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排序方式: 共有273条查询结果,搜索用时 750 毫秒
1.
山羊肺淋巴系的研究   总被引:2,自引:0,他引:2  
24例山羊肺经肺实质和肺胸膜下注射30%普鲁士蓝氯仿溶液,剖查其器官内淋巴管及淋巴流向。结果表明,山羊肺的器官内淋巴管有浅淋巴管和深淋巴管2种。左肺尖叶淋巴管注入左支气管肺淋巴结和气管支气管左淋巴结,左肺心叶淋巴管注入左支气管肺淋巴结、气管支气管左淋巴结和气管支气管中淋巴结,左肺膈叶淋巴管注入气管支气管左淋巴结、气管支气管中淋巴结和纵隔后淋巴结;右肺尖叶淋巴管注入右支气管肺淋巴结和气管支气管前淋巴结,右肺心叶淋巴管注入右支气管肺淋巴结和气管支气管右淋巴结,右肺膈叶淋巴管注入气管支气管右淋巴结、气管支气管中淋巴结和纵隔后淋巴结,右肺副叶淋巴管注入右支气管肺淋巴结、气管支气管中淋巴结和纵隔后淋巴结。  相似文献   
2.
Stems of the susceptible Early Sam and resistant Novada carnations were inoculated with a conidial suspension ofFusarium oxysporum f. sp.dianthi. Stem segments of either cultivar were sampled regularly and used for determination of fungal growth and for microscopical investigation.Early Sam showed typicalFusarium wilt symptoms and its stems were colonized intensively. The observed vascular browning appeared to be caused by discolouration of primary walls of infected vessels and surrounding cells. Vessels were rarely occluded with gel. Cell wall degradation led to the formation of stem cavities. Hyperplasia of xylem parenchyma was not seen.In Novada, fungal colonization remained low throughout the experiment. Macroscopic symptoms were absent except for longitudinal bursts in the stem, which appeared to be caused by hyperplasia of xylem parenchyma bordering infection. Vascular gelation occurred in the infected tissues, causing some vascular browning also. Xylem vessel regeneration was observed in the hyperplastic layer. Cavities were not formed, and wall discolouration was rare. Vascular gelation is considered part of theFusarium wilt resistance mechanism. It is followed by xylem vessel regeneration, which expresses a general plant response to vascular dysfunction rather than being part of the resistance mechanism.Although of different origin, vascular browning as such occurs in both susceptible and resistant interactions. In breeding for resistance, care should hence be taken with the current use of browning as an indication of disease.Samenvatting Anjers van de vatbare cultivar Early Sam en de resistente cultivar Novada werden geïnoculeerd met een conidiënsuspensie vanFusarium oxysporum f. sp.dianthi. Van beide cultivars werden regelmatig stengeldelen geoogst om deze microscopisch te onderzoeken en om de schimmelgroei te bepalen.Early Sam vertoonde de voor deze verwelkingsziekte kenmerkende symptomen en werd intensief gekoloniseerd. Aan het vaatweefsel waargenomen bruinkleuring bleek veroorzaakt te worden door verkleuring van de primaire wanden van geïnfecteerde vaten en de hen omringende cellen. Zelden trad er in de vaten gomvorming op. Celwandafbraak veroorzaakte de vorming van holten in de stengel. Hyperplasie van het houtparenchym werd niet waargenomen.In Novada bleef de schimmelgroei gedurende het hele experiment beperkt. Macroscopisch waren er enkel lengtescheuren in de stengel te zien, die veroorzaakt bleken te worden door hyperplasie van aan de infectie grenzend houtparenchym. In het geïnfecteerde vaatweefsel optredende gomvorming veroorzaakte ook enige bruinkleuring. In het hyperplastische weefsel werd regeneratie van houtvaten waargenomen. In de stengel werden geen holten gevormd, en verkleuring van de celwanden kwam weinig voor. De vorming van gommen in de houtvaten maakt waarschijnlijk deel uit van het resistentiemechanisme. De daarop volgende houtvatregeneratie is eerder een algemene reactie van de plant op vaatverstopping dan een deel van het resistentiemechanisme.Vaatverbruining, zij het van verschillende oorsprong, komt voor in zowel vatbare als resistente interacties. Om die reden moet men in de resistentieveredeling bij de anjer voorzichtig zijn met het gebruik van bruinkleuring als ziekteïndicatie.  相似文献   
3.
依据中国渔政指挥系统江苏省渔业船舶水上安全事故的统计资料,对2010—2019年事故的发生时间、事故起数、死亡人数、事故类型和事故等级等方面进行了统计分析。结果表明,江苏省渔业船舶水上安全事故以一般等级事故居多,事故发生时间呈现一定规律性,渔船自身安全隐患突出,从业人员岗位技能不足,渔船安全管理责任不到位。基于分析结果,提出压降一般等级事故,遏制较大等级以上事故,提高风险管控和事故防范能力的对策建议。  相似文献   
4.
实验结果表明,丹参注射液分别在3×10~(-3)g/ml和6×10~(-3)g/ml浓度时,小白鼠子宫活动呈轻度弛缓,记录图形波谷略下延,收缩间隔延长,子宫活动较用药前有明显差别(P<0.05);妊娠小白鼠每只一次皮下注射0.2 mI丹参注射液,每日1次,连续3次,试期无一例发生流产,妊娠鼠均产下健康乳鼠;用妊娠山羊作同样实验(山羊体重30kg左右,每次每只皮下注射10ml丹参液,约含生药10g,每日1次,连续3次),同样无一例发生流产,妊娠期满顺利产下健康羊羔;丹参注射液离体兔耳灌流后,兔耳皮肤血管短暂徼弱扩张,但用药前后流量变化差异不明显(P>0.05)。  相似文献   
5.
金枪鱼围网渔船的设计特点   总被引:1,自引:0,他引:1  
在收集大量资料的基础上 ,分别就金枪鱼围网鱼船主要尺度的选择、最佳船型的论证、航速性与稳性以及总布置特征进行了阐述 ,并且提供部分近似公式及有关数据以供设计时应用。最后 ,对金枪鱼围网渔船的鱼舱设置及与保鲜方法的关系作了介绍  相似文献   
6.
《Plant Production Science》2013,16(4):437-445
abstract

Nodal root anatomy was compared among twelve upland and lowland rice (Oryza sative L.) varieties with tropical origin which were grown in hydroponic culture and under field conditions. The traditional upland japonica varieties showed the largest diameter of root, stele, and xylem vessel followed by modern upland varieties. There was a clear varietal difference in the ratio of stele to root diameter, which was associated with the genetic group rather than with the ecosystems. The japonica varieties had a significantly larger stele diameter relative to the root diameter than indica and aus varieties. The indica and aus varieties displayed more xylem vessels per unit area of stele than the japonica varieties, but the diameter of xylem vessel was smaller. Equivalent xylem vessel diameter (De) was more dependent on the number of xylem in the indica varieties than in the japonica varieties. Distinctly different types of sclerenchyma anatomy were identified among the varieties. The development of sclerenchyma was classified into four different types based on thickening of cell wall in the outer cortical parenchyma and the number of sclerenchymatous cell layers. Like the xylem anatomy, the varietal differences in sclerenchyma development were more associated with genetic group rather than the ecotype. The japonica varieties had higher frequency of the types which have a doubled cell layer in sclerenchyma with thick cell wall than indica and aus. The difference among the genetic groups was nearly consistent across growing conditions, aerobic and submerged soils. These results indicated that sclerenchyma development is controlled by a genetic factor.  相似文献   
7.
The rates of sap flow and xylem vessel features were studied in two-year-old nongrafted and grafted avocado (Persea americana Mill.) trees. Daily sap flow rates were measured with heat and balance stem gauges in clonal Duke 7 (D7) and Toro Canyon (TC) trees and ‘Hass’ clonal scions grafted onto clonal D7 (H/D7) and TC (H/TC) rootstocks. Vessel features as size, number and total vessel area were determined histologically in the stem of the scion and rootstock and the roots of the grafted trees. Significant differences in the sap flow rate were found among the rootstocks, where D7 had a 29% higher sap flow rate than did TC (grafted and nongrafted trees). There were no differences among xylem vessel features in the stems of any of the varieties. However in the roots, D7 had wider and fewer vessels then TC do. Also, D7 had a 19% higher total vessel area than TC. These results suggest that the differences in water consumption of ‘Hass’ on different rootstocks may be associated with differences in the efficiency of the roots to absorb water across conductive tissue which may be linked to differences in the area of xylem vessels in the root.  相似文献   
8.
针对常规植物组培存在的问题,从植物无糖组培实用化角度出发,研制了带有新型CO2施放装置的180 L植物无糖组培容器及其环境控制系统,采用小流量控制、三通阀调节和PWM控制方式,实现了对CO2浓度的精确控制,控制精度达到±50 μmol·mol^-1;采用穴盘覆膜与气体循环吸附相结合的方式实现了对容器内相对湿度的自动控制,控制精度达到±22%.通过圆叶海棠的无糖组培的试验,结果表明,该系统对组培苗的生长环境和生理品质的提高具有显著的促进作用.  相似文献   
9.
黄皮次生木质部导管分子观察研究   总被引:1,自引:0,他引:1  
运用细胞图象分析系统及显微照相的方法对黄皮次生木质部导管分子进行了观察研究。在黄皮的次生木质部导管分子中存在着许多不同的样式,分别对其进行了描述,并从导管分子个体发育与系统发育的角度进行了讨论。  相似文献   
10.
We recently demonstrated that luteal cells flow out from the ovary via lymphatic vessels during luteolysis. However, the regulatory mechanisms of the outflow of luteal cells are not known. Matrix metalloproteinases (MMPs) can degrade the extracellular matrix and basal membrane, and tissue inhibitors of matrix metalloproteinases (TIMPs) inhibit the activity of MMPs. To test the hypothesis that MMP expression in luteal cells is regulated by luteolytic factors, we investigated the effects of prostaglandin F2α (PGF), interferon γ (IFNG) and tumor necrosis factor α (TNF) on the mRNA expression of MMPs and TIMPs in cultured luteal cells. Luteal cells obtained from the CL at the mid-luteal stage (days 8–12 after ovulation) were cultured with PGF (0.01, 0.1, 1 μM), IFNG (0.05, 0.5, 5 nM) and TNF (0.05, 0.5, 0.5 nM) alone or in combination for 24 h. PGF and IFNG significantly increased the expression of MMP-1 mRNA. In addition, 1 μM PGF in combination with 5 nM IFNG stimulated MMP-1 and MMP-9 mRNA expression significantly more than either treatment alone. In contrast, IFNG significantly decreased the level of MMP-14 mRNA. The mRNA expression of TIMP-1, which preferentially inhibits MMP-1, was suppressed by 5 nM INFG. One μM PGF and 5 nM IFNG suppressed TIMP-2 mRNA expression. These results suggest a new role of MMPs: luteal MMPs stimulated by PGF and IFNG break down the extracellular matrix surrounding luteal cells, which accelerates detachment from the CL during luteolysis, providing an essential prerequisite for outflow of luteal cells from the CL to lymphatic vessels.  相似文献   
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