The Alternating Group Explicit Iterative Method for the Regularized Long-Wave Equation

An Alternating Group Explicit (AGE) iterative method with intrinsic parallelism is constructed based on an implicit scheme for the Regularized Long-Wave (RLW) equation. The method can be used for the iteration solution of a general tridiagonal system of equations with diagonal dominance. It is not only easy to implement, but also can directly carry out parallel computation. Convergence results are obtained by analysing the linear system. Numerical experiments show that the theory is accurate and the scheme is valid and reliable.

Changes in the root system of the herbaceous peony and soil properties under different years of continuous planting and replanting

The herbaceous peony(Paeonia lactiflora Pall.)has high ornamental value.Replanting problems occur when seedlings are replanted into previous holes.We studied the root system and soil environment of the'Dongjingnvlang'variety under a continuous planting regime of one,four,and seven years,and a replanting regime of one and four years.Under the condition of continuous planting,with the increase of number of years,pH,ammonium nitrogen,and nitrate nitrogen decreased in the rhizosphere and non-rhizosphere soils,whereas organic matter,available phosphorus and potassium,enzyme activities,and the number of bacteria,fungi,and actinomycetes increased.Under the condition of replanting,with the increase of number of years,fungi and actinomycetes in both soils increased,while pH,organic matter,nutrients,enzyme activities,and bacterial number decreased.pH,organic matter,nutrient content,enzyme activity and the number of bacterial were lower in soil replanted for four years,whereas the abundance of fungi and actinomycetes was higher,altering the soil from“bacterial high-fertility”to“fungal low-fertility”with increasing years of replanting.The activity of antioxidant enzymes and MDA content in roots of peony in replanting were higher than those in continuous planting,while the content of osmotic regulatory substances in replanting was lower than that in continuous planting.The results showed that there were no obvious adverse factors in soil during seven years of continuous planting,and herbaceous peony could maintain normal growth and development.However,soils after four years of replanting were not suitable for herbaceous peony growth.Benzoic acid increased with years of replanting,which potentially caused replanting problems.This study provides a theoretical basis for understanding the mechanism of replanting problems in the herbaceous peony.

Effects of Waterlogging Stress on the Physiological Characteristics and Secondary Metabolites of Herbaceous Peony (<i>Paeonia lactiflora</i>Pall.)

Herbaceous peony is an ornamental plant with medicinal properties. Waterlogging can affect its yield and quality as it grows and matures. In this study, we subjected “Taohuafeixue”, “Yangfeichuyu” and “Hongxiuqiu” herbaceous peony varieties to a simulated waterlogging stress treatment and investigated the effects of waterlogging on their physiological characteristics and the secondary metabolite contents in their leaves and roots. Short-term waterlogging caused the leaves to turn yellow or red and the roots to turn black. The stele and the cell wall of the endothelial cells thickened, and the cortical cells enlarged. Waterlogging did not significantly change plant height, leaf length, and leaf area;however, it significantly decreased the root-shoot ratio of “Yangfeichuyu” and “Hongxiuqiu” varieties. The activity of antioxidant enzymes and the content of osmotic regulators increased under waterlogging. After short-term waterlogging stress treatment, the content of paeoniflorin and albiflorin increased in the roots of “Taohuafeixue” and “Yangfeichuyu”, and the content of benzoylpaeoniflorin increased in the root of “Hongxiuqiu”. The content of gallic acid and total flavonoids increased in the leaves of “Taohuafeixue” and “Yangfeichuyu”. After the waterlogging, paeoniflorin and benzoylpaeoniflorin increased in the autumn root of “Hongxiuqiu”. This study expands our knowledge about the medicinal properties of herbaceous peony and informs about its production and cultivation under waterlogged conditions.

Analysis of the Volatile Components in Flowers of <i>Paeonia lactiflora</i>Pall. and <i>Paeonia lactiflora</i>Pall. var. <i>Trichocarpa</i>

Paeonia lactiflora Pall. var. trichocarpa is a variety of Paeonia lactiflora Pall., and is currently the peony herb’s principal cultivar group. Here, we study the differences in aromatic components and flowers of different varieties between two groups of cultivars, providing a reference for applying natural fragrance substances of peonies, breeding fragrant flower types, and developing and using improved varieties. Headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS), peak area normalization for each component relative to content, component library (NIST14/NIST14S) retrieval, and a literature review were used to analyze the volatile compounds in flowers of eight peony varieties, such as “Gaoganhong”, and ten comospore peony varieties, such as “Jinshanhong”. Results showed that the main volatile compound constituents in flowers of the two groups were terpenes and alcohols. Additionally, the content of eucalyptol, caryophyllene, α-Pinene, citronellol, and 3-Hexen-1-ol, acetate, (Z) was high. Peony cultivars contained linalool, (1R)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene, and 1,4-dimethoxybenzene, while comospore peony varieties contained 1,3,6-octatriene, 3,7-dimethyl-, (Z)-, phenylethyl alcohol, and geraniol. In this study, the differences between the volatile components of flowers of different peony varieties were clarified, laying a foundation for further molecular biology research into the floral fragrance of peonies and the cultivation of new varieties of aromatic peonies. At the same time, it also provides a theoretical basis for the development and application of peony flower by-products.

Study on the Response and Recovery Characteristics of Different Herbaceous Peony (<i>Paeonia lactiflora</i>Pall.) Varieties to Waterlogging Stress

The root of herbaceous peony (Paeonia lactiflora Pall.) is fleshy, and different varieties have different tolerance to waterlogging stress. In order to explore its response and recovery characteristics to waterlogging stress, six varieties of herbaceous peony with strong, medium and weak waterlogging tolerance and high ornamental value were selected as experimental materials. After the vegetative growth of each variety was completed, the field simulated waterlogging stress experiment was carried out by the semi-flooded (the water surface is half the height of the flowerpot) pot method. Changes in photosynthetic parameters, chlorophyll fluorescence parameters, relative water content (RWC), relative conductivity (REC), chlorophyll content, lutein cycle, and leaf microstructure were analyzed during recovery from waterlogging stress and stress relief. The results showed that the time of reaching the most significant difference between CK and tested varieties was different. From the beginning of stress to 60% of the leaves with symptoms, the varieties with strong and moderate waterlogging tolerance experienced longer time;the proportion of palisade tissue in leaves was larger;the maximum photochemical quantum yield (Fv/Fm) was reduced less;it could increase xanthophyll cycle and heat dissipation (NPQ) to consume excess light energy, and maintain a higher net photosynthetic rate (Pn) for normal growth of plants in a short period of time. The REC in leaves of varieties with weak waterlogging tolerance increased more, and the damage of cell membrane was more serious. After the stress was removed, all indexes recovered to different degrees. Based on our comprehensive analysis, the comprehensive waterlogging resistance of the experimental materials followed the pattern: “Lihong” > “Yangfeichuyu” > “Taohuafeixue” > “Dafugui” > “Qihualushuang” > “Hongxiuqiu”. It is suggested that the variety “Lihong” and “Yangfeichuyu”, with strong comprehensive waterlogging tolerance, can be selected for propagation and cultivation in areas prone to waterlogging. In the later stage, it is still necessary to further expand the number and scale of varieties, combined with the in-depth study of waterlogging-resistance genes, so as to provide a theoretical reference for the cultivation and production of new waterlogging-resistant varieties.