Acta Physiologiae Plantarum最新文献

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.

In recent years, advances in computational technologies and new methods have been made available for plant growth and physiology studies. Due to its practicality and precision, studies with modeling for leaf area prediction have been carried out with several agricultural species, being considered a non-destructive method. Thus, the study aimed to develop non-destructive methods based on regression models, support vector machine (SVM) and random forest for predicting the leaf area of Sesamum indicum cultivars using linear leaf dimensions. A total of 9600 leaves were collected from four S. indicum cultivars, and 2400 leaves of each cultivar were collected. The cultivars used for sampling were BRS Seda, CNPA G2, CNPA G3, and CNPA G4. The measurements of each leaf’s length, width, and leaf area were obtained through scanned images using the ImageJ software. Then, the product between length and width was calculated. Allometric equations were constructed using linear, power, and exponential models. The criteria for choosing the best models were the coefficient of determination (R²), mean absolute error (MAE) and root of the mean square of error (RMSE). The SVM learning algorithm can be used with greater accuracy to predict the leaf area of S. indicum cultivars using leaf dimensions, such as length and width. Despite new technological advances in equipment, the methods proposed in this study, such as SVM and regression models, provided accurate predictions for the leaf area of all sesame cultivars.

The present study investigates the impact of the application of silicon (Si) on seed germination and early seedling growth of chia (Salvia hispanica L.), an important medicinal plant, under salinity constraint. For this reason, chia seed were germinated at 25 ± 1 °C for one week under salt stress (200 mM NaCl) with or without the treatment with 1 mM Si. Results indicated that salinity constraint decreased seed germination and impaired significantly (p < 0.001) seedling growth. Conversely, the treatment with exogenous Si neutralized the harmful effects of salt stress by improving the germination percentage (32%), velocity index (34%) and seedling vigor index (138%). In addition, Si alleviated the inimical impacts of salinity and enhanced the ability of the embryo to use seed reserves, in terms of soluble sugars and proteins. Besides, the exposition of chia seed to 200 mM NaCl stress significantly induced oxidative stress, reflected by significant (p < 0.001) accumulations of malonyldialdehyde and hydrogen peroxide, and the percentage of electrolyte leakage. Nevertheless, Si supply alleviated the induced oxidative stress under salinity through a significant raise in the activity of polyphenol oxidase and superoxide dismutase. Additionally, Si treatment considerably (p ≤ 0.01) augmented also the accumulation of proline as an osmoprotectant compound. Furthermore, relative to salt-stressed seed without Si treatment, Si significantly reduced the sodium accumulation in seed tissue. These findings suggest that Si had a biostimulatory effect on seedlings emergence of S. hespanica L. under salinity constraint, by modulating the use of seed reserve by the embryo and inducing an antioxidant defense system.

The prospective strategies to promote the growth and attaining of better grain yield by avoiding cadmium (Cd) phyto-toxic effects in plants are of greater importance for the glimpse into the future. The strategic measures to regulate the growth with the application of plant growth regulators have been adapted in past and also under consideration for future perspectives. This study aimed at the application of thiourea (TU) under Cd-stress to investigate the role of it as growth bio-regulator in maintaining the growth and final grain yield of wheat. Two genetically different wheat cultivars i.e., AARI-2011 and Faisalabad-2008 were grown in a sand filled pot experiment. The levels of Cd-stress (0, 1.0 mM) and TU (0, 0.2 mM) were applied. Applied Cd-stress regime (1.0mM) increased the root Cd (81-fold), shoot Cd (56-fold) and grain Cd (150-fold) of Faisalabad-2008, while 124-, 65-, 175-fold, respectively, of AARI-2011. The applied Cd-stress caused a significant reduction in growth, chlorophyll, nutrient ions acquisition (K, Ca, P) and grain yield characters, while increasing MDA, H₂O₂, of both wheat cultivars. Contradictory, TU-treated plants showed a remarkable increase in plant growth, chlorophyll traits grain yield, and decreased Cd, MDA and H₂O₂ contents, up-regulation of antioxidant system (CAT, POD, SOD) including osmolytes under Cd-stress. Application of TU significantly decreased the root Cd (1.9-fold), shoot Cd (2-fold) and grain Cd (2.1-fold) in Faisalabad-2008, while 1.7-, 1.7-, 1.8-fold, respectively, of AARI-2011 under Cd-stress level (1.0mM). Wheat cultivars including Cd-sensitive cultivar, exhibited better Cd-tolerance with TU treatments in improving growth and yield by increasing Cd-detoxification ability, nutrient ion acquisition and antioxidant defense. The outcomes of this study recommend the use of TU as efficient growth and yield promotor of wheat under Cd-stress for the future perspective.