Some factors influencing the sudden death syndrome in cut flower plants : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University

Soil/root mixes from plants with the Sudden Collapse Syndrome of cut flower plants were tested for Phytophthora infection using a lupin (Lupinus angustifolius) baiting technique. Boronia heterophylla and Leucadendron 'Wilsons Wonder' root samples both caused the lupin seedlings to exhibit symptoms of Phytophthora infection. The efficacy of phosphorous acid (Foschek® 500 at 1000 ppm and 2000 ppm) and a combination of phosphorous acid and an additional product (Foschek® 500 and C408 at 1000/200 ppm and 2000/400 ppm) in controlling Phytophthora cinnamomi root infections of L. 'Wilsons Wonder', B.heterophylla and B megastigma rooted cuttings was compared with fosetyl- Al (Aliette® 80 SP at 1000 ppm and 2000 ppm) under conditions of high disease pressure The fungicides were applied as a root drench 7 days prior to the roots being inoculated by a split wheat technique and the effect of the fungicides and their concentrations on the rate of plant mortality was measured The results were species dependent. The treatments delaying plant mortality most effectively were fosetyl-AI at 2000 ppm on L 'Wilsons Wonder', phosphorous acid at 2000 ppm on B. heterophylla and both fosetyl-AI at 1000 or 2000 ppm and phosphorous acid at 2000 ppm on B. megastigma. The allelopathic activity of the root bark of Protea cynaroides, L. 'Wilsons Wonder'. Macadamia 'Beaumont' and Knightia excelsa was evaluated as a growth inhibitor for Phytophthora cinnamomi. The results indicate that by day 4 the root bark of M. 'Beaumont' reduced the growth rate of Phytophthora cinnamomi by 76.8% while that of Protea cynaroides inhibited the growth totally. The root bark of L. 'Wilsons Wonder' had no effect on the growth rate but that of K. excelsa enhanced the growth rate by 128% by day 4. The root bark of Protea cynaroides plants previously infected with an unnamed, indigenous Phytophthora species provided greater resistance to the growth rate of Phytophthora cinnamomi than the root bark of uninfected plants On the corn meal agar the leachate of the infected Protea cynaroides root bark exhibited a 'zone of inhibition' which prevented the growth of Phytophthora cinnamomi. Possible reasons for this are discussed

Large Area Crop Inventory Experiment (LACIE). Examples of phase 3 omission labeling errors

There are no author-identified significant results in this report

Optical waveguide arrays: quantum effects and PT symmetry breaking

Over the last two decades, advances in fabrication have led to significant progress in creating patterned heterostructures that support either carriers, such as electrons or holes, with specific band structure or electromagnetic waves with a given mode structure and dispersion. In this article, we review the properties of light in coupled optical waveguides that support specific energy spectra, with or without the effects of disorder, that are well-described by a Hermitian tight-binding model. We show that with a judicious choice of the initial wave packet, this system displays the characteristics of a quantum particle, including transverse photonic transport and localization, and that of a classical particle. We extend the analysis to non-Hermitian, parity and time-reversal ($\mathcal{PT}$) symmetric Hamiltonians which physically represent waveguide arrays with spatially separated, balanced absorption or amplification. We show that coupled waveguides are an ideal candidate to simulate $\mathcal{PT}$-symmetric Hamiltonians and the transition from a purely real energy spectrum to a spectrum with complex conjugate eigenvalues that occurs in them.Comment: 16 pages, 12 figures, Invited Review for European Physics Journal - Applied Physic

Tunable waveguide lattices with non-uniform parity-symmetric tunneling

We investigate the single-particle time evolution and two-particle quantum correlations in a one-dimensional $N$-site lattice with a site-dependent nearest neighbor tunneling function $t_\alpha(k)=t_0[k(N-k)]^{\alpha/2}$. Since the bandwidth and the energy levels spacings for such a lattice both depend upon $\alpha$, we show that the observable properties of a wavepacket, such as its spread and the relative phases of its constitutents, vary dramatically as $\alpha$ is varied from positive to negative values. We also find that the quantum correlations are exquisitely sensitive to the form of the tunneling function. Our results suggest that arrays of waveguides with position-dependent evanascent couplings will show rich dynamics with no counterpart in present-day, traditional systems.Comment: 5 pages, 4 figure