bluuebunny/crossref_metadata_2025 huggingface dataset:
A review of the Australian Phytoseiinae (Acari : Mesostigmata : Phytoseiidae)
Authors: Walter David Evans , Beard Jennifer J.
Published: January 2006

We revise the Australian Phytoseiinae (Acari : Mesostigmata : Phytoseiidae)
based on a study of over 1000 slide-mounted specimens. Of the three currently
recognised genera in the subfamily, onlyPhytoseius is
known from Australia, but endemic species occur in each of its three
species-groups. We describe 11 new species, including
P. bunya, the first Australian representative of the
purseglovei-group. The
plumifer-group is represented by five species including
P. danutae, sp. nov. and
P. improcerus Corpuz, a Philippine mite newly reported
from Australia; in addition, P. leaki Schicha is newly
reported from New Zealand. In Australia, the
horridus-group contains two oceanic-island species,
P. hawaiiensis Prasad and
P. mayottae Schicha (newly reported), and two complexes
of Australasian endemics. The fotheringhamiae-complex has seven species,
including three new species from tropical rainforests in far north Queensland
– P. paluma,P. camelot and
P. devildevil; in addition,
P. fotheringhamiae is newly reported from New Zealand.
The douglasensis-complex also has seven species,
including six new species from Queensland and the Northern Territory:
P. oreillyi, P. acaciae,
P. brigalow, P. mantoni,
P. darwin and P. litchfieldensis.
All 22 species of Phytoseiusknown from Australia are
keyed and diagnosed, and their distributions are detailed.
Freshwater snails of the genera Fluvidona and Austropyrgus (Gastropoda, Hydrobiidae) from northern New South Wales and southern Queensland, Australia
Authors: Miller A. C. , Ponder W. F. , Clark S. A.
Published: January 2006

The freshwater snail genus Fluvidona (Gastropoda,
Caenogastropoda, Rissooidea, Hydrobiidae) is reapprasied and described using
anatomical, shell, radula and opercular characters. Five species, three of
them new, are described, being differentiated using anatomical, shell and
opercular character states. A sixth species, similar to the
Fluvidona species, is described and is tentatively
assigned to the genus Austropyrgus Cotton. All six
species live in northern New South Wales and southern Queensland and all are
from single localities or very restricted areas. All species live in small
streams, although one was found aestivating in soil in the bed of a small dry
creek. The new species placed in Austropyrgus, from the
Bunya Mountains, Queensland, is widely separated from putative congeners that
are found in southern New South Wales and other parts of south-eastern
Australia.
Cryptic species diversity and character congruence: review of the tribe Anthracini (Diptera : Bombyliidae) in Australia
Authors: Yeates David K. , Lambkin Christine L.
Published: January 2006

The Australian Anthracini are revised. In all, 28 new species are described,
bringing the total fauna to 34 species. The previously described species of
Anthrax Scopoli –
A. maculatus Macquart,
A. incomptus Walker,
A. confluensisRoberts,
A. lepidiotus Roberts and
A. proconcisus Hardy – are diagnosed and the
following eight new species of Anthrax are described:
A. argentia, A. asciculus,
A. clinatus, A. crenatus,
A. dolabratus, A. funestus,
A. opacus and A. torulus. This
taxonomic study reveals a group of at least 20 cryptic species previously
included in collections under the name Anthrax angularis
Thomson. A new genus, Thraxan, is erected to contain
this cryptic group of species and the following 20 new species are described:
T. acutus, T. abditus,
T. caligneus, T. cinctus,
T. cornuatus, T. depressus,
T. echinatus, T. ebenus,
T. emicatus, T. hamulus,
T. luteus, T. misatulus,
T. nodus, T. norrisi,
T. obstipus, T. patielus,
T. planus, T. prolatus,
T. simulatusand T. spiculus. Many
of these cryptic species have been collected sympatrically, hill topping
together in eastern Australia. A key is provided to the species of
Anthrax and Thraxan, genitalia
drawings are presented for most species and distribution maps of all species
are presented. A cladistic analysis of the species of
Anthrax and Thraxan is also
presented. A total of 26 of the species is compared for 125 synapomorphies in
39 adult morphological characters. Three species-groups were found:
Thraxan, and two species-groups within
Anthrax, the A. proconcisus
species-group and the A. maculatusspecies-group.
Previous authors divided Anthrax into species-groups on
the basis of wing patterns, but found that these species-groups were not
confirmed when other characters were taken into consideration. We studied the
congruence of seven different character sets within the clade comprising
Anthrax and Thraxan –
antennae, venation, wing patterns, vestiture, genitalia, male genitalia and
female genitalia – using several incongruence indices. Significance of
incongruence was measured using a randomisation procedure. Results of these
studies indicate that the wing-pattern character set is significantly
incongruent with the other morphological data. These quantitative cladistic
results explain the difficulty previous authors experienced in finding suites
of characters to support species-groups in Anthrax on
the basis of wing patterns. A relationship is found between the level of
incongruence and the distance over which mate-recognition signals operate.
Australian Sympycninae II: Syntormon Loew and Nothorhaphium, gen. nov., with a treatment of the Western Pacific fauna, and notes on the subfamily Rhaphiinae and Dactylonotus Parent (Diptera : Dolichopodidae)
Authors: Bickel Daniel J.
Published: January 2006

The Australian species of two genera, Nothorhaphium,
gen. nov. andSyntormon Loew (Diptera : Dolichopodidae),
are described, illustrated and keyed, and discussed in context of the Western
Pacific fauna. The two genera are phylogenetically close. The Australian
Nothorhaphium comprises four species:
N. aemulans Becker, comb. nov. (=
Xiphandrium pudicum Parent, syn. nov.),
N. nudicorne, sp. nov.,
N. callosum, sp. nov., and
N. curalo, sp. nov. The montane New Guinean
N. oro, sp. nov. is also described, and its close
relationship with the predominantly southern temperate Australian fauna is
discussed, suggesting it was part of a common Australian fauna which became
isolated with the uplift of New Guinea in the mid–late Tertiary. The
Australian Syntormon comprises six species:
S. xiphandroides Parent,
S. flexibile Becker,
S. singularis, sp. nov.,
S. tasmanense, sp. nov.,
S. janelithae, sp. nov., and
S. lucare, sp. nov. As well,
S. aotearoa is described from New Zealand. Genera once
thought to be close to Syntormon are discussed. The
subfamily Rhaphiinae is briefly discussed, noting the problem of subfamily
definition. The New Zealand Syntormon formosus Parent is
placed in new combination [=
Dactylonotus formosus (Parent)] in a genus
previously known only from southern Africa.
Revision of Yelicones (Hymenoptera : Braconidae : Rogadinae) from the Australasian region
Authors: Quicke Donald L. J. , Austin Andrew , Chishti M. Jamil K.
Published: January 2006

The braconid wasp genus Yelicones Cameron from the
Australasian region is revised. Fourteen species are recognised:
Y. paradoxus (Fischer) and
Y. buloloensis, sp. nov. from Papua New Guinea,
Y. fijiensis, sp. nov. from Fiji, and
Y. affinis, sp. nov.,
Y. cardaleae, sp. nov.,
Y. desertus, sp. nov., Y. doyeni,
sp. nov., Y. fittoni, sp. nov.,
Y. luridus Papp , Y. naumanni, sp.
nov., Y. nigridorsum, sp. nov.,
Y. shawi, sp. nov.,
Y. scutellaris, sp. nov., and
Y. vulgaris, sp. nov. from the Australian mainland.
Y. tenuis Papp from Australia is transferred from
Yelicones to Mesocentrus
Szepligéti (comb. nov.). A key to species is presented, and the
relationships of Yelicones within the Rogadinae s.l.,
its biology and distribution are discussed.
Revision of the monogenean family Gotocotylidae (Polyopisthocotylea)
Authors: Hayward Craig J. , Rohde Klaus , Hayward Craig J , Rohde Klaus
Published: January 2006

We revise the diagnosis of the Gotocotylidae Yamaguti, and acceptGotocotyla Ishii and CathucotyleLebedev as valid genera. We synonymise PseudomicrocotyleSandarsand Swakopella Lebedev & Parukhin withGotocotyla. The number of nominal species in the familyis reduced from ten to four, and six new species are described from newmaterial. Members of Gotocoty lahave asymmetrical clampswith a single row of internal ribs, and those ofCathucotyle have more or less symmetrical clamps withtwo rows of ribs. Members of both genera can be distinguished from congenersby the morphology of clamp sclerites and/or spines of the male copulatoryorgan, and the number of vaginae (0–2). The following species arerecognised: Gotocotyla acanthura (Parona & Perugia),G.africanensis, sp. nov.,G.bivaginalis (Ramalingam),G.elegatis (Meserve), G.heapae,sp. nov., G.niphonii, sp. nov.,G.queenslandici, sp. nov.,Cathucotyle cathuaui Lebedev,C.filipinensis, sp. nov.andC.sinensis, sp.nov.Gotocotyla acanthura as recognised here may be aspecies complex, but we could not distinguish the morphologies of individualsfrom different hosts and localities. There is strong evidence that larvae andyoung juveniles of G.acanthura infect intermediate hostsfor short periods (mostly pelagic fishes, belonging to at least eight orders),until eaten by the final host.
Revision of the genus Collettea Lang (Crustacea : Tanaidacea)
Authors: Larsen Kim
Published: January 2006

The genus Collettea Lang, 1973 (previously
Strongylura Sars, 1882) is revised. Two new species,
C. humbolti, sp. nov. from Antarctica and
C. cylindratoides, sp. nov. from the southeast
Australian slope and Antarctica, are described.
C. minima (Hansen, 1913) is redescribed and additions
are included to the description of C. arnaudi (Shiino,
1978). A key to the genus is provided. The systematic position of
Collettea with respect to the subfamilies of
Anarthruridae is discussed.
Revision of the Rugopharynx australis (Moennig, 1926) complex (Nematoda : Strongyloidea) from macropodid marsupials
Authors: Beveridge I. , Chilton N. B.
Published: January 2006

The Rugopharynx australis complex from macropodidmarsupials is revised. The nominal taxon is limited to specimens occurring inthe type host, Macropus rufus, and similar nematodes insympatric host species, M. fuliginosus,M. giganteus, M. robustus andPetrogale xanthopus. A single occurrence is reported inM. dorsalis. The following new species are described:R. macropodis, sp. nov. fromM. fuliginosus and M. giganteus;R. pi, sp. nov. fromM. rufogriseus and M. parryi;R. rho, sp. nov. from M. eugenii,M. fuliginosus, M. irma andPetrogale lateralis;R. longispicularis, sp. nov. fromM. parma; R. mu, sp. nov. fromWallabia bicolor; R. spratti, sp.nov. from M. rufogriseus; R. chi,sp. nov. from Thylogale billardierii;R. tau, sp. nov. from Th. thetisand R. petrogale, sp. nov. fromPetrogale penicillata, P. herbertiand P. inornata.Rugopharynx alpha(Johnston & Mawson,1938) isresurrected for specimens from Petrogale lateralis fromcentral Australia and north western Queensland. Specimens fromPetrogale lateralis pearsoni from South Australia andP. l. lateralis from Western Australia were not assignedto a species. A key to the species of Rugopharynx isprovided.
Revision of the Oriental and Australasian species of Chrysops (Diptera : Tabanidae)
Authors: Burger John F. , Chainey John E.
Published: January 2006

The genus Chrysops from the Australasian and Oriental
regions is revised. Two new species are described:
Chrysops fuscomarginalis, sp. nov. and
C. srilankensis, sp. nov. The status of two species is
revised: C. terminalis, stat. rev. is resurrected from
questionable synonymy with C. dispar, and
C. cinctus, stat rev. is resurrected from synonymy with
C. signifer. Fifteen Chrysops
names are placed in synonymy for the first time or placed as synonyms of
species with which they were not previously associated:
C. atrinus syn. of C. silvifacies,
syn. nov.; C. australis papuensis syn. of
C. australis, syn. nov.;
C. flavocallus syn. of
C. flavescens, syn. nov.; C. impar
syn. of C. translucens, syn. nov.;
C. indianus thailandensis syn. of
C. indianus, syn. nov.;
C. intercalatus syn. of
C. pettigrewi, syn. nov.;
C. paradesignatus syn. of
C. designatus, syn. nov.;
C. philipi syn. of C. alter, syn.
nov.; C. semicirculus syn. of
C. terminalis, syn. nov.;
C. silvifacies yunnanensis syn. of
C. silvifacies, syn. nov.;
C. stekhoveni syn. of
C. fixissimus, syn. nov.;
C. subchusanensis syn. of
C. chusanensis, syn. nov.;
C. unizona syn. of C. fixissimus,
syn. nov.; C. vietnamensis syn. of
C. flaviscutellus, syn. nov.; and
C. zhamensis syn. of
C. pettigrewi, syn. nov. An alphabetical list of
Chrysops names for the Oriental and Australasian regions
is given, as is a key to species and descriptions and notes for all valid
taxa. A brief discussion of the biology and economic importance is provided as
well as a discussion of the distribution patterns of Oriental and Australasian
Tabanidae and the northern and western limits of the Oriental region, based on
distribution of Tabanidae.
Identification of Australian canegrubs (Coleoptera : Scarabaeidae : Melolonthini)
Authors: Miller L. J. , Allsopp P. G.
Published: January 2006

Larvae of Melolonthini are commonly known as
whitegrubs or, in the Australian sugar industry, as canegrubs. In Australia,
there are 119 recognised species of Melolonthini, of which 75 are found in
Queensland. Of the 75 species, this study examines 19 species that are
recognised sugarcane pests. These belong to the genera
Antitrogus Burmeister, Dermolepida
Arrow, Lepidiota Kirby and Rhopaea
Erichson. Descriptions of adults and larvae of the 19 species are provided in
this paper, as well as species identification keys for both adults and larvae
and a key to the tribes, as a premise for introducing more effective
management strategies. Identification of canegrubs is pertinent because the
various species have different ecologies, behaviours and insecticide
susceptibilities, and their control requires different methods and rates of
application of insecticides. We have separated larvae of the species on the
basis of their raster pattern, locality and, where necessary, head width.
Larvae of some species are difficult to identify and we suggest use of
molecular tools for their identification.
A revision of the Mascarene weevil genus Syzygops Schonherr (Coleoptera : Curculionidae : Entiminae)
Authors: Williams J. R.
Published: January 2006

The Mascarene genus
Syzygops Schönherr (Curculionidae : Entiminae) is
revised and a key to the species is provided. Of the 17 species, seven are
described as new: S. insignis, sp. nov.,
S. similis, sp. nov., S. petilus,
sp. nov., S. globosus, sp. nov. and
S. robustus, sp. nov. from Mauritius, and
S. acuminatus, sp. nov. and
S. ornatus, sp. nov. from Réunion. Four species
previously described, S. prasinus
Guérin-Méneville,S. cinereus
Guérin-Méneville, S. fuscipes
Guérin-Méneville and S. hystrix
Rosenschoeld, are considered to be species inquirendae.
S. antelmei Hustache is synonymized
withS. desjardinsiiGuérin-Méneville
andS. laterivirens Fairmaire with
S. cyclops Schönherr. Lectotypes are designated for
S. alluaudi Hustache, S. vinsoni
Hustache, S. laterivirens Fairmaire,
S. coquerelii Fairmaire,
S. tuberculatus Guérin-Méneville,
S. obscurus Hustache and
S. aureoviridis Hustache. Eleven of the 17 species
considered valid are endemic to Mauritius and six to Réunion. Several
of the species display extreme sexual dimorphism. The adults of all species
are believed to occur exclusively on ferns. The immature stages are unknown.
Salticidae (Arachnida : Araneae) of the Oriental, Australian and Pacific regions, XIII: the genus Sandalodes Keyserling
Authors: Zabka Marek
Published: January 2006

The genus Sandalodes Keyserling, 1883 is revised to
include four species from Australia and Papua New Guinea:
S. bipenicillatus (Keyserling),
S. joannae, sp. nov., S. scopifer
(Karsch) and S. superbus (Karsch).
Sandalodes albobarbatus (Keyserling) is synonymised with
S. scopifer (Karsch).
Alcmena superba Karsch, 1878 is included in
Sandalodes. The Australian species,
S. albovittatus (Keyserling, 1883) and
S. calvus Simon, 1902, together with all of the
non-Australian species hitherto listed in Sandalodes,
are excluded. These species were misplaced in
Sandalodes. The genus Karschiolina
Brignoli, 1985 is synonymised with Sandalodes. Remarks
on relationships, biology and distribution of Sandalodes
are given.
The Australian Ommatidae (Coleoptera:Archostemata): new species, larva and discussion of relationships
Authors: F.Lawrence John
Published: January 2006

The Australian Ommatidae (Coleoptera:Archostemata) are reviewed and
Omma rutherfordi, sp. nov., is described from the South
Australian mallee and Stirling Range of Western Australia. A putative
Omma larvais also described from Western Australia and
compared with other larvae representing the suborder Archostemata. Comments
are made on the larvae of Archostemata, constitution of the suborder, and
relationships and ranking of family groups.
The systematics, biogeography and conservation status of species in the freshwater crayfish genus Engaewa Riek (Decapoda : Parastacidae) from south-western Australia
Authors: Horwitz Pierre , Adams Mark
Published: January 2006

This paper presents a review of the systematics of freshwater crayfish species
in the genus Engaewa Riek, endemic to south-western
Australia. Allozyme electrophoresis of six allopatric populations of
Engaewa and several outgroup taxa at 17 loci was
initially used to identify four distinct genetic groups within the genus.
Morphological characters were then used to establish within and between
species boundaries more precisely. Five species were recognised, comprising
the existing species E. subcoerulea Riek,
E. reducta Riek, and E. similis
Riek, plus two new species, E. pseudoreducta, sp. nov.
and E. walpolea, sp. nov. The genus is endemic to
south-western Australia where distributions of species conform to those
expected for slowly dispersing, inland aquatic organisms wedded to year-round
cool and wet conditions. The range of the genus occurs within the Warren
Bioregion of Australia. The species occupy well-defined and largely
non-overlapping geographical ranges. Within the bioregion, apparent incipient
speciation exists in the Cape Naturaliste–Cape Leeuwin subregion,
confirming a pattern observed for other aquatic organisms. Morphological and
electrophoretic evidence suggests that species in the genus are more closely
related to each other than they are to other species of extant freshwater
crayfish, suggesting that they represent a monophyletic group. Nevertheless,
the morphological variation displayed by Engaewa clearly
falls within that found for the genus Engaeus Erichson
from south-eastern Australia, indicating that a broad-scale generic revision
for the entire group would be appropriate. The narrow geographical ranges of
E. walpolea, sp. nov.,
E. pseudoreducta, sp. nov. and
E. reducta, coupled with known threats to populations,
warrant concern for these species from a conservation viewpoint. precisely.
Introduction
Authors: Nielsen Ebbe , Oberprieler Rolf
Published: January 2006

In this brief review we outline the contribution of Dr J. F. Lawrence to a
major long-term field experiment in the southeast forests of NSW that examines
the effect of habitat fragmentation on beetles. Dr J. F. Lawrence identified
and curated the beetle fauna, which proved to be a significant and long-term
commitment. The beetle data set has since provided great insight to the
complex effects of habitat fragmentation. In addition, the size and quality of
the data set mean that, on an international level, it is a major inventory of
beetle diversity in a temperate Eucalyptus forest, in
its own right. Here we outline Dr J. F. Lawrence’s contribution and
summarise the main features of the beetle data set and our findings about the
impacts of fragmentation on the beetle fauna.
Erratum to: Two novel chromosomal loci influence cultivar-specific nodulation failure in the interaction between strain ANU794 and subterranean clover cv. Woogenellup
Authors: Roddam Louise F. , Lewis-Henderson Wendy R. , Djordjevic Michael A.
Published: January 2006

The nodulation failure resulting from the interaction between
Rhizobium leguminosarum biovar
trifolii strain ANU794 and the
Trifolium subterraneum cv. Woogenellup was examined by
transposon mutagenesis to resolve whether multiple determinants were involved
in cultivar-specificity. Three new transposon-induced mutants of ANU794 (W72,
W78 and W710) with significantly enhanced nodulation ability on cv.
Woogenellup were identified. The W72 and W78 mutations are
chromosomally-located, whereas the W710 mutation isplasmid-located. The
ethylene synthesis inhibitor, aminoethoxyvinylglycine, fails to enhance the
nodulation ability of ANU794, ANU7943 (csn1::Tn5) and
W78 on cv. Woogenellup, but enhances the nodulation ability of W72,W710 and
ANU7941 (nodM::Tn5). DNA sequencing of the W78 locus
reveals strong homology to an unknown Mycobacterium open
reading frame, and to several bacterial non-haem chloroperoxidases. The
previously identified csn1 locus showed homology to the
50S ribosomal protein, L9, with the Tn5 insertion being located in the
5′-untranslated region. The results suggest that cultivar-specificity is
mediated by at least two independent mechanisms or determinants, and not by a
simple gene-for-gene interaction. The role of ethylene in cultivar specificity
is discussed. Cultivar-specific interactions may prove useful in identifying
pathways involved in efficient nodule formation and plant-microbe
interactions.
A mathematical model for quinone-herbicide competition in the reaction centres of Rhodobacter sphaeroides
Authors: Halmschlager Andrea , Tandori Júlia , Trotta Massimo , Rinyu László , Pfeiffer Ilona , Nagy László
Published: January 2006

A quantitative model describing the amplitude of semiquinone absorption in
photosynthetic reaction centres after successive flashes in the presence of
increasing inhibitor concentration is presented. By using relatively simple
algebra, the semiquinone signals can be calculated and fitted to the
oscillation pattern by optimizing only two parameters; the electron and
quinone equilibrium constants, Ke
and Kq, respectively. In this work
we expand our earlier model [Tandori et al. (1991)
Photosynthetica 25, 159–166] by introducing
the inhibitor equilibrium constant,
Ki, describing the best fit of the
model to the measured oscillation pattern. We found that there are
characteristic parameters of the measured and normalized signal, and of those
calculated from the mathematical model, which fit well with competitive
Michaelis-Menten kinetics.
Limitations to leaf photosynthesis in field-grown grapevine under drought — metabolic and modelling approaches
Authors: Maroco João P. , Rodrigues M. Lucília , Lopes Carlos , Chaves M. Manuela
Published: January 2006

The effects of a slowly-imposed drought stress on gas-exchange, chlorophyll
a fluorescence, biochemical and physiological parameters
of Vitis vinifera L. leaves (cv. Aragonez, syn.
Tempranillo) growing in a commercial vineyard (South Portugal) were evaluated.
Relative to well-watered plants (predawn water potential,
ΨPD = –0.13 ± 0.01 MPa),
drought-stressed plants (ΨPD = –0.97
± 0.01 MPa) had lower photosynthetic rates (ca
70%), stomatal conductance, and PSII activity (associated with a higher
reduction of the quinone A pool and lower efficiency of PSII open centres).
Stomatal limitation to photosynthesis was increased in drought-stressed plants
relative to well-watered plants by ca 44%.
Modelled responses of net photosynthesis to internal CO2
indicated that drought-stressed plants had significant reductions in maximum
Rubisco carboxylation activity (ca 32%),
ribulose-1,5-bisphosphate regeneration (ca 27%),
and triose phosphate (triose-P) utilization rates (ca
37%) relative to well-watered plants. There was good agreement between
the effects of drought on modelled biochemical parameters, and
in vitro activities of key enzymes of carbon metabolism,
namely Rubisco, glyceraldehyde-3-phosphate dehydrogenase, ribulose-5-phosphate
kinase and fructose-1,6-bisphosphate phosphatase. Quantum yields measured
under both ambient (35 Pa) and saturating CO2 (100 Pa)
for drought-stressed plants were decreased relative to well-watered plants, as
well as maximum photosynthetic rates measured at light and
CO2 saturating conditions (three times ambient
CO2 levels). Although stomatal closure was a strong
limitation to CO2 assimilation under drought, comparable
reductions in electron transport, CO2 carboxylation, and
utilization of triose-P capacities were also adaptations of the photosynthetic
machinery to dehydration that slowly developed under field conditions. Results
presented in this study confirm that modelling photosynthetic responses based
on gas-exchange data can be successfully used to predict metabolic limitations
to photosynthesis.
An increase in water deficit has no impact on the photosynthetic capacity of field-grown Mediterranean plants
Authors: Nogués Salvador , Alegre Leonor
Published: January 2006

In the Mediterranean, annual mean precipitation has continuously decreased
over the last three years (by ca 36% in Barcelona), and the decrease
has been dramatic during the summer (by ca 78 and
64% during July and August, respectively). The impact of increased
drought on the photosynthetic capacity of Mediterranean vegetation is
currently unknown. In this study, two native Mediterranean plants
[rosemary (Rosmarinus officinalis L.) and lavender
(Lavandula stoechas L.)] were grown outdoors and
subjected to two water regimes (50 mm month–1
during the summer, or no supplementary water at all). Rosemary and lavender
plants watered with 50 mm month–1 during the
summer had higher relative leaf water content and water potential than
non-watered plants. Changes in water status were accompanied by large
decreases in parameters of gas exchange [i.e. the light-saturated rate of
CO2 assimilation, the maximum velocity of
ribulose-1,5-bisphosphate (RuBP) carboxylation by Rubisco and the capacity for
RuBP] and of modulated chlorophyll fluorescence (i.e. the relative
quantum efficiency of PSII photochemistry and the efficiency of energy capture
by open PSII reaction centres) during the summer, but no differences were
found in any photosynthetic parameters for leaves subjected to the two water
regimes. The drought-induced decreases in the relative quantum efficiency of
PSII photochemistry in rosemary and lavender plants were attributable to
‘downregulation’ of electron transport. Photodamage to PSII in the
field appeared to be a later effect of drought in these plants.
Photorespiration was not a major mechanism protecting the photosynthetic
apparatus of these plants from photodamage in the field. After the autumn
rainfall, photosynthetic capacity fully recovered. We conclude that rosemary
and lavender are well adapted to drought, and that an increase in water
deficit is unlikely to have a significant impact on the photosynthetic
capacity of leaves.
The metabolic basis for 2,4-D resistance in two variant cell lines of carrot
Authors: Ceccarelli Nello , Mondin Alessandra , Lorenzi Roberto , Picciarelli Piero , Schiavo Fiorella Lo
Published: January 2006

In the present work, the characterization of two variant cell lines of carrot
capable of growing in high (92 μmol L–1)
concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) is reported. Both
these cell lines (4w77 and 4w13) show a significantly lower uptake of 2,4-D
with respect to wild-type (wt) cells. In contrast to wt cells, influx of IAA
is not reduced by the addition of 100 μM 2,4-D and the presence of this
compound appears to stimulate IAA uptake. When grown in the presence of high
concentrations of 2,4-D, both 4w77 and 4w13 cells show behavioural
differences: instead of lowering the endogenous level of free IAA, the two
resistant lines react to the high exogenous concentrations of auxin by raising
the level of the free hormone. In 4w77 cells, this is accomplished by
reduction of auxin released in the external medium or converted to
amide-linked conjugates. In 4w13 cells, the final level of endogenous IAA is
an equilibrium between increased synthesis of IAA and a massive release into
the medium of the ester- and free-forms of IAA. Both cell lines show
disturbances in embryogenesis: line 4w77 forms globular embryos that only
mature into aberrant forms having multiple axes, whereas line 4w13 has
completely lost its morphogenic capacity.
Laser-induced Chlorophyll Fluorescence Ratio in Certain Plants Exhibiting Leaf Heliotropism
Authors: Sailaja M. V. , Chandrasekhar Y. , Rao D. Narayana , Das V. S. Rama
Published: January 2006

Laser-induced
F685/F720
chlorophyll fluorescence of intact leaves in solar tracking plants from
Euphorbiaceae (Ricinus communis L.), Amaranthaceae
(Amaranthus gangeticus L.,
Amaranthus viridis L.), Malvaceae
(Hibiscus cannabinus L.,
Althaea rosea L.), Fabaceae
(Dolichos lablab L.) Capparadaceae
(Cleome gynandra L.) exhibited remarkable diurnal
constancy in contrast to those of compass plants from Poaceae
(Oryza sativa L.) and Amaranthaceae
(Telanthera ficoides Moq.) with fixed leaf orientation.
The
F685/F720
ratio remained constant in both the diaheliotropic and paraheliotropic plants,
but it decreased during midday in compass plants. The acquired spectra were
analysed in terms of Gaussian parameters to determine the relative intensity
of contribution of various bands; the data suggested a decrease in both the
F685 and the
F720 bands at 1230 h in compass
plants while they remained unaltered in reorienting leaves. The typical midday
depression in
F685/F720
ratio observed in compass plants may be due to down-regulation of both
photosystems, I and II. This unique behaviour of diurnal constancy in
laser-induced
F685/F720
suggests that the leaves of diaheliotropic plants maximise light-use
efficiency throughout the day and avoid the hazard of midday depression of
photosynthesis.
Regulation in Lolium temulentum of the Metabolism of Gibberellin A20 and Gibberellin A1 by 16,17-Dihydro GA5 and by the Growth Retardant, LAB 198 999
Authors: Junttila O. , King R.W. , Poole A. , Kretschmer G. , Pharis R.P. , Evans L.T.
Published: January 2006

The ring D-modified gibberellin [GA], 16,17-dihydro
GA5, can retard stem growth in
Lolium temulentum L. while promoting flowering (Evans
et al., 1994,
Planta193, 107–114). Using
[1,2,3-3 H]GA20 to study
the final biosynthetic step to GA1 (a known effector of
shoot elongation in higher plants), it was shown that C-3b-hydroxylation of
GA20 to GA1 is blocked by
16,17-dihydro GA5 but is little affected by
GA5. Another late-stage biosynthetic inhibitor, the
acylcyclohexanedione, LAB 198 999, also blocked GA1
formation. Furthermore, endogenous levels of GA20 built
up after application of 16,17-dihydro GA5. Consequently,
growth retardation by 16,17-dihydro GA5 and LAB 198 999
is likely to be the result of their inhibition of GA20
3b-hydroxylation to GA1. Another fate for
GA20 in Lolium is its
C-2b-hydroxylation to growth-inactive GA29. This
conversion was also inhibited by 16,17-dihydro GA5 but
less so by LAB 198 999. The analogous step involving 2b-hydroxylation of
GA1 to GA8 appeared to be
insensitive to either growth retardant.
When [3H]GA20 was
injected into the cavity within the young intact sheathing leaves, there was
an appreciable metabolism of this GA20 to
GA1 and thence to GA8
(ca 10% and 30% respectively within 5 h).
For excised shoot tips, however, [3H]GA20 was
converted rapidly and virtually completely to GA29 in
3–5 h. Interestingly, with these excised shoot tips,
GA3 and GA5 as well as
16,17-dihydro GA5 when applied via the agar strongly
inhibited 2b-hydroxylation of GA20 to
GA29. In contrast, while 16,17-dihydro
GA5 blocked GA20 metabolism to
GA29 in intact sheath/stem tissue, this conversion
was not inhibited by GA5. These differences in
structural specificity for GAs which inhibit 2b-hydroxylation as opposed to
3b-hydroxylation are in accordance with these two Ring-A hydroxylation steps
being catalysed by different enzymes. Finally, the differences in
GA20 metabolism between intact versus excised tissue
raise the possibility that tissue wounding with excision enhanced the activity
of the GA20 2b-hydroxylase(s).
A direct method for estimating the average sap flux density using a modified Granier measuring system.
Authors: Lu Ping
Published: January 2006

The Granier sap flow measuring system that normally uses one analogue input
channel of a datalogger for each sensor was modified to enable one channel to
measure the average value of signals from two or more sensors. The sap flux
density calculated from this average value of signals was very close
(difference < 6.0%) to the arithmetic mean of the sap flux densities
measured separately by means of individual sensors (using two or more input
channels). The dynamics of the sap flux density measured by the modified
method were similar to those measured by the original method. On a per-channel
basis, the modified method reduced the ‘estimation error’ of sap
flux density by 4–14-fold compared to the original method. By using the
modified Granier system, the error in sap flow measurement that is usually
associated with limited sampling can be substantially reduced without the need
for extra dataloggers, the greatest item of expense.
Clotrimazole, a Model Compound for the Host Release Factor of the Coral Plesiastrea versipora
Authors: Ritchie Raymond J. , Grant Adrienne J. , Eltringham Kylie , Hinde Rosalind
Published: January 2006

Crude homogenates of animal host tissues stimulate the release of
photosynthetic products from symbiotic dinoflagellates isolated from corals
and several other invertebrates. It is believed that specific ‘host
release factors’ stimulate the symbiotic algae to release water-soluble
compounds, chiefly glycerol and amino acids, to the host. Crude host
homogenates also contain compounds which sometimes inhibit photosynthesis in
isolated algal cells, although this inhibition is not apparent in the intact
association. Therefore, use of crude homogenates in translocation experiments
may sometimes lead to inconsistent results. We have found that the
commercially available synthetic fungicide, clotrimazole (mycosporin), a
chemical analogue of naturally occurring mycosporine-like amino acids, can be
used as a model for the host release factor of the coral
Plesiastrea versipora(Lamarck). Clotrimazole stimulated
isolated algal cells from P. versipora to release carbon
fixation products to the external medium. Chromatography experiments showed
that the released compounds were similar to those found when algae were
incubated with crude homogenates of P. versipora. We
propose that, in Plesiastrea versipora, clotrimazole may
be used as an internal control in experiments using crude host homogenate and
in screening partially purified fractions for ‘host factor’
activity. Clotrimazole is the first commercially available compound found to
have effects similar to the ‘host factor’ of a coral.
Growth and Root NO3- and PO43- Uptake Capacity of Three Desert Species in Response to Atmospheric CO2 Enrichment
Authors: BassiriRad H. , Reynolds J. F. , Virginia R. A. , Brunelle M. H.
Published: January 2006

In a phytotron experiment, we examined growth and rates of
NO-3 and
PO3-4 uptake in seedlings of two
desert C3 shrubs
(Larrea tridentata and
Prosopis glandulosa) and a desert
C4 perennial grass
(Bouteloua eriopoda) grown under
CO2 partial pressures of 35 or 70 Pa. Plants were grown
in soil but uptake studies were conducted on roots of intact seedlings placed
in nutrient solutions containing both
NO-3 and
PO3-4. Elevated
CO2 increased total biomass by 69 and 55% in
Larrea and Prosopis seedlings and
by 25% in Bouteloua.
NO-3 and
PO3-4 uptake rates were more than
doubled in Bouteloua at high compared to ambient
CO2. In contrast, CO2 enrichment
inhibited root NO-3 uptake
capacity in Larrea by about 55% without a
significant effect on PO3-4
absorption rate; rates of NO-3 and
PO3-4 and uptake in
Prosopis were insensitive to CO2
treatment. Elevated CO2 enhanced the proportion of
biomass allocated to the fine roots in Bouteloua but
markedly reduced this fraction in Larrea and
Prosopis. Foliar N concentration of both shrubs
decreased in response to elevated CO2, but was
unaffected in Bouteloua. We suggest that compensatory
changes in root size and activity are critical in determining interspecies
variation in plant nutrient relations under high CO2.
Effects of Exogenous Sucrose Feeding on Photosynthesis in the C3 Plant Tobacco and the C4 Plant Flaveria bidentis
Authors: Furbank Robert T. , Pritchard Jeni , Jenkins Colin L.D.
Published: January 2006

Seeds of the C4 dicot
Flaveria bidentis and the C3 dicot
Nicotiana tabacum were germinated on expanded cotton
plugs and grown for 28–35 days in a sterile culture system with liquid
nutrients supplied to the roots in the presence or absence of 5%
(w/v) sucrose. Despite previous reports that supplying sucrose exogenously
to plants inhibits expression of photosynthetic genes, sucrose application in
this system stimulated maximum photosynthetic rates and these were comparable
to those measured in glasshouse-grown material. The activities of many
photosynthetic enzymes in the youngest fully expanded leaves of both
Flaveria and tobacco plants were increased by sucrose
feeding. Sucrose levels were increased more than 2-fold in tobacco and 3-fold
in Flaveria leaves (on a leaf area basis) by sucrose
application, and both hexose and starch levels also increased. Chlorophyll per
unit leaf area in sucrose-fed plants increased by approximately 20% in
tobacco and 2-fold in Flaveria. There was no evidence of
sucrose repression of photosynthetic competence in this experimental system.
We propose that, over the concentration range present in the leaves in these
experiments, sucrose acts as a positive signal for photosynthetic gene
expression but that, above a threshold level, inhibition of gene expression
seen in other studies could still occur.
Sensitivity of root and leaf water status in maize (Zea mays) subjected to mild soil dryness
Authors: Schmidhalter U. , Burucs Z. , Camp K.H.
Published: January 2006

The aim of this work was to test the sensitivity of the water potential
(Ψw), osmotic potential
(Ψs) and turgor (Ψp) of
roots and leaves of maize seedlings (Zea mays L. cv.
Carla) subjected to a mild stress in drying soil in a growth chamber. To the
best of our knowledge there are no experimental data which describes diurnal
courses of Ψw in soil, roots, and leaves and the
parallel changes in the osmotic potential (Ψs) and
turgor (Ψp) of roots and leaves from plants grown in
moist and drying soil. Root and leaf Ψw varied
diurnally, the amplitude being much more marked in leaves than in roots. Root
and leaf Ψw did not achieve equilibrium at predawn
with the bulk soil matric potential (Ψm) but became
higher. Our results are at variance with data indicating root
Ψw is a sensitive indicator of soil dryness. Root
Ψw in the well-watered and drought-stressed
treatments did not differ, whereas daytime leaf Ψw
in the droughted treatment was lower 6 days after water was withheld. Diurnal
changes in Ψs and Ψp were
more marked in leaves than in roots. Withholding water lowered leaf
Yp, whereas root Ψp
substantially increased after only 3 days of withholding water. Early mild
stress can be more easily and more quickly identified by changes in root
Ψs, increases in root Ψp,
or the divergence in root and leaf Ψp than by a
lower Ψw of root or leaf. Relative water contents of
roots and leaves measured in the light period indicated also sensitively
falling Ψm.
Differential effects of enhanced UV-B radiation on reproductive effort in two chemotypes of Mentha spicata under field conditions
Authors: Grammatikopoulos G. , Karousou R. , Kokkini S. , Manetas Y.
Published: January 2006

Seedlings of two chemotypes of mint (Mentha spicata L.),
i.e. the piperitone and piperitenone oxide rich wild mint (chemotype I) and
the carvone and dihydrocarvone rich spearmint (chemotype II), were grown to
maturity in the field under ambient or ambient plus supplemental UV-B
radiation, simulating a 15% ozone depletion over Patras (38.3°N,
29.1°E). Enhanced UV-B radiation had no effect on total stem length,
photochemical efficiency of PS II, chlorophyll content, UV-B absorbing
capacity of epicuticular and internal compounds, photosynthetic capacity at
5% CO2 and relative water content of both
chemotypes. However, specific leaf mass in chemotype II, and leaf number in
chemotype I were significantly increased under UV-B supplementation, while
total leaf area remained unaffected. Dry mass accumulation measured at plant
harvest showed a slight, non-significant trend for increased above- and
below-ground biomass in both chemotypes, but a particularly significant
increase in the biomass allocated to inflorescences in chemotype II was found.
Seed yield was significantly improved by supplemental UV-B radiation in both
chemotypes, but, again, chemotype II was particularly responsive, increasing
the number of seeds by 100%. We conclude that the aromatic species
M. spicata is not only resistant to enhanced UV-B
radiation, but some chemotypes may be selectively benefited through increased
reproductive effort.
Responses of the apple plant to CO2 enrichment: changes in photosynthesis, sorbitol, other soluble sugars, and starch
Authors: Pan Q. , Wang Z. , Quebedeaux B.
Published: January 2006

There is no information on the effects of elevated
[CO2] on whole-plant photosynthesis and
carbohydrate metabolism in apple (Malus domestica
Borkh.) and other sorbitol-translocating plants. Experiments were conducted in
controlled growth chambers to evaluate how increases in
[CO2] affect plant photosynthesis and carbon
partitioning into soluble sugars and starch in apple leaves. Apple plants (cv.
Gala), 1-year-old, were exposed to [CO2] of
200, 360, 700, 1000, and 1600 µL
L-1 up to 8 d. Whole-plant net photosynthetic rates were
analysed daily after [CO2] treatments. Newly
expanded mature leaves were sampled at 1, 2, 4, and 8 d after
[CO2] treatments for sorbitol, sucrose,
glucose, fructose, and starch analysis. Midday whole-plant net photosynthetic
rates increased linearly with increasing
[CO2], but the differences in whole-plant
photosynthesis between CO2-enrichment and ambient
[CO2] treatments were less significant as
apple plants acclimated to high atmospheric
[CO2] for 8 d. Increases in
[CO2] significantly increased sorbitol and
starch, but did not affect sucrose concentrations. As a result, the ratios of
starch to sorbitol and starch to sucrose at 8 d after
[CO2] treatments were increased from 0.05 and
0.06 to 0.8 and 1.6 as [CO2] increased from
ambient [CO2] (360
µL L-1) to 1000
µL L-1
[CO2], respectively. The sorbitol to sucrose
ratio also increased from 1.3 to 2.2 as [CO2]
increased from 360 to 1000 µL
L-1. Elevated [CO2]
enhanced the photosynthesis of apple plants and altered carbohydrate
accumulation in mature leaves in favour of starch and sorbitol over sucrose.
Degradation of glutamine synthetase in intact chloroplasts isolated from pea (Pisum sativum) leaves
Authors: Thoenen Melanie , Feller Urs
Published: January 2006

Chloroplast proteins can be degraded in the intact organelle, but the relative
rates of degradation vary considerably. To investigate regulatory aspects of
glutamine synthetase (GS) degradation, isolated pea
(Pisum sativum L.) chloroplasts were used as a suitable
system. Since chloroplasts were re-isolated after incubation, only
chloroplasts remaining intact throughout the incubation and processes
occurring therein were analysed. Net changes of nuclear-encoded proteins
indicate degradation because protein synthesis is no longer possible under
these conditions. Incubation of intact chloroplasts in a medium which promotes
CO2 -assimilation led to the stabilisation of GS and
several other chloroplast proteins. This general effect suggests that
photosynthetic metabolism is relevant for the stability of stromal proteins.
In addition, GS was specifically stabilised by methionine sulfoximine (MSO), a
potent inhibitor of GS. However, other enzymes tested were not affected by
MSO. When chloroplasts were incubated with methyl viologen, the degradation of
several stromal enzymes including GS was accelerated, most likely by active
oxygen species. Again, MSO specifically delayed the degradation of GS. As MSO
is a substrate analogue, it appears likely that substrates or other ligands
influence the susceptibility of enzymes against degradation systems present in
the same compartment.
Leaf age effects on photosynthetic activity and sugar accumulation in droughted and rewatered Lupinus albus plants
Authors: David M. Manuela , Coelho Dulce , Barrote Isabel , Correia Maria João
Published: January 2006

Changes in the photosynthetic rate (A), stomatal
conductance (g), water relations, photosynthetic
pigments, Rubisco and soluble sugars accumulation were studied in different
aged leaves of white lupin during soil drying and following rehydration. In
water-stressed plants, A and g
sharply declined and recovered only partially after rewatering. The way
Ci and A/gchanged with drought was
strongly dependent on leaf age; only in the young leaves did
A/g increase and Ci decrease.
Drought induced accumulation of soluble sugars was also age dependent,
decreasing as leaves aged. In response to soil drying, the contents of
photosynthetic pigments, total soluble protein and Rubisco protein increased
in the young leaves and were either not affected or slightly decreased in the
older ones. Rehydration accentuated the losses in pigments and Rubisco in the
old leaves of water-stressed plants. These results suggest that the
contribution of mesophyll limitations to explain drought inhibition of
photosynthesis increases with leaf age, decreasing the ability to recover
after rewatering. In young leaves the tolerance of the photosynthetic
apparatus to dehydration and rehydration episodes is high and it is associated
with high contents of Rubisco and in soluble sugars, particularly hexoses.
CO2 refixation characteristics of developing canola seeds and silique wall
Authors: King Steven P. , Badger Murray R. , Furbank Robert T.
Published: January 2006

The potential for developing canola (Brassica napus L.)
seeds and the interior silique (pod) wall to refix respired
CO2 has been investigated. From
ribulose-1,5-bisphosphate carboxylase–oxygenase (Rubisco) and
phosphoenolpyruvate carboxylase (PEPC) activities, seeds
were estimated to have a greater CO2 fixation capacity
than silique wall endocarp during oil filling. The major component of seed
fixation capacity was embryo Rubisco, which had a total activity of 6.3 nmol
min-1 embryo-1 (3.7
µmol min-1 mg
chlorophyll-1) at 28 days after anthesis (DAA) with
smaller contributions from seed coat and embryo PEPC. Rubisco activities were
probably maximal in vivo because of high silique cavity
CO2 concentrations (0.8 to 2.5%). Seed
chlorophyll content rapidly increased over 10-fold from 20 to 30 DAA and, with
20% of incident light transmitted through the silique wall, embryos
demonstrated appreciable photosynthetic electron transport rates and most
energy produced appeared to be used for Rubisco-catalysed
CO2 fixation. Endocarp refixation capacity was less than
seeds because chlorophyll content was not enriched and PEPC activities were
relatively small. These data indicate that developing seeds and also endocarp
refix respired CO2 and that embryo chlorophyll plays a
critical role in this refixation.