Photosynthetic Electron Transport under Phosphorylating Conditions as Influenced by Different Concentrations of Various Salts

Osman, M. E-A. H. and El-Shentenawy, F. 1988. Photosyntheticelectron transport under phosphorylating conditions as influencedby different concentrations of various salts.—J. exp.Bot. 39: 859–863. The rate of light-induced electron transport by isolated spinachthylakoids under phosphorylating conditions, as affected bydifferent concentrations of Br^–, Cl^–, NO₃^–,HCO₃^–, SO₄^2– and CO₃^2– has been investigated.The results show that both low and high concentrations of HCO₃^2–stimulated the oxygen evolution capacity under phosphorylatingconditions, whereas only low concentrations of CO₃^2–,SO₄^2– and Cl^– stimulated the oxygen evolution capacity.However, irrespective of concentration, both Br^– and NO₃^–reduced this capacity. The rate of photosynthetic electron transportwas generally stimulated by addition of ADP, even in cases whereelectron transport was inhibited by addition of bromide andnitrate. The different concentrations of these anions also causedreduction of the power generated by proton pumping and usedfor phosphorylation. The greatest level of reduction was observedin the presence of high concentrations of Cl^– and HCO₃^–. Key words: Spinach thylakoids, photosynthetic electron transport, phosphorylation     

Developmental stress in wild-living Drosophilids inferred from biometry: metric and meristic traits react differently to heterogeneous environmental conditions

Abstract.  1. During their development in natural conditions, Drosophila larvae and pupae face heterogeneous environmental conditions (HEC). Analysing the morphology of wild-living adults is a means of evaluating the effects of HEC.
2. Two drosophilid species of the Zaprionus genus that recently invaded the Nile delta were investigated, and three metric, size-related traits, and one meristic trait, the sternopleural bristle number, were measured. Data were compared with those of F₁ generation reared under favourable laboratory conditions.
3. Body size was smaller in nature, but also extremely variable among individuals, with an average coefficient of variation (CV) of 9.1 ± 0.3, against a much lesser value of 2.4 ± 0.1 in laboratory flies. Correlations among size traits were also greater in nature (0.96 ± 0.01) than in the laboratory (0.75 ± 0.04).
4. By contrast, sternopleural bristles produced similar results in wild-living and laboratory flies. In nature, mean numbers were only slightly less than in the laboratory and the CVs were almost identical (10.87 ± 0.70 vs 10.80 ± 0.76).
5. Fluctuating asymmetry of sternopleural bristles was also identical in the two kinds of flies, and was not influenced by HEC, indicating a high level of developmental canalisation with respect to HEC.
6. The implications of the results for the problems of field heritability and developmental stability are discussed.     

Relationship of claw form and exoskeleton condition to reproductive system size and methyl farnesoate in the male spider crab,Libinia emarginata

Summary

Methyl farnesoate (MF) expression and reproductive system size were compared in five representative groups of male L. emarginata selected from a sample collected in November. The groups differed from each other with respect to carapace size (small, intermediate and large), relative propodus size (small and large claw forms), and condition of the exoskeleton (abraded and unabraded). Large males with large claws and abraded exoskeletons had reproductive system indices which were significantly larger than any other group. The mandibular organs of these crabs also had significantly higher rates of methyl farnesoate synthesis in vitro. Hemolymph titers of methyl farnesoate were also highest in this group, but were not significantly different from the group with small carapaces, small claws and unabraded exoskeletons. Methyl farnesoate titers were significantly lower in all other groups of unabraded animals with small or large claws. These results suggest that methyl farnesoate may play a role in morphogenesis and reproduction in male L. emarginata.     

Seed morphology of Iranian annual species of Euphorbia (Euphorbiaceae)

Euphorbia (Euphorbiaceae) is one of the largest and most diversified cosmopolitan genera of flowering plants. South‐west Asia is a major centre of diversity and contains c. 65 annual species, 35 of which occur in Iran. In this article, the seed morphology of all Iranian annual species was studied, including E. aulacosperma and E. rhabdothosperma, both new records for Iran. Quantitative and qualitative macro‐ and micromorphological features of seeds and caruncles were investigated using stereomicroscopy and scanning electron microscopy. Caruncle characters (shape, size, colour) and seed characters (shape, size, colour, ornamentation) are often constant and useful in identification and classification. An identification key and scanning electron micrographs are provided for all known Iranian taxa. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 212–234.     

Water relations and leaf gas exchange properties in some elite canola (Brassica napus) lines under salt stress

In order to examine whether growth of eight genetically diverse canola (Brassica napus) lines under salt stress is positively associated with their rate of photosynthesis and other gas exchange related attributes, 20‐day old plants of all eight lines were subjected to salinised soil containing 2.4 dS m^?1 NaCl (control), 4 dS m^?1 NaCl, 8 dS m^?1 NaCl or 12 dS m‐¹ NaCl. The lines DGL (non canola) and Dunkeld were found to be salt tolerant and Rainbow and Cyclon salt sensitive with regard to shoot dry matter production and seed yield under saline conditions. In most of the lines there was a negative relationship between growth and net CO₂ assimilation rate. For example, the salt sensitive line Cyclon was the lowest and Con‐III the highest, and the salt tolerant line Dunkeld intermediate in net CO₂ assimilation rate under salt stress. Stomatal conductance was found to be lower in the salt sensitive line Cyclon, followed by the salt tolerant line Dunkeld along with Oscar. Water use efficiency estimated as Pn/E was moderate in the salt sensitive line Cyclon and the salt tolerant line Dunkeld. In conclusion, high salt tolerance of Dunkeld and DGL (non‐canola) was not positively associated with net CO₂ assimilation rate or Pn/E.     

Phylogenetic classification of the Drosophilidae Rondani (Diptera): the role of morphology in the postgenomic era

Molecular sequences now overwhelm morphology in phylogenetic inference. Nonetheless, most molecular studies are conducted on a limited number of taxa, as DNA rarely can be analysed from old museum types or fossils. During the last 20 years, more than 150 molecular studies have challenged the current phylogenetic classification of the family Drosophilidae Rondani based on morphological characters. Most studies concerned a single genus, Drosophila Fallén, and included only few representative species from 17 out of the 78 genera of the family. Therefore, these molecular studies were unable to provide an alternative classification scheme. A supermatrix analysis of seven nuclear and one mitochondrial genes (8248 bp) for 33 genera was conducted using outgroups from one calyptrate and four ephydroid families. The Bayesian phylogeny was consistent with previous molecular studies including whole genome sequences and divided the Drosophilidae into four monophyletic clades. Morphological characters, mostly male genitalia, then were compared thoroughly between the four clades and homologous character states were identified. These states were then checked for 70 genera and a revised phylogenetic, family‐group classification for the Drosophilidae is proposed. Two genera –Cladochaeta Coquillett and Diathoneura Duda – of the tribe Cladochaetini Grimaldi are transferred to the family Ephydridae. The Drosophilidae is divided into two subfamilies: Steganinae Hendel (30 genera) and Drosophilinae Rondani (43 genera). A further two genera, Apacrochaeta Duda and Sphyrnoceps de Meijere, are incertae sedis, and Palmophila Grimaldi, is synonymized with Drosophila syn.n. The Drosophilinae is subdivided into two tribes: the re‐elevated Colocasiomyini Okada (nine genera) and Drosophilini Okada. The paraphyly of the genus Drosophila was not resolved to avoid affecting the binomina of important laboratory model species; however, its subgeneric classification was revised in light of molecular and morphological data. Three subgenera, namely Chusqueophila Brncic, Phloridosa Sturtevant and Psilodorha Okada, were synonymized with the subgenus Drosophila (Drosophila) Fallén syns.n. Among the 45 species groups and 5 species complexes of Drosophila (Drosophila), 22 groups and 1 complex were transferred to the subgenus Drosophila (Siphlodora) Patterson & Mainland and 6 groups, 2 species subgroups and 3 complexes are considered incertae sedis within the genus Drosophila. Different morphological characters provide different signals at different phylogenetic scales: thoracic characters (wing venation and presternal shape) discriminate families; grasping and erection‐related characters discriminate subfamilies to tribes; whereas phallic paraphyses, i.e. auxiliary intromittent organs, discriminate genera and Drosophila subgenera. The study shows the necessity of analysing morphological characters within a molecular phylogenetic framework to translate molecular phylogenies into taxonomically‐comprehensive classifications.     

Histochemical analysis of accessory genital gland secretions in female Pimpla turionellae L. (Hymenoptera: Ichneumonidae)

The secretions produced by the 3 accessory glands of the female genital tract of Pimpla turionellae were investigated histochemically. The uterus gland secretion was identified as a mixture of hyaluronic acid and lipoprotein, that of the poison gland as a neutral mucoprotein. The product of the alkaline gland (Dufour's gland) consists of lecithin and a cholesterol ester. Pimpla females, as parasites of Lepidoptera pupae, inject these secretions into the host hemocoel during oviposition, thus preventing hemocytic encapsulation of their eggs. The physiological functions of the secretions are briefly discussed.