Physiological Analysis of Drought Resistance of Seven Cultivars Spring Wheat in Northern Regions of China

In order to determine the physiological mechanism of drought resistance of northern wheat in China,six drought resistant wheat and one sensitivity to drought wheat were planted in pots.They were subjected to drought treatment and normal water when the plants grew to the 3-leaf stage.Samples were collected at 10,20,30,and 40 days after the drought treatment,respectively.The electrical conductivity,photosynthetic parameters,chlorophyll fluorescence parameters,sugar content,proline content,protein content,and active oxygen scavenging enzyme activity of the plants were detected,and the agronomic traits of the wheat varieties were investigated at maturity.The results indicated that the phenotype and yield-related factors of Darkhan 144 changed little under the drought stress.The relative electrical conductivity of Kefeng 6 and Darkhan 166 was lower under the drought stress,and their cell membrane was less damaged.The Darkhan 144 and Darkhan 166 had higher drought resistance coefficients,and were the wheat varieties with stronger drought resistance.However,the physiological mechanisms of drought resistance of these three wheat were different:Darkhan 144 maintained a higher photosynthetic activity under the drought stress;Darkhan 166 maintained a higher protein content,photosynthetic activity and active oxygen scavenging enzyme activity.In addition,other drought-resistant varieties Kefeng 6,Kefeng 10 and Longmai 26 had a higher content of osmoregulatory substances under the drought stress.

Advances on Seed Vigor Physiological and Genetic Mechanisms

Seed vigor is a more promising seed quality character reflecting potential seed germination, field emergence and seed storage ability under different conditions than standard germination. Standard germination is influenced by genetic background and environmental effects during seed development and storage conditions. The latest research on physiological mechanism in seed vigor showed that at the late stage of seed development, the development of seed vigor involves some stress-resistant substances including late embryogenesis abundant （LEA） protein, oligosaccharides and abscisic acid （ABA）. Whereas the loss of seed vigor, or seed aging and deterioration, could be attributed to lipid peroxidation, chromosome deformation and genes aberrance, and embryo protein degradation, etc. Seed vigor is a quantitative character controlled by multi-genes. Genetic and quantitative trait locus （QTL） analyses on seed-vigor trait in model plants, such as Arabidopsis and rice, are mostly concentrated on related morphology traits, whereas few physiological traits have been researched. It was concluded that, all of the QTL genetic characteristics of seed vigorincluding QTL quantities, its locus on chromosome, genetic effects, and interaction effects between genetic and environment, differed with plant species and used seed-vigor traits.

Sodium-glucose cotransporter 2 inhibitors’ mechanisms of action in heart failure

Three major cardiovascular outcome trials(CVOTs)with a new class of antidiabetic drugs-sodium-glucose cotransporter 2(SGLT2)inhibitors(EMPAREG OUTCOME trial with empagliflozin,CANVAS Program with canagliflozin,DECLARE-TIMI 58 with dapagliflozin)unexpectedly showed that cardiovascular outcomes could be improved possibly due to a reduction in heart failure risk,which seems to be the most sensitive outcome of SGLT2 inhibition.No other CVOT to date has shown any significant benefit on heart failure events.Even more impressive findings came recently from the DAPA-HF trial in patients with confirmed and well-treated heart failure:Dapagliflozin was shown to reduce heart failure risk for patients with heart failure with reduced ejection fraction regardless of diabetes status.Nevertheless,despite their possible wide clinical implications,there is much doubt about the mechanisms of action and a lot of questions to unravel,especially now when their benefits translated to nondiabetic patients,rising doubts about the validity of some current mechanistic assumptions.The time frame of their cardiovascular benefits excludes glucoselowering and antiatherosclerotic-mediated effects and multiple other mechanisms,direct cardiac as well as systemic,are suggested to explain their early cardiorenal benefits.These are:Anti-inflammatory,antifibrotic,antioxidative,antiapoptotic properties,then renoprotective and hemodynamic effects,attenuation of glucotoxicity,reduction of uric acid levels and epicardial adipose tissue,modification of neurohumoral system and cardiac fuel energetics,sodiumhydrogen exchange inhibition.The most logic explanation seems that SGLT2 inhibitors timely target various mechanisms underpinning heart failure pathogenesis.All the proposed mechanisms of their action could interfere with evolution of heart failure and are discussed separately within the main text.

Exogenous Melatonin Improves Physiological Characteristics and Promotes Growth of Strawberry Seedlings Under Cadmium Stress

Melatonin,as a plant growth regulator,is involved in plant stress resistance.We studied the effects of different concentrations(0,10,50,100,150,and 200μmol·L−1)of melatonin on the growth and physiological characteristics of strawberry under cadmium(Cd)stress.The results represented that the growth of strawberry seedlings was inhibited under Cd stress,and the seedling biomass,chlorophyll content and the activities of antioxidant enzymes such as superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and ascorbate peroxidase(APX)decreased.These toxic effects were,however,effectively remediated by exogenous melatonin pretreatment.Melatonin treatment slowed the inhibitory effect of seedling growth and significantly increased seedling biomass,chlorophyll content,antioxidant enzyme activities,and soluble protein levels in leaves and roots compared with the control.Melatonin treatment also reduced the malondialdehyde(MDA)content and the oxidative stress reactions,increased the anthocyanin content,and slowed the senescence rate,thereby reducing the toxic effects of Cd on strawberries.This indicates that foliar application of melatonin can effectively remediate the adverse effects of Cd on strawberry seedlings;the greatest effect was obtained with melatonin concentration of 100μmol·L−1.

Saline-Alkali Tolerance in Rice: Physiological Response, Molecular Mechanism, and QTL Identification and Application to Breeding

Salinity-alkalinity is incipient abiotic stress that impairs plant growth and development.Rice(Oryza sativa)is a major food crop greatly affected by soil salinity and alkalinity,requiring tolerant varieties in the saline-alkali prone areas.Understanding the molecular and physiological mechanisms of saline-alkali tolerance paves the base for improving saline-alkali tolerance in rice and leads to progress in breeding.This review illustrated the physiological consequences,and molecular mechanisms especially signaling and function of regulating genes for saline-alkali tolerance in rice plants.We also discussed QTLs regarding saline-alkali tolerance accordingly and ways of deployment for improvement.More efforts are needed to identify and utilize the identified QTLs for saline-alkali tolerance in rice.

Physiological Basis of Photosynthetic Function and Senescence of Rice Leaves as Regulated by Controlled-Release Nitrogen Fertilizer

The physiological mechanism of photosynthetic function and senescence of rice leaves was studied by using early rice variety Baliangyou 100 and late rice variety Weiyou 46, treated with controlled-release nitrogen fertilizer （CRNF）, urea and no nitrogen fertilizer. CRNF showed obvious effects on delaying the senescence and prolonging photosynthetic function duration of rice leaves. Compared with urea, CRNF could significantly increase the chlorophyll content of functional leaves in both early and late rice varieties, and this difference between the treatments became larger as rice growth progressed; CRNF increased the activities of active oxygen scavenging enzymes super oxide dismutase （SOD） and peroxidase （POD）, and decreased the accumulation amount of malondialdehyde （MDA） in functional leaves during leaf aging; Photosynthetic rate of functional leaves in CRNF treatment was significantly higher than that in urea treatment. The result also indicated that CRNF could effectively regulate the contents of indole-3-acetic acid （IAA） and abscisic acid （ABA） in functional leaves; IAA content was higher and ABA content was lower in CRNF treatment than those in urea treatment. Therefore, application of CRNF could increase the rice yield significantly due to these physiological changes in the functional leaves.

Physiological Mechanism on the Difference of Sugar Accumulation in Four Citrus Varieties

The concentration of sucrose, glucose, fructose, titratable acid, ABA and the activity of acid invertase (AI) were measured in juice sacs of Bendizao mandarin (Citrus succosa Hort), Ponkan (Citrus reticulata Blanco), Miyagawa wase (Citrus unshiu Marc) and Meyer lemon (Citrus meyeri Y). The acid hydrolysis of sucrose in vitro was also studied. The results showed that the sugar content, the ratio of different sugars, titratable acidity, ABA content and the activity of AI were obviously different in four citrus varieties. The sugar content in juice sacs of citrus fruit was related to that of ABA at the late stage of fruit development. The result suggested that ABA played an important role in sugar accumulation in juice sacs of citrus fruit. Bendizao mandarin and Miyagawa wase mainly accumulated sucrose in juice sacs of citrus fruit. Meyer lemon accumulated hexose, and Ponkan citrus was the sucrose-hexose accumulating type variety. In Meyer lemon with high acid degree, the composition of sugar in juice sacs was determined by acid-hydrolysis of sucrose. In Bendizao mandarin, Ponkan citrus and Miyagawa wase with low acid degree, the composition of sugars at the late stage of fruit development was obviously affected by the AI activity.

Review of Research on Nutritional Physiological Mechanism and Nutritional Diagnosis of Magnesium in Fruit Trees

Magnesium is an essential nutrient element for the growth and development of fruit trees.It not only participates in photosynthesis of plants,but also promotes physiological and biochemical reactions such as carbohydrate and protein synthesis,enzyme activation,and reactive oxygen species(ROS)metabolism.Magnesium deficiency in fruit trees will directly influence the growth and development of trees and the improvement of fruit quality.This study mainly reviews the nutritional and physiological mechanism of magnesium in plants and the nutritional diagnosis of magnesium deficiency in fruit trees,in order to provide a theoretical basis for further research on magnesium nutrition in fruit trees,and accordingly provide a certain reference for the application of magnesium fertilizer.

Priming: A promising strategy for crop production in response to future climate

Anticipated more frequent extreme events due to changes in global climatic variability requires adaptation of crop species to multi-occurrence abiotic stresses hereby sustaining the food security. Priming, by pre-exposure of plants to an eliciting factor, enables plants to be more tolerant to later biotic or abiotic stress events. Priming induced “stress memory” exists in both present generation and the offspring. Thus, priming is suggested to be a promising strategy for plants to cope with the abiotic stresses under global change scenarios. In this review, the underlying physiological and molecular mechanisms of priming induced enhancement of stress tolerance to the major abiotic stresses of drought and waterlogging, and high and low temperature in crop plants were discussed, and the potential to utilize the priming effect for sustaining crop productivity in future climates was also suggested.

Research Progress on the Biological Basis of Cereal Pollen Culture

This paper summarizes the physiological and metabolic mechanism of a series of processes in the cereal microspore culture from the angle of plant physiological metabolism, explores the physiological or cytology mechanism of several key processes, including microspore dedifferentiation and callus formation, differentiation and transformation, and sums up the current problems in this field and forecasts the direction of future development.

Free amino acid content in trunk,branches and branchlets of Araucaria angustifolia(Araucariaceae)

Araucaria angustifolia(Bertol.) O. Kuntze exhibits dimorphism in its stem structure, where the trunk is orthotropic and branches and branchlets(primary and secondary branches) are plagiotropic. These stems exhibit different behavior when used for vegetative propagation,and only segments of trunk can form a complete plant. The physiological and biochemical mechanisms that characterize these stems are still little known. The aim of this study was to describe the free amino acid profiles in trunks,branches, and branchlets of A. angustifolia. Segments of 5 cm in length were excised from young individuals below the stem apex. The needles were removed and samples were frozen and lyophilized. The determinations were made by high-performance liquid chromatography, and the results were expressed as lg/g fresh weight(FW). The trunks and branches had the highest content of total amino acids, which were 112.23 ± 20.57 lg/g FW and 111.97 ± 27.78 lg/g FW, respectively. The amino acids—glutamine, aspartate and c-aminobutyric acid and tyrosine—were noticeably higher in the three types of stems.In the trunk, a higher amount of asparagine and tryptophan,was also detected. Glutamic acid and glutamine were found in higher quantities in the branches. The branchlets had very low total amino acid content (30.79 ± 4.19 lg/g FW), wherein asparagine is the only amino acid not detected. Thus, it was observed that the profile of the free amino acid differs among trunks, branches, and branchlets in A. angustifolia, indicating that they perform different functions.

Causes of Poor Grain Plumpness of Two-Line Hybrids and Their Relationships to the Contents of Hormones in the Rice Grain

This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations, that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin （Z） ＋ zeatin riboside （ZR）, indole-3-acetic acid （IAA）, and abscisic acid （ABA）, the ethylene evolution rate, activities of sucrose synthase （SuSase） and starch synthase （StSase） in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z ＋ ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z ＋ ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and grain weight. The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight. Spraying ethephon （ethylene-releasing agent） at the early grain filling stage increased the evolution rate of ethylene, reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight. The results were reversed when cobatous nitrate （an inhibitor of ethylene synthesis） was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z ＋ ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents.

Research Trends in Rare Earth Element Hyperaccumulator

A brief introduce to environmental and ecological characteristics, hyperaccumulators of rare earth elements （REEs）, as well as the scientific significance of REE hyperaccumulators were presented. Based on this introduce, the achievements in REE hyperaccumulator research, which were ： （ 1 ） The species and regional distribution of REE hyperaccumulators,

Formation of Assimilating Surface Areas and Photosynthetic Potential of Various Assimilating Parts of Wheat Species under Drought Conditions

Some of environmental factors (weather sharp fluctuations) may accrue stress within a few minutes, while others may not be long for this period of stress in this situation. It has formed stress in organisms, to eliminate the stress, there starts over various biochemical and physiological mechanisms for protection. Therefore, a large variety of plants to examine ways of increasing the resistance against stress factors have a scientific and practical importance. Thus, the primary processes of photosynthesis, based on the results of the study and its corresponding morphophysiological higher photochemical activity, has been found in a range of genotypes. Their leaves and plants assimilate the biological productivity of the intensity of the symptoms associated with the use of photosynthetic learned of the opportunity to create a new perspective varieties. This allows the research to prove the expansion of the electronic delivery of high-yielding genotypes and phosphorised chloroplast high speed, as well as the pH of thylacoid membranes are characterized by a great price, also photosynthetic electron transport, CO2 assimilation and it was approved to be the link between productivity.

Bioinspired approaches for medical devices

Advances in medical devices have revolutionized the treatment of human diseases,such as stents in occluded coronary artery,left ventricular assist devices in heart failure,pacemakers in arrhythmias,etc.Despite their significance,the development of devices for reducing and avoiding the thrombosis formation,obtaining excellent mechanical performance,and achieving stable electronic physiology remains challenging and unresolved.Fortunately,nature serves as a good resource of inspirations,and brings us endless bioinspired physicochemical ideas to better the development of novel artificial materials and devices that enable us to potentially overcome the unresolved obstacles.Bioinspired approaches,in particularly,owe much of their current development in biology,chemistry,materials science,medicine and engineering to the design and fabrication of advanced devices.The application of bioinspired devices is a burgeoning area in these fields of research.In this perspective,we would take the cardiovascular device as one example to show how these bioinspired approaches could be used to build novel,advanced biomedical devices with precisely controlled functions.Here,bioinspired approaches are utilized to solve issues like thrombogenic,mechanical and electronic physiology problems in medical devices.Moreover,there is an outlook for future challenges in the development of bioinspired medical devices.