The Endodermoid in Garlic Scape: Its Fine Structure and Physiological Function

In garlic scape there is a distinct boundary layer of cells between the cortex and stele. Its fine structure and possible ruction seem to agree with the endodermoid first defined by Esau[7], hence the frame. Lightand electron-microscopic examination and cytochemical test have revealed that this particular laryer is probably responsible for the withdrawal of cellular contents of parenchyma to the peripheral vascular bundles, during a long period of storage the excised withering scape would thoroughly exhaust itself to give rise to the new apical cloves. As already shown, the laticiferous tubes scattered throughout the cortex are always turgid, and their sap is rich of nutrients in variable proportion[3]. Possibility of mobilizing these nutrients by the aid of endodermoid to join in phloem transport also has been discussed.     

大蒜不同品种蒜薹发育的解剖学研究

通过形态观测和石蜡切片法,比较了2个大蒜品种的蒜薹发育和解剖结构。结果表明：（1）“陇县火蒜”比“改良蒜”蒜薹的表皮细胞形状规则,排列致密;角质层较薄;（2）“陇县火蒜”比“改良蒜”蒜薹表面的气孔数量少,但开张度大;分泌细胞出现早、体积大、数量多;维管束数量少、直径小;（3）“陇县火蒜”蒜薹髓细胞卫多边形,髓细胞间隙率小,而“改良蒜”蒜薹的髓细胞呈椭圆形,髓细胞间隙率大。     

Intra and Inter-Cellular Changes in Constitution during the Development of Laticiferous System in Garlic Scape

Systematic investigations, mainly based on electron microscopy, have been conducted on constitutional changes in the laticifer and its adjoining parenchyma during the development of laticiferous system in garlic scape. The laticiferous system of the scape consists of several layers of articulated unbranched latieifers. About half of them are situated 2–3 cell layers below the epidermis, and the rest scattered throughout the cortex (Fig. 23). Latieifer differentiation starts with a thinning out and vacuolation of the dense protoplasm in the latieifer initials (Fig.2), which is followed by gradual degeneration of nuclei, plastids, endoplasmic reticulum, and dictyosomes; and by a sharp diminution of free ribosomes (Figs.3, 4). Remanent and defective forms of some organelles can still be found in the laticifer at the later stage. In spite of these drawbacks, the differentiating laticifer appears to function actively. Its protoplasm is delimited by a distinct plasmalemma (Figs. 3, 4). Its wall is interspersed with pits inclose spacings, to which most plasmodesmata are confined (Figs. 8, 24). The cell interior is packed with vesicles and mitoehondria (Figs. 4, 11, 15). Structurally, the laticifer seems well adapted to material exchange with the adjoining parenchyma. During the sprouting stage of the scape, the laticifer initials enlarge itself or fuse with each other by lateral wall dissolution to extend the diameter; at the same time, the laticifer elongates at an increasingly rapid rate. As a final result, the laticifer can attain 30–50 times the length and 2–3 times. the diameter of the adjoining parenchyma. The electron-dense material which protrudes into the laticifer initial from the parenchyma may be of lysosomal nature and probably concerned with wall dissolution and intracellular lytic processes in latieifer formation (Figs. 5, 7, 10). An excised garlic scape is employed in the observation of mature laticifers, which is always full of sap and is quite turgid. Once the scape is cut open, sap exudes almost exclusively from the cut end of the laticifers at the periphery, which lasts only some seconds. However, if the scape is left aside for a few days, exudation will again take place at the fresh cut end. Unlike the milky juice of many latex plants, the sap exuded from the garlic scape is watery and slightly turbid. The organic solute content is mainly made up of simple sugar and amino acids. It also contains a small amount of proteins and even protoplasmic fragments. Besides, it is worthy to note that decrease in organic solutes in the exudation is closely connected with the degree of exhaustion of cell contents from the withering scape, which is, as has already been shownm the sole agent of supplying materials required for the formation of apical cloves. All the above facts seem to indicate that there exists a loading and unloading process in the latieifer. Our electron micrographs (Figs. 16, 22) give evidence that vesicular transport through plasmodesmata in the pit field is capable of performing such a process: from the parenchyma to the laticifer in loading and from the latter to the former in unloading. The possible role of the laticifers in garlie scape could be a temporary storage of cell contents released successively from the deteriorating parenchyma. The sap content in the laticifer is in full turgidity as a result of loading, and can be readily drawn by unloading if so required. Transcellular cytosis is a term tentatively given by us to designate intercellular transport of sap, solutes, and macromolecular particles in small vesicles, which are formed and packed in one celt, traverse through plasmodesmata and merge into the other; whereas endo and exoeytosis refer to vesicular transport in a single cell only and to its moving in and out of the cell primarily through the plasma membrane, which also takes active part in the formation and dissolution of the vesicle and in the enclosure and release of its content. Transcellular cytosis was first observed by us in the withering parenchyma of an excised garlic scape; and, in the present case, between the latieifer and parenehyma, both being active functionally. As compared with the early notion that intercellular material transport is primarily carried out by secretion and reabsorption of highly degraded products through plasmalemma, transcellular eytosis appears to be a far more efficient means of translocating prefabricated assortment and well packed cargo from one cell into the other.     

Effects of Abscisic Acid in Senescence of Garlic Al1tium sativura Scape

Removing the apical cloves from the excised garlic scapes could delay the senescence of scape and decrease the rate of dry matter loss during storage. The ABA content of all the portions of the scapes with apical cloves is decreased as the prolongation of storage period; but its content of all the portions of the scapes with the cloves reaches their peak one after another within the first 6 days of the experiment period. The peak of ABA in the apical cloves appears earliest; the ABA content of any portion of the scapes is lower than that of the cloves, and gradually decreases from upper to lower portions, and the peak of ABA content appears in the sequence as above. Exogenous ABA which is added to the top of the scapes without cloves would simulate the function of the apical cloves in part and accelerates the chlorophyll destruction and senescence of the scapes. No ethylene can be detected by the G. C., in the process of senescence. The authors suggest that ABA is mainly synthesized in the cloves, and then transported into the scapes from there. In the senescence of garlic scapes and in the redistribution of material between the apical cloves and the scapes (the relation between the sink and source), ABA functions as transporting information and promoting senescence but ethylene has not such a function. The senescence of garlic scape could be divided into two stages: first the static phase and second, the active phase.     

离体蒜苔衰老过程中乙烯产生和纤维素酶活力的变化

自Horton和Osborne(1967)报道衰老、脱落中激素和纤维素酶活力相关性以来,许多实验证明,乙烯和纤维素酶与衰老和脱落有密切关系。关颖谦等(1981)指明离体水稻叶片衰老时,纤维素酶的活力     

肾脏脱细胞基质结构功能重建的初步研究

目的:本实验利用多种脱细胞剂通过半自动体外循环灌注洗脱肾脏细胞,摸索出最佳脱细胞剂种类及脱细胞方案.方法:以健康兔肾为研究对象,采用半自动体外循环灌注法,在10-15 ml/min流速及不同浓度、温度条件下经肾动脉灌注各种脱细胞剂,观察肾脏灌注过程中变化,灌注结束解剖肾脏,大体观察后行苏木精-伊红(HE)染色及组织形态学观察,重点观察肾小球、肾小管细胞结构的变化.结果:比较理想的肾脏脱细胞方案是1％Ⅳ型胶原酶-37℃,20 min,该酶能在相对较短的时间内洗脱部分肾实质细胞而对肾脏基质未造成明显损伤.该方案灌注时间短,能减少肾脏热缺血时间,有助于肾脏再生.其次是0.5％胰蛋白酶-25℃,2h,该方案能使肾小球细胞比较彻底的脱出,只留基质部分,对肾小管作用较小,但该方案用时较长,已达到肾脏体外耐受缺血的极限,理论上肾脏灌注后很可能会因缺血缺氧时间过长而坏死,故不推荐使用.洗脱效果最强的脱细胞剂是SDS,但其对肾脏实质结构造成不可恢复的破坏,尤其是引起基底膜断裂不利于肾实质细胞再生.其他脱细胞方案均不理想.结论:本研究证实通过选择适当的脱细胞剂,配合适合的温度、浓度、灌注压等条件,是可以实现肾脏部分脱细胞基质的,为下一步研究衰竭肾脏的部分脱细胞基质甚至是在体灌注乃至脱细胞后肾脏结构功能的重建提供了实验依据.     

颈卵器植物颈细胞结构与功能的研究进展

颈卵器是苔藓、蕨类、裸子植物的雌性生殖器官,由卵细胞、腹沟细胞和颈细胞(颈沟细胞)构成。其中,颈细胞是这类植物雄配子进入颈卵器并完成受精作用的唯一通道,在颈卵器的发育和受精过程中发挥着重要作用。该文就近年来国内外有关对颈细胞的发生和发育、结构特点和功能等进行较为系统全面的分析和总结,并对未来的研究方向进行展望。     

皂苷类成分对血管内皮细胞功能的调节作用研究进展

血管内皮细胞在维持血管生理稳态中发挥了重要的作用,其功能障碍是动脉粥样硬化、冠心病、脑卒中、肿瘤等多种重大疾病发生发展的病理基础,调节血管内皮细胞功能是防治上述疾病的主要途径之一。大量研究表明,皂苷类成分可通过改善血管内皮功能达到治疗疾病的目的。综述了近年来报道的皂苷类成分调节血管内皮功能的研究进展,旨在为皂苷类成分作用机制的阐明和相关重大疾病的防治提供一定参考。     

念珠伪角毛虫小核体功能初步研究

为了研究念珠伪角毛虫的小核是否具有及具有怎样的体功能,采用显微切割手术去小核并建立无小核细胞系。经蛋白银染色鉴定,无小核细胞系群体中大多数细胞的形态结构存在缺陷：口围带的部分小膜缺损或排列紊乱,大核的数目和形态也不正常。这表明,念珠伪角毛虫的小核对于保持口围带结构的完整性以及大核的数目和形态结构的稳定性起着明确的作用。     

Focus on Water: Intertissue Signal Transfer of Abscisic Acid from Vascular Cells to Guard Cells

Abscisic acid (ABA) is a phytohormone that responds to environmental stresses, such as water deficiency. Recent studies have shown that ABA biosynthetic enzymes are expressed in the vascular area under both nonstressed and water-stressed growth conditions. However, specific cells in the vasculature involved in ABA biosynthesis have not been identified. Here, we detected the expression of two genes encoding ABA biosynthetic enzymes, ABSCISIC ACID DEFICIENT2 and ABSCISIC ALDEHYDE OXIDASE3, in phloem companion cells in vascular tissues. Furthermore, we identified an ATP-binding cassette transporter, Arabidopsis thaliana ABCG25 (AtABCG25), expressed in the same cells. Additionally, AtABCG25-expressing Spodoptera frugiperda9 culture cells showed an ABA efflux function. Finally, we observed that enhancement of ABA biosynthesis in phloem companion cells induced guard cell responses, even under normal growth conditions. These results show that ABA is synthesized in specific cells and can be transported to target cells in different tissues.Hormones are chemical substances that exert a biochemical action on target cells at low concentrations. All multicellular organisms, including animals and plants, produce hormones to control their physiological status. In animals, many ordinary hormones are secreted from specific cells (such as endocrine cells) and transported to their target sites in other areas of the body. However, it remains unclear whether the concept of hormones as defined in animals is applicable to plants, because plant hormones are not generally synthesized in specific cells but are broadly produced (Weyers and Paterson, 2001; Gaspar et al., 2003; Forestan and Varotto, 2012).Abscisic acid (ABA) is a key phytohormone that prevents water loss from the plant body by acting on guard cells, of which stomata (epidermal pores) compose the aerial organs in plants (Hetherington, 2001; Schroeder et al., 2001; Fan et al., 2004; Joshi-Saha et al., 2011). Gene and protein expression analyses using antisense RNA or antibodies specific for ABA biosynthetic enzymes in Arabidopsis (Arabidopsis thaliana) have shown that parenchyma cells in vascular bundles are the abundant expression site of ABA biosynthesis under drought stress and well-watered growth conditions (Cheng et al., 2002; Koiwai et al., 2004; Endo et al., 2008). Because the vasculature is separated from guard cells, it has been suggested that ABA is transported from the site of synthesis to the site of action (Seo and Koshiba, 2011).We previously found that an ATP-binding cassette (ABC) transporter family, Arabidopsis thaliana ABCG25 (AtABCG25), is expressed mainly in vascular tissues, and it is expected to function as an ABA exporter that transports ABA from inside to outside cells (Kuromori et al., 2010). According to this observation, we have proposed a working model: ABA is exported from ABA-synthesizing cells in vascular tissues by AtABCG25 to reach distant guard cells and induce stomatal closure (Kuromori and Shinozaki, 2010; Umezawa et al., 2010, 2011). However, the parenchyma cells in vascular tissues expressing ABA biosynthetic enzymes or AtABCG25 transporting factor have not been identified.Here, we explored whether specific cells express ABA biosynthetic enzymes or an ABA transporter and found that their genes were expressed in phloem companion cells of vascular tissues. ABA synthesis in these cells enhances transsignaling to distant guard cells of the epidermis. These results show that ABA is synthesized in specific cells and transported to target cells in another tissue. This result is similar to endocrine hormones in animals and suggests that the ABA transport pathway between tissues in plants may be associated with specific transporters.     

Intercellular Transport of Macro-Molecular Substances as a Means of Redistribution of Cellular Contents in Detatched Garlic Scape

A detached garlic scape in long storage will eventually give rise to a whorl of freshy aerial cloves at its apex (Text fig. 2). This can only be brought about at the expense of the stalk proper, where withering starts from the lower end and extends gradually upward until the whole stalk is completely exhausted. The material transfer involved must be mainly concerned with the redistribution and reultilization of cellular contents from the senescing stalk to the growing cloves. The present systematic investigation on the whole process is primarily based upon serial microscopic and electronmicroscopic examination on conducting channels and withering parenchyma. Our previous investigations on garlic have shown that the exhaustive withdrawl of cellular contents from the senescing tissue is finally accomIished by intercellular movement of the partially disassembled protoplasm itself. The present result are essentially in agreement with such a general scheme. Light and electron-micrographs that show nuclear material and other macro-molecular substances tranversing through the plasmodesmata are rather common. The high resolving electronmicrographs have enabled us to detect the finer details in intercellular transport as given below: 1. Filamentous and fluffy material, somewhat similar in structure to P-protein in sieve tube, can be found in abundance in senescing parenchyma cells in which the demar- kations between protoplasmic components gradually become indistinct. The filamentous material is in transit through plasmodesmata between parenchyma cells and also between parenchyma and sieve tube (Plate Ⅱ, 16, 18). 2. Withdrawl of cellular contents from the deteriorating parenchyma may assume the form of vesicular transport through plasmodesmata (Plate Ⅰ 9, 10, 11). Some of the vesicles are simply filled with vacuolar sap; some fully packed with prefabricated material of maeromolecolar structure; and some actually loaded with disassembled protoplasmic fragments. 3. Fully packed vesicles as well as disassembled protoplasmie components (including disintegrated nucleus, degenerated mitoehondrion, etc.) may extrude into the intercellular spaces and may invade the vessel eavity (Plate Ⅱ, 12, 13, 20; Plate Ⅲ, 21, 22, 23, 24). The fine structure of the moving protoplasm in the vessel is quite distinct from that of the residual deposits which may cause plugging in the same cavity (Plate Ⅲ, 25, 26).     

家蚕转基因方法的初步研究

为建立家蚕转基因研究中切实可行的外源基因导入方法、分别用显微注射法、精子介导法、脂质体法和压力渗透法将含有绿色荧光蛋白(gfp)基因的转座子载体和辅助质粒转入到家蚕的受精卵中。在后代中检测到发绿色荧光的蚕茧,用PCR方法检测到后代个体染色体中含有gfp基因,并比较了上述几种方法的优缺点,为进一步进行转基因家蚕的研究奠定了基础。     

三峡库区消涨带维管植物区系的初步研究

三峡库区消涨带是指三峡库区范围内长江进一步充及其支流由于江（河）水水位季节性涨落。导致其沿江（河）两岸土地出现周期性淹没而自然形成的带状区域。该带维管植物区系具有以下特征;植物种类比较丰富,计有维管植物83科,240属,377种,26变种和2变型;地理成分复杂,联系广泛,温带成分占优势;区系组成表现进化性,生活型组成以多年生草本,一年生草本和灌木为主;地方特有成分不多,但中国特有种类比较丰富;带内不同区段物种丰富度有差异。干流多于支流,奉节以东多于奉节以西,带上部多于带中部和带下部;优势现象明显,表征类型丰富。     

弱激光对脂质体介导的血管平滑肌细胞基因转染的影响

本研究采用阳离子脂质体介导外源基因转染体外培养的兔血管平滑肌细胞（ＳＭＣ）,在基因转染过程中给予激光照射,用细胞化学染色方法测定基因转染阳性率。结果显示：用５１０．６ｎｍ激光于基因转染前,以功率密度１ｍｗ／ｃｍ２,能量密度２、４、６Ｊ／ｃｍ２和５ｍＷ／ｃｍ２,４、６Ｊ／ｃｍ２;及１０ｍＷ／ｃｍ２,２Ｊ／ｃｍ２进行照射均能显著提高基因转染率（ｐ＜０．０５）;于基因转染后即刻以功率密度１ｍＷ／ｃｍ２、能量密度２Ｊ／ｃｍ２和５ｍＷ／ｃｍ２、６Ｊ／ｃｍ２照射也能提高基因转染率（ｐ＜０．０５）。而用６２７．８ｎｍ激光照射对基因转染率无显著影响     

玉米胚乳传递细胞的结构观察研究

以玉米品种'登海11号'为材料,分别于授粉后8、10、15和20 d采集颖果,取所需部位并采用树脂包埋的方法及半薄和超薄切片技术,对玉米胚乳传递细胞进行了显微和超微结构观察.结果显示:(1)胚乳传递细胞的壁内突从外层向内层依次递减,溶质浓度逐步降低,形成了明显的溶质浓度梯度,有利于溶质的运输;(2)中层胚乳传递细胞和内层胚乳传递细胞的邻壁上存在胞间连丝或一些孔径较大的胞壁孔道,从而使溶质更快的进入内层胚乳传递细胞;(3)在壁内突周围存在许多线粒体.研究表明,玉米胚乳传递细胞的结构适合溶质运输.     

H_2O_2参与离体蒜苔细胞内含物再分配的调控(英文)

植物生长发育过程中经常发生新老器官更替和细胞内含物的再分配、再利用。Lepold提出新生器官向衰老器官传递某种信息 ,动员后者细胞内含物向前者再分配。但是该信息的化学本质迄今仍不清楚。大蒜 (Alliumsativum)的离体蒜苔是研究细胞内含物再分配的良好材料。细胞内含物大量从苔茎向珠蒜中再分配 ,结果珠蒜显著膨大而苔茎衰老死亡。蔡可等发现赤霉素 (GA3)处理可有效抑制细胞内含物再分配。我们此前的研究发现GA3处理苔茎基部可显著改变珠蒜和苔茎H2 O2 代谢。本研究中我们分别用GA3和 3-氨基 - 1 ,2 ,4-三唑 (AT)H2 O2 清除酶catalase的专一性抑制剂处理珠蒜 ,结果发现GA3和AT均可有效抑制离体蒜苔细胞内含物再分配 (Fig .1 )。根据浓度不同 ,H2 O2 可以诱导细胞产生保护性反应或凋亡。细胞内含物再分配过程中 ,珠蒜H2 O2 浓度显著下降后保持于低水平 ,相反苔茎H2 O2 浓度极显著升高 1 0倍以上 ,而且细胞内含物转移早的苔茎下部H2 O2 峰值出现也早 (Fig .2 )。GA3或AT处理珠蒜 ,珠蒜H2 O2 浓度显著提高而苔茎H2 O2 浓度保持稳定的低水平或峰值显著推迟 (Fig .2 )。可见苔茎高浓度的H2 O2 诱导了苔茎细胞凋亡并把细胞内含物转移给珠蒜。已知约 2 %的呼吸耗氧生成H2 O2 。珠蒜呼吸速率显著高于苔茎 (王     

利用脱细胞血管基质体外构建小口径组织工程血管

目的探讨利用犬的间充质干细胞诱导分化种子细胞,以异种脱细胞血管基质为基础体外构建小口径血管移植物。方法采用密度梯度离心和贴壁培养的方法从犬骨髓中分离出间充质干细胞并体外培养,诱导分化成内皮样细胞和平滑肌样细胞;采用非离子型去垢剂和胰蛋白酶去除猪颈动脉血管壁结构细胞,对脱细胞基质进行组织学、力学检测及孔隙率评估。在生物反应器内采用旋转种植的方法将犬骨髓间充质干细胞诱导的内皮样细胞种植到脱细胞基质上,体外构建小口径组织工程血管。结果犬的骨髓间充质干细胞体外能够定向诱导分化为平滑肌样细胞和内皮样细胞,可以作为血管组织工程的种子细胞。经过脱细胞处理后,光镜和电镜观察证实血管壁的细胞成分完全去除。具有良好的孔径和孔隙率。支架在生物力学、孔隙率等方面符合构建组织工程血管支架的要求。在生物反应器内剪切力条件下可以初步构建出组织工程血管。结论小口径血管移植物可以将间充质干细胞诱导种子细胞,以异种脱细胞血管支架作为基质,在搏动性生物反应器内培养的方法进行构建。     

人类线粒体转移方法初报

将人肝脏匀浆、差速离心、等密度梯度离心纯化得到线粒体,通过显微注射法将其转移到小鼠的受精卵细胞质内,有61 % 的卵注射后存活,而存活的卵中53 % 能顺利完成第一次卵裂。提示将人类线粒体向实验动物小鼠转移具有可行性