Acta Physiologiae Plantarum最新文献

Tropical Capsicum chinense is known for its strong leaf cooling capacity and stomatal responsiveness under high-temperature conditions. To better understand whole-plant acclimation strategies, we examined leaf-level physiological responses—including stomatal behavior and water potential under atmospheric stress based on combinations of temperature and humidity. Particular attention was given to signaling mechanisms beyond conventional VPD-based models and age-dependent differences in leaf responses. Under high-temperature and low-humidity conditions, transpirational cooling was markedly enhanced, lowering leaf surface temperature by up to 6.3 °C. This cooling effect contributed to the maintenance of high leaf water potential across canopy layers and sustained photosynthetic activity. In contrast, under moderate temperature and low humidity, stomatal closure occurred despite low intercellular CO₂ concentrations, suggesting the involvement of humidity-specific signaling mechanisms. Additionally, leaf age influenced stress sensitivity, with lower-position leaves showing greater vulnerability to senescence and water imbalance. These findings demonstrate that temperature and humidity act interactively to shape leaf water regulation and stomatal behavior. The results provide new insights into plant physiological adaptation under atmospheric stress and contribute to the refinement of stomatal response models and climate-resilient crop management strategies.

This research aimed to evaluate the effects of carbon dots on the physiological parameters of sesame. Carbon dots were prepared by hydrothermal treatment of Gum Tragacanth and characterized by TEM, FTIR, and XRD. Then the sesame treatment with concentrations of 0 (control), 5, 10, and 20 mg/L of carbon dots was carried out. Our data revealed that in the germination stage, the radicle length in all treatments, the seedling fresh weight in the concentration of 10 mg/L, and the amount of chlorophyll a and b in the concentration of 5 mg/L of carbon dots were significantly increased. In the hydroponic stage, the root fresh weight at a concentration of 20 mg/L of carbon dots was significantly increased. The highest amount of phenol, flavonoid, total carbohydrates, and total protein in the leaf, and phenol, flavonoid, and antioxidant capacity in the root was behold in the treatment with a concentration of 5 mg/L of carbon dots. The highest level of total protein in the root, and chlorophyll a, b, and total carotenoid were observed in a concentration of 10 mg/L of carbon dots. The activity of superoxide dismutase (SOD) in root and Ascorbate peroxidase (APX) in leaf and root in all treatments and the activity of catalase (CAT) in leaf and root at a concentration of 5 mg/L of carbon dots were significantly increased. It seems that low concentrations of carbon dots could be effective in improving physiological parameters of the sesame and therefore it is suggested as a suitable growth stimulant.

Iron (Fe) and sulphur (S) interactions have been widely studied, however there is little known about their interactive influence on other nutrients uptake, translocation and assimilation. The present study deciphered the role of Fe and S nutrition on carbon (C), nitrogen (N) and S uptake, assimilation and amino acid synthesis in bread and durum wheat through pot and nutrient culture experiments. The pot experiment was conducted with Fe deficient (Fe-, ~ 6.6 kg Fe ha⁻¹) and Fe sufficient (Fe + , ~ 26.4 kg Fe ha⁻¹) field soil with three levels of S i.e., 0 (S0), 30 (S1) and 60 (S2) kg S ha⁻¹ over two experimental years. Results showed that the Fe and S supply significantly increased shoot mass, photosynthesis, nutrient content, cysteine and methionine content and activities of key assimilating enzymes of C, N and S metabolism i.e. Rubisco, nitrate reductase (NR), serine acetyl transferase (SAT) and O-acetyl serine thiolyase (OASTL) respectively as compared to Fe-S0 treatment. Further, for the transcript expression of S (SULTR1;1 and SULTR2;1) and N (NRT2.1) uptake transporters, plants were raised under Fe- (1 µM) and Fe + (100 µM) nutrient solutions with three S levels viz., 0 (S0), 1.25 (S1) and 2.5 (S2) mM, equivalent to the pot culture experiment. SULTR1;1 expression was significantly induced under Fe + S0 condition whereas, viceversa results were observed in SULTR2;1 expression. NRT2.1 expression was induced under Fe- but with S supply. The study clearly reveals the interactive modulation of C-N-S-Fe uptake and metabolism by Fe and S supply in wheat.

The longitudinal growth of the primary root is determined by consecutive events that take place along the main axis of the root. These events divide the root in several zones based on criteria including cellular activities, such as cell proliferation, and morphological features, such as cell size. In general, the root apex is divided into four zones. The meristematic zone is characterised by active cell division, resulting in cells that subsequently move to the transition zone for slow elongation. Following this, cells enter the elongation zone, where the elongation rate increases significantly. Finally, cells reach the mature zone, where elongation ceases. In the case of maize roots, the delimitation of these zones is achieved through a mathematical procedure that calculates the breakpoint in cell length, thereby identifying the limit between two contiguous zones. It is well established that the exogenous application of auxin and cytokinin inhibits root elongation. The present work investigates these effects by analysing changes in cell length in the various zones. The results showed that external hormones slightly modify the meristematic zone. However, the reduction of the maximum cell length, along with a shortage in the extension of the elongation zone, can explain the root inhibition, as a strong correlation was measured.

Improving functional Fe status through the application of Fe with synthetic organic ligands is a strategy to overcome the Fe-deficiency problem. The study aimed to determine the effectiveness of different selected synthetic organic ligands (Fe-EDTA, Fe-EDDHA, Fe-Citrate) in terms of improving the functional Fe status of wheat (Triticum aestivum) plants grown under a hydroponic culture system. Fe was supplied as either FeCl₃ or in complex with organic ligands, viz., EDTA, EDDHA, and citrate. Wheat plants exhibited improved functional Fe status, as indicated by high chlorophyll and carotenoids concentrations, lipid peroxidation, and ferric chelate reducing capacity in Fe-EDTA and Fe-Citrate-supplied plants. Interveinal chlorosis along with mildly enhanced superoxide dismutase activity was observed in FeCl₃, and Fe-EDDHA-supplied plants. Chlorotic leaves of Fe-EDDHA show a decrease in lipid peroxidation, highlighting the essentiality of Fe in chlorophyll biosynthesis and lipid peroxidation in wheat plants. Fe-EDDHA was found to be an inefficient Fe supplier for wheat, as indicated by decreased growth with a low shoot Fe concentration. Fe-EDTA and Fe-Citrate have been proven to be effective Fe-suppliers in comparison to Fe-EDDHA and FeCl₃ in wheat plants. Fe-EDDHA is a poor Fe supplier in hydroponic systems, as EDDHA forms a strong complex with Fe and its aromatic and hydrophobic nature.

Copper, cadmium, and chromium are known to disrupt metabolic processes and induce oxidative stress. Chloroplasts are the main site of reactive oxygen species (ROS) production in photosynthetic cells under light. Exposure to various abiotic stress factors, including heavy metal (HM) ions, leads to increased ROS formation. Prenyllipid antioxidants, including carotenoids, tocopherols (Tocs), and plastoquinol, play an important protective role in chloroplast membranes. To examine the response of prenyllipid antioxidants to HM-induced stress in more detail, culture growth, the content of photosynthetic pigments, Tocs, plastochromanol, as well as plastoquinone (PQ) pool and the extent of its reduction were measured day by day in Chlamydomonas reinhardtii, exposed to Cu, Cr, and Cd ions in two experimental setups, i.e. stress evoked at the beginning of culture growth and stress evoked at the beginning of stationary phase. Algae exposed to stress from the very beginning were more susceptible to HM ions than grown cultures. The Cu ions displayed the highest toxicity of all the HMs tested. Exposure to HMs was expected to lead to the increase in prenyllipid content. However, grown cultures exposed to HMs showed either no changes or a decrease in Tocs and PQ content. In algae exposed to HM ions from the very beginning, the content of prenyllipids was increased during the first four days of growth compared to control, but the main reason for it was a slowdown in cell division and chlorophyll synthesis rather than an enhanced production. An increase in prenyllipid content appears to be more important during long-term acclimation to HMs than during short-term responses.

Increased level of antioxidants and enzymatic activity protects the plants from oxidative damage under stress conditions. In the present study antioxidants involved in the Ascorbate–Glutathione (ASC–GSH) cycle (Ascorbate Peroxidase, Glutathione Reductase, Ascorbate and Dehydroascorbate) were investigated under salt stress in two species of genus Prosopis (P. cineraria and P. juliflora). Both these species are economically very important in arid and semi-arid regions of Rajasthan. For the experimentation one-week-old seedling were treated with different salt concentrations ranging from 0 to 200 mM (0, 25, 50, 75, 100, 150 and 200). The leaves were harvested after 15 and 30 days. The Ascorbate content of both the species increased under salt stress. But Dehydroascorbate content decrease. The activity of enzymes Ascorbate Peroxidase (APX) and Glutathione Reductase (GR) were also increased under salt stress. The increase was comparatively more prominent in P. juliflora which indicates the upregulation of Ascorbate-Glutathione cycle is higher in P. juliflora and it plays a great role in making P. juliflora more tolerant under high salinity conditions.

This research aimed to improve the physiological response of Nigella sativa to drought stress using arbuscular mycorrhizal fungi, phosphate-solubilizing bacteria, and zinc foliar application. The results demonstrated that the reduction in irrigation water significantly affected photosynthetic pigments, relative water content, electrolyte leakage, proline content, leaf-soluble sugars, soluble proteins, biological yield, and grain yield. In addition, in 2018 and 2019 years elevated drought stress decreased total chlorophyll (63 and 70%), carotenoids (59 and 59%), relative water content (37 and 32%), soluble proteins content (36 and 37%), biological performance (48 and 45%), and grain yield (64 and 48%). Furthermore, it increased electrolyte leakage (37 and 35%), proline (132 and 138%), and soluble sugars content (65 and 56%). The combined use of arbuscular mycorrhizal fungus (AMF) and Phosphate barvar-2 bio-fertilizer (PB2) (containing two types of phosphate-solubilizing bacteria: Pseudomonas putida P13 and Pantoea agglomerans P5) alleviated for the decrease in the measured traits. Consequently, applying bio-fertilizer increased biological performance (24 and 26%) and grain yield (30 and 27%) and decreased electrolyte leakage (18 and 20%) compared to no bio-fertilizer application. Moreover, the combination of AMF and PB2 increased the grain nitrogen (66 and 40%) and grain phosphorus (18 and 20%). Zinc foliar application increased grain elements content, photosynthesis pigment, proline, soluble sugars content, soluble protein content, relative water content and biological performance. Furthermore, it decreased electrolyte leakage. Bio-fertilizers and zinc foliar application mitigated the detrimental effects of drought stress on the quality, grain yield, and biological performance of black cumin by improving the physiological mechanisms.

Mung bean is a fast maturing legume crop, grown for its nutritional value and a rich source of digestible protein. However, it is poor in grain yield due the breakdown of its photosynthetic machinery at reproductive stage as organic nitrogen is relocated heavily from source to economic sink for grain development. Therefore, in order to augment endogenous organic nitrogen sources by minimizing the deficit of organic nitrogen during reproductive phase, an experiment was accomplished to analyse the photosynthetic and yield responses of two IPM2-3 and Pusa Vishal varieties to exogenous treatments of amino compounds namely GABA (1 mM); Glutathione (0.5 mM); Proline (5 mM); Spermidine (0.25 mM); Arginine (1.25 mM); Glycine betaine (50 mM) and Tryptophan (5 mM). These treatments were applied at the flowering stage with water spray as control. Results of the present investigation demonstrated significant improvements in yield and its related traits such as SPAD value, photosynthetic pigments level, Fv/Fm ratio, electron transport rate (ETR), non-photochemical quenching (NPQ), photosynthesis rate, pod number, pod weight, and test weight. The most notable yield enhancement was observed with glutathione, followed by proline and GABA. These findings in turn suggested that foliar application of amino compounds may effectively be used to minimize the organic nitrogen deficits during flowering to enhance mung bean yield by improving photosynthetic activity and minimizing organic nitrogen deficits. Consequently, treatments of amino compounds may also be considered a viable agronomic strategy to improve mung bean productivity.

The rapid metabolic changes that occur in jujube fruit during ripening limit its shelf life (SL) and increase consumer rejection. In this study, the effects of 1% chitosan (CT) and 1% procyanidin (PN) treatments either alone or in combination were evaluated on ‘Apple Kul’ jujube fruit during SL at ambient conditions (22 ± 1˚C, 65% RH) for 15 days. CT coatings and PN treatments effectively reduced respiration and ethylene production, preserving fruit quality and delaying senescence in ‘Apple Kul’ jujube. Treated fruits showed greener peels, higher firmness, membrane stability index (MSI), titratable acidity (TA), and lower total soluble solids (TSS), TSS/TA ratio, and weight loss compared to the control. Despite declines during storage, total phenol content (TPC), flavonoids, vitamin C, chlorophyll, and free radical scavenging capacity (FRSC) were higher in treated fruits. Additionally, hydrolytic enzyme and polyphenoloxidase (PPO) activities were lower, while antioxidant enzyme activities (SOD, CAT, POD) were higher. Decay incidence, microbial counts, and malondialdehyde (MDA) increased but were suppressed in treated fruits. The combined CT and PN treatment were more effective in preserving quality and extending SL at ambient conditions than either treatment alone. Therefore, the combined treatment of CT coating and PN could be used to extend the SL of ‘Apple Kul’ jujube at ambient conditions. Using CT coating and PN together was more effective in maintaining fruit quality and delaying aging than applying them individually, offering a practical solution for extending the SL of ‘Apple Kul’ jujube at ambient conditions.