Comparison of the Endophytic Bacterial Microbiota of Asymptomatic and Symptomatic Ginger Rhizomes During the Activation of Adventitious Bud Development.

Bacterial infections are the cause of rhizome rot in ginger (Zingiber officinale). Key members of the endophytic microbial community in ginger rhizomes have not been identified, and their impact on the decay of rhizomes during the activation of adventitious bud development has not been investigated. High-throughput, 16S rRNA amplicon sequencing and inoculation experiments were used to analyze the microbial diversity, community structure and composition, and pathogenicity of isolated bacteria. Our results indicated that the composition of the endophytic microbiota underwent a shift during the progression of rhizome rot disease. Enterobacteriaceae, Lachnospiraceae, and the bacterial genera Clostridium, Bacteroides, Acrobacter, Dysgonomonas, Anaerosinus, Pectobacterium, and Lactococcus were relatively abundant in the bacterial community of rhizomes exhibiting bacterial decay symptoms but were also present in asymptomatic rhizomes. The presence of Enterobacteriaceae and Pseudomonadaceae were positively correlated (ρ = 0.83) at the beginning of the sampling period in the symptomatic group, while a positive correlation (ρ = 0.89) was only observed after 20 days in the asymptomatic group. These data indicate that the co-occurrence of Enterobacteriaceae and Pseudomonadaceae may be associated with the development of ginger rot. Bacterial taxa isolated from ginger rhizomes, such as Enterobacter cloacae, E. hormaechei, and Pseudomonas putida, induced obvious rot symptoms when they were inoculated on ginger rhizomes. Notably, antibiotic-producing bacterial taxa in the Streptococcaceae and Flavobacteriaceae were also relatively abundant in rhizomes with rot and appeared to be linked to the onset of rhizome rot disease. Our results provide important information on the establishment and management of disease in ginger rhizomes.

Ginger Straw Waste-Derived Porous Carbons as Effective Adsorbents toward Methylene Blue.

In this work, ginger straw waste-derived porous carbons, with high adsorption capacity, high adsorption rate, and good reusability for removing the toxic dye of methylene blue from wastewater, were prepared by a facile method under oxygen-limiting conditions. This study opens a new approach for the utilization of ginger straw waste, and the porous materials can be employed as great potential adsorbents for treating dye wastewater.

[Relationship between tumorous stem mustard yield and soil fertility in Fuling, Southwest China].

By combining field investigation and indoor chemical analysis, the relationship between tumorous stem mustard yield and soil fertility factors was investigated in the main planting areas of tumorous stem mustard in Fuling, Southwest China. The results showed that available Ca, Mg, Fe, Mn, Cu and Zn in the soil were rich (3034, 260, 11.2, 26.1, 1.15 and 1.50 mg x kg(-1), respectively), available P was moderate (19.3 mg x kg(-1)), and organic matter, available N, available K and available S were deficient (9.05 g x kg(-1), 89.2 mg x kg(-1), 106 mg x kg(-1) and 27.0 mg x kg(-1), respectively). The yield of tumorous stem mustard was significantly positively correlated with soil pH and available Ca, whilst significantly (P < 0.01) negatively correlated with available Fe. The influence order of soil fertility factors on the yield of tumorous stem mustard was available Mn > available Cu > pH > available Fe > available K > available Ca > available Mg > available S > available N > available Zn > organic matter > available P. The linear equation (Y = 31636 + 3.63X(6)) of soil available Ca and the yield, was established by stepwise regression analysis.

[Relationship between vegetable nutrition and nitrate content].

Nitrate accumulation in vegetables, which related well to vegetable nutrition, becomes one of the limiting factors of non-pollution vegetables production. Preference to nitrate is the nutritional characteristic of vegetables. Nitrate is absorbed by vegetables through high-affinity transport system (HATS) and low-affinity transport system (LATS), and is reduced and transformed under the effect of such essential elements as molybdenum, manganese, iron, copper, sulphur and phosphorus. In this paper, the effects of essential elements on nitrate absorption and reductive transform were reviewed, and the relationships of nitrate accumulation in vegetables with vegetable nutrition of nitrogen, phosphorus, potassium and mid-and microelements as well as with balanced fertilization were discussed. The research keys in the field were prospected for controlling nitrate accumulation, improving vegetables' quality and producing non-pollution vegetables.