Rhizome structure and evolution in the ant-associated epiphytic fern Lecanopteris Reinw. (Polypodiaceae)

GAY, H., 1993. Rhizome structure and evolution in the ant-associated epiphytic fern Lecanopteris Reinw. (Polypodiaceae). The Lecanopteris rhizome is expanded or hollow, and is used as a nest by ants of the genera Iridomyrmex and Crematogaster. The 13 species of Lecanopteris display six rhizome forms, unequally distributed between two subgenera. Subgenus Myrmecopteris comprises four species, each possessing a characteristic rhizome: L. mirabilis has a solid, arched rhizome, with the domatium between the rhizome underside and host trunk; L. sarcopus displays dimorphism between solid frond-bearing axes and hollow, frondless side branches; the rhizome of L. Crustacea is hollow but phyllopodia are solid; L. sinuosa has hollow rhizomes and phyllopodia. The architecture of L. mirabilis, L. sarcopus and L. Crustacea results in a compact, many-layered domatium, but L. sinuosa has a tittle-branched habit. Members of subg. Lecanopteris are completely hollow and have a compact architecture: six species typified by L. pumila have a central gallery and hollow phyllopodia, and three species typified by L. darnaedii have two gallery and chamber systems. The genus Lecanopteris is unlikely to be monophyletic; its nearest relative is Phymalodes. Phylogeny in subg. Myrmecopteris is unclear; no gradation of rhizome complexity exists. In subg. Lecanopteris, L. curtisii is considered most similar to the ancestral species, giving rise to the L. pumila group, which engendered the L. darnaedii group.     

Ant specificity and behaviour in mutualisms with epiphytes: the case of Lecanopteris (Polypodiaceae)

Seven species of the fern Lecanopteris: L. sinuosa, L. sarcopus, L. mirabilis, L. curtisii, L. pumila, L. celebica and L. damaedii are regularly inhabited by ants of five species: Iridomyrmex cordatus, I. murinus, Crematogaster treubi, C. difformis and Camponotus pallidas. Inhabitation is not obligate; either party can survive without the other, but ferns without ants are rare in their natural habitat. The total recorded diversity of ants in Lecanopteris is 31 species, 20 of which were only recorded once.
All five regularly inhabiting ant species kept larvae in the domatium (82% of Lecanopteris specimens examined). The major ant species inhabiting Lecanopteris deposited debris in the domatium, segregated from their brood (90% of Lecanopteris specimens). Iridomyrmex murinus did not build carton around the rhizomes, but the other major inhabitants constructed runways in 79% of Lecanopteris specimens. Goccid cultivation was variable within ant and plant species: I murinus tended them in 50% of specimens, and homopterans were also recorded with Crematogaster treubi (39%), C. bomeensis (27%) and I cordatus (16%). A high frequency of ant colonies inhabiting Lecanopteris , keeping larvae, depositing debris, building carton runways, and occasionally keeping coccids has been established. Specificity of ant species is high within a population of Lecanopteris , or a given habitat or geographical area, but outside the ranges of regular inhabitants other ant occupants are found. Comparable data from other genera of ant-epiphytes with domatia show similar diversity of inhabitance over geographical areas; no data are available within single plant populations.     

Unraveling the phylogeny of polygrammoid ferns (Polypodiaceae and Grammitidaceae): exploring aspects of the diversification of epiphytic plants

We explore the phylogeny of the polygrammoid ferns using nucleotide sequences derived from three plastid loci for each of 98 selected species. Our analyses recovered four major monophyletic lineages: the loxogrammoids, two clades consisting of taxa restricted to the Old World, and a largely neotropical clade that also includes the pantropical Grammitidaceae. The loxogrammoid lineage diverges first and is sister to a large clade comprising the three remaining species-rich lineages. One paleotropical clade includes the drynarioid and selligueoid ferns, whereas the second paleotropical clade includes the platycerioids, lepisoroids, microsoroids, and their relatives. The grammitids nest within the neotropical clade, although the sister taxon of this circum-tropic, epiphytic group remains ambiguous. Microsorum and Polypodium, as traditionally defined, were recovered as polyphyletic. The relatively short branch lengths of the deepest clades contrast with the long branch lengths leading to the terminal groups. This suggests that the polygrammoid ferns arose through an old, rapid radiation. Our analysis also reveals that the rate of substitution in the grammitids is remarkably higher relative to other polygrammoids. Disparities in substitution rate may be correlated with one or more features characterizing grammitids, including species richness, chlorophyllous spores, and an extended gametophytic phase.     

Temporal patterns of inorganic nitrogen uptake by mature sugar maple (Acer saccharum Marsh.) and red spruce (Picea rubens Sarg.) trees using two common approaches

Background: Plant uptake of nitrogen influences many ecosystem processes, yet uptake by trees in northern forests of the United States has not been quantified throughout the growing season.

Aims: To measure NH₄ ⁺ and NO₃ ^? uptake by mature sugar maple (Acer saccharum) and red spruce (Picea rubens) trees during the early, mid and late growing season.

Methods: At Hubbard Brook Experimental Forest, New Hampshire, we used two approaches to measure nitrogen uptake capacity by mature trees: an in situ depletion method using intact roots and an ex situ ¹⁵N tracer method using excised roots.

Results: NH₄ ⁺ uptake was greater than NO₃ ^? for both methods and tree species (P < 0.05). NH₄ ⁺ uptake was lowest during the early growing season, while NO₃ ^? uptake was lowest during the late growing season. Measured rates of NH₄ ⁺ uptake were 2–3 orders of magnitude greater using the in situ depletion method compared with the ex situ ¹⁵N tracer method.

Conclusions: These results demonstrate seasonal differences in nitrogen uptake by two dominant tree species in a northern forest and show that the method employed can significantly impact measured rates of uptake, which could have implications for understanding the magnitude of plant nitrogen uptake and for cross-study comparisons of this process.     

Lack of compensation by final instar larvae of the myrmecophilous lycaenid butterfly,Jalmenus evagoras,for the loss of nutrients to ants

Abstract Larvae and pupae of the Australian lycaenid butterfly, Jalmenus evagoras Donovan (Lepidoptera; Lycaenidae), are protected from parasites and predators by attendant ants. In return, the juveniles of J. evagoras secrete to the ants a solution containing substantial amounts of sugars and amino acids. Larvae of J. evagoras were reared from hatching until adult eclosion either with or without ants. Experiments were performed to examine whether fifth (final) instar larvae attempt to compensate for the nutrient loss to ants, by consuming more food, digesting food more efficiently, or extending development time. The presence or absence of ants had no effect on the feeding rate, efficiency of digestion or development time of fifth instar larvae. Larvae with ants converted a smaller proportion of ingested food into biomass, and consequently grew less than their counterparts without ants. Thus fifth instar larvae of J. evagoras do not appear to compensate for the nutrient loss to ants. Possible reasons for the failure to compensate are discussed.     

15N stable isotope labelling of slugs (Gastropoda: Pulmonata)

Stable isotope tracers are a promising tool for investigating the ecology of terrestrial slugs, including predator‐prey relationships, migration behaviour, nutrient turnover and dietary routing. The objective of the present feasibility study was to label two economically important slug groups, Deroceras reticulatum and keeled slugs (families Limacidae and Milacidae, respectively), with the stable isotope ¹⁵N under controlled laboratory conditions. Significant isotopic enrichment in slug tissue was detected after 4 days and persisted for at least 10 days after slugs had been fed on ¹⁵N enriched food for a period of 15 days. The time course of ¹⁵N uptake into slug tissues and its relation to food consumption were well described mathematically. Estimated mean ¹⁵N assimilation efficiencies from labelled maize mixed with unlabelled wheat bran were 30% and 38%, respectively, for the species groups studied. These findings suggest that slugs can be readily and efficiently labelled and that it is feasible to devise protocols for producing large numbers of isotopically labelled slugs for use in ecological studies. A simple method is described for the collection and analysis of cutaneous mucus from individual slugs which can be used to test uniformity of isotopic labelling.     

Leaf vs. epiphyte nitrogen uptake in a nutrient enriched Mediterranean seagrass (Posidonia oceanica) meadow

In situ nitrogen uptake by leaves and epiphytes was studied in a Mediterranean seagrass (Posidonia oceanica) meadow impacted from a fish farm and a pristine meadow, using ¹⁵NH₄ and ¹⁵NO₃ as tracers. In the impacted meadow both leaves and epiphytes yielded higher N concentrations and showed higher specific N uptake, suggesting a linkage between N uptake and its accumulation. Epiphytes took up N faster than leaves in relation to their corresponding biomass, but when assessed per unit area, N uptake was higher in leaves. Leaf N uptake was negatively correlated with epiphyte N uptake. With increasing epiphyte load on leaves, N leaf uptake decreased while N epiphyte uptake increased, indicating that epiphyte overgrowth hinders N uptake by P. oceanica leaves. Epiphyte contribution to total N uptake increased, while that of leaves decreased at the impacted meadow. However, 2-3 times less N was transferred daily from the water column to the benthic compartment, through seagrass and epiphyte uptake on total, at the impacted meadow. Therefore, it is probably still the loss of the key species - the seagrass - which plays the most important role in N cycling in seagrass ecosystems.     

The effects of varying culture nitrogen and phosphorus levels on nutrient uptake and storage by the waterhyacinth Eichhornia crassipes (Mart) Solms

The uptake of nitrogen (N) by waterhyacinth (Eichhornia crassipes) was maximal when the culture solution contained a combination of 36 ppm N and 6,53 ppm phosphorus (P). N uptake was inhibited by increasing P or decreasing N in the culture medium. Uptake of P was stimulated by the elevation of either N or P or both. An increase of P above O ppm inhibited the accumulation of N. Similarly, the accumulation of P was enhanced by increasing levels of P but was reduced with increasing levels of N. Both N and P levels were always greatest in leaves; next highest in floats and lowest in roots. High tissue levels of these two nutrients and the capacity for nutrient removal from water by waterhyacinth indicates a possible role for this plant in the reduction of eutrophication in nutrient polluted waters as well as the use of harvested, dried tissue for fertilizer.     

New species and new records of the fern genus Terpsichore (Polypodiopsida: Polypodiaceae) from Bolivia

We describe five new species, report a new record for the genus Terpsichore, and provide a key to the Bolivian species.     

Availability of water and inorganic nutrients in the persistent leaf bases of the grasstree Kingia australis, and uptake and translocation of labelled phosphate by the embedded aerial roots

Numerous lateral branches of the concealed aerial roots of the grasstree Kingia australis ramify through the persistent leaf bases, suggesting a role in uptake of water and nutrients localed up to 8 m above ground. These leaf bases were shown to hold up to more than three times their weight in water. Water and nutrients (N, P and K) available in the leaf bases may greatly exceed that in an equal volume of surface soil, especially during the dry summer months. At this time, ³²P injected# among the leaf bases is strongly absorbed by the aerial roots and translocated to the meristematic regions of other laterals beneath the point of application, but mostly to the stern and leaves above it. Scattered vascular bundles in the pith are the major routes for the rapid distribution of P up and down the trunk following its departure from the aerial roots. Water and nutrients stored in the leaf bases and their subsequent uptake by the associated aerial roots may therefore contribute significantly to this species' tolerance of long summer droughts and extremely impoverished soils.     

An investigation of noradrenaline uptake and release by the CATH.a cell line

The cell bodies of ascending noradrenergic neurons in the brain are located predominantly in the locus coeruleus. An in vitro model of locus coeruleus neurons could prove to be a useful tool in the investigation of noradrenergic neural networks and their associated pathophysiologies. The CATH.a cell line demonstrates some of the properties expected of locus coeruleus neurons, and the present study investigated the neurotransmitter uptake and release properties of the CATH.a cells. It was surprising that the CATH.a cells failed to accumulate [3H]noradrenaline ([3H]NA), suggesting the lack of a functional NA transporter. RT-PCR supported this finding by demonstrating the absence of NA transporter mRNA. Treatment of CATH.a cells with various differentiating agents failed to increase the [3H]NA uptake. Endogenous NA release was studied using HPLC detection, which revealed a lack of depolarisation-induced increases in endogenous NA release. A human NA transporter-transfected CATH.a cell line was generated (termed RUNT), and a study of the [3H]NA uptake revealed that the RUNT cells displayed significant uptake that could be blocked by cocaine (10 microM). Furthermore, the uptake capacity could be dramatically increased by differentiation of the cells with dibutyryl cyclic AMP (1 mM) for 24 h. Using dibutyryl cyclic AMP-differentiated RUNT cells, high K+ concentrations (50 mM) significantly increased [3H]NA release above basal levels.     

Effect of farm yard manure and iron on dry matter yield and nutrients uptake by oats (Avena sativa)

A pot culture experiment was conducted on a loamy sand soil to study the effect of FYM and Fe on dry matter yield and uptake of nutrients by oats (Avena sativa) crop in green-house. Application of Fe @ 5 and 20 ppm increased dry matter yield by 5.11 and 11.55 per cent, respectively. The per cent increase in dry matter yield over control with the application of 0.5 and 1.0 percent FYM was 19.06 and 30.07, respectively. Application of FYM increased concentration and uptake of P significantly. Phosphorus uptake increased by 23.60, 54.38, 91.01 and 134.61 per cent over control with 0.5, 1.0, 2.0 and 4.0 per cent FYM, respectively. Phosphorus concentration decreased at 20 ppm Fe but uptake increased significantly at 5 ppm Fe. Concentration and uptake of Ca increased with increasing amounts of Fe and application of FYM decreased concentration of Ca but uptake increased upto 1.0 per cent FYM over control. The Mg concentration and uptake decreased significantly with increased amount of Fe. Application of FYM also decreased Mg concentration but its uptake increased upto 1.0 per cent FYM and then decreased.Iron concentration and uptake increased upto 2 per cent FYM and then decreased. Whereas concentration of Fe decreased with increased amount of applied Fe but its uptake increased nonsignificantly with increased amount of added Fe.Managenese concentration and uptake decreased significantly with increased amount of applied Fe. Managenese concentration increased upto 0.5 per cent FYM but its uptake continued increasing with increasing amounts of applied FYM.     

Flow cytofluorometric investigation of the uptake by hepatocytes and spleen cells of targeted and untargeted liposomes injected intravenously into mice

Untargeted liposomes (composition: PC-PS-cholesterol) and targeted liposomes (composition: PC-PS-cholesterol-lactosylceramide) having encapsulated concentration-quenched carboxyfluorescein were injected intravenously into mice. 1 h after injection, the mice livers were perfused, excised and the hepatocytes were separated from nonparenchymal cells and analysed in a fluorescence-activated cell sorter analyzer. The result was that hepatocytes took up significantly more liposomes when lactosylceramide was inserted in the liposome bilayers, which was in good agreement with observations made on the in vivo uptake of liposome-encapsulated insulin gene (Soriano, P. et al. (1983) Proc. Natl. Acad. Sci. USA, 80, 7128–7133). Cytofluorimetric analysis of the spleen cells showed that approx. 10% of the splenic lymphocytes take up high amounts of lactosylceramide liposomes, whereas most of the phospholipid liposomes are taken up by the phagocytic cells. The flow cytofluorimetric analysis shows, moreover, the internalization of the liposomes by the target cells and allows a quantitation of this uptake. Thus, in vivo targeting of the liposomes to specific liver and splenic cells, by means of glycolipid insertion in the liposome bilayer, is shown to take place with delivery of the liposomal aqueous space marker to these cells.     

Studies on the uptake of trivalent and hexavelent chromium by onion (Allium cepa)

Abstract

Experiments were conducted to examine the uptake and translocation of root-absorbed trivalent and hexavalent state of chromium in the onion plant (Allium cepa) grown in soil and sand culture. Chromium content in plant tissues increased with increasing amount of added chromium. Distribution of chromium in the plant in general, found to be in the order: root>>bulb>shoot. Higher uptake in the plants grown in sand from both the sources of chromium was observed as compared with the corresponding values for soil culture. Morphological and growth effects of the treatments of different oxidation state of chromium indicated that higher doses of Cr(VI) [150 and 300 μg mL^?1] were more toxic to the onion plants compared to equivalent doses of Cr(III).     

Ellesmeris sphenopteroides,gen. ET SP. NOV., a new zygopterid fern from the Upper Devonian (Frasnian) of Ellesmere,N.W.T., Arctic Canada

A new fern-like fossil plant is described from the lower Upper Devonian of southern Ellesmere Island, Canadian Arctic Archipelago. The plant occurs in an Archaeopteris-dominated flora preserved in the Nordstrand Point Formation (Mid-Late Frasnian) near Bird Fiord. The plant has a pinnate vegetative system with three branch orders and laminate sphenopteroid pinnules. Primary pinnae usually diverge from the main axis in distichous pairs (quadriseriate), but can depart singly (biseriate). Each primary pinna bears a basal catadromic aphlebia. Anatomically, the plant exhibits a mesarch, bipolar protostele that is ribbon- to clepsydropsoid-shaped in the main axis. Primary pinna traces are also initially bipolar and crescent-shaped, but may become four-ribbed before dividing into a pair of bipolar traces. The morphology and anatomy of this plant are nongymnospermous and are most similar to Zygopteridales (particularly Rhacophytaceae and Zygopteridaceae). The Frasnian age of Ellesmeris shows that laminated foliage had evolved in some zygopterid ferns much earlier than previously recognized. The Sphenopteris-like pinnules of Ellesmeris indicate the need for caution when attributing such a convergent foliar design to other plant groups, such as the Devonian gymnosperms.     

The impact of pH and calcium on the uptake of fluoride by tea plants (Camellia sinensis L.)

BACKGROUND AND AIMS: Tea plants (Camellia sinensis L.) accumulate large amounts of fluoride (F) from soils containing normal F concentrations. The present experiments examined the effects of pH and Ca on F uptake by this accumulating plant species. METHODS: The effect of pH was assessed in two experiments, one using uptake solutions with different pHs, and the other using lime, as CaO, applied to the soil. The effect of Ca was examined by analysing F concentrations in plants supplied with varying amounts of Ca, as Ca(NO3)2, either in uptake solutions or through the soil. KEY RESULTS: F uptake was highest at solution pH 5.5, and significantly lower at pH 4.0. In the soil experiment, leaf F decreased linearly with the amounts of lime, which raised the soil pH progressively from 4.32 to 4.91, 5.43, 5.89 and, finally, 6.55. Liming increased the water-soluble F content of the soil. Including Ca in the uptake solution or adding Ca to soil significantly decreased leaf F concentrations. The distribution pattern of F in tea plants was not altered by Ca treatment, with most F being allocated to leaves. The activity of F- in the uptake solution was unaffected and water-soluble F in the soil was sometimes increased by added Ca. CONCLUSIONS: F uptake by tea plants, which are inherently able to accumulate large quantities of F, was affected both by pH and by Ca levels in the medium. The reduced F uptake following Ca application appeared not to be due simply to the precipitation of CaF2 in solution and soil or to the complexing of Ca and F in roots, although these factors cannot be dismissed. It was more likely due to the effect of Ca on the properties of cell wall or membrane permeability in the solution experiments, and to alteration of F speciations and their quantities in soil solutions following Ca application.     

Effects of external iron concentration upon seedling growth and uptake of Fe and phosphate by the common reed, Phragmites australis (Cav.) Trin ex. Steudel

The objectives of this study were to determine whether, and to what degree, the aqueous iron concentration in the growing medium affects the growth of, and Fe uptake by, Phragmites australis, and whether the presence of iron in the growing environment affects the uptake of the essential element phosphate. The wetland macrophyte P. australis was grown under laboratory conditions in nutrient solution (0.31 mg L(-1) phosphate) containing a range of iron concentrations (0-50 mg L(-1) Fe). A threshold of iron concentration (1 mg L(-1)) was found, above which growth of P. australis was significantly inhibited. No direct causal relationship between iron content in aerial tissues and growth inhibition was found, which strongly suggests that iron toxicity cannot explain these results. Phosphate concentrations in aerial tissues were consistently sufficient for growth and development (2-3 % d. wt) despite significant variation in concentration of phosphate associated with roots. External Fe concentration had a significant effect on the growth of P. australis and on both Fe and phosphate concentrations associated with roots. However, neither direct toxicity nor phosphate deficiency could explain the reduction in growth above 1 mg L(-1) external Fe concentration     

Soil acidification as caused by the nitrogen uptake pattern of Scots pine (Pinus sylvestris)

Three-year-old Scots pine (Pinus sylvestris) trees were grown on a sandy forest soil in pots, with the objective to determine their NH₄/NO₃ uptake ratio and proton efflux. N was supplied in three NH₄-N/NO₃-N ratios, 3:1, 1:1 and 1:3, either as ¹⁵NH₄+¹⁴NO₃ or as ¹⁴NH₄+¹⁵NO₃. Total N and ¹⁵N acquisition of different plant parts were measured. Averaged over the whole tree, the NH₄/NO₃ uptake ratios throughout the growing season were found to be 4.2, 2.5, and 1.5 for the three application ratios, respectively. The excess cation-over-anion uptake value (C_a-A_a) appeared to be linearly related to the natural logarithm of the NH₄/NO₃ uptake ratio. Further, this uptake ratio was related to the NH₄/NO₃ ratio of the soil solution. From these relationship it was estimated that Scots pine exhibits an acidifying uptake pattern as long as the contribution of nitrate to the N nutrition is lower than 70%. Under field circumstances root uptake may cause soil acidification in the topsoil, containing the largest part of the root system, and soil alkalization in deeper soil layers.