Botanical Studies最新文献

Background: Understanding the relationships between nutrition, human health and plant food source is among the highest priorities for public health. Therefore, enhancing the minerals content such as iron (Fe), zinc (Zn) and selenium (Se) in barley (Hordeum vulgare L.) grains is an urgent need to improve the nutritive value of barley grains in overcoming malnutrition and its potential consequencing. This study aimed to expedite biofortification of barley grains by elucidating the genetic basis of Zn, Fe, and Se accumulation in the grains, which will contribute to improved barley nutritional quality.

Results: A genome-wide association study (GWAS) was conducted to detect the genetic architecture for grain Zn, Fe, and Se accumulations in 216 spring barley accessions across two years. All the accessions were genotyped by single nucleotide polymorphisms (SNPs) molecular markers. Mineral heritability values ranging from moderate to high were revealed in both environments. Remarkably, there was a high natural phenotypic variation for all micronutrient accumulation in the used population. High-LD SNP markers (222 SNPs) were detected to be associated with all micronutrients in barley grains across the two environments plus BLUEs. Three genomic regions were detected based on LD, which were identified for the most effective markers that had associations with more than one trait. The strongest SNP-trait associations were found to be physically located within genes that may be involved in grain Zn and Fe homeostasis. Two putative candidate genes were annotated as Basic helix loop helix (BHLH) family transcription factor and Squamosa promoter binding-like protein, respectively, and have been suggested as candidates for increased grain Zn, Fe, and Se accumulation.

Conclusions: These findings shed a light on the genetic basis of Zn, Fe, and Se accumulation in barley grains and have the potential to assist plant breeders in selecting accessions with high micronutrient concentrations to enhance grain quality and, ultimately human health.

Background: Seed viability testing is essential in plant conservation and research. Seed viability testing determines the success of ex-situ conservation efforts, such as seed banking but commonly testing protocols of orchids lack consistency and accuracy, therefore, there is a need to select an appropriate and reliable viability test, especially when conducting comparative studies. Here, we evaluated the suitability of three seed viability tests, Evans blue test (EB), Fluorescein diacetate test (FDA) and Tetrazolium test (TTC), with and without sterilization, on seeds of 20 orchid species, which included five epiphytes and fifteen terrestrials, using both fresh seeds and seeds stored at - 18 ºC for 6 to 8 years.

Results: We found that sterilization and lifeform of seeds affected seed viability across all tests but the storage time was not an influential factor. Sterilization negatively affected seed viability under EB and FDA test conditions but increased the detection of viable seeds in the TTC test in both epiphytic and terrestrial species. The EB test, when administered without sterilization provided the highest viability results. Being non-enzymatic unlike TTC and FDA tests, as expected, the EB test was the most reliable with similar results between sterilized and not sterilized seeds for most epiphytic and terrestrial species as well as when compared between groups.

Conclusions: The lifeform of the species and seed sterilization prior to testing are important influential factors in orchid seed viability testing. Since EB test was found to be reliable we recommend the EB test for seed viability assessment in orchids rather than the less reliable but commonly used TTC test, or the FDA test, which require more expensive and sophisticated instrumentation. Since storage time was not an influential factor in orchid seed viability testing, the recommendations of this study can be used for both fresh as well as long-term stored orchid seeds. This is helpful for research and especially for conservation measures such as seed banking. However, due to the species specificity of the bio-physiology of orchids, we call for comprehensive viability test assessment in the hyper diverse orchid family to be extended to a greater number of species to facilitate efficient conservation and research.

Background: Against the background of a changing climate, the responses of functional traits of plateau wetland plants to increasing temperatures and CO₂ concentrations need to be understood. Hydraulic traits are the key for plants to maintain their ecological functions and affect their growth and survival. However, few studies have comprehensively considered the response strategies of wetland plants' hydraulic traits to environmental changes in the context of water and matter transport, loss, and retention. According to the latest IPCC prediction results, we performed experiments under increased temperature (2 °C) and CO₂ levels (850 μmol/mol) in an artificial Sealed-top Chamber (STC) to investigate the responses of the hydraulic characteristics of Schoenoplectus tabernaemontani, the dominant species in plateau wetlands in China.

Results: Compared with the CK group, net photosynthetic rate, transpiration rate, stomatal length, cuticle thickness, vascular bundle length, vascular bundle width, and vascular bundle area of S. tabernaemontani in the ET group were significantly reduced, whereas stomatal density and vein density increased significantly. Compared with the CK group, the hydraulic traits of S. tabernaemontani in the EC group were reduced considerably in stomatal length and cuticle thickness but increased dramatically in stomatal density, and there were no significant differences between other parameter values and the control group. Net photosynthetic rate was significantly positively correlated with stomatal length, cuticle thickness, and vascular bundle length, and stomatal conductance was significantly positively correlated with cuticle thickness. The transpiration rate was significantly positively correlated with cuticle thickness, epidermal cell area, vascular bundle length, vascular bundle width, and vascular bundle area. Regarding the hydraulic traits, there was a significant negative correlation between stomatal density and stomatal length, or cuticle thickness, and a significant positive correlation between the latter two. The epidermal cell area was significantly positively correlated with epidermal thickness, vascular bundle length, vascular bundle width, and vascular bundle area.

Conclusions: Increased temperature and CO₂ levels are not conducive to the photosynthetic activity of S. tabernaemontani. Photosynthetic rate, stomatal density and size, vein density, epidermal structure size, and vascular bundle size play an essential role in the adaptation of this species to changes in temperature and CO₂ concentration. In the process of adaptation, hydraulic traits are not isolated from each other, and there is a functional association among traits. This study provide a scientific basis for the management and protection of plateau wetlands.

Background: The oogamous green algal genus Volvox exhibits extensive diversity in mating systems, including heterothallism and homothallism with unisexual (male and/or female) and/or bisexual spheroids. Although four mating systems have been recognized worldwide in strains identified as "Volvox africanus", most of these strains are extinct. However, we previously rediscovered two types of the four mating systems (heterothallic, and homothallic with male and bisexual spheroids within a clone) from an ancient Japanese lake, Lake Biwa.

Results: Here, we obtained strains exhibiting the third mating system (homothallic with unisexual male and female spheroids within a clone) from a freshwater area of Kalasin Province, Thailand. When sexual reproduction was induced in the present Thai strains, both male and female unisexual spheroids developed to form smooth-walled zygotes within a clonal culture. Phylogenetic analyses of the internal transcribed spacer region-2 of nuclear ribosomal DNA sequences from all four mating systems, including the extinct strains, resolved the third mating system is basal or paraphyletic within the homothallic clade.

Conclusions: The present morphological and molecular data of the Thai strains indicate that they belong to the homothallic species V. africanus. The phylogenetic results suggested that third mating system (homothallic with separate male and female sexual spheroids) may represent an initial evolutionary stage of transition from heterothallism to homothallism within Volvox africanus. Further field collections in geologically stable intracontinental regions may be fruitful for studying diversity and taxonomy of the freshwater green algal genus Volvox.

Background: Cymbidium goeringii, belonging to the Orchidaceae family, is an important ornamental plant with striking petals and lips. Extremely diversified floral patterns and morphologies make C. goeringii good research material to examine floral development of orchids. However, no floral organ-specific protein has been identified yet. To screen floral development associated proteins, four proteomes from petal (PE), lip (LI), gynostemium (GY), and sepal (SE) were analyzed using Tandem Mass Tag-based proteomic analysis.

Results: A total of 6626 unique peptides encoding 2331 proteins were identified in our study. Proteins in several primary metabolic pathways, including amino acid metabolism, energy metabolism, and lipid metabolism, were identified as differentially expressed proteins. Interestingly, most of the energy metabolism-related proteins highly expressed in SE, indicating that SE is an important photosynthetic organ of C. goeringii flower. Furthermore, a number of phytohormone-related proteins and transcription factors (TFs) were identified in C. goeringii flowers. Expression analysis showed that 1-aminocyclopropane-1-carboxylate oxidase highly expressed in GY, IAA-amino acid hydrolase ILR1-like 4 and gibberellin receptor 1 C greatly expressed in LI, and auxin-binding protein ABP20 significantly expressed in SE, suggesting a significant role of hormones in the regulation of flower morphogenesis and development. For TFs, GY-highly expressed bHLH13, PE-highly expressed WRKY33, and GY-highly expressed VIP1, were identified.

Conclusions: Mining of floral organ differential expressed enzymes and TFs helps us to excavate candidate proteins related to floral organ development and to accelerate the breeding of Cymbidium plants.

Background: Light is the ultimate energy source of plant photosynthesis, which has an important impact on the growth, development, physiology and biochemistry of tea plant. Photosensitive etiolated tea plant belongs to a kind of colored leaf plant, which is a physiological response to light intensity. Compared with conventional green bud and leaf of tea plant, the accumulation of pigment compounds (chlorophyll and carotenoids, etc.) closely related to a series of reactions of photosynthesis in photosensitive etiolated tea plant is reduced, resulting in the difference of leaf color of tea. This specific tea resource has high application value, among which high amino acid is one of its advantages. It can be used to process high-quality green tea with delicious taste and attractive aroma, which has been widely attention. The mechanism of the color presentation of the etiolated mutant tea leaves has been given a high topic and attention, especially, what changes have taken place in the pigment compounds of tea leaves caused by light, which makes the leaves so yellow. At present, there have been a lot of research and reports.

Purpose of the review: We describe the metabolism and differential accumulation of key pigment compounds affecting the leaf color of photosensitive etiolated tea that are triggered by light, and discuss the different metabolism and key regulatory sites of these pigments in different light environments in order to understand the "discoloration" matrix and mechanism of etiolated tea resources, answer the scientific question between leaf color and light. It provides an important strategy for artificial intervention of discoloration of colored tea plant.

Conclusion: The differential accumulation of pigment compounds in tea plant can be induced phytochrome in response to the change of light signal. The synthesis of chlorophyll in photoetiolated tea plants is hindered by strong light, among which, the sites regulated by coproporphyrinogen III oxidase and chlorophyllide a oxidase is sensitive to light and can be inhibited by strong light, resulting in the aggravation of leaf etiolation. The phenomenon can be disappeared or weakened by shading or reducing light intensity, and the leaf color is greenish, but the increase of chlorophyll-b accumulation is more than that of chlorophyll-a. The synthesis of carotenoids is inhibited strong light, and high the accumulation of carotenoids is reduced by shading. Most of the genes regulating carotenoids are up-regulated by moderate shading and down-regulated by excessive shading. Therefore, the accumulation of these two types of pigments in photosensitive etiolated tea plants is closely related to the light environment, and the leaf color phenotype shape of photosensitive etiolated tea plants can be changed by different light conditions, which provides an important strategy for the production and management of tea plant.

Background: Water-deficit stress is known as one of the most severe environmental stresses affecting the growth of plants through marked reduction of water uptake, which leads to osmotic stress by lowering water potential. Adopting appropriate varieties using soil microorganisms, such as arbuscular mycorrhiza (AM) fungi, can significantly reduce the adverse effects of water deficiency. This study aimed to evaluate the role of Funneliformis mosseae on nutrient uptake and certain physiological traits of two chamomile varieties, namely Bodgold (Bod) and Soroksári (Sor) under osmotic stress. For pot culture, a factorial experiment was performed in a completely randomized design with three factors: osmotic stress (PEG 6000) was applied along with Hoagland solution at three levels (0, -0.4 and -0.8 MPa), two German chamomile varieties (Bodgold (Bod) and Soroksari (Sor)), and AM inoculation (Funneliformis mosseae species (fungal and non-fungal)) at four replications in perlite substrate.

Results: Osmotic stress significantly reduced the uptake of macro-nutrients (N and P) and micro-nutrients (Fe, Cu, Mn, and Zn) in the shoots and roots. Moreover, the level of osmolytes (total soluble sugars and proline) and the activity of antioxidant enzymes in the shoots of both varieties increased under osmotic stress. Regarding the Sor variety, the level of these compounds was more satisfactory. AM improved plant nutrition uptake and osmolyte contents while enhancing antioxidant enzymes and reducing the adverse effects of osmotic stress. Under osmotic stress, the growth and total dry weight were improved upon AM inoculation.

Conclusions: In general, inoculation of chamomile with AM balanced the uptake of nutrients and increased the level of osmolytes and antioxidant enzymes; hence, it improved plant characteristics under osmotic stress in both varieties. However, it was found to be more effective in reducing stress damages in the Sor variety.

Background: Phosphorus (P) is the limiting nutrient in many mature tropical forests. The ecological significance of declining P stocks as soils age is exacerbated by much of the remaining P being progressively sequestered. However, the details of how and where P is sequestered during the ageing in tropical forest soils remains unclear.

Results: We examined the relationships between various forms of the Fe and Al sesquioxides and the Hedley fractions of P in soils of an incipient ferralitic chronosequence on an altitudinal series of gently sloping benches on Green Island, off the southeastern coast of Taiwan. These soils contain limited amounts of easily exchangeable P. Of the sesquioxide variables, only Fe and Al crystallinities increased significantly with bench altitude/soil age, indicating that the ferralisation trend is weak. The bulk of the soil P was in the NaOH and residual extractable fractions, and of low lability. The P fractions that correlated best with the sesquioxides were the organic components of the NaHCO₃ and NaOH extracts.

Conclusions: The amorphous sesquioxides, Fe_o and Al_o, were the forms that correlated best with the P fractions. A substantial proportion of the labile P appears to be organic and to be associated with Al_o in organic-aluminium complexes. The progression of P sequestration appears to be slightly slower than the chemical and mineralogical indicators of ferralisation.

Background: Based on world experience, first, a modern assessment of the flora is needed to develop strategies for the conservation of ecosystems of rare and endangered plant species. A regional and global biodiversity strategy should focus on assessing the current state of bioresources. To preserve the biodiversity of the species and its habitat, we evaluated botanical features, ontogenetic phases, the ecological and phytocenotic structure of the rare and endangered of Rhodiola rosea L. (golden rose root) populations from the highlands of Eastern Kazakhstan.

Results: R. rosea in the study region lives on damp mossy rocks, rocky slopes, overgrown moraines and along the banks of mountain rivers in the upper limit of cedar-larch forests, subalpine and alpine belts, in the altitude limit of 1700-2400 m. In the studied region, R. rosea begins to vegetate in May-June, blooms in June-July, the fruits ripen in August. The species is encountered in the high mountain ranges of the Kazakh Altai and Saur-Tarabagatai. Unfavorable habitat conditions for the species are overgrown by sedge-grass and birch-moss communities. The most common species at sites with R. rosea are: Schulzia crinita, Achillea ledebourii, Doronicum altaicum, Macropodium nivale, Hylotelephium telephium, Rhodiola algida, Carex capillaris, C. aterrima. Ontogenetic study revealed that all age-related phases were present, with the exception of the senile states. Individual life expectancy shown to be 50-55 years. The analysis of the species composition in the communities with R. rosea showed that the leading families in terms of the number of accompanying species are Poaceae, Ranunculaceae, Asteraceae, Rosaceae and Caryophyllaceae, Apiaceae, Fabaceae; while the most dominant genera are: Carex, Aconitum, Dracocephalum, Festuca, Pedicularis, Poa, Salix; the ecological groups are dominated by psychrophytes, mesophytes mesopsychrophytes; the Asian, Eurasian, and Holarctic groups are the most represented groups. Dominant life forms according to Serebyakov were rod-rooted, brush-rooted, short-rooted and long-rooted grasses, while based on Raunkiaer's groups the overwhelming majority consisted of Hemincryptophytes (74%).

Conclusions: The R. rosea populations of Kazakhstan represent an important gene stock of the species. Our study provides new insights into the species' biology thus contributes to the conservation of biodiversity on a wide spatial scale.

Background: Many groups of fungi live as an endophyte in plants. Both published and undiscovered bioactive compounds can be found in endophytic fungi. Various biological activities of bioactive compounds from endophytic fungi had been reported, including anti-inflammatory and anticancerous effects. The chemical investigation of biologically active compounds from endophytic fungi Melaleuca leucadendra Linn. have not yet been stated.

Results: One new compound, namely nigaurdiol (1), along with five known compounds, xyloketal K (2), bostrycin (3), deoxybostrycin (4), xylanthraquinone (5), and ergosterol (6), were isolated from the Melaleuca leucadendra Linn. associated fungal strain Nigrospora aurantiaca ^#TMU062. Their chemical structures were elucidated by spectroscopic data and compared with literature. All isolated compounds were evaluated for inhibitory effect of NO production in LPS-activated microglial BV-2 cells.

Conclusions: Compound 6 exhibited considerable inhibitory effect on NO production with IC₅₀ values of 7.2 ± 1.4 µM and the survival rate of the cells was 90.8 ± 6.7% at the concentration of 10 µM.