Silicon Affects Rice Growth,Superoxide Dismutase Activity and Concentrations of Chlorophyll and Proline under Different Levels and Sources of Soil Salinity

Silicon - Silicon (Si) application shows beneficial effects on growth and salt tolerance of plants; however, its effects on the rice (Oryza sativa L. var. Hashemi) growth, superoxide dismutase...     

Effect of Trichoderma asperellum on Wheat Plants’ Biochemical and Molecular Responses,and Yield under Different Water Stress Conditions

Eight Trichoderma strains were evaluated for their potential to protect wheat seedlings against severe (no irrigation within two weeks) water stress (WS). Considering the plant fresh weight and phenotype, T. asperellum T140, which displays 1-aminocyclopropane-1-carboxylic acid deaminase activity and which is able to produce several phytohormones, was selected. The molecular and biochemical results obtained from 4-week-old wheat seedlings linked T140 application with a downregulation in the WS-response genes, a decrease in antioxidant activities, and a drop in the proline content, as well as low levels of hydrogen peroxide and malondialdehyde in response to severe WS. All of these responses are indicative of T140-primed seedlings having a higher tolerance to drought than those that are left untreated. A greenhouse assay performed under high nitrogen fertilization served to explore the long-term effects of T140 on wheat plants subjected to moderate (halved irrigation) WS. Even though all of the plants showed acclimation to moderate WS regardless of T140 application, there was a positive effect exerted by T. asperellum on the level of tolerance of the wheat plants to this stress. Strain T140 modulated the expression of a plant ABA-dependent WS marker and produced increased plant superoxide dismutase activity, which would explain the positive effect of Trichoderma on increasing crop yields under moderate WS conditions. The results demonstrate the effectiveness of T. asperellum T140 as a biostimulant for wheat plants under WS conditions, making them more tolerant to drought.     

Growth,Yield and Physiological Characteristics of Maize (Zea mays L.) at Two Different Soil Moisture Regimes by Supplying Silicon and Chitosan

Silicon - Water deficit is an important factor to challenge food security, particularly in arid and semi-arid climates. In present experiment, silicon (Si) and chitosan were evaluated to affect the...     

Evaluation of Silicon Bioavailability in Soil with Different Chemical Extractants

Silicon - This study was developed to examine the extracting power and efficiency of different methods in order to identify those that best correlate the available Si in the soil with Si uptake by...     

The Impact of Diet and Exercise on Drug Responses

It is well known that lifestyle changes can alter several physiological functions in the human body. For exercise and diet, these effects are used sensibly in basic therapies, as in cardiovascular diseases. However, the physiological changes induced by exercise and a modified diet also have the capacity to influence the efficacy and toxicity of several drugs, mainly by affecting different pharmacokinetic mechanisms. This pharmacological plasticity is not clinically relevant in all cases but might play an important role in altering the effects of very common drugs, particularly drugs with a narrow therapeutic window. Therefore, with this review, we provide insights into possible food–drug and exercise–drug interactions to sharpen awareness of the potential occurrence of such effects.     

不同氮磷水平下微小原甲藻对营养盐的吸收及光合特性

研究了微小原甲藻对无机氮、磷的吸收特性和在室内批量培养条件下,无机氮、磷浓度对微小原甲藻生长和光合作用的影响. 结果表明,低氮(0.0882 mmol/L NaNO3)条件下,微小原甲藻具有最高的比生长速率,为0.46 d 1,而中氮(0.882 mmol/L NaNO3)条件下具有最大的细胞密度,为54900个/mL,分别比低氮和高氮(2.646 mmol/L NaNO3)下增加7.2 和20.1 . 随着培养基中磷浓度的升高,最大细胞密度和比生长速率也增加,在高磷(0.108 mmol/L KH2PO4)条件下达到最大值,分别为57400个/mL和0.45 d 1. 高营养源(高氮或高磷)状态下生长的藻细胞具有更高的单位细胞和单位叶绿素a表示的光饱和的光合作用速率(Pmchl a和Pmcell)和光饱和点. 低氮和高氮条件下的藻细胞同样具有高的单位细胞和单位叶绿素a表示的光合效率( chl a和 cell),而单位叶绿素a表示的光合效率( chl a)则在高磷下最大. 在氮源充足条件下,低的N/P有利于微小原甲藻细胞的生长.     

土壤湿度对二氯喹啉酸药效及玉米安全性的影响

二氯喹啉酸(quinclorac)是优秀的稻田除稗剂。本试验通过研究土壤湿度对二氯喹啉酸除稗效果及对玉米安全性的影响。探讨二氯喹啉酸作为茎叶处理剂在玉米田施用的可行性。稗草和玉米作为生物材料，室内模拟不同的土壤湿度条件，运用二次正交旋转组合设计，以稗草鲜重及玉米生长率为目标函数，建立数学模型。模型解析结果表明。当土壤湿度相同时，二氯喹啉酸用量是除草效果及玉米安全性的关键，土壤湿度对二氯喹啉酸药效及玉米安全性有不同程度的影响。对稗草的防效及对玉米的抑制作用都随土壤湿度的增加而增加；在各土壤湿度条件下达到较好防效的二氯喹啉酸施药剂量对玉米安全性较好。从本试验来看，二氯喹啉酸有被开发为玉米田茎叶处理防除禾本科杂草除草剂的可能性。     

西玛津在甘蔗及土壤中的残留消解动态

为了探明西玛津使用后在甘蔗及其土壤中的残留降解规律,采用气相色谱法研究了西玛津90%水分散粒剂在甘蔗及其土壤中的残留消解降解动态和最终残留实验。结果表明:西玛津在甘蔗和土壤中的降解动态方程分别为Ct=19.157e-0.0587t和Ct=1.689 8e-0.036t,半衰期分别为11.8 d和19.3 d;以1 647 g a.i./hm2和2 470.5 g a.i./hm2的剂量在甘蔗田进行喷雾处理,收获期甘蔗和土壤中的最终残留量分别小于0.01 mg/kg和0.02 mg/kg。     

冬小麦生育期不同保水措施土壤水分变化研究

研究了不同保水措施及灌水对小麦田表层土壤保水及入渗性能的影响。结果表明,总的趋势是随着保水剂用量的增加,保水性能增强。在越冬期内,秸秆覆盖下的土壤表层水分略高于保水剂处理;从返青期到孕穗期,灌水和不灌水处理的土壤表层水分消耗差异明显,灌水处理的表层土壤含水量比不灌水处理下降的多;在孕穗后期,灌水处理表层土壤含水量明显高于不灌水处理,且随保水剂用量增加而增加,秸秆覆盖处理稍低于保水剂处理;收获后,处理间差异不显著。在土壤导水方面,耕作和保水措施都提高了土壤渗透性能,传统耕作和灌水处理均降低了土壤饱和导水率。灌水条件下,保水剂用量45kg／hm^2时有利于提高土壤饱和导水率。     

埋地管道在不同含水率的土壤中泄漏数值模拟

针对管道在土壤中发生泄漏问题,借助CFD软件及采用有限容积法建立土壤多孔介质中油气水三相流的流固耦合数学模型,分别模拟了管道在土壤含水率为0、0.1及0.2的三种情况下泄漏前后周围土壤温度场变化及油品在土壤中扩散分布情况。模拟结果表明:泄漏前,管道周围温度场分布相同,均呈椭圆形分布,热影响区温度由内向外逐渐降低。泄漏后,三种情况下,油品在土壤中运移趋势基本相同,但由于土壤含水率不同,管道周围温度场变化情况及相同时间内油品的泄漏量不同。     

A Study of Moisture Effects on Ti/Porous Silicon/Silicon Schottky Barrier

Results of capacitance-voltage and current-voltage measurements performed on Ti/porous silicon (PS)/p-Si diode structures are presented. A 5–10 increase of conductivity and capacity has been observed at f < 10000 Hz in response to the moisture change from 0 to 50%. Model of Schottky contact on thin PS layer with the charge carriers inside of pores and PS/Si interface is applied to explain the frequency dependence of conductivity/capacity as well as moisture effect.     

Direct and Residual Effects of Water Deficit Stress,Different Sources of Silicon and Plant-Growth Promoting Bacteria on Silicon Fractions in the Soil

Silicon - Silicon (Si) and plant growth promoting bacteria (PGPB) can effectively reduce the negative effects of water deficit stress and augment plant growth. Few studies have simultaneously...     

Silicon Mitigates Drought Stress in Wheat (Triticum aestivum L.) Through Improving Photosynthetic Pigments,Biochemical and Yield Characters

Silicon - Feeling prone to stress differs with plant production stage, water scarcity near commencement of grain filling phase has a significant reduced grain yield through fewer endosperm and sink...     

土壤水分盐分运移研究进展综述

土壤水分、盐分运移是个十分复杂的过程,它与环境,水文等方面紧密联系,研究土壤水分盐分运移对水资源的利用,水资源的保护和人类文明的发展有着极其重要的意义。本文首先对土壤水的提取方法进行了详细介绍,然后综述了氢氧同位素示踪法研究土壤水分运移规律和土壤盐分运移规律的研究现状。对于土壤水分盐分运移的研究,今后可以着重于农业方面和有助于生态系统的修复重建的研究,相信这对于今后的发展会有着重要的影响。     

Correction to: Direct and Residual Effects of Water Deficit Stress,Different Sources of Silicon and Plant-Growth Promoting Bacteria on Silicon Fractions in the Soil

Silicon - A Correction to this paper has been published: https://doi.org/10.1007/s12633-021-01161-w     

不同来源甲壳素和壳聚糖的吸湿性与保湿性

对虾、蟹、蝇蛹和蝉子虫为原普的甲壳素和壳聚糖的吸湿性和保湿性进行了研究,结果表明,蝉子虫甲壳素和壳聚糖有较高的吸湿性和保湿性。     

Application of Exogenous Silicon for Alleviating Photosynthetic Inhibition in Tomato Seedlings under Low−Calcium Stress

To address the low Ca−induced growth inhibition of tomato plants, the mitigation effect of exogenous Si on tomato seedlings under low−Ca stress was investigated using different application methods. We specifically analyzed the effects of root application or foliar spraying of 1 mM Si on growth conditions, leaf photosynthetic properties, stomatal status, chlorophyll content, chlorophyll fluorescence, ATP activity and content, Calvin cycle−related enzymatic activity, and gene expression in tomato seedlings under low vs. adequate calcium conditions. We found that the low−Ca environment significantly affected (reduced) these parameters, resulting in growth limitation. Surprisingly, the application of 1 mM Si significantly increased plant height, stem diameter, and biomass accumulation, protected photosynthetic pigments, improved gas exchange, promoted ATP production, enhanced the activity of Calvin cycle key enzymes and expression of related genes, and ensured efficient photosynthesis to occur in plants under low−Ca conditions. Interestingly, when the same amount of Si was applied, the beneficial effects of Si were more pronounced under low−Ca conditions that under adequate Ca. We speculate that Si might promote the absorption and transport of calcium in plants. The effects of Si also differed depending on the application method; foliar spraying was better in alleviating photosynthetic inhibition in plants under low−Ca stress, whereas root application of Si significantly promoted root growth and development. Enhancing the photosynthetic capacity by foliar Si application is an effective strategy for ameliorating the growth inhibition of plants under low−Ca stress.     

Morphological and Metabolite Responses of Potatoes under Various Phosphorus Levels and Their Amelioration by Plant Growth-Promoting Rhizobacteria

Low phosphorus (P) availability is a major limiting factor for potatoes. P fertilizer is applied to enhance P availability; however, it may become toxic when plants accumulate at high concentrations. Therefore, it is necessary to gain more knowledge of the morphological and biochemical processes associated with P deficiency and toxicity for potatoes, as well as to explore an alternative approach to ameliorate the P deficiency condition. A comprehensive study was conducted (I) to assess plant morphology, mineral allocation, and metabolites of potatoes in response to P deficiency and toxicity; and (II) to evaluate the potency of plant growth-promoting rhizobacteria (PGPR) in improving plant biomass, P uptake, and metabolites at low P levels. The results revealed a reduction in plant height and biomass by 60–80% under P deficiency compared to P optimum. P deficiency and toxicity conditions also altered the mineral concentration and allocation in plants due to nutrient imbalance. The stress induced by both P deficiency and toxicity was evident from an accumulation of proline and total free amino acids in young leaves and roots. Furthermore, root metabolite profiling revealed that P deficiency reduced sugars by 50–80% and organic acids by 20–90%, but increased amino acids by 1.5–14.8 times. However, the effect of P toxicity on metabolic changes in roots was less pronounced. Under P deficiency, PGPR significantly improved the root and shoot biomass, total root length, and root surface area by 32–45%. This finding suggests the potency of PGPR inoculation to increase potato plant tolerance under P deficiency.     

乙草胺在甘蔗和土壤中的残留分析及消解动态

采用GC-μECD法测定了乙草胺在甘蔗植株、茎秆及土壤中的消解动态和最终残留。样品用乙腈提取,PSA和碳纳米管净化。结果表明:当乙草胺在植株、茎秆和土壤中的添加浓度在0.005~0.5 mg/kg时,添加回收率分别为84.84%~95.54%、81.96%~99.40%和80.91%~95.70%,相对标准偏差分别为1.67%~5.20%、1.75%~5.50%和1.11%~2.24%。乙草胺在植株和土壤中的半衰期分别为2.7~3.2 d和8.0~8.7 d。乙草胺在甘蔗植株、茎秆和土壤中的最终残留量分别为0.005 mg/kg、0.005 mg/kg和0.010~0.099 mg/kg。     

Resistance and Tolerance of Terminalia sericea Trees to Simulated Herbivore Damage Under Different Soil Nutrient and Moisture Conditions

Resource availability, degree of herbivore damage, genetic variability, and their interactions influence the allocation of investment by plants to resistance and tolerance traits. We evaluated the independent and interactive effects of soil nutrients and moisture, and simulated the effects of herbivore damage on condensed tannins (resistance) and growth/regrowth (tolerance) traits of Terminalia sericea, a deciduous tree in the Kalahari desert that constitutes a major component of livestock diet. We used a completely crossed randomized-block design experiment to examine the effects of nutrients, water availability, and herbivore damage on regrowth and resistance traits of T. sericea seedlings. Plant height, number of branches, internode length, leaf area, leaf mass for each seedling, combined weight of stems and twigs, and root mass were recorded. Condensed tannin concentrations were 22.5 and 21.5% higher under low nutrients and low soil moisture than under high nutrient and high water treatment levels. Tannin concentrations did not differ significantly between control and experimental seedlings 2 mo after simulated herbivore damage. Tannin concentrations correlated more strongly with growth traits under low- than under high-nutrient conditions. No trade-offs were detected among individual growth traits, nor between growth traits and condensed tannins. T. sericea appeared to invest more in both resistance and regrowth traits when grown under low-nutrient conditions. Investment in the resistance trait (condensed tannin) under high-nutrient conditions was minimal and, to a lesser degree, correlated with plant growth. These results suggest that T. sericea displays both resistance and tolerance strategies, and that the degree to which each is expressed is resource-dependent.