The Occurrence of a Secondary Cuticle in Libertia elegans (Iridaceae)

A study of the formation of cuticle in Libertia elegans hasshown that the cuticle develops centripetally and is producedcontinuously at its juncture with the underlying pectic layer.Peroxidase activity may be demonstrated in this region duringdevelopment. Growth occurs in two discrete phases; initiallywhilst the underlying epidermal cells are expanding and laterwhen such expansion is complete. The phases are morphologicallydistinct and it is proposed that the terms primary and secondarybe applied to them. Cuticular channels with a pit-like appearancein T.S. are described here for the first time as is the fissuringand active replacement of inelastic secondary cuticular materialto accommodate costal expansion and the growth of papillae.     

Cyclone damage sustained by riparian revegetation sites in the Tully‐Murray floodplain,Queensland, Australia

Abstract Cyclones have been instrumental in shaping the structural and floristic composition of tropical forests, including tropical rainforests of north Queensland, Australia. The response of tropical riparian rehabilitation sites to cyclonic wind damage, however, is currently unknown. This lack of knowledge may severely hamper long‐term success of riparian restoration efforts, particularly in light of predictions that cyclones in north Queensland may become less frequent but more severe. In this study, we examined the extent, type and magnitude of damage inflicted on revegetation works in the Tully‐Murray floodplain of north Queensland by Severe Tropical Cyclone Larry. We compared wind damaged in 20 paired revegetated and associated rainforest remnant sites, using (i) gross community damage scores, (ii) mean weighted damage scores, and (iii) type of damage sustained by individual plants. Overall, wind damage due to Severe Tropical Cyclone Larry was surprisingly similar in revegetated and remnant sites. Both gross community damage scores and mean weighted damage scores did not differ between paired revegetated and remnant sites. In contrast, the type of damage sustained by individual plants was not independent of site, with a larger proportion in revegetated sites sustaining severe damage compared with remnant sites. This larger proportion of severely damaged individuals in revegetated sites was at least in part due to the significantly higher proportion of pioneers at these sites. The pioneer species Homalanthus novoguineensis was particularly susceptible to wind damage. The potential effects of spatial differences, such as consistent bias due to size, shape or exposure between the remnants and revegetated sites, on our results are discussed. In light of our results, we recommend that future revegetation sites include fewer pioneer species that are highly susceptible to wind damage, more pioneer species that are resistant to wind damage, and alteration of pioneer species distribution within planting matrices.     

Effects of 2,4-D butyl vapour on the growth of six crop species

Six species of crop plants (tomato, lettuce, clover, cabbage, sunflower and field bean) were exposed to concentrations of 2,4-D butyl in the range 3–50 ng/litre, for 3.5 h, using an air-flow system. Symptoms of phytotoxicity were recorded during the following 4 wk, after which the plants were harvested. Sunflower and field bean were found to be most sensitive, with tomato, lettuce and cabbage less affected and clover least sensitive, on the basis of weight. Small tomato plants were more sensitive than ones approximately twice the weight. A 50% reduction in dry weight was caused by a 3.5h exposure to less than 3 ng/litre 2,4-D butyl for sunflower, compared with over 50 ng/litre for clover. The ranking of sensitivities did not agree with reports based on liquid doses of 2,4-D, especially for field bean, which was found to be more sensitive than previously thought.     

Eocene tortoise beetles from the Green River Formation in Colorado,U.S.A. (Coleoptera: Chrysomelidae: Cassidinae)

Abstract The fossil history of leaf beetles (Chrysomelidae) is relatively poorly documented despite an abundance of available material. Of particular interest is the origin and radiation of the diverse tortoise beetles, a derived group within Cassidinae s.l. (=Cassidinae + Hispinae) defined by the exophagous life history and specialized morphology of the immature stages. Cassidinae is also a group with relatively few fossil records that can be assigned with any degree of certainty. Here we report two of the oldest definitive tortoise beetle fossils, Eosacantha delocranioides gen.n. et sp.n. and Denaeaspis chelonopsis gen.n. et sp.n. , from the Eocene Green River Formation (ca. 47 million years old) in northwestern Colorado, U.S.A. Owing to the fine level of preservation, many important features can be observed and are coded into the recent cladistic analysis for the subfamily. Phylogenetic analysis highlights that both genera have affinities with modern lineages, one restricted to the Old World and the other restricted to the Neotropics. Although Cassidinae as a whole extend into the Cretaceous, the available information suggests that the tortoise beetles perhaps originated and diversified during the Early Tertiary. As such, the morphological and biological transitions from the leaf‐mining hispiforms to the distinctive tortoise‐like cassidiforms, with their elaborate defensive larval shields and other unique behaviours, probably took place during the latest Paleocene or earliest Eocene. These Green River fossils are the oldest yet to document the specialized morphology associated with the transition in cassidine feeding and immature biology.     

Intraspecies Variability in the Esterases and Acid Phosphatases of Four Species of the Paramecium aurelia Complex1

ABSTRACT. One hundred eighty-eight stocks of Paramecium primaurelia. P. biaurelia, P. tetraurelia. and P. octaurelia were grown axenically and screened for variation in four different esterases and acid phosphatase using starch gel electrophoresis. Major observations: frequency of intraspecies variation for these enzymes is much lower in these four species than in other organisms; hypervariability for two esterases occurs in P. biaurelia both in isolates from worldwide locales and in a restricted locale; clustering of variations occurs in a high proportion of variant stocks in all four species; frequency of intraspecies variation is highest in Central and South America for all four species; and geographical differentiation is lacking between stocks in the same species both for common as well as variant phenotypes despite the cosmopolitan distribution of these species. These results are not correlated with adaptations that favor inbreeding over outbreeding. nor is the possession of bacterial endosymbionts strongly correlated with enzyme variation. When the riequency of intraspecies variation was examined for the aurelia complex of species as a whole for 13 enzymes, mitochondrial DNA, and ribosomal DNA, differences between enzymes in frequency of variation could be seen, ranging from less than 2% for seven enzymes to 12.4% for glucosephosphate isomerase, a value similar to that observed for malic dehydrogenase, mitochondrial DNA, and ribosomal DNA in P. tetraurelia. The percentage of polymorphic enzyme loci in the complex as a whole was found to be much lower than that observed for other organisms. For the species more intensely studied in this paper the level of genetic polymorphism was also much lower, although P. biaurelia showed greater variability for two of the enzymes.     

Selection of candidate coding DNA barcoding regions for use on land plants

An in silico screen of 41 of the 81 coding regions of the Nicotiana plastid genome generated a shortlist of 12 candidates as DNA barcoding loci for land plants. These loci were evaluated for amplification and sequence variation against a reference set of 98 land plant taxa. The deployment of multiple primers and a modified multiplexed tandem polymerase chain reaction yielded 85–94% amplification across taxa, and mean sequence differences between sister taxa of 6.1 from 156 bases of accD to 22 from 493 bases of matK. We conclude that loci should be combined for effective diagnosis, and recommend further investigation of the following six loci: matK, rpoB, rpoC1, ndhJ, ycf5 and accD. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 1–11.     

Pennsylvanian phylloid algae interpreted as shallow-water xenophyophores

Xenophyophores, a group of agglutinated rhizopod protists, occur in nearly all the world's oceans at depths generally in excess of 1OOO m. In certain areas they dominate deep-sea, megafaunal communities. Their widespread distribution indicates a well-established adaptive radiation. Only one fossil analogue, however, has been proposed. This is Paleodictyon , a trace fossil that superficially resembles the Recent infaunal xenophyophore Occultammina profunda in morphology. The platy xenophyophore genus Psammina closely resembles certain late Palaeozoic fossils from northeastern Kansas that have been referred to as 'phylloid algae'. Here we compare modern xenophyophore structure with that of the fossil phylloids. By reconstructing the fossils, analysing their thin sections with polarized, blue, and ultraviolet light and subjecting them to Q-switched laser ablation, we conclude that certain phylloids could represent shallow-water xenophyophores. *** Phylloid algae, xenophyophores, motphology, reconstruction, laser ablation, Pennsylvanian.