Botanical Studies最新文献

Background: Tomato plant (Solanum lycopersicum L.) suffers from numerous fungal pathogens that cause damage to yeild production qualitatively and quantitatively. One of the most destructive disease of tomato is Fusarium wilt that caused by soil borne fungus called F. oxysporum.

Methods: In this study, the anti-Fusarium capabilities of the foliar application of fungal endophytes extracts have been investigated on tomato under Fusarium challenges. Antifungal assay, inhibition of conidial germination, disease severity, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, peroxidase (POD) and polyphenol oxidases (PPO) isozymes were tested for potential resistance of tomato growing under Fusarium infection.

Results: Ethyl acetate extracts of A. flavus MZ045563, A. fumigatus MZ045562 and A. nidulans MZ045561 exhibited antifungal activity toward F. oxysporum where inhibition zone diameters were 15, 12 and 20 mm, respectively. Moreover, extracts of all fungal isolates at concentration 7.5 mg/mL reduced conidia germination from 94.4 to 100%. Fusarium infection caused a destructive effects on tomato plant, high severity desiese index 84.37%, reduction in growth parameters, photosynthetic pigments, and soluble protein. However, contents of proline, total phenol, malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and antioxidant enzymes activity were increased in tomato plants grown under Fusarium wilt. Treatment of healthy or infected tomato plants by ethyl acetate fungal extracts showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of Fusarium wilt disease on tomato plants have also been reduced by lowering MDA and H₂O₂ levels. Also, treated tomato plants showed different responses in number and density of POD and PPO isozymes.

Conclusion: It could be suggested that application of ethyl acetate extracts of tested fungal endophytes especially combination of A. flavus, A. nidulans and A. fumigatus could be commercially used as safe biostimulation of tomato plants as well as biofungicide against tomato Fusarium wilt disease.

Background: Foraminispora rugosa is a species reported from Brazil, Venezuela, French Guiana, Costa Rica and Cuba. It is a basidiomycete in the Ganodermataceae family. In this study, both chemical composition and cytotoxicity of the ethanolic extract of F. rugosa were investigated for the first time.

Results: Phylogenetic analysis confirmed the identification of the specimens, and the results of cytotoxicity assays showed that at concentrations of 7.8-500.0 µg/mL the ethanolic extract displayed weak cytotoxicity against the tested cell lines. Five oxylipins were identified by ultra high performance liquid chromatography coupled with quadrupole time-of-flight and mass spectrometry (UHPLC-QTOF-MS).

Conclusions: This study provides new insights into the current knowledge of bioactive compounds produced by macrofungi, and provides data for future biological assays with relative selectivity and safety.

Background: Alfalfa (Medicago sativa L.) is one of the most important forage crops, but its seed productivity varies from year to year due to weather conditions. Alfalfa is a forage crop rich in nutrients which makes it valuable. The present 5-year study aimed to identify the promising alfalfa varieties based on their economic and biological characteristics, such as high seed productivity, a high yield of forage mass, good quality, and stress resistance.

Results: The study contributes information about the promising varieties of alfalfa characterized by high biomass and seed productivity. Varieties such as P-88044, U-73+149 and S-302 had stable seed/green mass yields regardless of climatic conditions; hence, they may be used for alfalfa selection in the southern forest-steppe regions of Bashkortostan.

Conclusions: The present findings can be used for alfalfa selection in the Republic of Bashkortostan (Russia). In addition, the results will be of interest to crop breeders across the globe.

Background: Previous investigations carried out in ultramafic habitats emphasized the greater importance of site conditions over soil toxic metal content for vegetation composition. Very little is known about the floristic structure of the Southern Carpathian ultramafic grasslands and there is no information on the local environmental drivers of their composition and coenotic features. Here, we aim to fill these knowledge gaps by referring to similar phytocoenoses described in the Balkan Peninsula and central Europe. In particular, we searched for: (i) floristic and ecological patterns supporting the classification and taxonomic assignment of these grasslands, and (ii) simple relationships between serpentine vegetation characteristics and its physiographic environment. A total of 120 phytosociological relevés, of which 52 performed in the Southern Carpathians, were analysed through cluster, ordination and regression procedures.

Results: Despite some floristic similarities with their Balkan counterparts, the Southern Carpathian ultramafic grasslands were clustered into four distinct groups, which were assigned to as many new syntaxa: Plantago serpentinae-Armerietum halleri, Asplenio serpentini-Achnatheretum calamagrostis, Minuartio frutescentis-Plantaginetum holostei and Sileno saxifragae-Plantaginetum holostei. The latter was best individualised through the occurrence of several Carpathian endemic taxa. The first two ordination axes were significantly related with the terrain slope/presence of xerophilous species and respectively, with site elevation/presence of calcifugous species. The total plant cover showed a unimodal relationship with respect to site elevation. While controlling for the effect of the sampled area, species richness showed a unimodal response to both elevation and slope of the terrain, although their effects were not singular.

Conclusions: The syntaxonomic distinctiveness of the Southern Carpathian ultramafic grasslands is mainly supported by their overall species composition rather than regional differential species. The main limiting factors driving the composition, cover and species richness of all studied ultramafic grasslands are the water deficit at low elevation and on steep slopes, and the low soil fertility at higher elevations. Our results confirm the previous findings according to which physiographic conditions and, to a lesser extent, soil base nutrients are more important than heavy metal concentrations in structuring the ultramafic vegetation.

Background: Water scarcity is responsible for losses in the yield of many plants and this is expected to continue due to climate change. However, cowpea which is known for its drought tolerance, is considered as a plant without limitations to climate change. A two-year experiment was conducted to evaluate the effect of water restriction on phenolic compounds, antioxidant capacity and leaf nutrients concentration of four cultivars of cowpea at different growth stages. At second leaf stage, two irrigation regimes were initiated (Water irrigation was applied after 75% and 55% of field capacity, as well watered and drought stress treatment, respectively).Plants samples were collectedat three stages(immature pod, immature seed and dry seed stage) for total phenol and flavonoids content, ortho-diphenols andantioxidant capacity measurement and leaves sampling for nutrients concentration.

Results: The results indicated that polyphenolic compounds and antioxidant capacity increased under drought conditions. However, in both irrigation regimes, immature pods had the higher polyphenolic compounds, antioxidant capacity and leaf nutrients concentration rather than immature seeds and dry seeds. Among the genotypes, ILC482 revealed the highest content of total phenolics and ortho-diphenols (6.9 and 3.57 mg GA g^-1dry weight, respectively). In addition, nitrogen, phosphorus and magnesium concentration of leaves were higher in ILC482 genotype. Under drought stress, ILC482 maintained higher ABTS radical scavenging capacity (0.0083 mmol Trolox g^-1dry weight) compared to other genotypes.

Conclusions: It is suggested that drought stress affect the quality of cowpea productions through polyphenolic compounds, ABTS and DPPH radical scavenging capacity which can be used as a helpful strategy to save water in the regions where water is scare.

Background: Cambium in lianas, responsible for secondary growth, develop diverse and diagnostic traits during the climbing phase. Studies on the cross-section of Taiwanese liana cambial variants are scarce. We collected multiple stem cross-sections from 287 liana species belonging to 52 families. Each sample was examined on five occasions, and the observations were documented.

Results: The results showed that approximately 22 cambial variants types were displayed in Taiwan lianas. Among these, axial vascular elements in radial segments were the most common, followed by the variants with the irregular conformation and intraxylary phloem. Based on our assessment, we provide the following identification features of a few families: Apocynaceae had intraxylary phloem; Convolvulaceae had intraxylary phloem combined with successive cambia; Lardizabalaceae, Menispermaceae, and Ranunculaceae possessed axial vascular elements in segments; Piperaceae had external primary vascular bundle cylinder combined with axial vascular elements in segments; Vitaceae had axial vascular elements in segments combined with irregular conformation. Axial vascular elements in segments and intraxylary phloem appeared in six or five combination types, showing that these two types combined with many variants are helpful for the identification of lianas. Two species, Momordica charantia var. abbreviata, and Momordica cochinchinensis had a cambium element in the outer cylinder of cortical bicollateral vascular bundles and formed directional layers of successive cambia.

Conclusions: Our study documented regular secondary growth with a single cambium in 36 species and cambial variants present in 16 species of Taiwanese lianas. Furthermore, we provide crucial baseline data on liana cambial variations, thereby improving our understanding of their morphology and identification.

Background: The eggplant suffers from many biotic stresses that cause severe damage to crop production. One of the most destructive eggplant pathogens is Alternaria solani, which causes early blight disease. A pot experiment was conducted to evaluate the role of fungal endophytes in protecting eggplant against early blight as well as in improving its growth performance.

Results: Endophytic Aspergillus terreus was isolated from Ocimum basilicum leaves and identified morphologically and genetically. In vitro, crude extract of endophytic A. terreus exhibited promising antifungal activity against A. solani where minimum inhibitory concentration (MIC) was 1.25 mg/ml. Severity of the disease and rate of protection from the disease were recorded. Vegetative growth indices, physiological resistance signs (photosynthetic pigments, carbohydrates, proteins, phenols, proline, malondialdehyde (MDA), antioxidant enzymes), and isozymes were estimated. Alternaria solani caused a highly disease severity (87.5%) and a noticeable decreasing in growth characteristics and photosynthetic pigments except for carotenoids. Also, infection with A. solani caused significant decreases in the contents of carbohydrate and protein by 29.94% and 10.52%, respectively. Infection with A. solani caused enhancement in phenolics (77.21%), free proline (30.56%), malondialdehyde (30.26%), superoxide dismutase (SOD) (125.47%), catalase (CAT) (125.93%), peroxidase (POD) (25.07%) and polyphenol oxidase (PPO) (125.37%) compared to healthy plants. In contrast, the use of A. terreus on infected plants succeeded in recovering eggplants from the disease, as the disease severity was recorded (caused protection by 66.67%). Application of A. terreus either on healthy or infected eggplants showed several responses in number and density of peroxidase (POD) and polyphenol oxidase (PPO) isozymes.

Conclusion: It is necessary for us to address the remarkable improvement in the photosynthetic pigments, protein, carbohydrates, and enzymatic activity compared to infected control, which opens the way for more studies on the use of biocides as safe alternatives against fungal diseases.

Background: Rice is a key global food crop. Rice lodging causes a reduction in plant height and crop yield, and rice is prone to lodging in the late growth stage because of panicle initiation. We used two water irrigation modes and four fertilizer application intervals to investigate the relationship between lodging and various cultivation conditions over 2 years.

Results: Plant height data were collected and combined with aerial images, revealing that rice lodging was closely related to the nitrogen fertilizer content. The aerial images demonstrated that lodging mainly occurred in the fields treated with a high-nitrogen fertilizer, and analysis of variance revealed that plant height was signifi-cantly affected by nitrogen fertilizer. These results demonstrated that rice plant height in the booting stage was significantly positively correlated with the lodging results (r = 0.67) and nega-tively correlated with yield (r = - 0.46). If the rice plant height in the booting stage exceeded 70.7 cm and nitrogen fertilizer was continuously applied, according to the predicted growing curve of plant height, the plant would be at risk of lodging. Results showed more rainfall accumulated in the later stage of rice growth accompanied by strong instantaneous gusts, the risk of lodging in-creased.

Conclusion: The results provide predictions that can be applied in intelligent production and lodging risk management, and they form the basis of cultivation management and response policies for each growth period.

Background: Saline land in coastal areas has great potential for crop cultivation. Improving salt tolerance in rice is a key to expanding the available area for its growth and thus improving global food security. Seed priming with salt (halopriming) can enhance plant growth and decrease saline intolerance under salt stress conditions during the subsequent seedling stage. However, there is little known about rice defense mechanisms against salinity at seedling stages after seed halopriming treatment. This study focused on the effect of seed halopriming treatment on salinity tolerance in a susceptible cultivar, IR 64, a resistant cultivar, Pokkali, and two pigmented rice cultivars, Merah Kalimantan Selatan (Merah Kalsel) and Cempo Ireng Pendek (CI Pendek). We grew these cultivars in hydroponic culture, with and without halopriming at the seed stage, under either non-salt or salt stress conditions during the seedling stage.

Results: The SES scoring assessment showed that the level of salinity tolerance in susceptible cultivar, IR 64, and moderate cultivar, Merah Kalsel, improved after seed halopriming treatment. Furthermore, seed halopriming improved the growth performance of IR 64 and Merah Kalsel rice seedlings. Quantitative PCR revealed that seed halopriming induced expression of the OsNHX1 and OsHKT1 genes in susceptible rice cultivar, IR 64 and Merah Kalsel thereby increasing the level of resistance to salinity. The expression levels of OsSOS1 and OsHKT1 genes in resistant cultivar, Pokkali, also increased but there was no affect on the level of salinity tolerance. On the contrary, seed halopriming decreased the expression level of OsSOS1 genes in pigmented rice cultivar, CI Pendek, but did not affect the level of salinity tolerance. The transporter gene expression induction significantly improved salinity tolerance in salinity-susceptible rice, IR 64, and moderately tolerant rice cultivar, Merah Kalsel. Induction of expression of the OsNHX1 and OsHKT1 genes in susceptible rice, IR 64, after halopriming seed treatment balances the osmotic pressure and prevents the accumulation of toxic concentrations of Na⁺, resulting in tolerance to salinity stress.

Conclusion: These results suggest that seed halopriming can improve salinity tolerance of salinity-susceptible and moderately tolerant rice cultivars.