promising and an environmentally friendly agro-strategy. This study investigated its potential to mitigate the impacts of global climate change on maize cultivation, specifically focusing on temperature stress tolerance. The research examined how the source material of biochar influences key plant stress mechanisms, including antioxidant enzymes and heat shock proteins (HSPs). To achieve this objective, the study evaluated the effects of biochar derived from three distinct sources-apple orchard pruning waste (PWBC), urban waste (UWBC), and animal manure (AMBC)-on maize plants grown under controlled conditions. A completely randomized factorial design with three replications was employed. Each biochar type was applied at a rate of 4% (w/w) to the soil. The physiological responses of maize plants were assessed under normal (25 degrees C), low (4 degrees C), and high (48 degrees C) temperature conditions. Lipid peroxidation (indicator of oxidative stress), soluble protein content, activity of antioxidant enzymes, and expression levels of HSP70 and HSP90 were analyzed. The results revealed that PWBC application, compared to without BC, significantly reduced malondialdehyde (MDA) accumulation by 38% under both low- and high-temperature stress, suggesting its potential in alleviating oxidative damage. UWBC treatment, on the other hand, demonstrated a pronounced effect on protein metabolism, with soluble protein content increasing by 16% at low and 26% at high temperature. Furthermore, biochar application under temperature stress increased antioxidant enzyme activity, thereby mitigating oxidative stress, with UWBC proving to be the most effective in stimulating antioxidant responses. The expression levels of HSP70 and HSP90 were also significantly regulated by biochar application. UWBC and AMBC treatments displayed the most pronounced effects, with HSP70 expression increasing by 4.6- and 1.6-fold, and HSP90 expression by 8.2- and 45.4-fold, respectively, particularly under high-temperature stress, compared to without BC. These findings indicate that the reduction of lipid peroxidation, activation of antioxidant defense mechanisms, and regulation of HSP70 and HSP90 transcriptional and translational in maize plants under temperature stress vary based on the source material of the biochar. Long-term studies assessing plant yield and quality are recommended to validate these findings further.

Spring low-temperature stress (LTS) has become a major limiting factor for the development of high yield, quality and efficiency in wheat production. It not only affects the function of wheat leaves and the development of spikes but also impacts stem lodging resistance, and may experience elevated risk of stem lodging. This study conducted a field pot experiment to assess the effect of phosphorus fertilizer application mode on wheat stem lodging resistance under spring LTS. Two wheat varieties, Yannong19 (YN19, cold-tolerant variety) and Xinmai26 (XM26, cold-sensitive variety) used as the experiment material. Two phosphorus fertilizer application models including traditional phosphorus application (TPA) and optimized phosphorus application (OPA) were employed. Temperature treatment was conducted at 15 degrees C (CK) and -4 degrees C (LT) in a controlled phytotron. Our results showed that spring LTS decreased the stem wall thickness and internode fullness, and altered stem anatomical structure and chemical composition, resulting in a decrease in wheat stem mechanical strength and lodging resistant index. Compared with TPA, the OPA increased the stem wall thickness and internode fullness. The thickness of the stem mechanic tissue layer and parenchymatous tissue, and the area of the large vascular bundle and small vascular bundle were increased by the OPA, which alleviated the damage to stem cell walls caused by spring LTS. At the same time, the OPA also increased the contents of lignin, cellulose, and soluble sugar, improving the C/N ratio in wheat stem. Due to the improved stem morphological characteristics, anatomical structure, and chemical compositions, the wheat stem exhibited enhanced lodging resistance, which increased the lodging resistant index of the 2nd and 3rd internodes of YN19 and XM26 by 27.27%, 11.63% and 14.15%, 15.73% at the dough stage compared with TPA under spring LTS. Meanwhile, OPA could not only alleviate the yield loss caused by spring LTS, but also increase the grain yield without spring LTS. This study indicated that OPA enhances wheat stem lodging resistance under spring LTS, and would be meaningful and practical for improving wheat resistance to low-temperature stress.