Acta Physiologiae Plantarum最新文献

Maize (Zea mays L.) is an important cereal crop worldwide, but production is constrained by salt stress, which disrupts plant cell nutrient metabolism, leading to diminished growth and yield. Therefore, the mining of salt-tolerance genes and breeding of new salt-tolerant germplasm is crucial for improvement of maize yield. In this study, ZmWRKY17 (Zm00001d004086) overexpression and mutant lines were exposed to 250-mM and 300-mM NaCl, respectively, for 7 days. Exposed to salt stress, the overexpression lines produced significantly more malondialdehyde and hydrogen peroxide than the control line, accompanied by an increased rate of superoxide anion production and relative electrolyte leakage. The mutant line had a higher percentage survival, higher leaf relative water content, and lower cellular damage under extreme salt stress. According to these findings, ZmWRKY17 appears to have a negative regulatory effect on maize salt tolerance. In addition, under salt stress, ZmWRKY17 overexpression plants accumulated more abscisic acid (ABA) than the control plants. The root of ZmWRKY17 overexpression plants showed reduced sensitivity to ABA. Based on the results of transcriptome analysis, two candidate genes, Zm00001d016105 (ZmPYL10) and Zm00001d016294 (ZmPYL3), were screened for regulation by ZmWRKY17. The dual-luciferase experiments demonstrated that ZmWRKY17 binds to the promoter regions of ZmPYL10 and ZmPYL3, thereby regulating the expression of downstream genes. In conclusion, this study indicates that ZmWRKY17 is involved in regulating the expression of ABA receptor genes ZmPYL10 and ZmPYL3 to reduce the sensitivity of plants to ABA and, ultimately, negatively regulate plant salt tolerance.

This study reports the potential ability of melatonin (Mel) to induce endoreduplication, which may have connections with lateral root formation. Mel induces the lateral root formation in onions in a dose-dependent manner with the highest root forming potential at 50 µM Mel (Mel_2). ROS generation in this dose was significantly higher than the control and a low-dose (5 µM) Mel group (Mel_1), where no lateral roots were observed. Co-treatment of ascorbic acid (AsA) with Mel in the Mel_2 + AsA group can effectively scavenge the Mel_2 induced ROS, resulting in a reduced number of lateral roots in this co-treatment group. These results indicate the connections between the ROS level and the lateral root formation. An increase in DNA content was also observed in the Mel_2 group consistent with the level of ROS-induced DNA damage, suggesting the possible link between ROS-induced DNA damage, endoreduplication, and lateral root formation. The results of gene expression analysis also support the said linkage, where melatonin-induced ROS and DNA damage could initiate the endoreduplication cycle in a dose-dependent manner. The IAA (Indole acetic acid) analysis indicates that IAA accumulation, in the zone of differentiation due to auxin bio-synthesis, triggers lateral root formation in this region in corroboration with endoreduplication and ROS.

An excess amount of particular metal ions can cause nutrient imbalance and inhibit plant growth and development. In this preliminary study, the short-term (2 weeks) and long-term (6 weeks) application was carried out to investigate the potential ameliorative effect of foliar application of melatonin and reveal the changes in ion profiles of grain amaranth Amaranthus cruentus var. ‘Pribina’ treated with Cd, Zn, and Mn. Nine elements (Ca, K, Mg, Na, Cu, Fe, Cd, Zn, Mn) were examined using inductively coupled plasma optical emission spectrophotometry. Different ionomic responses were observed in root and shoot tissues. The results showed that Cu, K, Mn and Na were the most affected elements, which significantly changed after heavy metal applications. Application of Zn had the most prominent effect on the alternations in ion concentrations. In addition, short-term melatonin supplementation reduced Cd and Mn root-to-shoot translocation. No marked changes were recorded between short-term and long-term applications, indicating that short-term use is sufficient for restoring the mineral balance, albeit not for all elements.

Key message

The shift in tolerance mechanisms from antioxidant to osmotic adjustments in Calligonum mongolicum, resulting in high seedling survival rates under progressively increasing saline stress, indicates the plant’s suitability for desert restoration and revegetation programs.

Abstract

Salinity is a significant barrier to vegetation renewal in the nutrient-limited saline and hyperarid Taklamakan desert. Using a pot experiment, we evaluated the growth and physiological responses of Calligonum mongolicum seedlings to saline stress (0, 50, 150, and 300 mM). The survival rate, root length, shoot length, and chlorophyll a content significantly reduced under 150 mM and 300 mM salinity compared with the control. Additionally, plant height, total biomass, and chlorophyll b content showed significant reductions across all salinity stress levels. Conversely, the chlorophyll a/b ratio increased with increasing salinity concentrations, indicating that salinity may adversely affect Chl b more than Chl a (p < 0.05). Furthermore, significant increases were observed in Na⁺, H₂O₂, and TBARS, whereas K⁺/Na⁺, K⁺, NO₃⁻, and NH₄⁺ decreased with increased stress levels. Under all treatments, superoxide dismutase, catalase, and peroxidase activities were upregulated, whereas glutamate synthase was decreased, and glutamine synthase was unaffected. Nitrate reductase activity was significantly reduced under 300 mM salinity. Moreover, significant increases were observed in proline under medium and high stress and in soluble protein under all stress levels, while soluble sugars were only increased under high stress. Our findings suggest Calligonum seedlings may sacrifice biomass production to maintain their anti-stress mechanisms. Increasing salinity concentrations may cause an increase in energy expenditure for antioxidant enzymes (at 50–150 mM) and osmotic adjustment (at 150–300 mM). Based on univariate and multivariate analyses, Calligonum seedlings subjected to low salinity can grow and survive without substantial changes in their functionality. Consequently, Calligonum seedlings may be utilized in vegetation renewal efforts in the Taklamakan desert to combat desertification under climate change scenarios.

Strawberries are one of the preferred fruits due to their attractive appearance, flavour, taste and nutritional potentials. The quality of the fruits depends on the interactions between phytochemicals and bioactive compounds. These compounds change naturally with the advancement of the fruit growth. The major focus of this study was to investigate the effect of different type of mulches on biochemical attributes during fruit growth and maturation of ‘Winter Dawn’ strawberries. The results revealed that fruits harvested from the plants treated with silver-black mulch exhibited better quality parameters compared to paddy straw, black, and red mulch treatments. With the progression of maturation, fruits developed higher light to dark red pericarp and juice colour coordinates, TSS/acid , ascorbic acid, juice pH, sugars and anthocyanin content. A decline in fruit juice acidity, chlorophyll, carotenoid, phenol, polyphenol oxidase, and flavonoids parameters was observed up to final fruit harvest stages. Correlation and regression analyses showed the complex matrices governing strawberry attributes by unveiling the interdependence of various fruit quality parameters. It is intended that silver-black mulch emerged as a better option for strawberry cultivation as it enhances fruit color and biochemical attributes.

The prediction of grain yield (GY) is one of the most important breeding objectives in agricultural research. The aim of this study was to predict GY in wheat under both non-stress and salt-stress conditions using physiological, morphological, and phonological parameters. An artificial neural network (ANN) was trained to predict GY using a multilayer perceptron model and compare the performance of ANN models with multiple linear regression (MLR) models. For these purposes, an α-lattice design was used to study 110 wheat genotypes under non-saline and saline stress conditions (EC of 2 and 10 ds m⁻¹, respectively). Our results suggest that the Iranian wheat germplasm exhibits high genetic diversity for all studied traits. The ANN model with R² values of 0.98 and 0.95 under non-stress and saline stress conditions was a more accurate tool than MLR for predicting seed yield. According to the sensitivity analysis, biological yield and harvest index were identified as the most effective traits in GY. Therefore, these traits, along with GY were used to evaluate and screen salinity-tolerant wheat genotypes through rank sum and develop an integrated selection index. Nine promising advanced lines (No. 2, 3, 5, 7, 8, 10, 11, 12, and 13) and one tolerant cultivar (No. 31) was identified as the most salinity tolerant genotype. Overall, by selecting genotypes based on the rank sum and the developed integrated selection index in a field breeding experiment, favorable wheat genotypes can be identified for non-stress and saline stress conditions.

Rice productivity is adversely affected by drought stress. Genetic improvement is key to enhance the rice productivity in the drought prone areas. Towards identification of genes/QTLs governing root system architecture, 162 rice genotypes were phenotyped for root traits viz. primary root length, total root length, area of root surface and average root diameter under non-stress and osmotic stress (− 0.15 MPa) in hydroponics conditions. 50 k SNP genotyping data of these genotypes were used for genome-wide association study (GWAS) to identify genes/QTLs for root traits. Thirty-six most significant QTLs for constitutive and stress inductive root traits were identified of which 10 were novel QTLs. In addition, several suggestive loci governing root traits were identified. The constitutive and stress inductive root traits can be utilized in development of rice varieties that can perform well under both irrigated and stress environments.

Phytoremediation is a cost-effective and environmentally friendly approach to reclaim heavy metal-contaminated soils. The phytoremediation using tree species has been preferred over annual crops as they produce higher biomass and accumulate heavy metals for prolonged period. Toona ciliata M. Roem is a large perennial tree, known to produce high biomass in short rotation, can be used for phytoremediation experiments due to their alternative use in versatile timber production and absence of linkage with food chain. Thus, present investigations were conducted to untap the potential of T. ciliata grown on lead and cadmium contaminated soils during two constitutive years 2020–21. Regarding T. ciliata raised on soils treated with different concentrations of Pb, Cd, and their combinations for six months, the results depicted that plants accumulated higher concentrations of metals in shoots than roots having bioconcentration factor (BCF) and translocation factor (TF) more than one, indicating that plants have efficient metal translocation and accumulation capability. Further, heavy metal tolerance index and survival percentage (> 85%) denote the plant’s ability to tolerate heavy metals up to 300 mgPb/kg and 25 mgCd/kg. Anatomical changes induced due to heavy metals include reduced root area as well as vascular bundle area as compared to control, also reduced stomatal pore size and increased stomatal index and trichome density suggesting the plant’s adaptive response under heavy metal stress. Furthermore, distinct accumulation patterns of lead (Pb) and cadmium (Cd) in various tissues of both leaves and roots were meticulously identified and validated through the use of cutting-edge techniques like Field Emission Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), which reflects that plant had strong enrichment ability for Pb accumulation in roots and more Cd translocation, accumulation and sequestration in aerial tissues. Hence, the present study reflects that Toona ciliata had great phytoextraction efficiency for reclaiming Pb- and Cd-contaminated soils.

Dendrocalamus asper is a woody bamboo species that has monocarpic flowering with long flowering cycles and irregular seed production, which lose viability quickly when stored under inadequate conditions. In this context, we have characterized the behavior of D. asper seeds stored under varying temperatures in the medium to long term and evaluated the behavior of reserve material throughout storage. Moreover, a simplified protocol for the cryopreservation of seeds was developed. Seeds with 11% moisture content were stored at 25 (control), 6, − 20 and – 196 °C for 0, 30, 90, 180, 360, and 600 days. After each storage period, the seeds were inoculated in vitro for germination and then the obtained plants were acclimatized. During the storage periods of 0, 360, and 600 days, seed samples were collected for biochemical analyses. In a second step, seeds were desiccated, and a portion of the seeds was placed to germinate in vitro, while a second portion was immersed in liquid nitrogen (− 196 °C) for 48 h. After this period, the cryopreserved seeds were thawed and inoculated in culture medium for germination. D. asper seeds were found to maintain viability for up to 600 days when stored at − 20 °C and – 196 °C, producing normal, whole plants. At 6 °C, the seeds can only be kept for up to 360 days. At 25 °C, there is a decrease in viability at 360 days and a marked reduction in germination at 600 days, in addition to abnormal plant development. The analysis of the biochemical composition of the seeds revealed starch as the main reserve material, followed by proteins and, in smaller amounts, lipids. Desiccation of seeds for up to 144 h resulted in a moisture content of about 5%. At this humidity, the seeds showed no differences in germinability for either the control treatment or cryopreserved seeds. The results of this study indicate, in a pioneering way, orthodox behavior of D. asper seeds, which tolerated desiccation up to 5% humidity, besides supporting storage at – 20 °C and in liquid nitrogen, with maintenance of viability for up to 600 days.

Jasmonates, which include jasmonic acid (JA) and methyl jasmonate (MeJA), are compounds derived from linolenic acid. In recent years, the quality and phytochemical content of various fruits have been improved using plant growth regulators both before and after harvest. They play a significant role in improving the quality and biochemical composition of different fruit crops, including fruit peel colour, accumulation of anthocyanins, phenolic compounds, and antioxidant activities in the fruit. Further, the fruit ripening process is also accelerated by the application of jasmonate as it influences different physiological and molecular mechanisms of the plant system including regulation of the activities of different hormones during the entire period of fruit growth and development starting from fruit set to till ripening, activation of genes related to ripening, etc. In the case of apples, pre-harvest application of MeJA leads to enhanced fruit coloration by stimulating the anthocyanin biosynthesis gene MdUFGluT. The concentration of JA increases significantly during the early fruit development stage but then decreases sharply, reaching its lowest level when the fruits are fully ripe which signifies its role in initiating the fruit ripening process. Jasmonates can also induce the expression of genes related to ethylene synthesis and promote the production of ethylene gas. Application of jasmonates at the pre-climacteric stage increased the expression of 1-Aminocyclopropane-1-carboxylate synthase 1 (ACS 1) and 1-Aminocyclopropane-1-Carboxylic Acid Oxidase1 (ACO 1) genes. However, the accumulation of ACS1 mRNA decreased when Propyl Dihydro Jasmonate was applied at the climacteric stage, indicating that jasmonates influence system 2 ethylene synthesis pathway. In addition, these two compounds (MeJA and JA) are safe for human consumption; hence, can be applied at the commercial level to improve the fruit quality and ripening process in different fruit crops. This review provides an overview of the recent advancements in our understanding of the regulation of jasmonate biosynthesis, and the physiological and molecular mechanisms involved in the jasmonate-mediated fruit ripening process.