Exogenously applied Spd and Spm enhance drought tolerance in tea plants by increasing fatty acid desaturation and plasma membrane H+-ATPase activity.

Polyamines, due to their positive charges, bind to ROS Reactive oxygen species (ROS) thereby stabilizing the plasma membrane (PM). Drought is one of the main limiting factors affecting tea plant yield and quality. However, the effect of Spermidine (Spd) or Spermine (Spm) on membrane stability and fluidity in tea plants under drought stress is poorly understood. In this investigation, an exogenous supply of 1 mM Spd or Spm did not mitigate drought stress-induced damage, however, an exogenous supply of 0.2 mM Spd or Spm application significantly alleviated drought-induced damage in tea plants. To further illustrate the role of 0.2 mM Spd or Spm in maintaining membrane integrity and fluidity, the fatty acid percentage and PM H+-ATPase activity were analyzed. Spd and Spm application significantly increased PM H+-ATPase activity by 43.79% compared with that without the addition of polyamine under drought stress. In addition, exogenous application of Spd and Spm also significantly increased C18:3 by approximately 10%, hence alleviating drought-reduced fatty acid unsaturation. In contrast, Spd and Spm metabolic inhibitors dicyclohexylamine (DCHA) further impaired PM H+-ATPase activity and fatty acid desaturation under the drought + DCHA treatment compared with the drought treatment, respectively. Taken together, 0.2 mM Spd and Spm application significantly enhanced drought tolerance by increasing fatty acid unsaturation and maintaining PM H+-ATPase activity in tea plants. Therefore, foliar application of 0.2 mM Spd or Spm can be a potential foliar-spraying substances for improving tea drought tolerance.

The effects of different types of mulch on soil properties and tea production and quality.

BACKGROUND: Tea is an important economic crop in China. Mulching, a modern agricultural practice, can modify the soil microenvironment and maintain the crop yield. RESULTS: To investigate the effect of different mulching modes on tea plant growth, filed experiments were conducted in a Shizipu tea plantation located in Langxi Country (Xuanchen City, Anhui Province, China). Five treatments were carried out in a randomized complete block arrangement: (i) clean tillage (control); (ii) black plastic film; (iii) weed barrier fabric; (iv) rice straw mulch; and (v) intercropping with Vulpia myuros. The effects of different mulch modes on soil temperature, water moisture, soil compactness, root activity, soil enzyme activity and nutrition status on tea yield, quality and economic benefits were compared at the harvest stage. In the present study, compared with other mulch treatments, intercropping with V. myuros significantly reduced the topsoil temperature (to an optimum temperature) and soil compactness, and increased the water holding capacity in the deep soil layer, which contributed to increased tea root activity and respiration. Furthermore, intercropping with V. myuros significantly increased soil enzymes activity, soil organic matter, and the available nitrogen and phosphorus concentrations in the main root zone. Therefore, the stronger tea root activity accelerated nutrition uptake and increased the tea yield and quality-related components of the tea, thus resulting in a larger average net income. CONCLUSION: Intercropping with V. myuros could serve as a profitable agricultural method for tea production. © 2020 Society of Chemical Industry.

Efficacy of continuous irrigation combined with closed thoracic drainage for esophagojejunal anastomotic fistula complicated with mediastinal, thoracic and abdominal infections / 中华胃肠外科杂志

OBJECTIVE@#To investigate the clinical efficacy of continuous irrigation combined with closed thoracic drainage for esophagojejunal anastomotic fistula (EJAF) complicated with mediastinal, thoracic and abdominal infection after total gastrectomy.@*METHODS@#Clinical data of 22 EJAF patients complicated with mediastinal, thoracic and abdominal infection after radical gastrectomy at Department of General Surgery of the 901th Hospital of PLA from June 2012 to May 2018 were retrospectively analyzed. Case inclusion criteria:(1) gastric adenocarcinoma confirmed by preoperative endoscopic pathology undergoing radical total gastrectomy without severe organ dysfunction;(2)EJAF complicated with mediastinal, thoracic and abdominal infections diagnosed by postoperative radiography, the presence of pleural effusion confirmed by CT and ultrasound. Among them, 10 cases were treated with simple thoracic closed drainage (single drainage group); 12 cases received same closed thoracic drainage, and a rubber catheter was placed next to the closed thoracic drainage tube in the same sinus. A 0.9% sodium chloride solution was applied in continuous drip irrigation with drip velocity at 50 to 100 ml/h(continuous flushing plus drainage group). Infection indicators, anastomotic fistula healing time and related clinical indicators were compared between the two groups.@*RESULTS@#In the simple drainage group, 5 cases were males, age was (61.9±10.7) years old, 4 cases received laparoscopic surgery, 6 cases received open surgery, 6 cases were EJAF grade III, 4 cases were EJAF IV. In continuous flushing and drainage group, 6 cases were males, age was (61.7±11.0) years old, 7 cases received laparoscopic surgery, 5 cases received open surgery, 6 cases were EJAF grade III, and 6 cases were EJAF grade IV. Baseline data including gender, age, underlying diseases, preoperative hematological examination indexes, surgical methods, tumor TNM stage and EJAF grade were not significantly different between the two groups (all P>0.05). When postoperative EJAF was complicated with mediastinal, thoracic and abdominal infection, biochemical parameters including white blood cell, procalcitonin, C-reactive protein were not significantly different between two groups (all P>0.05). All patients of both groups achieved clinical cure without death. Compared with the simple drainage group after closed thoracic drainage, the continuous irrigation plus drainage group had significantly shorter duration of infection parameters returning to normal levels [white blood cell count: (6.8 ± 2.0) days vs.(10.5±3.0) days, t=4.062, P<0.001; procalcitonin: (7.5±1.0) days vs. (9.2±1.9) days, t=3.236, P=0.040; C-reactive protein: (8.8±1.0) days vs. (11.2±1.5) days, t=5.177, P<0.001], meanwhile time in surgical ICU [(4.9±2.5) days vs. (9.9±6.7) days, t=2.935, P=0.006], healing time of fistula [(42.9±12.5) days vs. (101.8±53.2) days, t=4.187, P=0.001] and total postoperative hospital stay [(62.3±15.8) days vs. (119.7 ±59.4) days, t=3.634, P=0.002] were significantly shorter, and total hospitalization cost was significantly lower (median 86 000 yuan vs. 124 000 yuan, Z=2.063, P=0.040) in the continuous irrigation plus drainage group.@*CONCLUSION@#The continuous closed thoracic drainage with 0.9% sodium chloride solution can accelerate infection control and remission of EJAF patients complicated with mediastinal, thoracic and abdominal infections, and shorten the healing time of anastomotic fistula.