STUDIES ON PLANT CUTICLE: THE CUTIN COMPONENT OF THE CUTICLES OF LEAVES

Methods are described for the chemical separation from leaf material of the ventral and dorsal surface cuticular membranes and for the determination of cutin in the membranes and leaf tissues.
The cutin contents of the cuticular membranes separated from leaves of laurel, rhododendron, and Euonymus , and of leaf tissues of cauliflower, red beet, banana, tomato, strawberry and blackcurrant are reported. The relationship between the cutin and waxy components of the leaf cuticle is discussed, and earlier work on the development, structure and chemistry of the cuticle is reviewed.     

STUDIES ON PLANT CUTICLE

The waxy coverings of the leaves of different species of plant have been fractionated into wax, acidic, volatile and oil components. The levels of the waxy deposits on the leaves and the relative proportions of the principal components of the waxy coverings differed widely. Wax predominated in the waxy coverings of the leaves of cabbage and cauliflower and acidic materials in those of apple and pear.
The role of ether-soluble acidic constituents in a possible defensive mechanism of leaves against fungi, the contribution of water-soluble acidic constituents to the toxic action of copper fungicides and the influence of the waxy covering on spray deposition, phytotoxicity and the behaviour of DDT deposits on leaves are discussed. Earlier work on the nature of leaf wax components is reviewed.     

Changing Activities During Senescence and Sites of Synthesis of Photosynthetic Enzymes in Leaves of the Labiate, Perilla frutescens (L.) Britt.

The changing activities of several regulatory enzymes of thephotosynthetic carbon reduction cycle accompanying ageing ofthe third leaf pair of Perilla frutescens fall into two distinctcategories: firstly, enzymes which reach maximum activity priorto the completion of leaf expansion followed by a rapid decline(phosphoribulokinase, ribulose-l,5-diphosphate carboxylase,and NADPH-dependent glyceraldehyde-3-phosphate dehydrogenase);secondly, enzymes which maintain high activity beyond completionof leaf expansion and decline only at a late stage in senescence(phosphoglycerate kinase, NADH-linked glyceraldehyde-3-phosphatedehydrogenase, alkaline fructose-1,6-diphosphatase, and ribose-5-phosphateisomerase). The introduction of the ribosomal inhibitors D-threochloramphenicol, lincomycin, D-2-(4-methyl-2,6-dinitroanilino)-N-methylpropionamide, and cycloheximide to illuminated, detached shootsystems of 2-d-darkened Perilla plants has suggested that synthesisof ribulose diphosphate carboxylase, NADPH-dependent glyceraldehyde-3-phosphatedehydrogenase, and possibly phosphoribulokinase, is mediatedby 70 S-based chloroplastic ribosomes. A chloroplastic siteof synthesis of these three photosynthetic enzymes is consistentwith their early deterioration during leaf ageing.     

First record of Alysia alticola Ashmead (Hymenoptera: Braconidae) in the Neotropical region

Alysia alticola Ashmead, 1890, is recorded for the first time in central Argentina, reared from pig carcasses. This is also the first mention of the genus Alysia Latreille, 1804, in Argentina, which represents the southernmost record in the Neotropical region.     

Seasonal composition and temporal succession of necrophagous and predator beetles on pig carrion in central Argentina

Insects are the most important components of the terrestrial fauna associated with carrion because they recycle organic matter back into the ecosystem. They can be classified into four ecological categories comprising: necrophages; parasites and predators of necrophagous species; omnivores, and incidentals. To determine the composition and temporal succession of necrophagous and predator beetles on pig carrion, four experiments, one in each season, were carried out during 2004 in a rural area of Cordoba, central Argentina. Two pigs (Sus scrofa L.), weighing approximately 8 kg each, were used in each of the four experiments. The animals were killed by a sharp blow to the head and immediately placed in an appropriate trap. One pig was placed in the shade and the other in direct sunlight. Beetle fauna were collected daily during the first 4 weeks and thereafter every 2 or 3 days. Five stages of decomposition were observed and a total of 1586 adults and 4309 immatures of Coleoptera belonging to the Staphylinidae, Nitidulidae, Cleridae, Dermestidae, Histeridae, Anthicidae and Trogidae families were collected during the four experiments. The necrophagous community was represented by Dermestes maculates (De Geer), nitidulid species and members of the Trox genus. Staphylinidae, Cleridae and Histeridae species were considered to be the main predators of the necrophagous species.     

Ammonite morphotypes as indicators of oxygenation in a Cretaceous epicontinental sea

An examination of ammonite morphotypes through stratigraphic sections of the Greenhorn Cyclothem of the Cretaceous Western Interior suggests that they may be useful indicators of oxygenation within ancient epicontinental seas. Because some morphotypes appear to reflect a nektobenthic and others a pelagic habitat, the presence of specific morphotypes may be used to indicate benthic and water-column oxygenation, respectively. At the same time, their absence may provide a valuable indicator of dysaerobic to anaerobic conditions that may have promoted the development of petroleum source rocks. □ Ammonites, anoxia, Cretaceous, Greenhorn Cyclothem, western Interior.     

A test of a new technique illustrating faunal dominance trends: Application to the 'Trilobite Beds' interval of the Middle Devonian Wanakah Shale in western New York

Batt, R.J. 1995 11 30 A test of a new technique illustrating faunal dominance trends: Application to the 'Trilobite Beds' interval of the Middle Devonian Wanakah Shale in western New York. Lethaia , Vol. 28, pp. 245–258. Oslo. ISSN 0024–1164.
A new graphic technique illustrating species relative abundance trends through stratigraphic sections facilitates recognition of subtle temporal and geographic changes in environment. This technique is illustrated by application to three closely spaced sections through the 'Trilobite Beds' interval of the Wanakah Shale of western New York. Graphic representation of faunal data from bed-by-bed sampling of these sections allows recognition of water depth changes that may be related to small-scale cyclic eustatic sealevel fluctuations. Comparison of graphs for neighboring sections, aided by excellent chronostratigraphic control, allows delineation of seafloor topography. During deposition of the study interval, the seafloor was consistently shallowest at the western section and deepest at the middle site. □ Wanakah Shale, Hamilton Group, Devonian, Darien Center Submember, 'Trilobite Beds', Expanded Bandygram .