Acta Physiologiae Plantarum

Manokari, M.; Faisal, Mohammad; Alatar, Abdulrahman A.; Singh, Rupesh Kumar; Shekhawat, Mahipal S.

doi: 10.1007/s11738-025-03827-zpmid: N/A

Key messageThe incorporation of optimal concentration of polyethylene glycol with the optimized growth regulators in the nutrient medium promoted shoot growth and improved foliar micro-morpho-anatomical traits of Hedyotis biflora which improved the survival success of the plantlets during ex vitro hardening and field trials.Polyethylene glycol (PEG) is widely recognized as an effective agent for stimulating osmotic stress in plant tissue cultures. In this study, the micropropagated shoots of Hedyotis biflora (L.) Lam was subjected to varied concentrations of polyethylene glycol (PEG-6000) under in vitro conditions to evaluate the effect of PEG on the morpho-anatomical development of shoots. The cultures were established by culturing nodal shoots on Murashige and Skoog (MS) medium supplemented with 2.0 mg L−1 6-benzylaminopurine (BAP), and the shoots were proliferated on the optimized plant growth regulators (1.0 mg L−1 BAP + 0.5 mg L−1 Kinetin (Kn) + 0.1 mg L−1 Indole-3-acetic acid (IAA). Among the varied concentrations of PEG used in the MS medium, 60 mg L−1 PEG with optimized growth regulators in the medium increased the rate of proliferation and elongation of shoots (14.0 shoots with 7.0 cm length) and leaf area (1.6 cm length × 1.0 cm width) than the control (medium without PEG). The foliar micro-morpho-anatomical elucidations revealed that the control leaves showed a thin cuticle, non-functional stomata, mesophyll with isobilateral tissues, and poorly developed mechanical, dermal, and vascular tissues. The incorporation of 60 mg L−1 PEG (optimal) in the medium increased cuticle thickness, palisade and spongy mesophyll differentiation, functional stomata, dense vascular tissues, and well-developed ground tissues. The PEG-treated shoots showed better rhizogenesis on half-strength MS medium containing 2.0 mg L−1 Indole-3-butyric acid (IBA) (21.0 roots with 4.0 cm average length). These morphometric and structural improvements were sequentially reflected in the increased survival of plantlets (96%) during acclimatization and field transplantation of H. biflora.

Gupta, Himani; Goyal, Meenakshi; Kapoor, Rahul

doi: 10.1007/s11738-025-03829-xpmid: N/A

Oat (Avena sativa L.) is prone to stem lodging under field conditions that negatively affect productivity. The present study aimed to determine the association between lodging resistance with culm morphological, anatomical and biochemical traits. The experiment was laid out in randomized block design in Rabi season of 2020–21 and 2021–22 using eight recently released oat genotypes (OL-1769-1, RO-11-1, OL-13, OL-1896, JHO-822, OL-15, OL-14 and OL-12) to evaluate the impact of stem lodging on oat genotypes. Dendrogram analysis depicted that Cluster I genotypes (OL-1769-1, RO-11-1, OL-13) proved to be more efficient in overcoming lodging stress as compared to Cluster III (OL-15, OL-14, OL-12) and Cluster II (OL-1896, JHO-822) genotypes. Cluster I had lower lodging scores plus lower percent reduction in thousand grain weight, lignin content, dry matter yield of lodged plants and higher breaking strength (BS), culm lodging resistance index (CLRI) than Cluster III. Increased lodging also had a negative impact on biomass partitioning. The correlation analysis depicted a negative association of CLRI with second internode length (− 0.841**) while significant positive correlation with second internode diameter (0.808*) and BS (0.949**). Water-soluble carbohydrates (WSC) and starch content varied significantly with lodging. Increased vascular bundle area and xylem tissue contributed towards lodging resistance. This study provides the direct estimation of the differential behavior of oat genotypes towards stem lodging and its effect on morpho-anatomical and biochemical characters. Genotype RO-11-1 showed resistant behavior while OL-15 showed susceptible behavior towards lodging. Our findings demonstrate the potential of using commercially viable genotypes to achieve high and stable yield under field conditions and to identify lodging tolerant genotypes to support future breeding programs.

Singh, Amantika; Choudhary, Krishna Kumar

doi: 10.1007/s11738-025-03820-6pmid: N/A

Salinity stress is posing serious threat to global food production and accountable for 20–50% of yield loss in various crops via hampering morphological, biochemical, and physiological processes of plants. To evaluate the impact of 0-, 50-, and 100-mM salinity levels, a pot experiment was conducted under ambient conditions on mung bean cultivars (HUM 1 and HUM 16). Reduction in plant height was observed by 15.1% and 34.8% for HUM 1 and 7.3% and 27.5% for HUM 16 under 50 and 100 mM, respectively. Higher generation of superoxide radical (51.3%) and hydrogen peroxide (29.1%) was observed for HUM 1 under 100 mM resulting into higher membrane damage (51.0%), assessed in the form of MDA content. To counter this oxidative stress, significant induction in non-enzymatic and enzymatic antioxidants like ascorbic acid (11.2% and 28.9%), superoxide dismutase (29.9% and 48.0%), and catalase (25.4% and 60.9%) was observed for HUM 1 and HUM 16 under 100 mM, respectively. On the other hand, significant accumulation of phenols and flavonoids was also noticed for HUM 16 under 50 and 100 mM. Reduction in yield was recorded more for HUM 1 (33.6% and 46.9%) as compared to HUM 16 (15.8% and 41.4%) under 50 and 100 mM, respectively. Results of the present study clearly demonstrated that 100-mM salinity stress was more severe as compared to 50 mM, and the magnitude of impact was observed higher for HUM 1 as compared to HUM 16.

MacAlister, Dunja; Rafudeen, Suhail; Gabier, Hawwa; Muasya, A. Muthama; Ogola, John B. O.; Ottosen, Carl-Otto; Rosenqvist, Eva; Chimphango, Samson B. M.

doi: 10.1007/s11738-025-03828-ypmid: N/A

Aspalathus linearis (Burm.f.) R.Dahlgren, or rooibos, is an important commercial crop in the Western Cape, South Africa. The growth rate of rooibos is highest during the hot, dry summers typical for this region. This suggests that the plants have a wide range of adaptive responses including morphological, physiological, molecular, and biochemical mechanisms that help them cope with drought and heat stress. This study investigates differential expression of proteins in leaf samples harvested in summer from rooibos plants at two relatively cool, and two relatively hot sites in the Cederberg region. A total of 180 proteins were differentially expressed and of these, 113 proteins were more abundant at cooler sites while 67 proteins were more abundant at the heat-stressed (HS) sites. The higher temperatures at the HS sites led to a reduced protein abundance due to temperature thresholds for protein production during HS. Heat shock proteins were more abundant in the HS plants indicating an enhanced thermotolerance. Plants at the cooler sites overexpressed proteins associated with aiding photosynthesis and protecting photosystems, resulting in better photosynthetic rates and biomass accumulation. High light and moderate HS conditions prompted the regulation of proteins involved in chlorophyll synthesis and light protection to maintain effective functioning. Proteins involved in oxidative stress responses were expressed in plants at all sites, which was mirrored by high concentrations of antioxidants. Rooibos thermotolerance relies on the expression of HSPs and oxidative stress response proteins, while photosynthesis-related proteins dominate the cooler sites, optimizing their function and ultimately growth.

Animasaun, David Adedayo; Lawrence, Judith Amaka

doi: 10.1007/s11738-025-03825-1pmid: N/A

Fonio millet is an orphan crop with great potential for economic and food security. However, drought negatively affects its production and yield in semi-arid and arid regions. This study compared the growth and metabolomic profiles of two contrasting fonio cultivars (NGB02089 and NGB02082) in response to water stress at the seedling stage. The results showed variation in the morph-agronomic characters of the cultivars. There were also significant (p < 0.05) positive correlations in the traits studied, which means that the traits can be improved simultaneously. Chlorophyll content increased progressively with weeks after sowing (WAS) but decreased when seedlings were exposed to water stress. The biomass yield of NGB02082 was higher than that of NGB02089, although the latter grew more vigorously. However, NGB02089 had longer roots. The GC–MS analysis identified 12 significant metabolites that differed in composition between the fonio cultivars, including sugars, fatty acids and siloxanes. The amount of siloxane decreased in NGB02082 with increasing drought duration, but increased in NGB02089. Similarly, cis-13-octadecenoic acid was present in NGB02082 at 4 WAS but absent at 5 WAS, while NGB02089 produced more metabolites. Similarly, phthalimide, triacontane, vaccenic acids, and cholestane were produced in response to drought stress duration. The results of this study showed that NGB02089 and NGB02082 have different metabolomic responses to drought, conferring resistance to NGB02089 while NGB0282 is susceptible to drought. The result of this study suggests that metabolic responses to drought may be useful in developing varieties with better tolerance or adaptation to drought conditions.

Daler, Selda; Yağcı, Adem; Cangi, Rüstem

doi: 10.1007/s11738-025-03821-5pmid: N/A

In the study carried out as a two-year greenhouse experiment, the effects of salicylic acid (SA; 0.5, 1.0 and 2.5 mM), methyl jasmonate (MJ; 5, 10 and 15 mM) and sodium nitroprusside (SNP; 0.5, 1.0 and 1.5 mM) treatments at different concentrations against cold stress (4 °C, 16 h) in Victoria variety grapevine saplings were investigated, and the most effective concentration ranges were investigated. 1.0 mM SA was found to be the most effective treatment to promote cold stress resistance of grapevines by increasing superoxide dismutase (114.23 U mg−1 protein), catalase (1.024 U mg−1 protein) and ascorbate peroxidase (20.43 U mg−1 protein) enzyme activities while decreasing electrolyte leakage (14.44%) and lipid peroxidation (6.07 nmol g−1) levels. Moreover, 10 mM MJ and 1.0 mM SNP treatments also contributed to the improvement of the osmotic adjustment capacity of grapevines by increasing proline content (MJ, 0.185 μmol g−1; SNP, 0.435 μmol g−1) and relative water content (MJ, 90.06%; SNP, 89.78%), and decreasing electrolyte leakage (MJ, 14.71%; SNP, 16.06%) and lipid peroxidation (MJ, 4.10 nmol g−1; SNP, 5.96 nmol g−1). Additionally, principal component analysis, heatmap and comprehensive evaluation based on the analytic hierarchy process indicated that 1.0 mM SA, 10 mM MJ and 1.0 mM SNP treatments performed better than other treatments in terms of both increasing plant resistance and reducing the severity of damage. This study contains important information that can provide a reference for researchers to enhance the adaptation ability of grapevines to cold stress and can enhance the success of future studies.

Yousefvand, Parvaneh; Pilehvar, Babak; Nasrolahi, Ali Heidar

doi: 10.1007/s11738-025-03832-2pmid: N/A

The elevated atmospheric CO2 concentration is expected to increase plant growth and productivity and improve water use efficiency. Hence, elevated CO2 is considered to mitigate to some extent the adverse effects of drought. We aimed to investigate physio-morphological and biochemical responses of 2-year-old Persian oak (Quercus brantii Lindl.) seedlings to the elevated CO2 concentration and drought alone and when combined. Persian oak seedlings were grown in growth chambers at two CO2 concentrations (ambient; 380 ppm and elevated; 700 ppm) and two water regimes (well-watered; 100% of field capacity and water stress; about 50% of this value) for one growing season (8 months). The results showed elevated CO2 concentration significantly increased collar diameter, shoot height, leaf area, biomass production, root volume, photosynthetic traits, leaf pigments (chlorophyll and carotenoids) content, and relative leaf water content. While, it decreased total N content of leaves, proline content, electrolyte leakage, Malondialdehyde content, and antioxidant enzymes (catalase, peroxidase, and ascorbate peroxidase) activity in comparison to ambient CO2 concentration. However, the root length was unaffected in response to elevated CO2. In contrast, drought had an adverse effect on the studied traits except for root length. These effects were alleviated by the presence of CO2, as apparent in physio-morphological and biochemical traits. Our findings suggest that in different proposed climate change scenarios, Persian oak trees may tolerate drought in the presence of elevated CO2.

Karimi, Zohreh; Zarea, Mohammad Javad; Fazeli, Arash; Zarei, Batool

doi: 10.1007/s11738-025-03826-0pmid: N/A

Further research related to the role of plant-associated bacteria at the molecular level, gene regulation, modulation, and function can lead to hope for enhancing the growth and performance of agricultural plants in harsh environment. Two studies were performed to investigate the function of Azospirillumbrasilense in the regulation of proline-responsive gene expression, as well as some important physiological and biochemical traits related to drought resistance in wheat. Wheat seedlings grown from inoculated and uninoculated seeds were grown under no-water-limitation condition for 21 days and then were subjected to two water regimes: 80% of soil water-holding capacity (WHC) and 25% of WHC. The relationship between A. brasilense inoculation and proline accumulation caused by delta-1-pyrroline-5-carboxylate synthase (P5CS) as well as antioxidant system defense was elucidated 2 weeks after water-deficit imposition. Experiment 2 was conducted under greenhouse condition to assess the modulation of photosynthetic traits, cell membrane stability, and relative water content of leaves as well as grain yield in repose to A.brasilense inoculation. Treatments performed in the two experiments were the same, except water-deficit condition in experiment 2 was imposed at anthesis stage. Under water-deficit conditions, inoculation led to lower accumulation rate (82%) of P5CS mRNA as compared to control plants. Under water-deficit condition, inoculated plants showed lower (13.8%) content of proline compared to control plants. Inoculation alleviated the negative effect of water deficiency by increasing the antioxidant enzyme activity as it increased the activity of peroxidase by 11.7%, glutathione peroxidase by 7.3%, catalase by 65% and glutathione reductase by 70% as compared to uninoculated plants. Under water deficiency, plants inoculated with A. brasilense maintained higher photosynthetic parameters such as net carbon dioxide assimilation rate (84%), stomatal conductance (182%), and sub-stomatal carbon dioxide concentration (69%) compared to uninoculated plants. The present study confirmed that expression of the evaluated gene (P5CS) along with the accumulation of proline was a common response of wheat to water deficiency. Both experiments conducted confirmed that. The inoculated plant displayed a lower level of the evaluated gene and proline content, which can be considered for future research and could open a new hope for improving crop resistance to water-deficit stress.