Acta Physiologiae Plantarum最新文献

An experiment was conducted to study the effect of pre-harvest application of spermine on fruit ripening, yield and quality of litchi cv. Deshi. Spermine was applied at 0.10, 0.20 and 0.30 mM concentration on the litchi plants at 20, 40 and 20 + 40 days after fruit setting. It was observed that the fruit ripening delayed by 9 days as compared to control when 0.10 mM spermine solution was applied at 40 days after fruit set. Maximum fruit weight (22.74 g) and yield per plant (24.24 kg) was recorded under pre-harvest application of 0.10 mM spermine at 40 days after fruit set. The membrane electrolytic leakage, peroxidase and polyphenol oxidase activities in the fruit pericarp were recorded minimum in this treatment with statistically at par result in its two applications (0.10 mM) at 20 and 40 days after fruit set. However, the activities of catalase and phenylalanine ammonia-lyase were recorded maximum in these two treatments. Further, the biochemical attributes of the harvested fruit in terms of TSS, total sugar content, ascorbic acid and anthocyanin content, total phenol and flavonoid content as well as antioxidant capacity were also enhanced significantly by the application of 0.10 mM spermine at 20 and 40 days after fruit set (23.06 °B, 17.34%, 43.78 mg 100 g^-1 FW, 33.98 mg 100 g^-1 FW, 596.11 µg GAE g^-1 FW, 33.85 µg CE g^-1 FW and 6.41 µ mol TE 100 g^-1 FW, respectively) with par value in its single application at 0.10 mM concentration at 40 days after fruit set (22.77 °B, 17.23%, 43.56 mg 100 g^-1 FW, 33.58 mg 100 g^-1 FW, 594.11 µg GAE g^-1 FW, 33.58 µg CE g^-1 FW and 6.38 µ mol TE 100 g^-1 FW, respectively). Hence, it can be concluded that pre-harvest application of 0.10 mM spermine at 40 days after fruit set is optimum for improving the yield and quality of litchi cv. Deshi with delayed harvesting which can makes the best quality litchi fruits available in the market for longer period of time.

Cultivating threatened plant species is vital for conservation, safeguarding against extinction by ensuring propagation and maintaining genetic diversity. Here, we conducted an integrative morphological, physiological, and quantitative proteomic analysis of Stephanopodium engleri plants grown under different substrates and nutritional sources. Stephanopodium engleri is a threatened tree endemic to the Iron Quadrangle, a Brazilian mining region. Different nutritional sources resulted in changes in the growth of S. engleri, with N, P, and micronutrients identified as the most limiting nutrients. The species exhibited maximum growth with half of the applied fertilization, suggesting a low nutritional requirement. The highest growth was related to adjustments in the photosynthetic apparatus and protein regulation, with no significant differences in morpho-anatomical traits. The most representative proteins displayed a diverse array of metabolic functions, particularly related to iron and zinc homeostasis, photosynthesis and energy pathways and reactive oxygen species signaling. Plants with lower carbon assimilation and growth exhibited down-regulation of these proteins. Our findings provide valuable insights into S. engleri physiology and adaptations, emphasizing the importance of minimum fertilization to produce high-quality seedlings. These results also support broader conservation efforts aimed at preventing the species from becoming extinct, including reinforcing natural populations, establishing new ones, and supporting the maintenance of germplasm banks and living collections.

Drought stress is one of the main abiotic stressors affecting wheat yield. In recent years, plant-derived compounds have played a key role in improving wheat stress resistance and have been widely used to enhance crop drought resistance and yield. Currently, flavonoids, as important secondary metabolites in plants, are related to drought resistance. In this study, we found through screening that the flavonoid compound dihydroquercetin can improve the drought resistance of wheat. The results indicate that exogenous dihydroquercetin can significantly improve the survival rate, relative water content, fresh weight, and dry weight of wheat seedlings under drought conditions. Biochemical assays combined with transcriptome analysis demonstrate that under drought stress, dihydroquercetin simultaneously enhances antioxidant capacity and upregulates the expression of β-glucosidase (BGLU2) and aldehyde dehydrogenase (ALDH) in the phenylpropanoid biosynthesis pathway. These changes collectively enhance the antioxidant capacity of wheat and reduce the content of superoxide anions and hydrogen peroxide. Dihydroquercetin also upregulated the expression of important genes in the glycerophospholipid metabolism pathway, including phospholipase D (PLD), no special phospholipase C (NPC), and glycerophosphodiesterase (GDPD), alleviating damage to the cell membrane, reducing malondialdehyde content. Therefore, the application of dihydroquercetin improves drought resistance in wheat by promoting antioxidant capacity and alleviating drought-induced oxidative damage. This study lays the groundwork for implementing dihydroquercetin to boost wheat's drought resilience in agricultural settings.

The increasing global food demand necessitates innovative and sustainable methods to enhance plant growth and productivity without relying excessively on chemical inputs. Pulsed magnetic fields (PMFs) have emerged as a non-chemical alternative with the potential to modulate key physiological and biochemical processes in plants. However, the precise mechanisms through which PMFs influence plant growth and development, as well as their varying effects under standard and stress conditions, remain areas of active investigation. This review aims to consolidate recent findings on the application of PMFs in modulating plant growth and development, with a particular focus on elucidating the underlying mechanisms, the dynamic interactions, and the potential agricultural applications. Emphasis is placed on the bio-electromagnetic interactions underlying PMF-induced changes in plant metabolism, stress resilience, and crop productivity. By understanding these interactions, researchers can optimize PMF parameters for targeted agricultural applications, balancing benefits and potential drawbacks. While challenges persist in terms of scalability and result variability, advancement in bio-electromagnetic research offers promising opportunities for integrating PMFs into sustainable agricultural practices. Ultimately, PMFs represent a frontier technology with significant implications for improving crop resilience, resource efficiency, and food security in an environmentally responsible manner.

Cyclin-dependent kinases (CDKs) critical regulators of cell proliferation; however, their role in fruit size remains largely unexplored. This study identified 35 CDK genes from the pear genome, which were categorized into eight groups. The expression levels of 15 CDK genes exhibited a correlation with cell number variations during pear fruit development. Combining with the gene expression levels, PbCDK9, PbCDK17, and PbCDK18 were selected for over-expression analysis in pear fruit callus. Transgenic fruit calli displayed a greater number of cells compared to control calli, suggesting the involvement of PbCDK9, PbCDK17, and PbCDK18 in cell proliferation. Moreover, four concentrations of exogenous forchlorfenuron (CPPU), a synthetic cytokinin, were applied to fruitlets on the tree, resulting in a significant increase in fruit size at 1 and 25 mg/L CPPU. Notably, the expression levels of PbCDK17 and PbCDK18 were increased in CPPU-treated fruits compared to untreated fruits. These results suggest that exogenous CPPU treatment promotes cell proliferation by enhancing the expression of PbCDK17 and PbCDK18, leading to increased fruit size. The findings provide a foundational understanding of the regulatory mechanisms underlying fruit size in agricultural production.

Endophytic fungi symbiotically reside within plant tissues without eliciting apparent pathological responses. Positive interactions between endophytic fungi and plants help the host overcome biotic and abiotic stressors. Spodoptera frugiperda is a fall armyworm that devastates the revenue of farmers worldwide and is a major threat to food security. Here, we investigated the cytotoxicity of extracts of endophytic fungi isolated from brinjal (Solanum melongena L.) var. Mattu Gulla on the insect cell line Sf21 (Spodoptera frugiperda ovarian cells). Among the 13 endophytic fungi tested, Colletotrichum sp. presented the greatest cytotoxic ability, with an IC₅₀ of 103.6 µg mL⁻¹. LC‒MS analysis revealed the presence of several fungal metabolites (232), and 12 metabolites were identified, among which regiolone is known to have potent insecticidal activity. The fungal extract disrupted oxidative homeostasis in Sf21 cells by increasing the total reactive oxygen species (ROS) content according to the treatment concentration and duration. The mitochondrial membrane potential analysis by flow cytometry indicated the presence of depolarized mitochondria in cells treated with the fungal extract. Furthermore, fragmented mitochondria and clear signs of apoptosis, including nuclear condensation, the presence of necklace, ring-like structures and collapsed nuclei, were observed. Our data revealed that the Colletotrichum sp. extract had cytotoxic effects by inducing apoptosis in vitro, which could be explored with respect to the Colletotrichum sp. extract in further investigations.

Key message

The research aimed at studying the impact of drought stress on rapeseed and evaluated the role of methanol foliar spraying in providing a source of carbon dioxide during its deficiency conditions. Further, the focus was on the key genes responsible for the alternative respiration pathway, uncoupling, and calcium-binding proteins.

Abstract

Oilseeds are the largest food reserves in the world after cereal. One of the most significant sources of edible oil is rapeseed. However, environmental stressors, such as drought, play a crucial role in reducing crop yield worldwide. This study was conducted to investigate the impact of drought stress on genes and to analyze the protein-protein interactions among key genes related to alternative respiration, uncoupling, and calcium-binding proteins. Additionally, the research aimed to detect any miRNAs that could potentially modulate target genes in the drought-sensitive (Hyola308) and drought-tolerant (SLM046) rapeseed genotypes. Gene network analysis using STRING v11.5 and cytoHubba (MMC method) identified UCP1, NDB2, NDA2, and AOX1A as major hub genes. To explore their post-transcriptional regulation, we used psRNATarget (expectation threshold ≤ 5) along with Brassicaceae-specific miRNAs from miRBase v22. This analysis predicted 22 microRNAs targeting these four rapeseed genes, primarily from the miR169, miR168, miR319, miR390, miR397, miR393, and miR171 families. These miRNAs are predicted to regulate mitochondrial alternative respiration pathways under drought stress, primarily by modulating key genes involved in ROS scavenging and cellular energy homeostasis. Among the identified miRNAs, bna-miR169a/b/n, bna-miR168a/b, bna-miR403, bna-miR390a/b/c, bna-miR397a/b, bna-miR393, and bna-miR171f/g were found to be rapeseed-specific. For instance, bna-miR169a/b/n, known to regulate NF-YA transcription factors during drought stress, targets NDB2, a gene critical for maintaining NADH oxidation. bna-miR393 is involved in modulating auxin signaling, while bna-miR171f/g targets SCL6 transcripts, influencing genes related to root architecture and contributing to stress adaptation. Furthermore, miR403 is known to modulate responses to both drought and cold stress, and miR390 targets ARF genes, which influence root development and play a crucial role in stress tolerance mechanisms. qRT‐PCR (three biological × three technical replicates) on drought‐stress (DR; 30% field capacity) and methanol‐treated (DM; 20% v/v foliar spray) plants (CL = fully irrigated control) showed that methanol application significantly upregulated UCP1 in tolerant plants at 24 h post‐stress and induced NDA2/AOX1A in sensitive plants at 72 h (DR) and 24 h (DM). Our results demonstrate that foliar methanol enhances drought resilience by boosting alternative respiration and suggest that the identified miRNAs may serve as post‐transcriptional regulators o