Primary Phloem Development in the Shoot Apex of Rhizophora mangle L. (Rhizophoraceae)

The primary phloem in the shoot apex of the mangrove Rhizophora mangle L. is largely confined to the comparatively condensed area between the first three leaf pairs. The main extension zone, surrounded by the stipular sheath of the third leaf pair, contains vascular bundles arranged in a procambial ring and characterized by a well-developed primary phloem and a less advanced xylem. The phloem consists of a great number of sieve elements, an equal number of associated companion cells, and a few phloem-parenchyma cells. The differentiation of the sieve-element protoplast (with e.g., chromatolytic nuclear degeneration, loss of the vacuole and most organelles) proceeds largely according to a well-known pattern. Their P-type plastids, however, form their protein crystals rather late and therefore cannot be used as an early cell marker. Lateral sieve-element walls are distinct from other wall parts and walls of other cells by their heavy nacreous thickenings, the formation of which is shown to be strictly correlated with the occurrence and orderly arrangement of cortical microtubules.     

A phloem-specific,lectin-like protein is located in pine sieve-element plastids by immunocytochemistry

Two co-purifying phloem polypeptides of 24 and 25 kilodaltons (kDa) were isolated from homogenates of Pinus sabiniana Dougl. phloem by differential centrifugation, selective solubilization and electrophoresis, and rabbit antibodies raised against them. The antisera were found to be specific for doublet bands between 23 and 25 kDa in Western blots of whole phloem extracts of Pinus species; no xylem polypeptides were labelled, nor did labelling occur in blots of phloem extracts from other genera in the Pinaceae. Solubilized phloem polypeptides bind strongly to chitin (oligomeric N-acetylglucosamine) columns and are sensitive to thiol reagents, both characteristics which relate them to phloemspecific lectins isolated from angiosperm species (C. Allen, 1979, Biochem. J. 183, 133–137; A.K. Gietl et al., 1979, Planta 144, 367–371). Fluorescence microscopy and immuno-gold electron microscopic cytochemistry demonstrated antigenic sites specifically associated with protein crystals peculiar to the sieve-element plastids of the Pinaceae.Abbreviations DAB diamino benzidine tetrachloride - FITC fluorescein isothiocyanate - kDa kilodalton - PBS phosphate-buffered saline - PP phloem polypeptide(s) - SDS-PAGE Sodium dodecyl sulphate-polyacrylamide gel electrophoresis - Tris 2-amino-2-(hydroxymethyl)-1,3-propanediol     

THE RATE OF TRANSLOCATION IN ALARIA ESCULENTA (LAMINARIALES,PHAEOPHYCEAE)12

The rate of translocation of organic carbon in blades of Alaria esculenta (L.) Grev. (Laminariales) was calculated from blade growth data. The cross sectional area of sieve filaments in the midrib medulla was estimated from light microscopic examination of fresh material. Files of these filaments form a perimedullar ring occupying ca. 2/3 of the medulla. Values computed for specific mass transfer of carbon into the blade meristem ranged from 36.2 to 60.8 mg C.wk^?1.0.1 mm^?2 sieve filaments.     

乳腺癌患者的超声征象表现与组织学特征的关系研究

目的:研究乳腺癌患者的超声征象表现与组织学特征的关系。方法:收集自2012年5月-2016年5月在我院接受诊治的240例乳腺癌患者作为研究对象,所有患者手术前接受超声检查,分析超声征象与病理组织学分型、分级以及雌激素受体(ER)、孕激素受体(PR)表达之间的关系。结果:240例乳腺癌患者中,有57例(23.75%)呈规则形态,183例(76.25%)呈不规则形态;171例(71.25%)肿块边界有毛刺,69例(28.75%)肿块无毛刺;210例(87.50%)肿块呈现后方回声无衰减或增强,30例(12.50%)肿块呈现后方回声衰减;118例(49.17%)出现微小钙化,122例(50.83%)没有出现微小钙化。在不同病理学分型中,不规则形态、肿块边界毛刺发生率具有明显差异(P0.05),不规则形态发生率由高到低的顺序为:浸润性小叶癌、浸润性导管癌、导管内癌、特殊类型癌,浸润性导管癌和浸润性小叶癌边界毛刺发生率显著高于导管内癌和特殊类型癌(P0.05),而在不同病理组织学分型、病理学分级、ER表达、PR表达中,后方回声衰减、微小钙化发生率比较无明显差异(P0.05)。结论:乳腺癌超声征象表现与病理组织学特征密切相关,超声诊断对于病理组织学类型具有一定的预测作用。     

TRANSLOCATION OF 11C-PHOTOASSIMILATE IN THE BLADE OF MACROCYSTIS PYRIFERA (PHAEOPHYCEAE)1

Radioactive bicarbonate was pulse fed to blades of Macrocystis pyrifera (L.) C. A. Ag. and the movement of the ¹¹C-labelled photoassimilates was monitored in vivo using an externally mounted array of Geiger-Müller detectors. Results of experiments conducted in August 1982 and February 1983 showed kinetic transport profiles composed of short pulses of ¹¹C (periods of two to three minutes and six to eight minutes) and a mass flow component travelling with a speed of 6–22 cm · h^?1. The pulse-like movement of ¹¹C-photoassimilates, revealed for the first time in a kelp, may be driven by an energy-assisted transport mechanism. Light microscopy revealed a putative symplastic transport pathway from the photo synthetic meristoderm to the medullary sieve cells in the M. pyrifera blade. Of particular importance were the connections between the inner cortical cells and thin-walled medullary sieve cells. Electron microscopy showed sieve plate pore diameters ranging between 35–60 nm in the cortex and ca. 40 nm in the end walls of the thin-walled sieve cells.     

Sieve element characters and the systematic position ofAustrobaileya,Austrobaileyaceae—with comments to the distinction and definition of sieve cells and sieve-tube members

The ultrastructure of the sieve elements ofAustrobaileya is compared with that of angiosperm sieve tubes and gymnosperm sieve cells (mostly fromCycadales). Except for the size of the sieve poresAustrobaileya shares all ultrastructural characters (e.g., chromatolytic nuclear degeneration, presence of p-protein, formation of sieve pores from unbranched plasmodesmata) and other features (e.g., companion cells) with angiosperm sieve tubes. Gymnosperm sieve cells on the contrary are characterized by pycnotic nuclear degeneration, absence of p-protein, formation of sieve areas from branched plasmodesmata with median cavities. — The exact ordinal assignment ofAustrobaileya within the subclassMagnoliidae is still disputed, a placement close to eitherMyristicaceae andWinteraceae orMonimiaceae being possible as judged from both S-type sieve-element plastids and p-protein bodies. — On the basis of the ultrastructural results fromAustrobaileya it is proposed to reconsider concepts and terminology of sieve elements. i.e., to include features from sieve pore development, nuclei degeneration and presence of specific proteins into the definitions and to restrict the term sieve cell to gymnospermous sieve elements which differ much from those of other vascular plants.     

Ploidy dependence of chromosomal variation in callus cultures ofHyoscyamus muticus L.

Summary Remarkable variation for chromosome number was observed in both diploid (2x) and autotetraploid (4x) callus cultures continuously examined for 12 months at monthly subsculture intervals. Initially, the subcultures exhibited predominantly the genomic level of the starting material which subsequently and gradually developed into heterogenous populations of euploid and aneuploid cells imparting the subcultures a aneusomatic status. The comparison of chromosomal instability recorded in 2x vs. 4x callus cultures revealed that with time both types of calli stabilized at a chromosome number around the 4x level. However, the chromosomal examination of the adventitious roots emerging from the disorganized calli revealed the euploid (both 2x and 4x) chromosome levels suggesting the occurrence of amorphogenetic sieve.This paper is dedicated to Professor A. K.Sharma of Calcutta University on his 65th birthday by his former student U. C. L. and grandstudent S. S. (CIMAP Publication no. 739).     

Precolumn concentration of protein samples by displacement electrophoresis (isotachophoresis) followed by high-performance molecular sieve chromatography on a packed agarose column

The use of displacement electrophoresis for the concentration of dilute protein solutions and the construction of a column suitable for this purpose are described. The concentrated protein zone can be pumped directly from the electrophoresis column into a gel-filtration column, which greatly reduces losses of protein. Recoveries of 95% or better were obtained even for small amounts of protein. The electrophoretically concentrated samples gave virtually the same elution profiles as did samples injected in a small volume without the use of electrophoretic preconcentration.     

Münch,morphology, microfluidics – our structural problem with the phloem

The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the ‘Münchian’ pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue that the downscaling of such models to realistic, low‐Reynolds‐number sizes will boost our understanding of phloem transport in this century just as Münch's models did in the previous one. However, biologically meaningful physical models that could be used to test predictions of the many existing mathematical models would have to be designed in analogy with natural phloem structures. Unfortunately, the study of phloem anatomy seems in decline, and we still lack basic quantitative data required for evaluating the plausibility of our theoretical deductions. In this review, we provide a subjective overview of unresolved problems in angiosperm phloem structure research within a functional context.