Acta Physiologiae Plantarum最新文献

Methyl jasmonate (MeJA) is a phytohormone involved in plant defense against stress. However, its application as pretreatment in soybean seeds is limited. Here, we investigated whether seed pretreatment with MeJA mitigated the negative effects of water restriction (WR) and mechanical wounding (MW) in soybean seedlings at the V1 vegetative stage. Seeds of Glycine max (Monsoy 6410 variety) were pretreated with water or 12.5 µM MeJA for 14 h. The obtained seedlings were transferred to pots containing substrate (soil and sand) kept in a greenhouse and subjected to different growth conditions: control (no stress), WR (40% water retention), and MW. The experiment was conducted in a 2 × 3 factorial scheme (2 seed pretreatments × 3 growth conditions). The variables analyzed were ethylene levels, hydrogen peroxide, lipid peroxidation, antioxidant system enzymes, sugars, amino acids, proteins, proline, and growth (root and shoot length). WR negatively affected seedling growth, regardless of seed pretreatment, but proline levels increased with MeJA application. In seedlings subjected to MW, MeJA increased ethylene release, which was related to reduced damage. It suggests that pretreatment of soybean seeds with MeJA is a promising tool to mitigate the deleterious effects of biotic and abiotic stresses during seedling establishment, inducing distinct tolerance strategies.

Climate change is introducing several challenges to agriculture’s sustainability. The drought stress is hampering cereal crop productivity. There is an increasing interest in exploring how well physiological flexibility in plants can buffer drought stress. Our study investigated how plant growth-promoting bacteria (PGPB) and SORGAAB, which is a water-based extract of Sorghum bicolor L. (10 g/100 ml), affect the physiological, biochemical, and vegetative profiles of Zea mays L. under drought conditions (50% field water capacity). Among all treatments, the application of drought + PGPB + SORGAAB spray at the three-leaf phase (V3) showed significant improvement in growth. We found that the drought + PGPB + SORGAAB treatment increased the amount of amylase (58%), chlorophyll-a and b (67 and 83%, respectively), catalase (58%), superoxide dismutase (45%), peroxidase (52%), and crude protein (69%), compared to the drought treatment alone. However, H₂O₂ levels went down by 57%. Our results also showed a 90.5% and 95% increase in macro- and micronutrient concentrations, respectively, under PGPB + SORGAB treatment. The combined application of PGPB + SORGAAB at the V3 phase was more effective in enhancing the vegetative biomass by yielding 2.41 and 5.67 g/pot of the shoot and root dry weights, thereby impacting the root-to-shoot ratios, and enabling maize plants to improve growth under drought conditions.

Fritillaria cirrhosa is a remarkably representative endangered species on the plateau, and its phenotype has undergone dramatic alterations due to global climate change and habitat destruction. However, the mechanism behind the phenotypic change associated with color variation has not been characterized, and subsequent physiological responses are still unknown. We investigated different phenotypes of cultivated F. cirrhosa and conducted a comprehensive transcriptomic analysis. Their agronomic traits, photosynthetic parameters, and the content of pharmaceutical ingredients were also compared. In the transcriptomic profiling, the purple phenotype had 754 up-regulated and 980 down-regulated genes compared with the green F. cirrhosa, in which a total of 37 significant differential expression genes (DEGs) regulated the anthocyanin biosynthesis by coding 6 vital enzymes (C4H, F3′H, ANS, DFR, DFT, and BA1). These DEGs were key genes responsible for the form of the purple phenotype of F. cirrhosa. Moreover, 10 DEGs were observed to be related to biotic and abiotic stress responses, such as regulation of defense response to bacterium and UV regulation in the actual unshaded field environment. The results of agronomic traits indicated that the purple phenotype exhibited a multitude of merits in plant height and stem diameter (p < 0.05), and produced more high-quality fruit and seeds, which demonstrated that the purple phenotype has high regeneration ability and potential resistance to cultivation conditions. Importantly, the content of total alkaloids as bioactive ingredients in medicinal bulbs of purple F. cirrhosa was significantly higher than that in the green phenotype by 57.14%. Overall, the present study not only reveals the potential mechanisms of phenotypic variation in F. cirrhosa but also contributes to a better understand adaptation of highland species related to ecological changes, as well as paves the way for the further breeding and large-scale cultivation of F. cirrhosa.

Modified atmospheric packaging (MAP) has emerged as a leading postharvest technique to minimize losses and maintain quality of cut products. The present investigation was conducted to design passive MAP for gladiolus spikes to enhance their postharvest life. The harvested spikes (tight bud stage) were packed in low-density polyethylene (LDPE, 150 guage) and polypropylene (PP, 100 gauge) at 5 °C and 10 °C from 4 to 24 days. The MAP design was based on respiration rate and weight of gladiolus spikes, storage temperature, package gas exchange area and desirable in-pack O₂ and CO₂ concentrations (O₂: 3–5%, CO₂: 5–8%). The headspace O₂ and CO₂ concentrations (%) in PP package were, respectively, 5.05 and 7.35 at 5 °C, whereas 4.55 and 8.05 at 10 °C after storage for 8 days. Further, the vase life of spikes in these PP package was 13.86 days after 8 days of storage and declined to 8.86 days after 12 days of storage. The gladiolus spikes packed in PP sleeve (120 cm length, 18 cm width and 50 perforations) could be best stored vertically in cold room (5 ± 0.5 °C) for 10 days with acceptable flower quality and vase life up to 13 days as supported by higher membrane stability index, relative water content, total soluble sugars and proteins, and lower lipid peroxidation. Thus, designed MAP gives a window of 7 days (postharvest life of unpacked spikes 16 days and packed 23 days) for market regulation during glut period to earn remunerative prices without any adverse effect on quality.

Spinach (Spinacia oleracea L.) is a well-known leafy plant with valuable nutritional properties. The nutritional and marketing values of vegetables are highly affected by bolting. So far, researchers have studied the morphological properties of spinach, but its traits and characteristics in accessions with different bolting times have not been comprehensively studied. Therefore, the study was carried out to investigate the variations in morpho-biochemical characteristics of different spinach accessions based on bolting time. This study aims to find out whether or not bolting time causes morpho-biochemical changes in different spinach accessions. Here, "Varamin 88", "Matador", "D'inverno", "Viroflay" and "Spinagh" were used as late-bolting accessions groups, while "Lorestan" and "Kashan" were applied as early-bolting accessions groups. This spring field experiment was set up in a complete randomized block of 3 replicates and 18 observations. The results revealed significant differences between the early- and late-bolting spinach accessions (comparisons between groups) in their leaf number, plant height, yield, fresh and dry shoot weight, day to bolting, flavonoid, phenol, vitamin C, carbohydrate, nitrate, calcium (Ca), and iron (Fe) content. Late-bolting spinach group had more leaf numbers (23.9% increase), yield (64.3% increase), fresh and dry shoot weight (56.4% and 74% increase), day to bolting (55.9% increase), flavonoid (40.6% increase), phenol (37% increase), vitamin C (7.2% increase), and nitrate (37% increase), while early-bolting spinach group only had more plant height (45.9% increase), carbohydrate (21.8% increase), calcium (87.5% increase), and iron content (more than 100% increase). The biplot analysis showed the superiority of the late-bolting spinach accession dry and fresh weight, flavonoid, phenol, and vitamin C in spring planting. Conclusively, it was found that early-bolting spinach accessions were taller in leaf and petiole form, which is an advantage for mechanized harvesting. Late-bolting spinach accessions, particularly "Viroflay" and "Varamin 88" among the non-Iranian and Iranian masses, respectively, were preferred for spinach production and biochemical features, according to PCA and cluster analysis. This study recommends that if the quantity of production is important, the farmers use late-bolting plants for cultivation, and if mechanization is important, they use early-bolting plants for cultivation.

Weeds are one of the biotic factors that cause crop productivity losses worldwide. Due to the consequences to human health and the environment of the indiscriminate use of synthetic herbicides, alternative methods involving the use of the allelopathy phenomenon have been gaining prominence. Here, we explore the allelopathic effect of Jatropha gossypiifolia L. on the weed Bidens bipinnata L. and investigate its potential herbicidal allelochemicals. In vitro bioassays demonstrated that the use of J. gossypiifolia leaf powder was able to inhibit seed germination and early growth of B. bipinnata seedlings, obtaining significant reductions with increasing concentration. Bioguided fractionation of the aqueous extract indicated that the hexane and ethyl acetate fractions were bioactive in inhibiting weed growth. Metabolomics based on mass spectrometry and molecular networks was used to annotate the allelochemicals of the bioactive fractions, generating the dereplication of metabolites from the classes of alkaloids, phenolics, fatty acids, steroids, and terpenoids, which may be associated with herbicidal activity. These results point to the allelopathic effect of the J. gossypiifolia leaf powder and its putative herbicide allelochemicals, providing subsidies for future studies on the application of this species in alternative weed management strategies.

Although forage cactus is a CAM plant capable of adjusting to adverse conditions, little is known about the regulation of the antioxidant defense system under typical growth conditions and even less under competitive environment such as intercropping system. Therefore, this study aimed to investigate the regulation of the antioxidant defense system in three forage cactus genotypes grown in intercropping. The experimental design was in randomized blocks set up in a 3 × 2 factorial with three replications, consisting of three forage cactus genotypes (‘Orelha de Elefante Mexicana’—Opuntia stricta (Haw.), ‘Miúda’—Nopalea cochenillifera (L.) Salm. Dyck, and ‘Baiana’ – N. cochenillifera (L.) Salm. Dyck) and two cropping systems (monocropping and intercropping with Gliricidia sepium). Intercropping significantly affected the antioxidant metabolism of forage cactus genotypes. ‘Orelha de Elefante Mexicana’ in intercropping showed higher contents of photosynthetic pigments and H₂O₂, and activities of SOD (EC 1.15.1.1) and CAT (EC 1.11.1.6), and lower contents fresh mass, dry mass, and MDA, and activity of APX (EC 1.11.1.11), than under monocropping. ‘Miúda’ showed similar results except for dry mass, which was the same in both cropping systems. In turn, ‘Baiana’ in intercropping showed higher contents of fresh and dry mass, water, photosynthetic pigments, and H₂O₂, activities of SOD, CAT, and APX, and lower lipid peroxidation than under monocropping. Thus, intercropping favored the ‘Baiana’ as a function of the effective role of the antioxidant enzyme system, reducing lipid peroxidation, maintaining the stability of the photosynthetic process, and increasing growth.

Salt stress is a worldwide major threat to agricultural production. The aim was to investigate the effects of exogenous dopamine (DA) treatments on physiological, morphological and biochemical characteristics of tomato seedlings under salinity stress. Salt stress was created using a 100 mM NaCl solution. Dopamine solutions (0, 50, 100 and 200 µM) were applied with 7-day intervals. Salt stress significantly suppressed plant growth and DA treatments alleviated the negative effects of salt stress on the growth of tomato seedlings. 100 µM DA treatment increased plant and root dry weights, plant stem diameter, plant height and, leaf area by 286.84%, 150.00%, 108.37%, 160.89%, and 158.28%, respectively, compared to the control. Under salinity LRWC, SPAD, chl-a, chl-b, and total chlorophyll contents decreased; membrane permeability (MP), H₂O₂, MDA, proline and sucrose contents, CAT, POD and SOD activities increased. Under salt stress, when 100 µM DA was applied, LRWC, SPAD, chl-a, chl-b, and total chlorophyll contents of plants increased by 13.64%, 18.62%, 43.08%, 64.90%, and 50.00%, while MP reduced by 21.08% compared to the control. When 200 µM DA was applied under salt stress, H₂O₂, MDA, proline and sucrose contents, and CAT, POD and SOD activities were reduced by 31.86%, 18.66%, 56.00%, 38.24%, 11.16%, 17.81% and 10.80%, respectively, compared to non-DA-treated plants. Exogenous application of DA increased IAA content, decreased ABA content and increased ratio of K⁺/Na⁺ and Ca²⁺/Na⁺ under salt stress as well. In conclusion, exogenous dopamine treatments effectively prevent cellular damage in tomato seedlings and improve plant tolerance to salt stress.

The mechanisms of tolerance to desiccation are one of the main factors related to the ability to survive the conditions of water deficit imposed by abiotic stress. Understanding the limits of desiccation tolerance in species and environmental factors promotes this capacity, which is of great ecological importance since it can help in the choice of species used for ecological recovery. In this study, we analyze tolerance limits, and physiological and biochemical parameters in desiccation tolerance (DT) of Tabebuia aurea (Silva Manso) Benth. & Hook.f. ex S. Moore (Bignoniaceae) seeds and germinating seeds. First, we analyzed the DT in seeds under different free water contents (0.25, 0.75, 1.5, 2.25, and 3% of free water content) in silica gel at 25 °C and forced air circulation oven at 40 °C. During development, we evaluated the ability of germinating seeds with different root sizes (0 to 2, 2 to 5, and 5 to 10 mm) to tolerate desiccation. We quantified reducing sugars and total proteins in all evaluated treatments. Seeds and seedlings of T. aurea showed large DT to both types of desiccation. The concentration of reducing sugars increased with decreasing seed-free water contents. The germinating seed also contents of reducing sugars reduced. We conclude that the large DT before and after germination of T. aurea with roots of up to 10 mm is related to changes in biochemical mechanisms that are important to maintaining this tolerance.

The role of protein modifications and amino acid metabolism in the dormancy breaking of pistachio (Pistacia vera L.) kernels during moist chilling (5 ºC) and warm stratification (25 ºC) were studied. Cold-stratified kernels showed germination up to 97%, while warm-stratified ones had low germination (40%). Increased protein solubility at neutral pH was accompanied by protein carbonylation in both cotyledons and embryonic axes during cold treatment, whereas these values decreased under warm incubation. Amino acid accumulation occurred in both tissues of cold- and warm-stratified kernels. Arginase activity increased in both tissues of cold-stratified kernels but significantly declined during warm treatment. While arginine decarboxylase activity of both organs increased under cold and warm stratification of pistachio kernels, ornithine aminotransferase activity declined during these periods. These results show that increased protein solubility and its carbonylation during cold stratification may induce the protein mobilization and accumulation of amino acids for their subsequent direction to the proper metabolic pathways. In this way, protein modification and arginine metabolism by arginase can be considered germination-specific events during cold stratification of kernels.