Mitigative Effects of Foliage Spraying and Root Irrigation of ALA on Banana Plantlets Exposed to Cold Stress

[Objective] This study aimed to investigate the effect of ALA applied by foliage spraying and root irrigation on banana plantlets exposed to cold stress. [Method] After applied by foliage spraying and root irrigation with 5-aminolevulinic acid （ALA） at four different concentrations, ＂Brazil banana＂ plantlets were placed in artificial climate boxes at 7 ℃ to imitate low-temperature stress. [Result] The results showed that ALA application by both foliage spraying and root application can significantly increase SOD and POD activities, and reduce O2- generation rate, MDA content and relative conductivity in leaves of banana plantlets, as well as raising proline content, soluble protein content and relative water content, and maintaining the stability of chlorophyll. Foliage application of ALA within concentration range of 0.505.00 mg/L had best effect, which increased the chlorophyll content and reduced the relative conductivity and MDA content significantly compared to root irrigation at the same concentration, and raised SOD and POD activities by 64.5% and 12.3% respectively at 5 mg/L compared to their counterparts by root irrigation. [Conclusion] Foliage spraying of ALA can better mitigate the injuries to banana plantlets caused by low-temperature stress.

Water and nitrogen input optimization for jujube trees under surge root irrigation based on weighted grey correlation model

In order to obtain the optimal input of water and nitrogen(W&N)suitable for the jujube trees in Northern Shaanxi,12 treatments had been set in the demonstration base of micro-irrigation jujube tree of Mizhi County in 2014-2015 through field experiment of jujube trees under surge root irrigation(SRI),in which three soil moisture levels(high moisture level W1:60%-85%θ,middle moisture level W2:50%-75%θ,low moisture level W3:40%-65%θ)and four nitrogen input levels(high nitrogen F75:0.75 kg/plant,middle nitrogen F50:0.50 kg/plant,low nitrogen F25:0.25 kg/plant,no nitrogen F0:0.00 kg/plant)were set.Through analyzing the effects of different W&N inputs on the yield,net income(NI)and W&N utilization efficiency(WUE and NUE)of jujube trees and establishing a weighted grey correlation model,the optimization of W&N input for jujube trees could be achieved under SRI.Results showed that different W&N inputs had significant influences on yield,NI,WUE and NUE.Along with the increase of soil moisture content,the yield and NUE increased,while WUE decreased gradually,and the NI had the tendency to increase first and then decrease.Along with the increase of nitrogen input,the yield,NI and WUE had the tendency to increase first and then decrease while the NUE decreased significantly,and the yield,NI,WUE and NUE could not reach the maximum at the same time.Through the study on the grey correlation model of jujube tree’s comprehensive benefit based on the yield,NI,WUE and NUE,results showed the comprehensive benefit of jujube trees was significantly different when W&N input was different,and the gray correlation degree of W2F25 treatment was the highest in two years,which means that the soil moisture content of 50%-75%θand nitrogen input of 0.25 kg/plant was the optimal W&N input for jujube trees under SRI in Northern Shaanxi area.

Root length density distribution and associated soil water dynamics for tomato plants under furrow irrigation in a solar greenhouse

Furrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in water-limited regions. The objectives of this study are to analyze root length density distribution and to explore soil water dynamics by simulating soil water content using a HYDRUS-2D model with consideration of root water uptake for furrow irrigated tomato plants in a solar greenhouse in Northwest China. Soil water contents were also in-situ observed by the ECH_2O sensors from 4 June to 19 June and from 21 June to 4 July, 2012. Results showed that the root length density of tomato plants was concentrated in the 0–50 cm soil layers, and radiated 0–18 cm toward the furrow and 0–30 cm along the bed axis. Soil water content values simulated by the HYDRUS-2D model agreed well with those observed by the ECH_2O sensors, with regression coefficient of 0.988, coefficient of determination of 0.89, and index of agreement of 0.97. The HYDRUS-2D model with the calibrated parameters was then applied to explore the optimal irrigation scheduling. Infrequent irrigation with a large amount of water for each irrigation event could result in 10%–18% of the irrigation water losses. Thus we recommend high irrigation frequency with a low amount of water for each irrigation event in greenhouses for arid region. The maximum high irrigation amount and the suitable irrigation interval required to avoid plant water stress and drainage water were 34 mm and 6 days, respectively, for given daily average transpiration rate of 4.0 mm/d. To sum up, the HYDRUS-2D model with consideration of root water uptake can be used to improve irrigation scheduling for furrow irrigated tomato plants in greenhouses in arid regions.

Endodontic irrigants from a comprehensive perspective

This review article explores the fundamental principles of modern endodontics with a focus on root canal cleaning and shaping.It reviews commonly used endodontic irrigant,namely sodium hypochlorite(NaOCl),herbal extracts,chlorhexidine(CHX),and chelating agents,highlighting their properties,applications,and potential drawbacks.NaOCl,a key antimicrobial agent,demonstrates effectiveness against various microorganisms but poses challenges such as high cytotoxicity.Herbal extracts,gaining recognition in endodontics,present an alternative with potential advantages in preserving dentin integrity.CHX,known for its broad-spectrum antimicrobial activity,is discussed in both liquid and gel formulations,emphasizing its role in reducing smear layer formation and preserving hybrid layer durability.Chelating agents,specifically ethylenediaminetetraacetic acid and citric acid,play a vital role in removing the smear layer,enhancing dentin permeability,and facilitating the penetration of antimicrobial agents.The review article underscores the importance of careful application and consideration of each irrigant's properties to ensure safe and effective endodontic procedures.It serves as a valuable guide for clinicians in selecting appropriate irrigants based on specific treatment requirements.

Efficacy of Solution Form of Ethylenediaminetetraacetic Acid on Removing Smear Layer of Root Canal at Different Exposure Time In Vitro

Summary： This study was aimed to evaluate the effectiveness of solution form of 17% ethylenediaminetetraacetic acid （EDTA） on removing smear layer of root canals at different exposure time periods and to provide scientific basis for EDTA as a choice of root canal irrigation in clinical practice. Twenty-five single-rooted teeth were randomly divided into 5 groups： control group （group A） was given 2.5% NaOC1, and 4 experimental groups were given 2.5% NaOC1 and 17% EDTA, including groups B, C, D and E with exposure time of 1, 3, 5 and 7 min, respectively. After preparation of the root canals, the teeth were split along their longitudinal axis, and the root sections were examined under scanning elec- tron microscope for evaluation of smear layer removal and erosion on the surface of the root canal walls. The specimens in group B showed presence of smear layer on the walls of the root canal with no statistical difference from that in group A （P〉0.05）. In groups C and D, partial removal of smear layer was obtained, and there was no significant difference between the two groups （P〉0.05）, but there was significant difference in removal of smear layer between group C and group B （P〈0.05）. Root canal walls in group E specimens showed almost complete removal of smear layer, and the removal of smear layer was significantly different from that in group D （P〈0.01）. There was no significant change in the structure of the surface of root canal for each sample. It was concluded that combined irrigation with 17% EDTA and 2.5% NaOC1 could remove the smear layer with no significant alteration in dentinal structure when the chelating agent was applied for 7 min. At 3 and 5 min of application, partial removal of smear layer was observed and at 1 min negligible removal of smear layer was achieved.

Translocation and Distribution of Imidacloprid in Tobacco with Two Application Methods

[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used to determine the con- tent of imidacloprid in different parts of tobacco plants （roots, stems, the upper, middle and lower leaves） at different time. [Results] The imidacloprid could be absorbed by root and could be transported to all parts of the tobacco plant after irrigating root, but the original deposition amount was larger and the transport efficiency was lower after spraying. [Conclusion] The translocation and distribution of imidacloprid by spraying was more uniform and the holding efficiency was better, but imidacloprid with root irrigation could act on leaf directly, and had better readily availability.