Zealand Grass Research Articles

Adhesion of bacteria (Serratiaspp.) to the foregut of grass grub (Costelytra zealandica(white)) larvae and its relationship to the development of amber disease

Adhesion of pathogenic strains of Serratia spp. to the foregut tissue of the New Zealand grass grub (Costelytra zealandica) was shown to be associated with the development of amber disease. Bacteria were always found adhering to the crop in the region of the cardiac valve in larvae showing disease symptoms after in vivo treatment with pathogenic bacteria while no significant colonization was observed in larvae treated with wild‐type, non‐pathogenic strains. The in vitro inoculation of excised crops with pathogenic and non‐pathogenic strains resulted in a similar pattern of adhesion. It is suggested that adhesion is an early step in pathogenesis and that farther bacterial mediated factors could be required for fall expression of amber disease.

Hirsutella stylophoraMains, a pathogen ofCostelytra zealandica(Coleoptera: Scarabaeidae) in New Zealand

The entomopathogenic fungus, Hirsutella stylophora, is described as a pathogen of larvae of the New Zealand grass grub, Costelytra zealandica, for the first time. This species is the anamorph of Cordyceps stylophora. Infected grass grub larvae were dull brown in colour, usually with a distinctive stromatal growth extending from the head capsule. Despite the frequent production of stromata on diseased larvae, no ascospores (sexual stage) were found. Collections of diseased C. zealandica were made from several sites in the southern half of the South Island.

Serological identification of Serratia entomophila, a bacterial pathogen of the New Zealand grass grub ( Costelytra zealandica)

A competitive inhibition enzyme-linked immunosorbent assay was used to examine the antigenic relationships between strains of the bacterium Serratia entomophila and other members of the genus. S. entomophila causes amber disease of the New Zealand grass grub ( Costelytra zealandica) and is currently being developed as a biological agent to control this pasture pest. The assay distinguished S. entomophila from other Serratia species and indicated variability in the antigenic structure of the species, suggesting the existence of several serotypes. The method is potentially useful as an identification method as an alternative to biochemical testing.

Breeding systems in New Zealand grasses X. Species at risk for conservation

Abstract Fifteen species of indigenous grasses are considered to be at some conservation risk. One species of Poa is dioecious; all other taxa bear perfect flowers. Self-compatibility is common and expressed as cleistogamy in Bromus arenarius. Rytidosperma tenue appears to be sterile; no other species is at particular risk because of its breeding system.

Serratia entomophila sp. nov. Associated with Amber Disease in the New Zealand Grass Grub Costelytra zealandica

Serratia entomophila sp. nov. is a homogeneous deoxyribonucleic acid relatedness group most closely related to Serratia ficaria and Serratia marcescens. All 19 strains studied resembled S. marcescens (the phenotypically closest species) by their inability to ferment or utilize l-rhamnose, l-rhamnose, d-melibiose, dulcitol, and d-raffinose but differed from S. marcescens by their inability to ferment or utilize sorbitol and their lack of lysine and ornithine decarboxylases. All strains utilized itaconate, a unique characteristic among Serratia species. Two biotypes could be distinguished. Strains of biotype 1 utilized d-arabitol but not l-arabitol or d-xylose. Strains of biotype 2 utilized l-arabitol and d-xylose but not d-arabitol. S. entomophila has been isolated from insect larvae and water. Most strains were isolated in New Zealand from the grass grub Costelytra zealandica infected with amber disease. None of the strains were isolated from infected humans, animals (other than insects), or plants. The type strain is strain A1T (ATCC 43705T).

Glutathione [formula omitted] from the New Zealand grass grub, Costelytra zealandica Their isolation and characterization and the effect on their activity of endogenous factors

Isolation of glutathione S- transferase from the New Zealand grass grub, is complicated by the marked loss of activity from crude homogenates. This loss may be due to proteolysis or to modification by endogenous chemicals. The effect may be minimized by immediate fractionation with ammonium sulphate and by inclusion of 5mM glutathione in homogenates. Two enzymes species, isoelectric at pH 8.7 and 5.9 respectively, could be isolated by ammonium sulphate fractionation, affinity chromatography, anion exchange chromatography and chromatography on hydroxyl apatite. They had different substrate specificities and had differing subunit structure. The pI 8.7 enzyme appeared to be a homodimer of subunits of M r 23,700 and the pI 5.9 enzyme one of subunit M r 22,500. A third major enzyme species, isoelectric at pH 4.3 differed from the other two enzymes in having low affinity for the affinity matrix. This preparation was heterogeneous. The enzymically active species in this preparation had the same molecular weight as that of the pI 8.7 enzyme, had a very similar substrate specificity to the basic enzyme species and was characterized by kinetic parameters almost identical to those of the pI 8.7 enzyme.

Breeding systems in New Zealand grasses IX: Sex ratios in dioeciousSpinifex sericeus

Abstract Male and female colonies are of equal frequency and of equal size in S. sericeus in New Zealand. This sex ratio is consistent with counts in other dioecious grasses including S. sericeus in Australia. Dioecism, its evolution and the a~sociated selection pressures, is discussed. Androdioecism which is described for several species S. considered relative to the strict dioecism of S. sericeus in New Zealand.

Kinetic studies on a glutathione S-transferase from the larvae of Costelytra zealandica.

Of the glutathione S-transferases from the New Zealand grass grub (Costelytra zealandica) active in conjugating the model substrate 1-chloro-2,4-dinitrobenzene, the most active was isolated in a functionally homogeneous form. This had an isoelectric point of 8.7. Preliminary evidence suggests that it is a homodimer with subunits of Mr 23 500. The dependence of the enzyme-catalysed reaction on substrate concentration was analysed in terms of the rate equation characteristic of Ordered Bi Bi or Rapid-Equilibrium Random mechanisms. Evidence was found for a critical ionizing event at pH 9.3 at 37 degrees C. This event appears to involve a twofold change in charge on the enzyme, which may be the result of co-operative ionizations rather than independent ionizations. This appears to affect neither the binding of the aromatic substrate to the enzyme, nor the maximum catalytic velocity of the enzyme-catalysed reaction. The variation of the kinetics with temperature was studied. Apparent thermodynamic parameters characteristic of the reaction were derived. The possible relevance of the temperature-dependence of the enzyme-catalysed reaction in vivo is discussed.

Relationships and taxonomy of New Zealand wheatgrasses

Abstract Studies of the genomic constitution of the New Zealand grasses of the tribe Triticeae confirm their relationship to the widespread genus Elymus L. as typified by E. sibiricus L., and defined by an alloploid genome. That genome is composed of the haplome H, derived from Critesion Rafin. (Hordeum subgenus Hordeastrum) , and the haplome S, derived from Pseudoroegneria (Nevski) Löve (Elytrigia sect. Pseudoroegneria). Five species found in New Zealand and previously included in Agropyron are referable to the East African-Central Asiatic-Australasian section Anthosachne (Steud.) Tzvelev of Elymus. These species are (chromosome numbers and synonyms in parentheses): Elymus reetisetus (Nees) Löve et Connor (2n = 42, Agropyron scabrum p.p, A. youngii), E. multiflorus (Hook. L) Löve et Connor (2n = 42, A. kirkii) with var. multiflorus and var. longisetus (Hack.) Löve et Connor; E. enysii (Kirk) Löve et Connor (2n = 28, A. enysii); E. tenuis (Buch.) Löve et Connor (2n = 56, A. tenue); E. apricus Löve et Connor described as new (2n = 42, A. scabrum p.p.). The tetraploid has the genomic formula HS, the octoploid HHSS, and the hexaploids have the constitution HSS. Two species, formerly placed in Cockaynea Zotov, also share the genomic formula HS, but represent in Elymus the endemic section Stenostachys (Turcz.) Löve et Connor. Their correct names are E. narduroides (Turcz.) Löve et Connor (2n = 28, Cockaynea gracilis), and E. laevis (Petrie) Löve et Connor (2n = 28, C. laevis). All 7 species are obligately sexual and at least facultatively autogamous, but E. rectisetus includes populations that are facultatively to obligately agamospermous and obligately pseudogamous.

Phomaon New Zealand grasses and pasture legumes

Abstract Fifteen species of Phoma were isolated from grasses and legumes in New Zealand pastures: P. chrysanthemicola Hollos, P. exigua Desm., P. fimeti Brun., P. glomerata (Corda) Wollenw. et Hochapf., P. herbarum Westend., P. huancayensis Turkensteen, P. leveillei Boerema et Bollen, P. macrostoma Mont. var. macrostoma, P. macrostoma var. incolorata (Home) Boerema et Dorenbosch, P. medicaginis Malb. et Roum., P. pomorum Thuem., and an as yet undescribed Phoma sp ., together with three newly described species, P. lotivora, P. paspali, and P. plurivora. In glasshouse tests P. lotivora, P. chrysanthemicola, and P. medicaginis were found to be pathogenic on some legumes, the remaining species being plurivorous saprophytes or weak wound parasites.

Breeding systems in New Zealand grasses

Abstract Single, clandestine, cleistogamic spikelets occur in leaf axils of Microlaena stipoides from New Zealand, Australia, Norfolk Island, and Hawaii, and in the New Zealand endemic, M. polynoda. These cleistogamic spikelets are additional to the previously reported cleistogamic and chasmogamic systems in aerial inflorescences of M. stipoides, and to chasmogamy in M. polynoda. Flowers in other New Zealand species included in Microlaena are chasmogamous only.

Studies on the Insect Attractant Resin Durez 12687: Presence of an Odor Synergist1

Males of the New Zealand grass grub beetle, Costelytra zealandica (White), are more strongly attracted to the phenol/formaldehyde resin Durez 12687 than to phenol or aqueous phenol. The activity of the resin is thus not explicable in terms of phenol content alone. An odor synergist is present in the resin.

Electroantennogram responses of maleCostelytra zealandica(Coleoptera: Scarabaeidae) to phenol and related compounds

Electroantennograms recorded from male New Zealand grass grub beetles, Costelytra zealandica (White), were used to compare the activity of phenol with that of closely related phenolics. These compounds had no masking effect on the antennal response. A comparison of activity between phenol and a crude female extract indicated that phenol is the sole pheromone.

The conjugation of phenols with phosphate in grass grubs and flies.

1. Houseflies, blowflies and New Zealand grass grubs were dosed with 1-naphthol, 2-naphthol or p-nitrophenol. 2. The corresponding monoaryl phosphates were identified in extracts of insects or excreta along with the beta-glucosides and ethereal sulphates of the phenols. 3. No diaryl phosphates or glucosiduronates were detected but an unidentified metabolite of [(14)C]1-naphthol was present in extracts of flies dosed with [(14)C]1-naphthol.

Breeding systems in New Zealand grasses

Summary Flowering seasons in C. rigida occur most commonly at three-year intervals, and for the period 1948/49 to 1965/66 are coincident with those in species of Nothofagus. The relationship between flowering and burning, tillering, and autumn initiation of inflorescences is discussed.

Breeding Systems in New Zealand Grasses

Breeding Systems in New Zealand Grasses

Breeding systems in New Zealand grasses

Summary The South American species of Cortaderia naturalised in New Zealand are C. selloana and another species, probably C. atacamensis. The genus has long been considered dioecious, but C. selloana is gynodioecious as are the three species indi~enous to New Zealand. In the populations of C. sel/oana examined in New Zealand the ratio of hermaphrodites to females is 1:1. Cortaderia atacamensis occurs here as female plants only and reproduces freely by seed produced in an autonomous apomictic process. Gynodioecism is reported in the South American species C. pilosa and C. araucana.

Breeding systems in New Zealand grasses

Gynodioecism is established is the breeding system of the three indigenous species of Cortaderia. The frequencies for sex form in C. richardin vary among populations, the functionally female plants...

Breeding systems in New Zealand grasses

Summary Dimorphism in flowers of Arundo richardii is described, and gynodioecy is established as the breeding system.

Breeding systems in New Zealand grasses

Summary Studies on the breeding systems of five species of indigenous grasses Festuca nouae-zelandiae, F. matthewsii, F. multinodis, Koeleria kurtzii, and Deyeuxia billardieri are reported on, together with some notes on seed setting in Danthonia rigida.