Effects of walnut/Rosa roxburghii compound planting on growth, fruit yield, quality of Rosa roxburghii and soil properties.

Walnut and Rosa roxburghii are important arbor and shrub fruit trees cultivated in the southwest mountainous area of China. Furthermore, those two species are compound cultivated in this area. In this study, we investigated the growth, yield, fruit quality, photosynthesis, and soil fertility of R. roxburghii in a 7-year typical 'Qianhe 7'/ 'Guinong 5' compound planting pattern in Guizhou. The results showed that compared with the monoculture, photosynthetic pigment content and photosynthetic rate of R. roxburghii leaves were significantly lower in the compound plantation. The growth and yield of R. roxburghii decreased significantly, with a 77.7% reduction of yield. Fruit quality of R. roxburghii was improved. The content of ascorbic acid (Vc), total phenol, carbohydrate, K, Ca, Mg, Fe, Mn, Zn, and other substances increased significantly. Fruit Vc and Mn content increased by 34.1% and 64.1%, respectively. The contents of total N, available N and K in the soil increased by 45.8%, 34.8% and 67.8%, respectively. The abundance of soil microorganisms and functional bacteria increased significantly, with the increase of bacteria and fungi being more than 36.0%. The increase of potassium bacteria and nitrogen fixing bacteria was 71.3% and 124.8%, respectively. However, the contents of organic matter, carbon-nitrogen ratio, total P, total K, available mineral nutrient (P, Ca, Mg, Fe, Mn, Cu, Zn) contents decreased. While the activities of soil urease and catalase were increased, the activities of other soil enzymes (sucrase, cellulase, protease, phosphatase) were significantly reduced. In summary, with continuous growth of walnuts in the walnut/R. roxburghii compound plantation, there was obvious shade and soil fertility competition for R. roxburghii, which affected its yield, but had a improvement effect on fruit quality.

First report of Diplodia mutila causing leaf blight on Magnolia grandiflora in China.

Magnolia grandiflora is a widely cultivated ornamental tree in China. In June 2020, a leaf blight disease was observed on M. grandiflora in Guizhou University (26° 44' 57'' N, 106° 65' 94'' E) in Guiyang, China. The initial symptoms on leaves were expanding round necrotic lesions with a grey center and dark brown edge, and twigs were withered when the disease was serious. Of the 100 plants surveyed 65% had symptoms. To isolate the potential causal pathogen, diseased leaves were collected from an M. grandiflora tree at Guizhou University. Isolations from made form the junction between healthy and symptomatic tissue and disinfested by immersing in 75% ethanol for 30 seconds, 3% NaOCl for 2 minutes, and then washed 3 times in sterile distilled water. Symptomatic tissue was then plated on potato dextrose agar (PDA) and incubated at 25ºC with 12-hour light for 3-5 days. Three isolates (GUCC 21235.1, GUCC 21235.2 and GUCC 21235.3) were obtained. Colonies on PDA after 7 d were dark brown, pycnidia embedded in the mydelium were dark brown to black, single and separated. Conidiophores were transparent measuring 7-12.5 × 2.5-4.5 µm (mean = 9.5 × 3.6 µm, n = 30) in length. Conidia were transparent becoming brown when mature with a diaphragm, with round ends measuring, 21-27 × 10-15 µm (mean = 23.6 × 12.6 µm, n = 30). To confirm the pathogen by molecular characterization, four genes or DNA fragments, ITS, LSU, tef1 and ß-tubulin, were amplified using the following primer pairs: ITS4-F/ ITS5-R (White et al., 1990), LR0R/ LR5 (Rehner & Samuels, 1994), EF1-688F/ EF1-986R (Carbone & Kohn, 1999) and Bt2a/ Bt2b (O'Donnell & Cigelnik, 1997). The sequences of four PCR fragments of GUCC 21235.1 were deposited in GenBank, and the accession numbers were MZ519778 (ITS), MZ520367 (LSU), MZ508428 (tef1) and MZ542354 (ß-tubulin). Bayesian inference was performed based on a concatenated dataset of ITS, LSU, tef1 and ß-tubulin gene using MrBayes 3.2.10, and the isolates GUCC 21235.1 formed a single clade with the reference isolates of Diplodia mutila (Diplodia mutila strain CBS 112553). BLASTn analysis indicated that the sequences of ITS, LSU, tef1 and ß-tubulin revealed 100% (546/546 nucleotides), 99.82% (568/569 nucleotides), 100% (302/302 nucleotides), and 100% (437/437 nucleotides) similarity with that of D. mutila in GenBank (AY259093, AY928049, AY573219 and DQ458850), respectively. For confirmation of the pathogenicity of this fungus, a conidial suspension (1×105 conidia mL-1) was prepared from GUCC 21235.1, and healthy leaves of M. grandiflora trees were surface-disinfested by 75% ethanol, rinsed with sterilized distilled water and dried by absorbent paper. Small pieces of filter paper (5 mm ×5 mm), dipped with 20 µL conidial suspension (1×105 conidia mL-1) or sterilized distilled water (as control), were placed on the bottom-left of the leaves for inoculation. Then the leaves were sprayed with sterile distilled water, wrapped with a plastic film and tin foil successively to maintain high humidity in the dark dark. After 36 h, the plastic film and tin foil on the leaves was removed, and the leaves were sprayed with distilled water three times each day at natural condition (average temperature was about 25 °C, 14 h light/10 h dark). After 10 days of inoculation, the same leaf blight began to appear on the leaves inoculated with conidial suspension. No lesion was appeared on the control leaves. The fungus was re-isolated from the symptomatic tissue. Based on the morphological information and molecular characterization, the isolate GUCC 21235.1 is D. mutila. Previous reports indicated that D. mutila infects a broad host range and gives rise to a canker disease of olive, apple and jujube (Úrbez-Torres et al., 2013; Úrbez-Torres et al., 2016; Feng et al., 2019). This is the first report of leaf blight on M. grandiflora caused by D. mutila in China.

Effect of storage temperature and time on the nutritional quality of walnut male inflorescences.

The objective of this study was to investigate the effect of storage temperature and time on nutrients, bioactive compounds, and antioxidant activities of walnut male inflorescences. The results showed that the moisture, saccharides, fat, protein, amino acids, ascorbic acid, phenolic and flavonoid compound contents, and antioxidant activities of walnut male inflorescences were markedly influenced by storage temperature, and different degrees of decrease in these parameters were observed during the entire storage period. Moreover, higher storage temperature had a more significant effect on the nutrients, bioactive compounds, and antioxidant activities of walnut male flowers, and the loss rate of these components at 25°C was higher than that determined at 4°C. However, the results also presented that the ash and mineral contents did not appear to be influenced significantly by the storage temperature, and slightly significant changes were observed in crude fiber throughout storage, which indicated that the influence of storage on the individual mineral and crude fiber content was minimal. Based on the findings in this study, in order to maximize nutrients concentration, walnut male inflorescences should be kept at 4°C for <6 days and be consumed as fresh as possible.

[Risk factors for congenital anal atresia].

OBJECTIVE: To investigate the risk factors for the development of congenital anal atresia in neonates. METHODS: A total of 70 neonates who were admitted to 17 hospitals in Foshan, China from January 2011 to December 2014 were enrolled as case group, and another 70 neonates who were hospitalized during the same period and had no anal atresia or other severe deformities were enrolled as control group. Univariate and multivariate logistic regression analyses were used to investigate the risk factors for the development of congenital anal atresia. RESULTS: The univariate analysis revealed that the age of mothers, presence of oral administration of folic acid, infection during early pregnancy, and polyhydramnios, and sex of neonates showed significant differences between the case and control groups (P<0.05). The multivariate logistic regression analysis revealed that infection during early pregnancy (OR=18.776) and male neonates (OR=9.304) were risk factors for congenital anal atresia, and oral administration of folic acid during early pregnancy was the protective factor (OR=0.086). CONCLUSIONS: Infection during early pregnancy is the risk factor for congenital anal atresia, and male neonates are more likely to develop congenital anal atresia than female neonates. Supplementation of folic acid during early pregnancy can reduce the risk of congenital anal atresia.