Effect of Auxins and Light on Rooting Stem Cuttings of Populus nigra Salix tetrasperma, Ipomea fistulosa and Hibiscus notodus in Relation to Polarity

The apical and basal ends of stem cuttings of Populus nigra, Salix tetrasperma, Ipomoea fistulosa and Hibiscus notodus were treated with 10 mg/l solutions of IAA and IBA for 24 hours and were planted either erect or inverted both in light and dark. Observations for the number of cuttings that rooted and the roots produced on them were recorded at weekly intervals. In Salix, Ipomoea and Hibiscus rooting was more on cuttings planted erect, while in populus it did not differ much with the manner of planting. The reduced rooting in inverted cuttings may be ascribed to the low level of endogenous auxin at the apex due to polar transport. An exogenous application of auxins enhanced rooting on inverted cuttings. In dark, roots on Populus and Salix cuttings were produced both above and within the rooting medium. The weak polarity of these two plants may be due to the potential root primordia reported in their stem. The formation of callus occurred on the top of Populus cuttings whether planted erect or inverted but it differentiated into branches on erect cuttings only. In those planted in an inverted position the callus failed to differentiate in spite of the application of kinetin, auxins, TIBA, coumarin and sucrose, and dried ultimately.     

CO2 exchange under varying light intensities in some under- and overtemperature subtropical tree species

CO₂ exchange, transpiration and stomatal conductance of 39 subtropical tree species were studied under five light intensities at around atmospheric air temperatures found in subtropics during the active growth period of these species. Photosynthesis rates under different light intensities were strongly dependent on leaf to air temperature differences (T). Based on T, 39 species fell in two distinct categories namely, undertemperature and overtemperature. Majority of the species in the former group were found to have relatively higher rate of photosynthesis, stomatal conductance, transpiration as well as water use efficiency. These species also showed higher light saturation for photosynthesis. The significance of the results is discussed in terms of adaptive potential in the two types of species.     

Development of laticifer cells in callus cultures of Calotropis procera (Ait.) R. Br.

Tissue cultures were established from stem explants of Calotropis procera, a hydrocarbon yielding desert shrub on Murashige and Skoog's medium supplemented with 1.5 mg. 1^–01 2,4-D + 0.5 mg.1^–1 kinetin and polyvinylpyrrolidone. Laticifer cells were not present in young callus but were observed after 4 weeks of callus growth when examined histochemically. These young laticifers were detected in the 5th week of culture and were distinguished from surrounding cells by the presence of characteristic cytoplasm and thin walls. A group of cells with extensive branching was developed after 8 weeks of growth of the callus cultures. These cells were thick walled and contained latex particles in coagulated masses. Positive Liebermann-Burchard test proved the presence of terpenoids in these laticifers.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - KIN Kinetin - PVP Polyvinylpyrrolidone - HHS Heidenhain's Haematoxylin and safranin     

Long-term effects of ungulates on phytophagous insects

Abstract.  1. Most plants interact with a diverse suite of herbivores, allowing the opportunity for the existence of positive and negative interactions between highly dissimilar organisms. However, most studies on herbivorous interactions have been performed under the assumption that they occur mainly between similar species. Consequently, ecologists are still far from a full understanding of the ecological factors that determine insect population dynamics.
2. In this study, a 7-year field experiment was conducted that manipulated the presence of ungulates to evaluate their effects on the abundance, attack rate, and survival of four guilds of co-occurring herbivorous insects living on the same host plant: seed predators, stem borers, gall makers and sap suckers. These four guilds differed in habits and behaviour, the first three being sessile and endophytic and the last being free-living.
3. This study shows that the abundance of all four guilds was negatively affected by ungulates. However, the effect on attack rate differed among guilds, as mammals do not affect the seed predator attack rate. Ungulates also differentially affected insect survival, ingesting only seed predators and gall makers.
4. In summary, this study suggests that diverse mechanisms may affect different insect guilds in different ways. Therefore, competition between disparate herbivores appears to be complex and can be provoked by multiple mechanisms.     

Antisense RNA decreases AP33 gene expression and cytoadherence by <Emphasis Type="Italic">T. vaginalis</Emphasis>

Background  

Host parasitism by Trichomonas vaginalis is complex. Adherence to vaginal epithelial cells (VECs) is mediated by surface proteins. We showed before that antisense down-regulation of expression of adhesin AP65 decreased amounts of protein, which lowered levels of T. vaginalis adherence to VECs. We now perform antisense down-regulation of expression of the ap33 gene to evaluate and confirm a role for AP33 in adherence by T. vaginalis. We also used an established transfection system for heterologous expression of AP33 in T. foetus as an additional confirmatory approach.     

Phenol-mediated improved performance of active biomass for treatment of distillery wastewater

Activated sludge from a wastewater treatment plant consists of a consortium of microbes that utilize various organic molecules including persistent organic pollutants for their survival. Phenolic compounds and their derivatives along with dibenzofuran (DBF) are found as dominating pollutants in distillery waste. The acclimatization process leads to selective enrichment of the microbial community; and in this study, we report the acclimatizing effect of phenol on improving the treatment efficiency of two different distillery sludges—sludge from conventional aeration tanks (CAT), and from an extended aeration tank (EAT). The adaptation-dependent performance of activated biomass was studied by monitoring the increase in colony-forming units (CFUs) on mineral media and the utilization pattern for phenol (300×10³ and 530×10³ CFU for CAT and EAT sludge, respectively) and DBF (260×10³ and 430×10³ CFU for CAT and EAT sludge, respectively). The study showed that the acclimatization process remarkably improved the performance sludge for treatment of distillery wastewater. There was an improvement in chemical oxygen demand (COD) removal efficiency from 19% (unacclimatized sludge) to 31% in the case of acclimatized sludge (raw wastewater), which improved further to 82% and 87% with dilution of wastewater by 10 times (0.1×) and by 50 times (0.02×), respectively. Highest growth yields were observed with 0.1× wastewater (0.324 and 0.308 g g⁻¹ d⁻¹ for CAT and EAT sludges, respectively), while lower values are reported for the remaining two forms of wastewater. The study proposes that acclimatization step could be included as part of a treatment plant where the activated biomass could be intermittently metabolically charged by exposing it to selected molecules to increase treatment efficiency.     

Lactic dehydrogenase activity and cellular localization of several dehydrogenases in Neurospora and Allomyces

Summary Lactic dehydrogenase (LDH) activity has been cytochemically localized and its activity measured in wild-type and mutant strains of Neurospora crassa and male and female hybrids of Allomyces.In all strains, less intracellular staining is found, by oxidative assay of lactic dehydrogenase, ethanol dehydrogenase and a few other dehydrogenases, in the hyphal tips than in the older regions of the hyphae.The extractible activity of LDH, assayed reductively in the soluble fraction, is much greater in Allomyces than Neurospora. In Allomyces the least activity is found in the female differentiated strain. The male differentiated strain and especially the vegetative cultures of both strains have much more activity. In Neurospora, conidiating cultures have unexpectedly more activity than vegetative cultures. The crisp mutant which forms increased numbers of conidia has more activity than the wild-type which, in turn, has more activity than the aconidial fluffy mutant.     

Strain improvement for tannase production from co-culture of Aspergillus foetidus and Rhizopus oryzae

Spores from the co-culture of Aspergillus foetidus and Rhizopus oryzae were subjected to UV, heat and NTG (3-nitro,5-methylguanidine) mutagenesis. A few colonies were screened from the selected media for tannase study. Amongst all, the best mutant isolated from the heat treatment (60 degrees C for 60 min) was SCPR 337. The maximum yield of gallic acid and tannase in case of mutant strain was 95.2% and 53.6 U/ml with an incubation period of 30 h as compared to wild strain where the incubation period was 48 h with an enzyme activity of 44.2 U/ml and gallic acid yield of 94%, respectively. The mutant was sensitive to tetracycline and was also an over-producer of protease and amylase.     

Morphometric analysis and taxonomic revision of the Vriesea paraibica complex (Bromeliaceae)

The species related to Vriesea paraibica (Bromeliaceae, Tillandsioideae) have controversial taxonomic limits. For several decades, this group has been identified in herbarium collections as V. × morreniana, an artificial hybrid that does not grow in natural habitats. The aim of this study was to assess the morphological variation in the V. paraibica complex through morphometric analyses of natural populations. Two sets of analyses were performed: the first involved six natural populations (G1) and the second was carried out on taxa that emerged from the first analysis, but using material from herbarium collections (G2). Univariate ANOVA was used, as well as discriminant analysis of 16 morphometric variables in G1 and 18 in G2. The results of the analyses of the two groups were similar and led to the selection of diagnostic traits of four species. Lengths of the lower and median floral bracts were significant for the separation of red and yellow floral bracts. Vriesea paraibica and V. interrogatoria have red bracts; these two species are differentiated by the widths of the lower and median portions of the inflorescence and by scape length. These structures are larger in the former and smaller in the latter. Of the species with yellow floral bracts, V. eltoniana is distinguished by longer leaf blades and scapes and V. flava is characterized by its shorter sepal lengths. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 163–181.