Vanillin, a Newly Discovered Autotoxic Substance in Long-Term Potato Continuous Cropping Soil, Inhibits Plant Growth by Decreasing the Root Auxin Content and Reducing Adventitious Root Numbers.

Phenolic acids are known to reduce root biomass and hinder plant development, but it is unclear how they affect potato root traits. Over a 10 year field experiment, we found a negative correlation between the potato yield and continuous cropping years. The substantial reduction in adventitious root (AR) numbers was found to be primarily inhibited by soil vanillin accumulation. The study also found that vanillin had a more pronounced inhibitory effect on the potato yield than commonly reported ferulic acid and p-hydroxybenzoic acid. The decrease in yield was attributed to the reduction of root indole-3-acetic acid (IAA) content, which impeded the formation of AR. Exogenous IAA was found to increase the root IAA content and stimulate AR formation under vanillin stress, ultimately leading to an increase in the potato yield. This study provides valuable insights into potential strategies for the degradation of autotoxic substances and breeding of potato cultivars with enhanced resistance to autotoxicity.

Effects of different altitudes on the structure and properties of potato starch.

The main element influencing the quality of potato starch is the environment. To investigate the effects of different altitude cultivation locations on the molecular structure and physicochemical properties of starch, two potato varieties, Jiusen No.1 B1 and Qingshu No.9 B2, were planted in three different altitude zones: A1 at low altitude (Chongzhou 450 m), A2 at middle altitude (Xichang 2800 m), and A3 at high altitude (Litang 3650 m). The results showed that the average volume, number, surface area diameter, average branched polymerization degree, crystallinity, and gelatinization temperature of two potato granules in high altitude areas were significantly lower than those in middle and low altitude areas were, and the gelatinization performance of potato starch was affected according to the correlation of starch structure characteristics. Potato starch with more short-branched chains and less long branched chains resulted in a lower gelatinization temperature in high altitude areas. The results showed that Jiusen No. 1 and Qingshu No. 9 were mainly affected by accumulated radiation and accumulated rainfall in Litang, a high altitude area, and by effective accumulated temperature in Xichang, a middle altitude area. This study quantified the influence of meteorological factors on the main starch quality of potato tubers. The results can be used as a theoretical basis for the scientific planting of high-quality potatoes.

Potato tillage method is associated with soil microbial communities, soil chemical properties, and potato yield.

Intensive potato continuous cropping (IPCC) results in low potato yields compared with non-intensive potato continuous cropping (PCC) and potato-maize rotation (PMRC). However, it is still unclear whether the degree of potato continuous cropping obstacle is related to the soil environment formed by the previous crop. To investigate the effect of planting potatoes and planting maize after harvesting the spring potatoes on soil chemical properties and soil microbial community structure, an experiment was carried out in the same origin soil environment over a period of seven years: (a) PCC, i.e., spring planting; (b) IPCC, i.e., autumn and spring planting (IPCC); (c) PMRC, i.e., spring potatoes and summer maize (PMRC), and (d) fallow (CK). We confirmed that the potato yield under PMRC was significantly higher than that under PCC and IPCC. Under IPCC, soil total phosphorus content was significantly higher than other treatments, whereas ammonium nitrogen content was the lowest. Compared with PCC and IPCC, PMRC had a higher ammonium nitrogen content and lower total phosphorus content. The significantly different fungal taxa in IPCC (Glomerellales, Plectosphaerella, Thelebolales) may threaten the health of the plant and positive correlated with soil total phosphorus, while other microbial taxa in PMRC (Bacillales, Polythrincium, Helotiales) can mainly promotes plant nitrogen uptake and protects plants against diseases. The PMRC-promoting taxa were positively correlated with the ammonium nitrogen content and negative correlated with soil total phosphorus content. In summary, the cropping systems might have affected potato yields by changed soil microorganism community structures - especially fungal community structures - and by the chemical properties of the soils that also depends on microbes.

Snakin-2 interacts with cytosolic glyceraldehyde-3-phosphate dehydrogenase 1 to inhibit sprout growth in potato tubers.

The potato tuber is the main nutrient supply and reproductive organ; however, tuber sprouting can reduce its commercial value. Snakin-2 (StSN2) was first reported as an antimicrobial peptide that positively regulates potato disease resistance. Our recent study suggested StSN2 overexpression inhibited sprout growth, while the sprouting process was accelerated in StSN2 RNAi lines. Cytoplasmic glyceraldehyde-3- phosphate dehydrogenase 1 (StGAPC1) was identified as a candidate protein that interacts with StSN2 by coimmunoprecipitation/mass spectrometry (CoIP/MS) experiments. Here, we report that the expression levels of StSN2 and StGAPC1 decreased during sprouting compared with dormancy. Coexpression of StSN2 and StGAPC1 in bud eyes and apical buds was verified by immunofluorescence analysis of paraffin sections. In addition, interaction of StSN2 and StGAPC1 was confirmed by yeast two-hybrid, coimmunoprecipitation and split luciferase complementation assays. Overexpression of StGAPC1 depressed sprout growth, which is similar to the function of StSN2, and StSN2- and StGAPC1-overexpressing lines showed decreased glucose, fructose and galactose content. The interaction of StSN2 and StGAPC1 enhanced StGAPC1 activity and decreased its oxidative modification to inhibit sprout growth. Our results suggest that StSN2 plays a regulatory role in tuber sprout growth through interaction with StGAPC1.

Quantitative phosphoproteomics analysis reveals that protein modification and sugar metabolism contribute to sprouting in potato after BR treatment.

Brassinosteroids (BRs), a new class of steroid hormones, are involved in the regulation of plant cell elongation and seed germination. Nevertheless, the molecular mechanism of the effect of BRs on tuber sprouting remains largely unknown. In this study, quantitative phosphoproteomics was employed to investigate the protein phosphorylation changes in sprouting induced by BRs. Our results showed that BRs accelerated the conversion of starch into soluble sugar in tubers. A functional enrichment cluster analysis suggested that the "amino acid metabolism pathway" was upregulated and that "plant hormone signal transduction and protein export" were downregulated. BR treatment also changed the phosphorylation of proteins involved in the BR, ABA, starch and sugar signal transduction pathways, such as serine/threonine-protein kinase (BSK), 14-3-3, alpha-glucan water dikinase (GWD), sucrose-phosphate synthase (SPS), sucrose synthase (SS) and alkaline/neutral invertase (A/N-INV). These results shed more light on the pattern of protein phosphorylation in BR promoting potato sprouting.

Response of Potato Tuber Number and Spatial Distribution to Plant Density in Different Growing Seasons in Southwest China.

The aim of this study was to explore the effects of different density treatments on potato spatial distribution and yield in spring and fall. Plant density influenced yield and composition, horizontal, and vertical distribution distances between potato tubers, and spatial distribution position of tuber weights. The results indicated that: (1) Spring potato yield had a convex quadratic curve relationship with density, and the highest value was observed at 15.75 × 10(4) tubers per hectare. However, the yield of fall potatoes showed a linear relationship with plant density, and the highest value was observed at 18 × 10(4) tubers per hectare; (2) Density had a greater influence on the tuber weight of spring potatoes and fruit number of single fall potatoes; (3) The number of potato tubers in the longitudinal concentration exhibited a negative linear relationship with density, whereas the average vertical distribution distance of tubers exhibited a positive incremental hyperbolic relationship. For spring and fall potato tubers, the maximum distances were 8.4152 and 6.3316 cm, and the minimum distances 8.7666 and 6.9366 cm, respectively; and (4) Based on the artificial neural network model of the spatial distribution of tuber weight, density mainly affected the number and spatial distribution of tubers over 80 g. Tubers over 80 g were mainly distributed longitudinally (6-10 cm) and transversely (12-20 cm) within the high density treatment, and the transverse distribution scope and number of tubers over 80 g were reduced significantly. Spring potato tubers over 80 g grown at the lowest density were mainly distributed between 12 and 20 cm, whereas those at the highest density were primarily distributed between 10 and 15 cm.

[Potato Spectrum and the Digital Image Feature Parameters on the Response of the Nitrogen Level and Its Application].

In order to know the potatoes nitrogen situation rapidly and accurately, promoting the efficient use of nitrogen fertilizer on the potatoes. Using the feature of portable hyperspectral spectrometer, digital cameras and SPAD-502 chlorophyll meter to abtain the potato digital indicators, leaf spectral and SPAD. Analysing the change status of digital indicators, leaf spectral index, SPAD and production of potatoes under different nitrogen levels in two key periods. Analysing the correlation between canopy image, leaf spectral and SPAD and production, with SPAD as auxiliary validation index, nitrogen fertilizer efficiency evaluation of yield to make sure potato canopy image under the most economic nitrogen application levels and leaf spectral's critical value to explore the methods of nitrogen nutrition diagnosis quickly and simply. The results show: (1)With nitrogen levels increased, potato tuber formation stage and tuber bulking stage leaf spectral reflectance is the emergence of the "red shift" phenomenon, and the red edge parameters REP, Lwidth, FD_Max increased, Lo decreased. (2)With the nitrogen levels increased, potatoes tuber formation stage and tuber bulking stage digital indicators G/B, (G-B)/(R+G+B) decreased gradually, B/(R+G+B) increased gradually. (3) with the increase of nitrogen application rate SPAD is increased.It is obvious low nitrogen levels increase production with nitrogen increased. It is not obvious the high level of nitrogen stimulation effect. Potato canopy image, leaf spectral and red edge parameters have good correlation with SPAD value and productions, establishing the index evaluation of nitrogen nutrition abundance or lack of quantitative standard of potatoes. Indicating digital image and spectrum technology to nitrogen nutrition diagnosis of potatoes is feasible, provide research ideas and technical support for the potato accurate monitoring of nitrogen nutrition.

Optimisation of high-pressure ultrasonic-assisted extraction and antioxidant capacity of polysaccharides from the rhizome of Ligusticum chuanxiong.

High-pressure ultrasound-assisted extraction was used to extract polysaccharides from the Ligusticum chuanxiong rhizomes. Three independent variables, namely, extraction temperature (X1), ultrasonic power (X2) and extraction time (X3) were investigated. Response surface methodology was performed based on the results of single-factor tests. Experimental data were fitted to a second-order polynomial equation using multiple regression analysis, and results were examined using appropriate statistical methods. The optimal conditions were as follows: extraction temperature of 85°C, ultrasonic power of 187 W and extraction time of 29 min. Under these conditions, the experimental yield of polysaccharides was 5.33%, which is close to the predicted yield of 5.41%. The extracted and purified polysaccharides showed excellent antioxidative effects on 2,2-diphenyl-1-picryl-hydrazy, hydroxyl and superoxide radicals in vitro.

[Quantitative determination of 5 active ingredients in different harvest periods of Ligusticum chuanxiong by HPLC].

A simple and quick method is described for the determination of ferulic acid, senkyunolide I, senkyunolide H, senkyunolide A and ligustilide in rhizomes of Ligusticum chuanxiong. The 5 active ingredients in the sample was extracted using 40% ethanol and analyzed by reversed-phase high performance liquid chromatography (HPLC). Chromatography separation was performed using Agilent 1100 series HPLC system with a Symmetry C18 column and gradient elution with a mixture of three solvents : solvent A, acetonitrile, solvent B, methanol and solvent C, 1% aqueous acetic acid, 0 min to 5 min A: B: C 20: 40: 40, 5 min to 30 min A: B: C 60 to 100 : 0 : 40 to 0. The effluent was monitored using a VWD detector set at 321 nm (0-4.3 min) and 275 nm (4.31-30 min). The flow rate was set at 1 mL x min(-1) and the injection volume was 10 microL. The column temperature was maintained at 35 degrees C. The calibration curve was linear (r > or = 0.99) over the tested ranges. The average recovery was 94.44%-103.1% (n = 6). The method has been successfully applied to the analysis in different harvest periods of L. chuanxiong samples. In this paper, single-factor randomized block design to study the 5 components content of L. chuanxiong on ten collecting stages. For the L. chuanxiong collected from April 15th to May 30rd, the content of 5 ingredients increased primarily, and then decreased. Determine the appropriate harvest time has important significance to the promotion of the quality of L. chuanxiong.

Optimization of high-pressure ultrasonic-assisted simultaneous extraction of six major constituents from Ligusticum chuanxiong rhizome using response surface methodology.

High-pressure ultrasound-assisted extraction technology was applied to extract ferulic acid, senkyunolide I, senkyunolide H, senkyunolide A, ligustilide and levistolide A from Ligusticum chuanxiong rhizomes. Seven independent variables, including solvent type, pressure, particle size, liquid-to-solid ratio, extraction temperature, ultrasound power, and extraction time were examined. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize the experimental conditions (extraction temperature, ultrasonic power, and extraction time) on the basis of the results of single factor tests for the extraction of these six major components in L. chuanxiong rhizomes. The experimental data were fitted to a second-order polynomial equation using multiple regression analysis and were also examined using appropriate statistical methods. The best extraction conditions were as follows: extraction solvent: 40% ethanol; pressure: 10 MPa; particle size: 80 mesh; liquid-to-solid ratio: 100:1; extraction temperature: 70 °C; ultrasonic power, 180 W; and extraction time, 74 min.

[Effects of low-light stress on photosynthetic characteristics of Paris polyphylla var. chinensis in artificial domestication cultivation].

OBJECTIVE: To decide on the optimum artificial domestication cultivation light environment for Paris polyphylla var. chinensis through investigating the effect of light intensity on leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point of Paris polyphylla var. chinensis. METHODS: Different low-light stress gradients' effect on the growth of Paris polyphylla var. chinensis was compared with no low-light stress treatment through calculating leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point, and then all these parameters were statistically analyzed. RESULTS: Light intensity had significant influence on the photosynthetic characteristics of Paris polyphylla var. chinensis. With the strengthening of the low-light stress, chlorophyll content, gas exchange parameters, photosynthetic parameters P., AQY and light saturation point all gradually increased at first, and then decreased. However, both photosynthetic parameters Rd and light compensation point firstly decreased and then rose again. These results showed that too strong or too weak light intensity affected the optimization of photosynthetic parameters of Paris polyphylla var. chinensis. The optimal illuminance for each parameter was not completely same, but they could all reach a relative ideal state when the shading ranges between 40% and 60%. However, photosynthetic parameters deteriorated rapidly when the shading surpass 80%. CONCLUSION: For artificially cultivating Paris polyphylla var. chinensis in Baoxing,Sichuan or the similar ecological region, shading 40%-60% is the optimal light environment, which can enhance the photosynthesis of Paris polyphylla var. chinensis and promote the accumulation of photosynthetic products.

[Effects of water stress in spring on membrane lipid peroxidation in in leaves of Ligusticum chuanxiong].

OBJECTIVE: To study the effects of continuous dry-stress and full-water treatments in different periods of spring on the water condition, permeability of plasma membrane and protective enzymes activities in leaves of Ligusticum chuanxiong. METHOD: Pot cultivation method was applied and physical and biochemical indexes were measured. RESULT: Under dry-stress treatment the soil relative water content (SRWC) and the relative water content (RWC) in leaves decreased gradually with the days of treatment increased, the content of malondialdephyde (MDA) and permeability of plasma membrane increased significantly. The activities of superoxide dismutase (SOD) and catalase (CAT) increased at first and then decreased while the activity of peroxidase (POD) increased. The influence of full-water treatment to all above indexes was the same trend with that of dry-stress treatment approximately but was not significant. CONCLUSION: In this experiment, the suitable soil relative water content for growth of Chuanxiong is about 60%.

[Effect of spring topdressing on yield, ferulic acid and total alkaloids of Ligusticum chuanxiong].

A field trial was carried out to study the influence of different kinds of spring topdressing on growth, yield and quality of Ligusticum chuanxiong. The results showed that the spring topdressing had effects of improving root length, tiller numbers and plant height to some extent. At the same time the chlorophyll content and dry weight accumulation especially the dry weight of root increased significantly. It also showed that the yield increased and quality was improved significantly. The effect of different treatment with urea58.7 kg x hm(-2)(N 27 kg x hm(-2)) was the best and the treatment with N,P,K the second.