Indica rice restorer lines with large sink potential exhibit improved nutrient transportation to the panicle,which enhances both yield and nitrogen-use efficiency

The yield and nitrogen use efficiency(NUE)of hybrid rice combinations are closely related to restorer line.Therefore,it is essential to evaluate the agronomic characteristics of restorer lines with high yield and high NUE(HYHN).However,it is unclear which restorer lines are HYHN,and neither have the common agronomic traits of the HYHN restorer lines been identified.Aiming to address this issue,we conducted two filed experiments using three nitrogen applications,which screened five HYHN restorer lines from 15 indica restorer lines.Yield,NUE and nutrient transportation of restorer lines with different yields and NUE types were examined.Yield and total nitrogen absorption in aboveground biomass(TNA)increased,whereas NUE for grain production decreased with increasing nitrogen application levels.The HYHN restorer lines had large spikelets and high weight per panicle that were significantly positively correlated with yield and NUE.Therefore,large sink potential may be beneficial for both yield and NUE.We further studied the differences in nutrient transportation to panicles between the HYHN and low yield and low NUE(LYLN)restorer lines and found that the former had a higher nitrogen absorption level and dry matter weight ratios of panicle in maturity.Moreover,the HYHN lines also had a higher root and neck-panicle node bleeding intensity per stem after heading and more developed vascular bundles of neck-panicle nodes and leaves than the LYLN lines,which could contribute to the transportation of nutrients from root to ground and from stem and leaf to spike.Therefore,the advantages of large sink potential of the HYHN restorer lines include large nutrient accumulation in and distribution to the panicles and smooth flow of nutrients along the transportation channels.

Effect of genotype on duodenal expression of nutrient transporter genes in dairy cows

Background： Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This study examined gene transcript abundance of important classes of nutrient transporters in the duodenum of non lactating dairy cows of different feed efficiency potential, namely Holstein-Friesian （HF）, Jersey （JE） and their F1 hybrid. Duodenal epithelial tissue was collected at slaughter and stored at -80℃. Total RNA was extracted from tissue and reverse transcribed to generate cDNA. Gene expression of the following transporters, namely nucleoside amino acid; sugar; mineral; and lipid transporters was measured using quantitative real-time RT-PCR. Data were statistically analysed using mixed models ANOVA in SAS. Orthogonal contrasts were used to test for potential heterotic effects and spearman correlation coefficients calculated to determine potential associations amongst gen, expression values and production efficiency variables. Results： While there were no direct effects of genotype on expression values for any of the genes examined, there was evidence for a heterotic effect （P 〈 0.05） on ABCGS, in the form of increased expression in the F1 genotype compared to either of the two parent breeds. Additionally, a tendency for increased expression of the amino acid transporters, SLC3A1 （P= 0.072）, SLC3A2 （P= 0.081） and SLC6A 14 （P= 0.072） was also evident in the F1 genotype. A negative （P 〈 0.05） association was identified between the expression of the glucose transporter gene SLCSA1 and total lactational milk solids yield, corrected for body weight. Positive correlations （P 〈 0.05） were also observed between the expression values of genes involved in common transporter roles. Conclusion： This study suggests that differences in the expression of sterol and amino acid transporters in the duodenum could contribute towards the documented differences in feed efficiency between HF, JE and their F1 hybrid. Furthermore, positive associations between the expression of genes involved in common transporter roles suggest that these may be co-regulated. The study identifies potential candidates for investigation of genetic variants regulating nutrient transport and absorption in the duodenum in dairy cows, which may be incorporated into future breeding programmes.

Nutrient transport following water transfer through the world's largest water diversion channel

Nutrient levels in the artificial channel constructed for the Middle Route Project are significant indicators of water quality safety and aquatic ecological integrity for this large,interbasin scheme.However,the distribution and transport of nutrients along the channel were poorly understood.Based on a time-series dataset as well as mass balance and material flow analysis methods,the water and nutrient transport fluxes in the Middle Route of the South-to-North Water Diversion Project were identified in this study.The results indicate that the nutrient concentrations varied considerably with time,but there was no significant difference among the 30 stations of the main channel.Seasonal temperature difference was the major factor in the large fluctuations of water quality indicators over time.The nutrient loadings varied with the water volume outputs from the main channel to the waterreceiving cities.Atmospheric deposition was an important source of nutrients in the main channel,accounting for 9.13%,20.6%,and 0.635%of the nitrogen,phosphorus,and sulfur input from the Danjiangkou Reservoir,respectively.In 2021,a net accumulation of 988 tons of N,29 tons of P,and 2,540 tons of S,respectively,were present in the main channel.The increase of these external and internal nutrient loadings would cause water quality fluctuation and deterioration in some local sections of the main channel.Our study quantified the spatial and temporal patterns of nutrient transport in the Middle Route and revealed the ecological effects on the aquatic environment,assisting authorities on the project to develop effective water conservation strategies.

Numerical modeling of nutrient transport to assess the agricultural impact on the trophic state of reservoirs

A trophic state increase relates to surface water bodies nutrient enrichment,due to the chemical products used such as fertilizers in agriculture and residues from cattle raising activities.This research consists of nutrient transport numerical modeling to analyze the Betancíreservoir trophic state in Colombia;Water samples were collected to analyze total nitrogen,total phosphorus,ammonia,nitrates,nitrites,phosphates,chlorophyll-a,dissolved oxygen,BOD,COD,suspended solids,and water trans-parency.The water quality model MOHID Studio was implemented and after its calibration,scenarios of increase and decrease of nutrients and inflows to the reservoir through its main tributaries were simulated to reproduce the agricultural activity changes in the basin and the effects that would have on the reservoir's trophic state dynamics;Therefore,the Carlson Trophic Status Index was calculated for each case.The results show that variations in total nitrogen concentration and increased inflows present short-term consequences on the reservoir's trophic state.Increasing the incoming total nitrogen con-centrations by 100%causes the reservoir to change from a light eutrophic to a hypereutrophic state.The results of this research provide a starting tool to water resources integrated management in reservoirs.

Numerical simulations of nutrient transport changes in Honghu Lake Basin, Jianghan Plain

Nutrients transported from catchments are one of the most important sources for lake eutrophication. In this study, the Honghu Lake Basin, located at the middle reaches of the Yangtze River, was chosen as the study area, and the watershed hydrological distribution model SWAT (Soil Water Assessment Tool) was applied to evaluate the trajectory of watershed nutrient transportation over time. Based on the analysis of driving factors, three experiments corresponding to natural, traditional and modern agriculture processes respectively were designed to evaluate the changes of nutrient inputs from catchments under the three environments. The simulation results showed that there were variations in nutrient production and changes in the range and rate. For three periods of the experiments, TN concentrations have changed as 0.12→0.31→1.15 mg/L, and production as 420→1650→6522 T/a; while TP concentrations changed as 0.018→0.057→0.117 mg/L, and production as 78→303→665 T/a. The nutrient transportation experienced slowly long-term increases during 1840―1950, then showed a relatively rapid increase during the period of 1950―1980s and the period from 1980 to early 1990s, with increasing rate of 1.4% and 2.4% respectively. And from the later 1990s to now, an obviously increasing trend with 15% increasing rate occurred. The effect from human activities on the watershed nutrient transportation increased rapidly, and had become a dominant factor in changes of the nutrient transportation.

TRANSPORT OF OXYGEN,NUTRIENTS AND CARBONATES BY THE KUROSHIO CURRENT

Measured concentrations of dissolved oxygen,phosphate,silicate,total alkalinity and calculated totalCO2 in a section between 121°E and 125°E across the Kuroshio near 22°N off Taiwan and thegeostrophic velocity were used to estimate the gross transport of oxygen,nutrients and carbonates. The flux of dissolved oxygen is 6.7×106 mol/s northward and 0.9×106 mol/s southward.The netflux equals 5.8×106 mol/s down-stream.The northward flux of phosphate is 22.6×103 mol/s;the south-ward flux is 1.4×103 mol/s.The net phosphate flux is 21.2×103 mol/s northward.The flux of silicateis 967×103 northward and 59×103 mol/s southward;the net transport is 908×103 mol/s down-stream.The flux of alkalinity is 75.5×106 mol/s northward,and 10.8×106 mol/s southward,the net flux is64.7×106 mol/s northward.For total CO2 the transport is 73.4×106 mol/s northward and 10.8×106 mol/ssouthward,or a net transport of 62.6×106 mol/s northward.

Variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang(Yangtze River) Estuary

Dissolved inorganic nutrient elements were analyzed from the samples collected in the South Passage of the Changjiang (Yangtze River) Estuary in March 2003, including NH4+, NO3-, NO2- and PO43-. The water samples were collected with a Niskin sampler hourly at the near-surface, middle and near-bottom depths at the three stations -A1, A2 and A3-during two complete tidal cycles of neap tide and spring tide. Results showed that 1) the concentrations of NH4+, NO3- and NO2- were a little higher respectively during the neap tide than those during the spring tide, while PO43- showed an opposite trend, and each was higher in the ebb tide than in the flood tide, either for the neap tidal cycle or the spring tidal cycle; 2) higher stratification of the nutrients existed obviously in this area, with the concentrations of which increased from the bottom to the surface, especially for NH4+ and NO3-; 3) the coefficient of variation (C.V.) values of all dissolved inorganic nutrients varied from 4.06% to 36.8% beyond different influences of the tidal current and Changjiang runoff; 4) with increasing suspended matter in the water column, the concentrations of PO43- became lower in the filtered water; and 5) the total transport of each tidal cycle was much more in the spring tide than in the neap tide, and the positive values indicated that the nutrients had been exported to the East China Sea. Studies on the variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang Estuary will provide the scientific basis for the study of the mechanism of red tide in the East China Sea.

The Effect of Dietary Nutrient Density on Growth Performance, Physiological Parameters, and Small Intestinal Type IIb Sodium Phosphate Co-transporter Expression in Broilers

A 3 × 4 factorial experiment was con- ducted to determine the effect of dietary nutrient den- sity on growth performance, physiological parame- ters, and small intestinal epithelial phosphate trans- porter expression in broiler chicks fed different dietary nutrient density （DND） and non-phytate phosphorus （NPP） levels. Dietary energy densities used had ME values of 2,850, 2,950, and 3,050 kcal/kg of diet and the NPP levels were 0.35%, 0.40%, 0.45%, and 0.50% within each ME value. Crude protein and essential amino acids levels were maintained propor- tionally to dietary ME levels. Each of the twelve diets was fed to five pens of seven male broiler chicks from 1 to 21 days of age. Broiler growth performance, ser- um physiological parameters, 1-hydroxylase activity in the kidney, type-IIb sodium phosphate co-trans- porter （NaPi-IIb）, and vitamin D receptor （VDR） expression levels in the duodenal mucosa were deter- mined. Our results showed that an increase in dietary nutrient density increased body weight and improved feed conversion. Additionally, serum parathyroid hormone concentration, 1-a-hydroxylase activity in the kidney, NaPi-IIb mRNA expression and VDR protein expression in the duodenal mucosa increased as DND increased. Feed intake and body weight in- creased as NPP levels increased. Serum parathyroid hormone, VDR and NaPi-IIb gene expression also in- creased as the level of NPP in the diet increased at the medium range level. The results of this study suggest that high DND can increase small intestinal type IIb sodium dependent phosphate co-transporter mRNA expression by up-regulating parathyroid hormone and activation of 1-ot-hydroxylase activity which might be in consistent with high growth rate of broilers. Small intestinal NaPi-IIb mRNA expression increases linear- ly only within the range of dietary NPP dosage levels close to the requirement recommended in the broilers feeding standards.

Transport patterns of micro nutrient elements from the continental shelf of the East China Sea to the Kuroshio area

On the basis of the in situ data of DO2, pH, SiO2. PO4-P, NO3-N and NO2-N collected in the north of the East China Sea during 1987-1988, the following points are mainly expounded.1.The inorgonic nutrients are obviously affected by continent runoff in the north of the East China Sea. Their distributions are characteristic of its distribution of terrigenous materials.2.There are three transport paths of nutrients from the shelf to the Kuroshio area. The first is mixing-diffusing-advec-tion and upwelling process, the process of biology and biochemistry belongs to the second, and the sinking process is the last one.3.The swing of the Kuroshio axis affectes both the range of the migration of substances through mixing-diffusing-advec-tion process and the upwelling degree of the subsurface Kuroshio water to the shelf.4.Most part of the substances sink as macroparticles to the deep layer before reaching the Kuroshio area.

滴灌水盐氮调控对棉田水肥盐运移及棉花产量的影响

为明析覆膜滴灌条件下水盐氮调控对土壤水盐养分运移变化、棉花生长指标及产量的影响,通过两年三因素全组合大田试验,设置灌水量三水平(W1:2700 m^(3)·hm^(-2)、W2:3600 m^(3)·hm^(-2)和W3:4500 m^(3)·hm^(-2))、含盐量三水平(S1:3 dS·m^(-1)、S2:6 dS·m^(-1)和S3:9 dS·m^(-1))、施氮量三水平(F1:105 kg·hm^(-2)、F2:210 kg·hm^(-2)和F3:315 kg·hm^(-2)),研究了不同水盐氮组合对土壤水分、盐分、氮素分布及植株生长、产量的影响。结果表明:土壤水分主要聚集在30~40 cm土层,不同土层深度的含水率基本呈先增大后减小的变化趋势;蕾期和花铃期的S3F3W1和S2F3W1比S1F3W1的0~40 cm土层平均含水率增大1.3%~21.8%;同一灌溉量下S1F3组合的平均含水率比S1F2和S1F1增大1.39%~13.83%。土壤盐分生育期内呈现先减少后增加的变化趋势;S1土壤盐分随施氮量的增大而先增大后减小,S2、S3土壤盐分随施氮量的增加而减少。W2、W3处理中,氮素在40~60 cm土层中缓慢积聚;S1处理的氮素含量明显高于S2、S3。土壤水分、盐分、氮素含量交互影响,在适宜的土壤水分、氮素条件下,较低的土壤含盐量,能使植株更好地利用养分,利于植株的生长进而促进产量的形成。为获得较高的经济效益,低、中盐土壤推荐灌溉量为3600 m^(3)·hm^(-2),施氮量为210 kg·hm^(-2);高盐土壤推荐灌溉量为4500 m^(3)·hm^(-2),施氮量为315 kg·hm^(-2)。研究为探索干旱区多年膜下滴灌棉花农田生态系统水盐养分运移机制及水肥高效利用提供科学的理论依据。

维生素对动物胚胎发育的影响及机制

维生素是维持机体健康所必需的一类有机化合物。这类物质不参与机体的细胞组织构成和能量供应,但会促进动物体内的多种生物化学反应和机体新陈代谢。维生素能够通过调节机体激素和生长因子的分泌、促进细胞增殖、提高生殖细胞的活性、增强机体抗氧化能力和免疫能力等方式改善胚胎发育。本文从维生素的生物学特性和体内代谢方式入手,总结分析了维生素对动物胚胎发育的影响及潜在机制,为进一步研究维生素在胚胎发育方面的影响与应用提供参考。

Placental accommodations for transport and metabolism during intra-uterine crowding in pigs

Litter size and birth weights are limited by uterine capacity, defined as the ability of the uterus to maintain the appropriate development of some number of conceptuses. Uterine capacity is the result of the combined effects of uterine, placental and embryo/fetal function. The number of living conceptuses that the uterus is capable of supporting is greater during early gestation compared to later gestation. Plots of log fetal weight versus log placental weight also indicate that fetal weights are less sensitive to reduced placental weight （and therefore reduced intrauterine space） in early gestation compared to late gestation. However, even in late gestation, mechanisms still exist that maintain fetal growth when the size of the placenta is reduced. One such mechanism is likely to be improved development of the folded placental-epithelial/maternal-epithelial bilayer. Fold depth, and therefore the maternal fetal interactive surface, increases as gestation advances and is greater in placenta from smal fetuses. On the fetal side of the placenta, the epithelial bilayer is embedded in stromal tissue. Glycosaminoglycans are major components of stroma, including hyaluronan and heparan sulfate. Hyaluronidases and heparanases are present within placental tissues, and likely play roles in modification of stromal components to facilitate fold development. Glycosaminoglycans are polymers of forms of glucose （glucosamine, glucuronic acid, iduronic acid） suggesting that glycosaminoglycan synthesis may compete with the glucose needs of the developing fetus. Pig conceptuses are fructogenic, such that a substantial portion of glucose transferred from mother to fetus is converted to fructose. Fructose is an intermediate product in the synthesis of glucosamine from glucose, and glucosamine is linked to regulation of trophoblast cell proliferation through regulation of mTOR. These findings suggest a link between glucose, fructose, glucosamine synthesis, GAG production, and placental morphogenesis, but the details of these interactions remain unclear. In addition, recent placental epithelial transcriptome analysis identified several glucose, amino acid, lipid, vitamin, mineral and hormone transporter mechanisms within the placenta. Further elucidation of mechanisms of placental morphogenesis and solute transport could provide clues to improving nutrient transport to the pig fetus, potentially increasing litter size and piglet birth weights.

盐碱胁迫对骏枣养分吸收、积累及运转的影响

为揭示基于树体养分吸收、利用与积累特征的骏枣耐盐碱适应性生理机制,通过测定不同浓度盐碱处理下10年生骏枣各器官中N、P、K、Ca、Mg、Fe、Mn、Zn、Cu、Na等矿质元素的含量,分析养分在骏枣不同器官中的吸收、积累与运输分配特征。结果表明:矿质离子在盐碱胁迫下主要集中在主根、多年生枝,有无盐碱胁迫时Na^(+)都主要聚集在主根中,K+浓度在叶片中最高,可以保持较高的K+/Na^(+)。在低浓度盐碱胁迫(60 mmol·L^(-1))下Mg、Ca的运输能力增强;高浓度盐碱胁迫(180 mmol·L^(-1))下须根至叶片的Mg、Ca运输能力分别显著下降44.7%和33.1%,叶片中Ca^(2+)/Na^(+)、Mg^(2+)/Na^(+)值分别显著降低72.8%和71.6%,但仍大于1;其他器官中K+/Na^(+)、Ca^(2+)/Na^(+)、Mg^(2+)/Na^(+)保持稳定且大于1。相较于CK,高浓度盐碱胁迫下当年生枝中的Mn、Fe含量与多年生枝中的Mg含量分别升高了14.01%、11.11%、10.52%,Cu、Zn、Mn、Fe在须根中的含量分别升高了117.53%、25.65%、84.98%、26.19%,主根中N、P、Zn、Mn、Fe、Ca的含量分别下降了23.07%、15.38%、80.48%、49.58%、8.82%、30.44%。结果表明成年骏枣树的盐适应机制主要是通过根对Na^(+)的聚积作用,以及叶对K、Mg和Ca的选择性吸收能力增强来实现的。

Factors controlling nutrient availability to the developing fetus in ruminants

Inadequate delivery of nutrients results in intrauterine growth restriction （IUGR）, which is a leading cause of neonatal morbidity and mortality in livestock. In ruminants, inadequate nutrition during pregnancy is often prevalent due to frequent utilization of exensive forage based grazing systems, making them highly susceptible to changes in nutrient quality and availability. Delivery of nutrients to the fetus is dependent on a number of critical factors including placental growth and development, utero-placental blood flow, nutrient availability, and placenta metabolism and transport capacity. Previous findings from our laboratory and others, highlight essential roles for amino acids and their metabolites in supporting normal fetal growth and development, as well as the critical role for amino acid transporters in nutrient delivery to the fetus. The focus of this review will be on the role of materna nutrition on placental form and function as a regulator of fetal development in ruminants.

玉米种植密度对大豆玉米带状复合种植体系干物质养分积累与转运的影响

为探索大豆玉米带状复合种植模式下适宜的玉米种植密度,通过田间试验,研究大豆玉米带状复合种植模式(3+2)下,玉米种植密度(52500、60000和67500株·hm^(-2),分别以SM1、SM2和SM3表示)和玉米单作(MM,种植密度60000株·hm^(-2))对大豆玉米带状复合种植体系产量及玉米干物质、养分积累和转运的影响。结果表明,与单作相比,带状复合种植体系玉米产量降低5.25%~14.30%,其中SM2产量与MM差异未达显著水平,但带状复合种植体系总产值显著提高10.80%~16.71%。在复合种植模式下,与SM1和SM3相比,SM2显著提高玉米穗粒数和百粒重,延长干物质快速积累的时间,提高干物质积累最大增长速率,促进花后干物质向籽粒中转运,提高养分吸收,产量分别较SM1和SM3提高10.56%和9.67%。综上,相比较玉米单作,大豆玉米带状复合种植(3+2模式)可实现“玉米不减产或稍减产,多收一季豆”;在大豆玉米带状复合种植模式下,大丰30系列玉米的种植密度在60000株·hm^(-2)左右时可作为晋南小麦玉米一年两熟轮作区合理的密度选择,实现稳产高效。本研究可为晋南小麦玉米一年两熟轮作区推广大豆玉米带状复合种植及提高我国大豆自给率提供理论依据。

荒漠草原产流产沙过程及养分运移特征

[目的]荒漠草原夏季降雨强度大且集中性强,水力侵蚀危害严重,明确荒漠草原区产流产沙过程及养分运移规律对该地区开展水土保持工作有重要意义。[方法]试验基于天然降雨观测和人工模拟降雨的方法,研究荒漠草原区产流产沙过程及养分运移规律,并通过对植被进行不同处理研究植被对产流产沙的影响。[结果](1)不同植被处理方式的水土保持效果不同。3种不同处理方式中天然草地的水土保持效果最好,减流率与减沙率分别为11.37%和49.67%。(2)产流产沙过程改变地表土壤物质组成,使地表土壤粗粒化,还对土壤养分产生影响。降雨后砂粒含量增加5.97%~15.71%,土壤速效N、P及有机质分别减少40.84%,27.08%,33.49%。(3)坡面产流产沙量随坡度和降雨强度的增加而增加,幂函数能较好地拟合降雨历时与产流量和产沙量的关系。随降雨强度增加,坡度为5°~25°的峰值产流量平均增加6.70 L;降雨强度0.6~2.0 mm/L时,产沙量增长速度加快的拐点出现在坡度15°~20°。[结论]研究结果可为荒漠草原区水土流失的综合防治提供理论参考,有助于改善荒漠草原区生态环境,有利于该地区开展水土保持工作。

叶面喷施氨基酸对水稻Cd转运特性和稻米氨基酸含量的影响

为了探讨氨基酸叶面肥的降Cd潜力,在湖南水稻开花期喷施6种氨基酸,对水稻Cd转运特性及其稻米Ca、Fe、Mn、Zn和氨基酸含量的变化进行了分析。试验结果表明:喷施2次10 mmol·L^(-1)苯丙氨酸(Phe)、甘氨酸(Gly)、异亮氨酸(Ile)、丝氨酸(Ser)、蛋氨酸(Met)和0.02 mmol·L^(-1)的色氨酸(Trp),能使稻米、穗颈、穗下节中的Cd含量显著下降,稻米中的Cd平均含量从0.63 mg·kg^(-1)分别下降至0.27~0.48 mg·kg^(-1)。其中喷施Ser、Trp和Met的降Cd幅度高达51.1%~57.3%,而Phe和Gly的降Cd幅度仅为24.7%~35.1%。与此同时,水稻各器官中Ca和Fe的含量显著上升,Mn的含量显著下降,Zn的含量无显著变化。喷施氨基酸对Cd在水稻器官间的转移系数无显著影响,但显著降低了稻米、穗颈和穗下节中Cd含量与Ca、Fe、Mn含量的比率。喷施Ser和Met使稻米中的必需氨基酸含量分别增加7.5%和10.5%、非必需氨基酸分别增加13.9%和5.5%;喷施6种氨基酸都能显著增加稻米谷氨酸(Glu)、亮氨酸(Leu)和半胱氨酸(Cys)的含量。稻米Cd含量与Cd∶Ca、Cd∶Fe、Cd∶Mn的含量比率呈极显著正相关,与Glu和Ca含量呈极显著负相关。综上所述,喷施Ser、Trp和Met能显著促进Ca、Fe转运和Glu合成,提高Ca、Fe、Mn离子通道对Cd的拦截能力,从而有效降低稻米、穗颈和穗下节中的Cd含量。

典型自然源气溶胶沉降引起的海洋初级生产响应

大气沉降是陆源物质向海洋输入营养盐的重要方式,沙尘、野火和火山喷发均能够产生气溶胶,这些典型的自然源气溶胶在风场的作用下,能够进行远距离的输运,期间由于沉降作用进入海洋,为上层海洋提供限制性营养盐促进海洋浮游植物生长,提升海洋的初级生产力,促进碳循环过程。以海表叶绿素浓度作为海洋初级生产力的重要指标,通过海表叶绿素浓度的响应,探究沙尘、野火和火山这三种典型自然源气溶胶的传输路径及其沉降对海洋初级生产的影响。结果显示,海洋初级生产对气溶胶沉降的响应不仅与气溶胶排放类型有关,也与温度、动力过程、光合有效辐射等海域初级生产影响因素有关,体现了海洋初级生产对自然源气溶胶的敏感性,自然源气溶胶沉降所驱动的海洋初级生产在全球碳循环中具有重要的潜在影响。

海藻肥对枇杷幼苗养分吸收及转运的影响

为研究海藻肥对枇杷幼苗养分吸收及转运的影响,以大五星枇杷幼苗为材料,研究叶面喷施不同稀释倍数的海藻肥对枇杷幼苗氮、磷和钾养分吸收及转运的影响。叶面喷施不同浓度海藻肥均增加了枇杷幼苗根、茎、叶和地上部分的生物量及全氮、全磷和全钾含量,且随海藻肥稀释倍数的增加呈先增后降的趋势。喷施海藻肥提高了枇杷幼苗各部位氮、磷、钾的吸收量、转运量、转运效率和转运贡献率,且均以650倍稀释液海藻肥处理效果最佳。不同浓度的海藻肥可增加枇杷幼苗地上部分的氮收获指数和根系的磷收获指数。此外,喷施海藻肥后土壤碱解氮、有效磷和速效钾含量提高,土壤pH值降低。相关性分析表明,枇杷幼苗各部分生物量及全氮、全磷、全钾含量和土壤碱解氮、有效磷、速效钾含量之间均呈显著正相关关系。喷施海藻肥能促进枇杷幼苗对氮、磷和钾的吸收和转运,以650倍稀释倍数为最佳浓度。

糖尿病胃轻瘫与“脾阴”“脾气散精”二者间关系

文章从“脾阴”与“脾气散精”的解剖学、病理生理学等方面阐述二者与糖尿病胃轻瘫的相关性。何绍奇先生提出“脾胰同源”学说,指出主运化是脾的生理功能之一,认为胰的功能包含于脾的转输与散精之中。脾阴的充足是脾正常转运的基础,唐宗海在《血证论》中提到脾的运化不仅需要脾阴的滋润,同时也需要脾阳的温煦,二者缺一不可。脾阴具有促消化作用,在饮食水谷进入人体内之后,脾阴开始发挥作用,将饮食水谷转化为水谷精微,输送至人体五脏六腑、四肢百骸,以达营养全身的作用,维持各个脏腑的正常生理活动功能。脾运的本质为脾气散精,散精不足则精微物质布散失常,导致血糖等精微物质停聚于脉中,导致高血糖,引发糖尿病。而精微物质布散失常也会导致脾失健运,脾气不升,胃气不降,最终导致胃动力障碍、胃排空延迟,形成糖尿病胃轻瘫。糖尿病日久会引起多种并发症,糖尿病胃轻瘫便是其中一种。脾阴虚是糖尿病的发病基础,脾阴虚导致脾阳虚,进而导致脾阴阳两虚,从而影响脾散精功能,所以说从脾论治成为治疗糖尿病的重中之重。有较多专家提出自己的独到理解,为今后治疗糖尿病提供可以借鉴的临床经验。