共查询到20条相似文献，搜索用时 62 毫秒
1.
L Barajas 《Science (New York, N.Y.)》1971,172(982):485-487
By means of electron microscopy of serial sections and three-dimensional reconstruction of the juxtaglomerular apparatus a quantitative study has been made of the distribution of the areas of contact between the tubular and vascular components. Of the two arterioles the efferent is the only one consistently in contact with the distal tubule. The extraglomerular mesangium is also in contact with the distal tubule in all the apparatuses examined. Two morphologically distinct types of contact are described; one is thought to be permanent and the other reversible. An analysis of the cells of the juxtaglomerular apparatus for their position, granularity, and contact has revealed that the majority of granular cells are not in contact with the distal tubule. The anatomical findings are integrated in a model of the control of renin secretion based on variations in contact between the elements of the juxtaglomerular apparatus. 相似文献
2.
The posterior sublingual gland of sea snakes is a salt gland. It secretes a fluid surpassing seawater in sodium chloride concentration. The gland lies on the ventrolateral surfaces of the tongue sheath and empties through multiple ducts into the sheath. Fluid is expelled from the sheath when the tongue is extended. For freshly captured Pelamis, the plasma concentrations of sodium, chloride, and potassium were 210, 167, and 8 millimoles per liter, respectively. Injections of sodium chloride led to a rise in its concentration in the plasma and to an increase in the rate and concentration of fluid secreted by the sublingual gland. The ultrastructure of this gland is similar to that of other reptilian salt glands. However, the gland is not homologous with any other salt gland. The sublingual gland in Pelamis is larger than that in Laticauda, and the rate of electrolyte excretion from the larger gland is greater. 相似文献
3.
INOUE T 《Science (New York, N.Y.)》1963,142(3597):1299-1300
The nasal salt-secreting gland of the domestic duck can produce a fluid with a sodium chloride concentration about three times that in blood plasma. To study the cellular mechanism responsible for the formation of the highly concentrated fluid, the gland was poisoned by retrograde injection of mercuric chloride into the lumen, decreasing the salt concentration to that in plasma while the volume of secretion was unchanged. Carbonic anhydrase inhibitor (acetazoleamide) caused a moderate decrease in salt concentrations, again with maintenance of volume of secretion. The results suggest that concentration and volume of the secreted fluid depend on two different cellular mechanisms. 相似文献
4.
Inherited renal cysts in rats 总被引：1，自引：0，他引：1
S Solomon 《Science (New York, N.Y.)》1973,181(98):451-452
A strain of rats that form renal cysts has been developed. The number of visible cysts increases with age after animals are 20 days old. Micropuncture studies indicate that the cystic fluid has a variable sodium concentration, but that the ratios of inulin concentration in tubular fluid to that in plasma are high. 相似文献
5.
The rectal gland of the spiny dogfish, Squalus acanthias, secretes a fluid which is essentially a sodium chloride solution with a concentration about twice that of the plasma and greater than that of sea water. Observed volumes of flow are sufficiently large to make it clear that the rectal gland can remove from the blood relatively large amounts of sodium chloride, and presumably this is its function. 相似文献
6.
Chromatography, on methylated-albumin columns, of DNA from calf thymus, mouse testis, and Bacillus subtilis, yielded, on elution by a sodium chloride gradient, fractions differing in density. The fractions eluted by higher sodium chloride concentrations had lower densities in a CsCl density gradient. Since DNA with higher guaninecytosine content is eluted from the column with lower concentration of sodium chloride and has higher density, the density heterogeneity of DNA is best interpreted as a result of heterogeneity of base composition. An extra band observed in calf-thymus DNA had a higher density than that of the main DNA; it was eluted at a lower concentration of NaCl, indicating a higher content of guanine and cytosine. On the other hand, an additional DNA component in the mouse-testis DNA had a lower density and also it was eluted at a lower salt concentration, possibly an indication of an unusual base component in its structure. 相似文献
7.
[目的]探讨生姜渗透脱水的最佳工艺条件,建立生姜渗透脱水的传质数学模型。[方法]以生姜为研究对象,以NaCl溶液为渗透液,在不同的渗透脱水条件下考察物料失水率、固形物增加率的变化。[结果]确定了不同条件下生姜失水率、固形物得率常数,建立了生姜渗透脱水传质模型。在一定实验范围内,生姜脱水率、固形物得率均随渗透时间、渗透液浓度及温度的增加而增加;最佳条件为：渗透液浓度20%,渗透时间1.00h,渗透温度50℃。[结论]该研究为生姜脱水工艺的改进提供了一定理论依据。 相似文献
8.
白鲢腌制过程中鱼肉与盐卤成分的变化 总被引：7，自引：1，他引：6
以白鲢为材料,研究了不同腌制条件下鱼肉与盐卤成分的变化及其动力学特性。结果表明,腌制条件对鱼肉中氯化钠含量及盐卤中可溶性蛋白和氨基态氮含量变化有明显影响。随着盐水浓度的提高,鱼肉中氯化钠含量显著上升,盐卤中可溶蛋白和氨基态氮含量明显降低。降低腌制温度、缩短腌制时间、提高盐水浓度可降低鱼肉中氯化钠含量,控制肌肉中营养成分的析出。试验建立的扩散动力学方程可较好地描述腌制过程中氯化钠、可溶蛋白和氨基态氮含量的变化。 相似文献
9.
Angiotensin-sodium interaction in blood pressure maintenance of renal hypertensive and normotensive rats 总被引：6，自引：0，他引：6
A specific inhibitor of angiotensin II was used in rats to investigate whether angiotensin is involved in the maintenance of blood pressure in one-kidney Goldblatt hypertension, in which plasma renin levels are not usually increased. The inhibitor produced marked falls in blood pressure, often down to normal levels in the hypertensive animals only when they were depleted in sodium and not after sodium repletion. Much lesser but still significant falls in blood pressure were also produced in normotensive sodium-depleted rats but not in repleted rats. We conclude that the importance of angiotensin for maintaining blood pressure is largely determined by its relation to available sodium or fluid volume, since the renin component in maintenance of either the hypertensive or the normotensive state could be exposed only by sodium deprivation. Therefore, volume expansion per se or other pressor factors may be involved in maintaining blood pressure of these sodium-replete normotensive or hypertensive animals. 相似文献
10.
不同盐胁迫处理下番茄种子萌发期的耐盐性研究 总被引：1，自引：0，他引：1
[目的]为番茄耐盐种质资源的筛选、利用及设施抗盐栽培提供理论依据。[方法]采用皿内培养法,对NaCl单一盐和Ca(NO3)2、NaCl复合盐胁迫下番茄种子萌发期的耐盐性进行研究。[结果]随着2种盐浓度的增大,种子萌发的整齐度下降,萌发率降低,发芽受损率增加,发芽指数和幼苗活力指数下降;盐浓度为0.2%~0.4%时,2种盐胁迫处理下各指标差异较小,盐浓度为0.6%~1.0%时,2种盐胁迫处理下各指标之间差异显著。[结论]番茄种子对Ca(NO3)2、NaCl复合盐胁迫的耐性高于NaCl单盐胁迫。 相似文献
11.
《（《农业科学与技术》）编辑部》2008,(4)
[Objective] The aim of this study was to provide the theoretical basis for screening and utilizing salt-tolerant tomato varieties as well as for cultivating salt-resistance.[Method] Salinity tolerance of tomato during seed germination under simple salt sodium chloride and double salt calcium nitrate or sodium chloride stress were studied by Petri dish culturing.[Result] As the two kinds salt concentration increased,the germination regularity,the germination rate,the germination index and the growing vigor index of tomato seedlings decreased,but the germination losing rate increased.When salt concentration was from 0.2% to 0.4%,there was little difference among all indexes under two kinds of salt stress.However,when salt concentration was from 0.6% to 1.0%,the difference among all indexes under two kinds of salt stress was significant.[Conclusion] Salinity tolerance of tomato seeds under double salt calcium nitrate or sodium chloride stress was higher than that under simple salt sodium chloride stress. 相似文献
12.
Study on Salinity Tolerance of Tomatoes during Seed Germination under Different Salt Stress Conditions 总被引：6，自引：0，他引：6
MA Hong-ying GUO Rui LI Hong-an ZHANG Yuan-fang The New High Agricultural Technology Demonstration Gardens of Tianjin City Tianjin 《（《农业科学与技术》）编辑部》2008,(4)
[Objective] The aim of this study was to provide the theoretical basis for screening and utilizing salt-tolerant tomato varieties as well as for cultivating salt-resistance.[Method] Salinity tolerance of tomato during seed germination under simple salt sodium chloride and double salt calcium nitrate or sodium chloride stress were studied by Petri dish culturing.[Result] As the two kinds salt concentration increased,the germination regularity,the germination rate,the germination index and the growing vigor index of tomato seedlings decreased,but the germination losing rate increased.When salt concentration was from 0.2% to 0.4%,there was little difference among all indexes under two kinds of salt stress.However,when salt concentration was from 0.6% to 1.0%,the difference among all indexes under two kinds of salt stress was significant.[Conclusion] Salinity tolerance of tomato seeds under double salt calcium nitrate or sodium chloride stress was higher than that under simple salt sodium chloride stress. 相似文献
13.
不同盐胁迫处理下番茄种子萌发期的耐盐性研究(英文) 总被引：16，自引：3，他引：13
[Objective] The aim of this study was to provide the theoretical basis for screening and utilizing salt-tolerant tomato varieties as well as for cultivating salt-resistance.[Method] Salinity tolerance of tomato during seed germination under simple salt sodium chloride and double salt calcium nitrate or sodium chloride stress were studied by Petri dish culturing.[Result] As the two kinds salt concentration increased,the germination regularity,the germination rate,the germination index and the growing vigor index of tomato seedlings decreased,but the germination losing rate increased.When salt concentration was from 0.2% to 0.4%,there was little difference among all indexes under two kinds of salt stress.However,when salt concentration was from 0.6% to 1.0%,the difference among all indexes under two kinds of salt stress was significant.[Conclusion] Salinity tolerance of tomato seeds under double salt calcium nitrate or sodium chloride stress was higher than that under simple salt sodium chloride stress. 相似文献
14.
[目的]探讨不同浓度KCl、Na Cl、Ca Cl2、Mg Cl2溶液对蓝曼龙精子活力的影响。[方法]选取成熟蓝曼龙雄鱼,解剖取5期性腺,匀浆后获得组织液,在显微镜下观察不同浓度KCl、Na Cl、Ca Cl2、Mg Cl2溶液对精子活力的影响。[结果]当KCl浓度为0.5 g/L时蓝曼龙精子活力最高,精子活力为245 s,浓度高于0.5 g/L时,精子活力逐渐下降;Na Cl浓度为0.4 g/L时蓝曼龙精子运动时间最长,精子活力为103 s;Ca Cl2浓度为0.4 g/L时,蓝曼龙精子活力最高,精子活力为26 s;Mg Cl2浓度为0.3 g/L时,蓝曼龙精子活力最高,精子活力为20 s。[结论]该研究可为蓝曼龙的人工繁殖提供参考。 相似文献
15.
采用微胶囊固定化技术,利用聚乙烯醇、海藻酸钠和氯化钙制备汉逊德巴利酵母微胶囊,探讨了聚乙烯醇、海藻酸钠、氯化钙的浓度对汉逊德巴利酵母微胶囊的制备工艺及其产3-羟基丙酸量的影响。结果表明,随着聚乙烯醇、海藻酸钠和氯化钙浓度的分别增加,3-羟基丙酸含量先增加后减少。聚乙烯醇最佳浓度为10.0%,此时3-羟基丙酸含量为(20.01±0.66)g/L;海藻酸钠为最佳浓度为1.0%,此时3-羟基丙酸含量为(18.71±0.54)g/L;氯化钙最佳浓度为2.1%,此时3-羟基丙酸含量为(18.37±0.45)g/L。聚乙烯醇和海藻酸钠联合固定汉逊德巴利酵母制备微胶囊最佳工艺为10.0%聚乙烯醇,1.0%海藻酸钠和2.1%氯化钙,在此条件下3-羟基丙酸含量为(21.53±1.12)g/L。 相似文献
16.
以分蘖葱头根尖为试验材料,研究了氯化钠对分蘖葱头根尖的毒性效应。用不同浓度(0.05、0.1、0.2、0.3 mol/L)的氯化钠水溶液对分蘖葱头根尖细胞染毒12 h、24 h、48 h,观察分蘖葱头根尖细胞有丝分裂指数、微核率以及染色体畸变情况。结果表明:在试验剂量范围内,随着氯化钠水溶液浓度的升高,染毒时间增长,分蘖葱头根尖细胞的有丝分裂指数逐渐降低,染色体畸变率和微核率逐渐升高,并且均在氯化钠水溶液浓度为0.3 mol/L、染毒时间为48 h时达到最大值,说明氯化钠是一种胁迫因子。 相似文献
17.
研究氯化铵、亚硝酸钠和硫化钠水平对缢蛏(Sinonovaculaconstricta)存活的影响,共3个实验:实验1研究了氯化铵水平(0、100、158、251、398、631、1000和1585mg/L)对缢蛏存活的影响,发现随氯化铵水平的升高,缢蛏存活率呈下降趋势;在24、48、72和96h,LC50分别为515.65、163.44、104.99和85.48mg/L,安全浓度为4.93mg/L。实验2研究了亚硝酸钠水平(0、4、10、25、63、158、398和1000mg/L)对缢蛏存活的影响,发现随亚硝酸钠水平的升高,缢蛏存活率呈下降趋势;在24、48、72和96h,LC50分别为713.00、217.07、87.90和23.61mg/L,安全浓度为6.04mg/L。实验3研究了硫化钠水平(0、13、25、50、100、200、398、794、1585、3162和6310mg/L)对缢蛏存活的影响,发现随硫化钠水平的升高,缢蛏存活率呈下降趋势;在24、48、72和96h,LC50分别为3843.18、2072.71、1011.95和306.30mg/L,安全浓度为180.87mg/L。 相似文献
18.
Bean plants subjected to a sodium chloride concentratioz about onetenth that of seawater for 1 week suffered no damage if the calcium concentration of the nutrient solution was 1 millimole per liter or higher, but at lower calcium concentrations damage was severe and apparently due to a massive breakthrough of sodium into the leaves. 相似文献
19.
NaCl和Na2SO4胁迫对蒲公英种子发芽及成苗的影响 总被引：5，自引：0，他引：5
以蒲公英种子为试材，在NaCl和Na2SO4盐溶液中发芽，幼苗在持续盐胁迫条件下成苗生长。结果表明，当浓度为3500mg／kg时，NaCl和Na2SO4分别严重抑制了蒲公英种子的发芽，达到极显著水平。NaCl对种子发芽率的抑制强于Na2SO4。蒲公英成苗胁迫试验中，NaCl，Na2SO4浓度分别为5000mg／kg时，严重影响蒲公英成苗率、幼苗根、茎的生长和鲜干重比值，对叶绿素含量影响不大。种子发芽期问适当浓度的NaCl和Na2SO4盐溶液胁迫有助于诱导蒲公英幼苗耐盐性的产生。 相似文献
20.
以加工番茄品种里格尔87-5和石红12为试材,研究了在果实发育期叶面喷施不同质量浓度NaCl对果实耐挤压性和品质的影响。结果表明,在适宜质量浓度范围内,叶面喷施NaCl可以提高加工番茄果实硬度、耐压力和产量,改善果实品质,但两个品种对NaCl质量浓度的反应有一定差异。对品种里格尔87-5,3.0 g/L NaCl处理使产量和果实硬度极显著提高,果实耐压力、可溶性总糖、还原糖和Vc含量增加;6.0 g/L NaCl处理可显著增加还原糖和可溶性总糖含量,对果实硬度、耐压力、Vc含量和产量的影响不大;9.0 g/L NaCl处理使果实硬度极显著降低,并对果实耐压力和产量有一定的不利影响。对品种石红12,3.0 g/L NaCl处理能显著提高产量,并有增加可溶性总糖、还原糖、Vc含量、果实硬度和耐压力的趋势;6.0 g/L NaCl处理能极显著提高产量,显著增加果实耐压力和Vc含量,但还原糖含量显著降低;9.0 g/L NaCl处理则显著降低果实耐压力和还原糖含量,对其他指标的影响不大。综合各指标分析认为,NaCl处理加工番茄的适宜质量浓度为3.0-6.0 g/L。 相似文献