bluuebunny/crossref_metadata_2025 huggingface dataset:
X-Ray, Quantum Mechanics and Density Functional Methods in the Examination of Structure and Tautomerism of N-Methyl-Substituted Acridin-9-amine Derivatives
Authors: Rak Janusz , Krzyminski Karol , Skurski Piotr , Jozwiak Ludwika , Konitz Antoni , Dokurno Pawel , Blazejowski Jerzy
Published: August 2004

X-Ray diffraction has shown that
N,N-dimethylacridin-9-amine (4)
and N ,10-dimethylacridin-9-imine (5) both crystallize
in the monoclinic space group
P21/c
(No. 14) with four molecules in the unit cell. The dimethylamino group in (4)
is twisted through an angle of 58·6° relative to a nearly planar
acridine moiety. On the other hand, the central ring in (5) is folded along
the C(9) · · · N(10) axis through an angle of
26·3° and the exocyclic nitrogen atom with the methyl group
attached to it is directed away from the concave side of the acridine nucleus.
Theoretical ab initio Hartree–Fock (HF) and
semiempirical (MNDO, AM1, PM3) quantum mechanics, as well as density
functional (DFT) methods predicted that the
N,N-dimethylacridin-9-amine
molecule is planar within the acridine moiety and exhibits
Cs symmetry, while the other four
derivatives originating from the amino or imino tautomeric forms of
acridin-9-amine do not have any symmetry elements. Molecules retaining the
amino constitution are thermodynamically somewhat more stable than those
arising from the imino form. The negative LUMO and HOMO energies, both
predicted at the semiempirical level of theory and at the
HF level in the latter case, imply that the relevant
states are electronically stable. The comparable thermodynamic stabilities of
both types of derivatives, as well as the fact that they can be synthesized,
undoubtedly speak in favour of the existence of tautomeric phenomena in
acridin-9-amine
Linear Metal(II)-4,4′-Bipyridine (4,4′-bpy) Chains Organized into Two-Dimensional Rhombic Networks by Hydrogen Bonding. Crystal Structures of [Co(4,4′-bpy)(H2O)4] (ClO4)2.(4,4′-bpy)2.2H2O and [Zn(4,4′-bpy)(H2O)3(ClO4)] (ClO4).(4,4′-bpy)1·5.H20
Authors: Tong Ming-Liang , Cai Ji-Wen , Yu Xiao-Lan , Chen Xiao-Ming , Ng Seik Weng , Mak Thomas C. W.
Published: August 2004

Two substances with extended two-dimensional networks through hydrogen-bond
cross linkages, namely,
[Co(4,4′-bpy)(H2O4]
(ClO4)2.(4,4′-bpy)2.2H2O
and
[Zn(4,4′-bpy)(H2O)3(ClO4)]
(ClO4).(4,4′-
bpy)1·5.H2O, were
synthesized, in EtOH/H2O solution. The cobalt
complex crystallizes in the triclinic space group
P-1 with a
9·113(2), b 11· 093(2),
c 11·394(2) Å, α 64·04(3),
β 70·18(3), γ 66·91(3)°, V
932·9(3) Å3. The crystal structure contains
4,4′-bpy-bridged linear polymeric
[Co(4,4′-bpy)(H2O)4]n
chains, where the cobalt(II) is coordinated in a slightly distorted octahedral
environment by four water molecules (Co-O 2·088(2)-2·101(2)
Å) at the equatorial positions and two nitrogen atoms of the bridging
4,4′-bpy ligands (Co–N 2·149(2) Å) at the axial
positions. The chains are interconnected into a two-dimensional rhombic
network by double hydrogen-bond bridges of the type
Co–H2O · · · bpy ·
· · H2O–Co. The zinc complex also
crystallizes in the triclinic space group
P-1 with a
9·0230(11), b 11·299(2),
c 16·397(2) Å, α 74·429(11),
β 83·132(9), γ 70·654(12)°, V
1518·5(3) Å3. The crystal structure
contains 4,4′-bpy-bridged linear polymeric
[Zn(4,4′-bpy)(H2O)3(ClO4)]n
chains, where the zinc atom is coordinated in a distorted octahedral
environment by two nitrogen atoms of the bridging 4,4′-bpy ligands
(Z–N 2·104(2)–2·117(2) Å), three water
molecules (Zn–O 2·068(2)–2·091(2) Å) and one
monodentate ClO4- anion (Zn–O 2·320(2)
Å). The chains are interconnected into a rhombic network alternately by
single or double hydrogen-bond bridges of the type
Zn–H2O · · · 4,4′-bpy
· · · H2O–Zn.
Synthesis of Nanotubule-Forming Cyclic Octapeptides via an Fmoc Strategy
Authors: Polaskova Martina E. , Lambert John N. , Ede Nicholas J.
Published: August 2004

New syndiotactic cyclic octapeptides, namely
cyclo(–D-Phe-L-Asp–D-Phe–L-Asn–D-Phe–L-Asp–D-Phe–L-Asn–)
(1) and
cyclo(–D-N-MeAla–L-Asp–D-N-MeAla–L-Asn–D-N-MeAla–L-Asp–D-N-MeAla–L-Asn–)
(2), have been prepared, and preliminary structural studies have been
conducted. The synthesis of the linear peptides was performed by using Fmoc
chemistry, and head-to-tail cyclization was accomplished by using an
orthogonal protection strategy and a support-bound cyclization step.
Acidification of aqueous solutions of cyclic octapeptide (1) initiated
formation of needlelike crystals whose morphology and infrared absorption
behaviour suggested that they were hydrogen-bonded nanotubular aggregates of
(1).
Trunculins G - I: New Norsesterterpene Cyclic Peroxides from a Southern Australian Marine Sponge, Latrunculia sp.
Authors: Ovenden Simon P. B. , Capon Robert J.
Published: August 2004

A Latrunculia sp. collected off Port Phillip Bay,
Victoria, returned three new norsesterterpene cyclic peroxides. Trunculins G
(9), H (10) and I (11) were isolated as their methyl esters (12), (13) and
(14) respectively. Gross structures for these new trunculins were assigned on
the basis of spectroscopic analysis, while the absolute stereochemistry about
the cyclic peroxide terminus was established by application of the Horeau and
Mosher procedures.
Destructive Oxidation of Mirex
Authors: Beattie James K. , Fleming Douglas S.
Published: August 2004

The perchlorinated aliphatic substance Mirex (perchloropentacyclo[5.3.0.0
2,6.0 3,9.0
4,8]decane) once had widespread use as an
insecticide and still has limited application as a termiticide. Mirex resists
direct oxidation by ruthenium tetraoxide. It undergoes a six-electron
reduction in acetonitrile at –1·2 V from the Ag/AgCl
reference potential. One or more chlorines are readily substituted by
methoxide at 90°C. Both the reduced and the methoxylated derivatives are
oxidized at room temperature by alkaline hypochlorite or persulfate in the
presence of a homogeneous ruthenium catalyst. Only a trace amount of
cyclohexane-extractable residue remains, but not all of the chlorine is
released as ionic chloride. This implies that the oxidation products include
some unidentified water-soluble organochlorine substances.
A Synthesis of Triptoquinones D, E, and F from Podocarpic Acid
Authors: Cambie Richard C. , Mitchell Lorna H. , Rutledge Peter S.
Published: August 2004

The First total synthesis of enantiopure triptoquinone F (6) starting from
podocarpic acid (10) is reported, as well as formal syntheses of enantiopure
triptoquinones D (4) and E (5). An acid-promoted Fries rearrangement of a
benzannulated lactone (14) has been used as a direct, moderately high yielding
route for introduction of C11 functionality. Treatment of methyl
12-methoxypodocarpa-8,11,13-trien-19-oate (11) with t-butylhydroperoxide and a
catalytic amount of ruthenium(III) chloride gives a mixture (1 : 1) of
diastereomeric t-butylcyclohexadienones (26) and (28).
Ritter Reactions. XIII Reactivity of Methyl Schiff Bases with Dimethyl Acetylenedicarboxylate and Mercaptoacetic Acid
Authors: Lin Qinghong , Djaidi Djamal , Bishop Roger , Craig Donald C. , Scudder Marcia L.
Published: August 2004

Reactions of several methyl imines with dimethyl acetylenedicarboxylate and
with mercaptoacetic acid have been studied to investigate further the
capricious behaviour of this functionality. The 1 : 1 adduct of imine (1) and
dimethyl acetylenedicarboxylate is confirmed as the pyrroloisoquinoline
structure (7) by X-ray methods
[C17H17NO5,
P -1, a
9·037(2), b 9·276(2),
c 10·033(2) Å, α 81·99(1),
β 81·28(1), γ 64·9(2)°, Z 2,
R 0·044]. New products from (2) and dimethyl
acetylenedicarboxylate, the 1 : 1 adduct (10) which is readily converted into
the known product (9), and the 1 : 2 adduct (12), are described. The structure
of the last compound, which arises through a rearrangement process, was
determined by X-ray crystallography
[C27H36N2O9,P ca21,
a 19· 083(4), b
15·217(3), c 9·669(2) Å,
Z 4, R 0·038]. Methyl
imines (1) and (4) undergo cyclocondensation with mercaptoacetic acid yielding
thiazolidinone products but others are inert under similar conditions.
The Synthesis and X-Ray Crystal Structure of t-Butyldimethylsilyl 2-[4-{4-(Hex-5-enyloxy)-phenylazo} phenyl]ethyl Ether
Authors: Lynch Daniel E. , Forkan Michael G. , Miller L. Sid , Parsons Simon
Published: August 2004

t-Butyldimethylsilyl
2-[4-{4-(hex-5-enyloxy)phenylazo}phenyl]ethyl ether (1)
was synthesized on route to a polysiloxane system with azobenzene pendent
groups. Compound (1) produced clear, orange-coloured crystals (space group
P -1 with
aa6·346(2), b
7·602(2),c 28·706(8) Å, α
89·84(2), β 85·17(2), γ 72· 29(2)°,
Z 2) which allowed the structure to be determined by
X-ray diffraction.
Micellar Catalysis of Organic Reactions. XXXVIII A Study of the Catalytic Effect of Micelles of 3-Hydroxymethyl-1-tetradecylpyridinium Bromide on Amide Hydrolysis and Nucleophilic Aromatic Substitution
Authors: Broxton Trevor J.
Published: August 2004

The preparation of 3-hydroxymethyl-1-tetradecylpyridinium bromide and its use
as a catalyst of nucleophilic aromatic substitution and also amide hydrolysis
are reported. It was found that the hydroxydehalogenation of nitro-activated
aryl halides was much faster in these micelles than in the presence of
cetyl(2-hydroxyethyl)dimethylammonium bromide. It was concluded that the
increased catalysis of nucleophilic aromatic substitution by this micelle was
due to a faster decomposition of the aryl micellar ether which must occur
before the phenolate product is released. No such difference in the two
micelles was found for amide or thioamide hydrolysis since in these reactions
the product amine is produced in the first step of the reaction and
decomposition of the acylated micelle is not required in the rate-determining
step of the reaction.
Reaction of Acyclic Hydrocarbons Towards t-Butoxy Radicals. A Study of Hydrogen Atom Abstraction by Using the Radical Trapping Technique
Authors: Dokolas Peter , Loer Steven M. , Solomon David H.
Published: August 2004

The reaction of 3-methylpentane and 2,4-dimethylpentane toward t-butoxy
radicals has been investigated, in neat and benzene solutions, by using the
radical trapping technique. Abstraction occurs principally from the tertiary
and secondary C-H reaction sites of 3-methylpentane and the tertiary position
of 2,4-dimethylpentane. The tertiary and in particular secondary C-H reaction
sites of 2,4-dimethylpentane are shown to be considerably less susceptible
towards t-butoxy radical facilitated abstraction compared with the equivalent
reaction sites of 3-methylpentane. As a result, the latter is three times as
reactive as 2,4-dimethylpentane as a neat hydrocarbon solution and seven times
as reactive in a diluted mixture of benzene. Diferences in selectivity and
rate of hydrogen abstraction, between the substrates, are interpreted in terms
of non-bonding interactions retarding t-butoxy radicals from approaching
sterically demanding C-H reaction sites. The selectivity from 3-methylpentane
is solvent-insensitive whereas abstraction from 2,4-dimethylpentane is
modified in benzene. Further, the rate of hydrogen abstraction, from either
substrate, to t-butoxy radical β-scission is considerably smaller in
benzene. Both observations are interpreted in terms of t-butoxy radical
solvation by the aromatic solvent.
A New Route to Silicon Alkoxides from Silica
Authors: Kemmitt Tim , Henderson William
Published: August 2004

A novel route to tetraethoxysilane and other silicon alkoxides is described,
from amorphous silica
(SiO2.nH2O)
as the raw material. The reaction of amorphous silica with triethanolamine is
enhanced by using an alkali metal hydroxide catalyst, to form a range of
triethanolamine-substituted silatrane species. These can undergo alkoxide
exchange in acidic alcohols to form alkoxysilatranes, tetraalkoxysilanes,
hexaalkoxydisiloxanes and higher siloxanes. Reaction of
triethanolamine-substituted silatranes with acetic anhydride produces
acetoxysilatrane. Products were identified by multinuclear
(1H, 13C and
29Si) magnetic resonance spectroscopy, electrospray mass
spectrometry or high-resolution gas chromatography electron impact mass
spectrometry.
Structural Studies of Complexes of Tridentate Terimine Systems. Crystal Structure of Bis(2,2′:6′,2′′-terpyridine)ruthenium(II) Perchlorate Hydrate, Bis(2,2′:6′,2′′-terpyridine)- osmium(II) Perchlorate Hemihydrate and Bis((1,10-phenanthrolin-2-yl)(pyridin-2-yl)amine)iron(II) Tetrafluoroborate Dihydrate
Authors: Craig Donald C. , Scudder Marcia L. , McHale Wendy-Anne , Goodwin Harold A.
Published: August 2004

The crystal structures of
bis(2,2′:6′,2″-terpyridine)ruthenium(II) perchlorate
hydrate, bis(2,2′:6′,2″- terpyridine)osmium(II) perchlorate
hemihydrate and bis((1,10-phenanthrolin-2-yl)(pyridin-2-yl)- amine)iron(II)
tetrafluoroborate dihydrate are described. In the terpyridine complexes the
ruthenium-nitrogen distances and the corresponding osmium-nitrogen distances
are not significantly different. In both complexes the ligand geometry and the
metal ion environment show the distortions usual for bis(terpyridine) systems.
Distortions are less marked in the
bis((1,10-phenanthrolin-2-yl)(pyridin-2-yl)amine)iron(II) cation in which each
tridentate unit forms one five-membered and one six-membered chelate ring.
[Ru(trpy)2]
[ClO4]2.(H2O)1.1:
tetragonal, space group I
41/a, a,
b 12·527(2), c
40·202(11) Å, Z 8.
[Os(trpy)2]
[ClO4]2.(H2O)0·5:
monoclinic, space group P
21/n, a
8·842(3), b 8·861(1),
c 39·22(2) Å, β93·89(2)°,
Z 4. [Fe(phpyam)2]
[BF4]2.(H2O)2:
triclinic, space group P -1,
a 12·43(1), b
12·45(1), c 13·35(1) Å, α
62·70(10), β 78·55(8), γ 72·46(9)°,
Z 2.
Adaptation and complementarity of Digitaria eriantha and Medicago sativa on a solodic soil in a subhumid environment with summer and winter rainfall
Authors: Tow P. G. , Lovett J. V. , Lazenby A.
Published: August 2004

Summary. A cutting experiment was conducted over 4 years
on a solodic soil on the Far North-West Slopes of New South Wales to compare
the environmental adaptation of Digitaria eriantha ssp.
eriantha cv. Premier and
Medicago sativa cv. Hunter River. Adaptation was tested
by comparing seasonal yield responses of the monocultures and the mixture at
high and low levels of nitrogen (N); monoculture yields were also compared
with those predicted by a simple climate-based model.
When N was non-limiting, digitaria yields were highest in summer while lucerne
yields were highest in spring. Lucerne yields in summer were often much lower
than those predicted by the model but the plant recovered well during periods
of milder temperature, until decimated by flooding. Yields of the mixture were
similar to those of digitaria in summer when it was grass dominant, and
similar to lucerne in spring when it was legume dominant. Overall, at high N
the mixture did not outyield digitaria.
In the absence of fertiliser N, digitaria and lucerne monocultures gave
similar dry matter yields. However, over the 3 warm seasons, the mixture
produced 72% more dry matter than the monocultures and 263% (325
kg/ha) more N than digitaria.
The complementary seasonal responses of digitaria and lucerne, and high yields
of the mixture suggest a role for the mixture on solodic soils on the Far
North-West Slopes of New South Wales provided the effects of irregular
flooding on lucerne can be minimised by management or more tolerant cultivars.
Response of winter-grown potatoes (Solanum tuberosum L.) to applied and residual phosphorus on a Karrakatta sand
Authors: Hegney M. A. , McPharlin I. R. , Jeffery R. C.
Published: August 2004

Summary. The response of winter-grown potatoes
(Solanum tuberosum L. cv. Delaware), as determined by
yield, to applied (broadcast) phosphorus (P) (0–480 kg/ha) and to
residual P was measured on an acutely P-deficient, newly cleared Karrakatta
sand in experiments over 2 years.
Tuber yield responded significantly (P<0.001) to
level of applied P. Phosphorus at 162 kg/ha was necessary for 99%
of maximum total yield, which corresponded to maximum economic yield. For
95% of maximum yield 99 kg/ha was necessary. Phosphorus recovery
efficiency by tubers (P uptake by tubers/P applied, both in kg/ha)
decreased from 0.14 at 30 kg P/ha to 0.04 at 480 kg P/ha.
Bicarbonate-soluble P (soil test P) extracted from the top 15 cm of soil was
determined on residual P sites in each experiment to which P was applied (as
superphosphate) 9 months earlier at levels from 0 to 800 kg/ha. These soil
test P levels were related (R2
= 0.91) to total tuber yield. The soil test P level required for
95% of maximum total yield was 33 g/g and for 99% was 51
µg/g.
When tubers were 10 mm long, the total P in petioles of youngest fully
expanded leaves which corresponded to 95% of maximum yield was
0.7% (dry weight basis), and for 99% was 0.87%.
These results, while based on responses measured at 2 sites only, provide
strong evidence that maximum yield of winter-grown potatoes on Karrakatta
sands can be achieved with lower levels of P fertiliser than are currently
used in commercial practice (125–300 kg P/ha). The results also show
that soil testing can be used to improve the P management of potato crops
grown on the sandy soils of the Swan coastal plain.
Comparison of winter habit and photoperiod sensitivity in delaying development in early-sown wheat at a site in New South Wales
Authors: Penrose L. D. J. , Martin R. H.
Published: August 2004

Summary. This study compared 2 mechanisms that delay the
development of early-sown wheat, winter habit and sensitivity to photoperiod.
To conduct this study, ear emergence dates were recorded for serial sowings of
15 wheats over 4 consecutive years at Temora, New South Wales, comprising 36
sowings in total. Ear emergence was measured as day of the year, and in both
thermal and photothermal time from sowing.
The timing of ear emergence was first considered in 3 wheats that were
insensitive to photoperiod and vernalisation. In contrast to thermal time, the
duration from sowing to ear emergence did not vary with sowing time when
measured in photothermal units. Such a measurement is essential for the study
of mechanisms whose effect in delaying development is a function of sowing
time. These results were obtained using a more simply calculated measure of
photothermal time than has been previously reported.
For early-sown wheat, winter habit was found to more strongly delay ear
emergence and provide greater flexibility in sowing time than responsiveness
to photoperiod. Our study provided evidence that winter habit is a more
attractive method of delaying ear emergence in early-sown wheat than
photoperiod sensitivity. This finding supports the continued breeding of
winter wheats for early sowings in the south-central wheat belt of New South
Wales.
Herbicide strategies for reducing nutgrass (Cyperus rotundus L.) density in cotton (Gossypium hirsutum L.)
Authors: Charles G. W.
Published: August 2004

Summary. A range of herbicides and combinations of
herbicides were evaluated for controlling nutgrass
(Cyperus rotundus L.) in 5 experiments in irrigated
cotton in northern New South Wales. Control was assessed by comparing the
density of tubers before and after treatment. Cotton lint yield and ginning
percentage were also assessed. Combinations of herbicides, including 2,4-D,
were evaluated in an additional experiment in fallow.
Multiple in-crop applications of glyphosate reduced tuber density by up to
96% over 2 seasons. This was improved with successive applications of
glyphosate. Nutgrass tuber density was also reduced when glyphosate was
combined with norflurazon (96%), benfuresate (92%), fluometuron
(84%) or EPTC (87%). Similar reductions in nutgrass density were
observed with methazole, dimethenamid, atrazine, and the combination of
norflurazon + MSMA. Treatments which reduced nutgrass density generally
resulted in average or above-average lint yields.
From these results, a strategy for controlling nutgrass in cotton can be
developed using norflurazon preplanting, and multiple applications of
glyphosate and/or MSMA in-crop.
Reducing spray volumes and dosages on conventional airblast orchard sprayers using low volume nozzle systems
Authors: Bound S. A. , Oakford M. J. , Jones K. M.
Published: August 2004

Summary.Low volume, fine-droplet hollow cone (HC)
Delavan nozzles were fitted to a conventional airblast machine in an attempt
to reduce both the volume of spray and the dosage of chemical to thin apples.
Red ‘Delicious’ trees at the Grove Research Station in southern
Tasmania were thinned with ethephon at full bloom and the post-bloom thinner
6-benzyladenine at 20 days after full bloom. An unthinned control was compared
with a treatment hand-thinned at 20 days after full bloom and chemically
thinned treatments. The chemical sprays were applied with an airblast sprayer
at high volume using conventional nozzles or Delavan HC nozzles at 50, 100,
200, 400 or 800 L/ha at 50, 75 or 100% of the dosage used at high
volume. Most chemical treatments had some effect on the parameters measured
when compared with the unthinned control while some were as effective as the
hand-thinned treatment. The most consistent treatments were at 200 L/ha at
the 75 and 100% dosages. Higher or lower volumes tended to be less
effective, however, this could have been caused by either spray drift or
evaporation of the smaller droplets used at these volumes. Although reducing
the dosage to 75% did not reduce thinning effects, reduction of dosage
to 50% resulted in significantly less thinning. These results offer a
breakthrough for many orchardists to convert to low volume spray application
very economically using the Delavan HC nozzles which produce a better droplet
size than traditional high volume hydraulic nozzles. It also offers
possibilities to significantly lower chemical usage by reducing dosage of
chemical applied per hectare. Even more important is the reduction of wastage
and pollution.
Comparison of suckering, leaf and corm characteristics of taro grown from tissue culture and conventional planting material
Authors: Johnston M. , Onwueme I. C. , Dowling A. J. , Rodoni B. C.
Published: August 2004

Summary. The growth of taro plants propagated either
from tissue culture plantlets or conventionally using huli (sections of corm
containing the shoot apex) was followed throughout a season. The plants grown
from huli began suckering 11 weeks after planting and produced an average of 5
suckers per plant. During most of the season, the huli-grown plants maintained
4–5 leaves at any one time, but had a high turnover of leaves producing
25 leaves during the 30 week period (0.8 leaves per week). At harvest the
corms of the suckers contributed about one-third of the total corm weight to
the entire huli stand.
Plants grown from tissue culture exhibited earlier suckering (starting 8 weeks
after planting) and a more profuse suckering, producing an average of about 8
suckers per plant. The tissue culture plants had a similar number and turnover
of leaves on the main plant as the huli plants. However, due to the early and
more profuse suckering of the tissue culture plants, the suckers contributed
more to the leaf area, leaf number and yield of the entire stand than the huli
suckers. The tissue culture main plants had a decreased leaf area, leaf size
and shorter petiole length than the huli plants. The total corm yield of the
huli and tissue culture entire stand was similar. However, the main corm of
the tissue culture plants was smaller as the suckers contributed over
50% to the total corm weight of the entire stand in tissue culture
plants.
Comparison of secale with other perennial grasses under grazing at a cool site in the high rainfall zone of New South Wales
Authors: Freer M. , Donnelly J. R. , Axelsen A. , Myers L. F. , Davidson J. L , Dymock J.
Published: August 2004

Summary. In 2 field experiments on the southern
highlands of New South Wales, the short-lived perennial grass secale
(Secale montanum Guss. cv. Black Mountain) was grazed by
Merino wether weaners at stocking rates of 10–17 animals/ha to test
the suggestion that persistence might be enhanced by occasional deferment of
grazing to encourage seedling germination.
In the first of these experiments (experiment 1), designed to compare secale
and phalaris, when accompanied by white and subterranean clovers, growth and
survival of both grasses was poor, despite the application of >600
kg/ha superphosphate and the experiment was abandoned after 2 years. A
subsequent pot trial (experiment 2) with secale grown in soil from the
experimental site, where the fertiliser had been applied, showed a large
growth response to additional phosphorus.
Because inadequate soil fertility may have been the cause of poor grass
persistence in experiment 1, a second field experiment (experiment 3) was
established on the same site to compare secale, perennial ryegrass and
cocksfoot, each accompanied by white and subterranean clovers and with the
application of a further 850 kg/ha superphosphate over 3 years. Initial
growth of all the grasses was good and animal production on the secale and
ryegrass plots was high (up to 100 kg/ha greasy wool and 300 kg/ha
liveweight gain). Secale failed to survive more than 3 years, despite
deferment of grazing and it may be that persistence depends more on the
reliability of autumn rainfall. However, mean weight gain from the clovers and
volunteer grasses on the secale plots in the fourth year was as high as from
the ryegrass plots and double that from the cocksfoot plots, which became
increasingly cocksfoot-dominant.
While the results indicate a need for more work on the fertiliser requirements
of perennial grasses on these soils, they also raise questions about whether
these grasses benefit animal production sufficiently to justify the cost of
establishing them.
Integrating Cytolin into a chemical thinning program for red ‘Delicious’ apple
Authors: Bound S. A. , Jones K. M. , Oakford M. J.
Published: August 2004

Summary. The thinning efficiency of Cytolin and its
interaction with the blossom thinner naphthalene acetic acid (NAA) and the
post-bloom thinner CyLex (a formulation of 6-benzyladenine) were examined in a
trial on Hi-Early red ‘Delicious’ apples in northern Tasmania.
Cytolin was applied as either a single or split application at 4
concentrations (25, 40, 55, 70 mg/L). The split application was followed
by a low rate of NAA at full bloom or by CyLex as a post-bloom thinner. While
the higher concentrations of Cytolin achieved some thinning it was not
sufficient. Satisfactory thinning levels, with a corresponding increase in
fruit size, were achieved by the addition of either NAA or CyLex to the
program. There was no consistent difference in thinning effect or fruit size
between the single and split applications of Cytolin. High concentrations of
Cytolin followed by NAA resulted in a high proportion of pygmy fruit but there
were no pygmy fruit at the lower Cytolin rates. In general, split applications
of Cytolin improved fruit typiness better than single applications. Cytolin
alone had no effect on seed numbers, whereas addition of either NAA or CyLex
to the program reduced seed numbers. Fruit firmness was improved by the CyLex
treatments. Return bloom decreased with increasing concentration of Cytolin.
Thinning and fruit quality can be improved with the recommended label rate of
Cytolin (25 mg/L) applied as a split application (12.5 mg/L applied at
king petal stage and 12.5 mg/L 3 days later) followed by 3 mg/L NAA at
full bloom or by CyLex as a post-bloom thinner. The improvement in fruit
firmness and increase in soluble solids by CyLex compared with NAA may make
this combination preferable for long-term storage fruit although further
assessment is needed.
Herbicide dose rate response curves in subterranean clover determined by a bioassay
Authors: Sandral G. A. , Dear B. S. , Pratley J. E. , Cullis B. R.
Published: August 2004

Summary. Herbicide dose response curves were developed
for 5 herbicide treatments, MCPA, 2,4-DB, bromoxynil, MCPA + terbutryn
and MCPA + diuron, when applied to 2 cultivars of subterranean clover
(Trifolium subterraneum L.) in a glasshouse experiment.
The effect of varying spraying time (14 May and 14 June) and leaf stage
(3–4 v. 8–10 trifoliate leaves) at spraying
was also examined.
The dose rate multiple of the recommended rate required to reduce the clover
herbage yield by 50% (I50)
differed markedly between herbicide treatments. The 2 MCPA mixtures were the
most phytotoxic with an I50 value
between 0.45 and 0.83, bromoxynil and MCPA alone were intermediate. 2,4-DB was
the least phytotoxic with an I50
value between 2.36 and 2.94 depending on cultivar and leaf stage at the time
of application.
The effect of leaf stage at spraying, time of spraying and cultivar on
herbicide phytotoxicity was relatively small, the major factors being
herbicide choice (which accounted for 83% of the variation in
I50 values) and rate of herbicide
applied. While there was differential cultivar tolerance to the herbicide
2,4-DB, there was no difference between the cultivars in their response to the
other herbicide treatments.
The phytotoxicity of the herbicides applied at either the 3–4 or
8–10 leaf stage in the glasshouse bioassay was highly correlated
(r = 0.84, P<0.01) with
previous estimates of phytotoxicity determined under field conditions,
although slightly overestimated phytotoxicity compared with field tests.
European Weed Research Council (EWRC) scores of herbicide damage in the
glasshouse bioassay were found to be highly negatively correlated with dry
matter yield losses in both the glasshouse (r =
–0.78 to –0.98, P<0.001) and field
(r = –0.72,
P<0.001) and are therefore an acceptable alternative
where destructive sampling is not practical. The EWRC scoring system was found
to be more effective at quantifying damage where it was manifest as burning or
stunting rather than as leaf distortion. The study indicated that a glasshouse
herbicide bioassay is a useful technique for rapidly screening herbicides for
phytotoxicity on subterranean clover.
Yield and stolon characteristics of white clover (Trifolium repens L.) cultivars in perennial pasture in Victoria
Authors: Clark S. G. , McFadden M. J.
Published: August 2004

Summary. The herbage yield, stolon characteristics and
soil seed reserves of a diverse range of white clover
(Trifolium repens L.) cultivars were studied at Hamilton
in south-western Victoria. The cultivars were sown with perennial grass
(Phalaris aquatica L.) and the pasture was rotationally
grazed by sheep. The aim of the study was to identify white clover types which
would persist under sheep grazing. The widely used cultivar, Haifa, fails to
persist in this environment.
Cultivars were divided into 3 groups depending on leaf size (range
2.5–13.0 cm2). Large-leaved cultivars were the
most productive in the first year of the experiment but by year 3 some of the
intermediate leaf-size cultivars were the most productive. Haifa (large
leaved) was particularly unproductive in the third year compared with other
large and intermediate leaf-size cultivars.
Stolon characteristics were measured in early spring 1987, mid summer 1988 and
early autumn 1988. Total stolon yield on each occasion was 0.46–0.99,
0.65–1.68 and 0.05–0.25 t DM/ha respectively. Intermediate
leaf- size cultivars tended to have the highest stolon yields on each
occasion. Stolon yield declined at the same rate (mean 87%; range
81–92%) in all cultivars between the second and third sampling
date indicating that there is no variation in the cultivars’ ability to
survive the summer drought period.
Although seed reserves for most cultivars were high at the end of the
experiment (range 11–130 kg/ha) no seedling recruitment was observed
and seed is thought to play no role in sward survival in this environment.
Plant breeders developing white clover cultivars for this environment should
concentrate on maximising stolon yield at the beginning and end of the summer
drought period (January–mid March). Intermediate leaf-size genotypes are
likely to provide the best combination of stolon and herbage yield. Grazing
management should also aim to maximise stolon yield at these critical times.
The use of large-leaved, non-stoloniferous cultivars should be discouraged by
advisers as they are not suited to this marginal environment under sheep
grazing.
Factors affecting the germination of Giant Parramatta grass
Authors: Andrews T. S. , Jones C. E. , Whalley R. D. B.
Published: August 2004

Summary. Four experiments were conducted to determine
the effects of temperature, light and leaf extract solutions on the
germination of Giant Parramatta grass [GPG,
Sporobolus indicus (L.) R. Br. var.
major (Buse) Baaijens] collected from a population
on the North Coast of New South Wales. In the first experiment, seeds were
subjected to one of a range of temperature combinations immediately after
collection and again after 8 and 27 weeks. Germination was restricted to a
narrow range of alternating temperatures with a peak at 35°C
day/15°C night when seeds were tested immediately after collection.
More seeds germinated when the samples had been stored, although germination
remained depressed at constant temperatures. These data indicate that freshly
collected GPG seeds are subject to primary dormancy and that few would
germinate in the field immediately after seed fall.
In a second experiment, seeds were buried beneath leaf litter in a pasture
immediately after collection. After 7 months, the seeds were exhumed and
subjected to either constant (20°C) or alternating (35/15°C)
temperatures in either full light, reduced red:far-red (R : FR) light or dark
treatments. Over 95% of GPG seeds germinated when subjected to
alternating temperatures, regardless of light treatment. At constant
temperatures, 97% of seeds germinated under full light, 59% at
reduced R : FR light and <1% in dark treatments.
A germination response to alternating temperatures and/or light treatments
has been reported in pasture weeds and may be an adaptation to detecting gaps
in the pasture canopy. Consequently, the germination of GPG in a pasture may
be manipulated to some extent by altering the amount of pasture cover using
grazing management, mowing and fertiliser applications.
In experiment 3, leaves from a range of coastal grasses were mixed with water
and the solutions were used to germinate GPG seeds. Solutions extracted from
setaria (Setaria sphacelata) leaves completely inhibited
GPG germination while 27% of GPG seeds germinated when imbibed with
kikuyu leaf extract solution. Solution extracted from carpet grass
(Axonopus affinis) leaves had the least effect on GPG
germination.
In experiment 4, the effects of solutions that had been leached from the
leaves of either setaria or carpet grass on seed germination, and root and
shoot lengths of GPG seedlings were compared. Germination was less inhibited
by leachate solutions compared with the extract solutions used in experiment
3. Seedlings in setaria leachates had significantly shorter roots and shoots
than both those germinated in carpet grass leachates and control seedlings.
This may explain, at least in part, why carpet-grass-based pastures are
readily infested with GPG while setaria-based pastures are relatively
resistant to infestation. The potential for allelopathic interactions between
GPG and setaria to be fully utilised to reduce the abundance of GPG in coastal
New South Wales pastures is discussed.
Effect of seed source and seed phosphorus content on the growth and yield of wheat in north-eastern Victoria
Authors: Burnett V. F. , Newton P. J. , Coventry D. R.
Published: August 2004

Summary. Wheat (Triticum aestivum
L.) seed was grown at 2 locations differing in phosphorus (P) status (low and
high) in north-eastern Victoria (36°S, 146°E), with applied
superphosphate (kg P/ha: 0, 12, 24, 100 and 200), to produce seed of
different P content. This seed was used in field and glasshouse experiments in
1993 and 1994 to investigate the effects of seed source and P content on the
growth and yield of wheat.
Wheat seed grown at the low P status site was smaller than seed grown at the
high P status site, irrespective of the amount of applied P. Seed from the low
P status site produced less early dry matter in both field and glasshouse
experiments in 1993, but there was no effect of seed source on grain yield in
either experiment. High seed P content either had no effect or reduced
seedling emergence in the field experiments. In the glasshouse, low P content
in seed from the low P status site resulted in reduced emergence. Increases in
dry matter production and grain yield with higher seed P content were only
observed in the drought season of 1994. Application of P resulted in increased
emergence, dry matter production and grain yield at most seed P content levels
but there were no significant interactions between seed P content and applied
P. Application of N did not affect dry matter production in either year, but
increased grain protein in both years and grain yield in 1993.
Seed from low P status environments can affect early seedling growth but in
average growing seasons, or in glasshouse conditions, wheat growth compensates
so that differences in grain yield are not observed. However, in order to
avoid risk of poor early seedling growth and possible yield penalties when the
crop is stressed, wheat seed should be collected from adequate soil P status
sites.
An evaluation of growth and adaptive traits of different cattle genotypes in a subtropical environment
Authors: Burns B. M. , Reid D. J. , Taylor J. F.
Published: August 2004

Summary. The ability of the large, late maturing, high
grade Simmental (HGS), purebred Hereford (H), Hereford x Shorthorn crossbred
(HSH) and grade Belmont Red (BR) genotypes to withstand both tick and
intestinal helminth burdens and high ambient temperatures and to grow in a
subtropical environment was investigated.
Compared with the H, HSH and BR genotypes the HGS was the least heat tolerant
and tick resistant, while there was no difference among genotypes in helminth
resistance. The HGS had the heaviest weaning (228 kg v.
average of 186 kg for the other breeds) and 12 month of age (235 kg
v. average of 210 kg for the other breeds) weights,
however, by 18 months of age there was little difference in the weights of the
HGS and BR genotypes (323 v. 317 kg, respectively), with
the HSH intermediate (302 kg) and the H the lightest (288 kg).
When compared with H, HSH and HGS genotypes, the BR genotype is the
recommended breed for this subtropical environment because it demonstrated
superior adaptive trait performance and, as high, or higher growth performance
at 18 months of age.
Models for pasture yield in response to phosphate application
Authors: Ratkowsky D. A. , Sale P. W. G. , Tennakoon S. B. , Johnson D. , Simpson P. G.
Published: August 2004

Summary. This paper examines the response of total
annual dry matter production of pastures to a range of rates of phosphate
application supplied in fertilisers from various sources. Data from the
National Reactive Phosphate Rock Project were used to compare the
goodness-of-fit of 2 non-linear regression models, the Mitscherlich and
rational functions models, both of which are convex curves lacking an
inflection point. These models were fitted to the data from the 2 ‘core
experiments’ and tended to give closely equivalent results, with the
Mitscherlich model fitting somewhat better in two-thirds of the cases.
Generally, both models fitted the data well, with a test for ‘lack of
fit’ being non-significant. The models proved capable of fitting all the
various responses observed in the 2 experiments, including: (i) the
‘classic’ asymptotic regression response where dry matter
production rises gradually with decreasing slope from a baseline at zero added
phosphorus to approach an asymptote at very high rates of phosphate
application; (ii) a very rapid rise at a low phosphate rate to an almost
constant response value with increasing phosphate application; and (iii) an
almost linear growth rate with non-zero slope throughout the phosphate
application rate range. The Mitscherlich model was generally more stable for
the less classical responses, and its parameters were consistently easy to
interpret. Hence, the Mitscherlich model is recommended as suitable for
describing pasture yield as a function of phosphate application. A new measure
of relative fertiliser performance is proposed, based upon the area below the
curved line defined by the fitted Mitscherlich curve, which is simultaneously
above the horizontal straight line representing the baseline of no added
phosphate. The ratio of this area calculated for a test fertiliser to the
similarly defined area calculated for a soluble reference fertiliser such as
superphosphate serves as a relative performance index. Also, when the area
calculated for the reference fertiliser is less than 10% of the total
area under the fitted curve, the site is considered to be unresponsive to
phosphate addition.
The agronomic effectiveness of reactive phosphate rocks 4. Early season lag in herbage production when reactive phosphate rock is used as a pasture fertiliser
Authors: Johnson D. , Sale P. W. G. , Simpson P. G. , Cayley J. W. D.
Published: August 2004

Summary. The agronomic effectiveness of highly reactive
North Carolina phosphate rock (NCPR), relative to triple superphosphate (TSP),
was determined for individual harvests at 26 permanent pasture sites in the
National Reactive Phosphate Rock Project from 1992 to 1995. The aim was to
determine whether the performance of NCPR relative to TSP was consistent over
the growing season. Poor performance of NCPR early in the growing season
(early seasonal lags), and its subsequent improvement later in the season, was
observed at 15 of the 26 sites in this project and for 20 of the 103 possible
site x year combinations. At 3 additional sites the apparent early season lag
in NCPR performance was followed by harvests where there was no phosphorus (P)
response. At one P-leaching site with a long growing season the relative
yields from NCPR plots increased as the year progressed and exceeded those
from TSP late in th e season. The duration of the early season lag phase was
associated with the rate of build-up in plant-available P over the 4-year
duration of the trials. The lag disappeared after 1 or 2 years at sites with
low P-sorbing, sandy soils where there was a significant build-up in Colwell
P, but persisted for 4 years on high P-sorbing soils where limited increases
in Colwell P occurred. The average early season yield reduction associated
with use of NCPR, compared with using TSP, was 28%. Colwell soil test
values alone did not provide a good indication of the likelihood of a seasonal
effect occurring. The occurrence of an early season lag phase needs to be
taken into account by farmers considering the use of RPR as reductions in feed
supply at this time of the year have the potential to reduce stocking rates
and farm profitability. The use of partially acidulated NCPR, or large
applications of NCPR applied in the first year, were management strategies
that minimised the occurrence of these seasonal effects. The suggestion that
the early season lag effect is due to the inability of NCPR to meet P demands
from newly establishing pasture legumes, and increased P requirements by
pasture plants in cold conditions is also discussed.
Prediction of grain protein in wheat and barley in a subtropical environment from available water and nitrogen in Vertisols at sowing
Authors: Dalal R. C. , Strong W. M. , Weston E. J. , Cooper J. E. , Thomas G. A.
Published: August 2004

Summary. In many subtropical environments, cereal crops
develop and mature largely on residual water in the soil. This research
involves evaluation of the impact of plant available nitrogen (N) and water in
soil at sowing on grain protein in wheat and barley in such a subtropical
environment.
Estimates of grain protein concentration of wheat (cv. Hartog) were made using
plant available water and available N (soil nitrate-N and fertiliser N, where
applied) at sowing using data obtained from an experiment conducted at Warra,
Queensland, from 1987 to 1995. Treatments included: grass + legume leys
of 4-year duration followed by continuous wheat with 0 or 50 kg N/ha.year
applied as urea at sowing; 2-year rotation of lucerne and wheat; 2-year
rotation of annual medics and wheat; 2-year rotation of chickpea and wheat,
no-tillage wheat; and conventional tillage wheat. Fertiliser N as urea was
applied to both no-tillage wheat and conventional tillage wheat at 0, 25 and
75 kg N/ha.year. The conventional tillage wheat also received N at 12.5
and 50 kg N/ha.year. Estimates of wheat grain yield required both rainfall
during the fallow period or plant available water in the soil profile at
sowing and rainfall from sowing to anthesis and, therefore, it could not be
predicted precisely at sowing. Increasing plant available water (mm) in soil
at sowing linearly reduced grain protein. In comparison, available N at sowing
increased grain protein curvilinearly from 10.0% at 50 kg N/ha to
14.5% at 200 kg N/ha (0–120 cm depth). Variation in grain
protein concentration was best accounted for by the available water :
available N ratio at 0–90, 0–120 or 0–150 cm depths. The
protein concentrations of wheat (cv. Hartog) grown in 1996 at Warra and
Nindigully, and wheat (cv. Cunningham) grown from 1991 to 1995 at Billa Billa,
and barley (cv. Tallon) grown in 1996 at Nindigully and Formartin, Queensland,
were successfully predicted using the relationship between the available water
: available N ratio and wheat grain protein concentration developed using data
from Warra during 1987–95. Thus, available water should be matched by N
supply at sowing to ensure the production of Prime Hard grade wheat and
malting grade barley in the subtropical environment. As a ‘rule of
thumb’, for 0–120 cm depth of soil sampling, each millilitre of
available water matched with each kilogram of N per hectare of available N, at
sowing, would produce about 13% protein wheat in this semi-arid region.
It requires only 0.5 kg of N/ha for each millilitre of available water in
0–120 cm depth of soil to produce malting grade barley of about
10.5% protein concentration. Available water in soil at sowing can be
approximated with rainfall during the fallow period, with rainfall (mm) :
available N (kg/ha for 0–120 cm depth) ratios of 3.7 and 7.4 for
respective 13 and 10.5% grain protein concentrations for both wheat and
barley.