Microautoradiographic investigations of sulfate uptake by glands and epidermal cells of water lily (Nymphaea) leaves with special reference to the effect of poly-l-lysine

1971 ◽  
Vol 4 (1) ◽  
pp. 395-407 ◽  
Author(s):  
Ulrich Lüttge ◽  
Charles K. Pallaghy ◽  
Katharina von Willert
Keyword(s):  
Special Reference ◽  
Epidermal Cells ◽  
Sulfate Uptake ◽  
Water Lily

Leaf Marks in Medicago, With Special Reference to Their Inheritance in Medicago truncatula

1974 ◽  
Vol 22 (1) ◽  
pp. 67 ◽  
Author(s):  
JA Mccomb
Keyword(s):  
Special Reference ◽  
Genetic Control ◽  
Medicago Truncatula ◽  
Epidermal Cells ◽  
Purple Pigment ◽  
Anatomical Basis ◽  
Palisade Cells ◽  
The One

Leaf marks in the genus Medicago are described and the anatomical basis and genetic control of marks and flecks in M. truncatula analysed. The purple pigment in flecks or marks is confined to the epidermal cells. Yellow marks are due to reduced chlorophyll in palisade cells, and white marks to reduced chlorophyll, as well as larger air spaces between palisade cells and detached upper epidermis. White and yellow marks are controlled by a gene in which seven alleles were identified which determine colour and position, white being dominant to yellow, and, in order of decreasing dominance, upper, central, and basal positions along the midrib. Another gene, independent of the one controlling yellow or white marks, controls both the production of a central purple mark and the purple borders around marks. A comparison is made between the genetic control of marks in M. truncatula and those reported for other Medicago and Trifolium species.

Structure and ecdysial process of the larval spiracles of the scarabaeoidea, with special reference to those of Lepidoderma

1967 ◽  
Vol 15 (5) ◽  
pp. 947 ◽  
Author(s):  
HE Hinton
Keyword(s):  
Special Reference ◽  
Electron Micrographs ◽  
Epidermal Cells ◽  
Ambient Atmosphere ◽  
Serial Sections ◽  
Gas Exchanges ◽  
Spiracular Plate

The structure of the larval spiracles of the scarabaeid beetle, Lepidoderma albohirtum Waterh., has been examined by means of serial sections and stereoscan electron micrographs of whole and dissected specimens. Gas exchanges with the ambient atmosphere are effected through aeropyles in the spiracular plate. The aeropyles are of two types: (1) slit-like aeropyles about 4 � long and 0.1-0.5 � wide; and (2) round or oval aeropyles that are usually about 0.2-0.3 u wide. The ecdysial tube is often open in preparations, and this has led to the commonly expressed view that it is the chief or only opening into the spiracular atrium. The open condition of the ecdysial tube in preparations is an artifact. The formation of a new spiracle is briefly described. Cuticular struts project inwards from the peritreme and branch at their apices. Then the apical branches divide and those from different struts anastomose to form the plate and the network immediately below the plate. All of these structures are secreted by very long cytoplasmic projections. The nuclei of the epidermal cells remain in the region of the peritreme and do not enter the main columns of cytoplasm that in due course secrete the cuticular struts. The cytoplasmic columns that form the largest struts consist of projections from many epidermal cells. The chief differences in the structure of the spiracles within the superfamily Scarabaeoidea are briefly noted. A closing apparatus is present in the Trogidae, Lucanidae, Passalidae, and Glaphyrinae but is absent in the Geotrupidae and Scarabaeidae. The ecdysial process in primitive Scarabaeoidea is of the typical elateroid type, whereas specialized Scarabaeoidea have a bulla that carries the ecdysial tube. The modified elateroid process of specialized forms is here named the pseudopanorpoid type. The spiracles of some species of Trox are biforous. Those of other species of Trox and all other Scarabaeoidea examined are cribriform. The cribriform type of spiracle has been evolved on at least two occasions within the superfamily.

A study of the branched cells of the mammalian epidermis with special reference to the fate of their division products

1953 ◽  
Vol 237 (644) ◽  
pp. 151-170 ◽  
Keyword(s):  
Special Reference ◽  
Langerhans Cells ◽  
Basal Layer ◽  
Skin Surface ◽  
Quinone Imine ◽  
Epidermal Cells ◽  
Metallic Gold ◽  
Clear Cells ◽  
One To One

The branched cells of the superficial epidermis of mammals are divisible into two classes: those that occupy a position in the basal layer, and those that occur in more superficial layers. The first class comprises melanocytes visible in the living epidermis after its enzymatic fission from the corium; cells that blacken upon exposure to dihydroxyphenylalanine; cells that maintain quinoneimine dyes in the oxidized state in living skin; and clear cells. It is shown that these are merely different preparation images of the same cell, the melanocyte. The second class comprises cells that may be more or less specifically impregnated by metallic gold (Langerhans’ cells); cells stainable in living skin by quinone-imine dyes; and the ‘clear cells’ of superficial strata. It is shown that these, too, are so many preparation images of the same cell. It is argued that the branched cells of superficial strata, which have never been seen to divide, represent effete melanocytes which, having discharged or otherwise lost their pigment, participate in the general outward movement of epidermal cells to be cast off at the skin surface. This argument is supported by evidence of their similarity of structure, mode of branching, and relationship to neighbouring Malpighian cells; by their position in the epidermis; by their one-to-one correspondence of number; and by their coincidence of distribution.

Sign in / Sign up

Export Citation Format

Share Document