Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.     

Acacia ochracea (Leguminosae-Mimosoideae), a new species from Somalia

Acacia ochracea , a new species in the A. Senegal complex, is described and illustrated. It is a common and conspicuous tree over large areas in the western Bay Region and in the Gedo Region in SW Somalia.     

Relationship of scrotal circumference and testicular volume to age and body weight in the swamp buffalo (Bubalus bubalis)

Scrotal circumference (SC) and testicular volume (TV) were measured in 65 swamp buffalo bulls ranging in age from 7 to 60 months and weighing 130 kg to 560 kg. Ages and body weight (BW) were recorded for each male at the time of measurement to find out if they correlated with SC and TV. SC and TV increased linearly and correlated significantly with age and BW (SC vs age: r = 0.74, p<0.01; SC vs BW: r = 0.88, p<0.01; TV vs BW: r = 0.82, p<0.01). SC measurements ranged from 15.1 +/- 1.1 cm to 24.0 +/- 0.4 cm for ages ranging from 10.0 +/- 0.6 to 48.5 +/- 6.3 months, revealing that testicular size in swamp buffaloes was very much smaller than domestic cattle. The SC norms distributed with age would be useful in the evaluation of swamp buffalo males for breeding soundness.     

Role of glutathione in the regulation of hepatic cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme of bile acid biosynthesis

The effect of in vivo variation of hepatic glutathione (using diethyl maleate and L-cysteine) on in vitro cholesterol 7 alpha-hydroxylase activity was studied in male Sprague-Dawley rats. Cholesterol 7 alpha-hydroxylase activity in glutathione-depleted rats (ca. 10% of control glutathione) was significantly reduced compared to that in vehicle-injected controls. While L-cysteine treatment of glutathione-depleted animals increased glutathione levels somewhat (ca. 20% of control glutathione), they were still significantly less than control levels. Similarly, cholesterol 7 alpha-hydroxylase activity in the partially glutathione replete animals was approximately 50% greater than that in the glutathione-depleted animals, but still significantly less than that in the controls. The rate of 7 alpha-hydroxylation of cholesterol was found to be dependent on liver glutathione content. The calculated maximal rate was 34.4 picomoles/mg/min with a half maximal activity at 1.89 mumoles glutathione/gm liver. These results suggest that hepatic glutathione may be an important modulator of in vivo activity of cholesterol 7 alpha-hydroxylase.     

Der Einfluss des Wirtes in der Massenzucht auf die Qualität des EiparasitenTrichogramma evanescens bei der Bekämpfung des Maiszünslers,Ostrinia nubilalis

Zusammenfassung In vier Feldversuchen wurde die Wirksamkeit eines an den Maiszünsler besonders angepassten Stammes vonTrichogramma evanescens Westw. bei der Bek?mpfung des MaiszünslersOstrinia nubilalis Hübner geprüft. Die Parasiten wurden entweder auf Eiern der GetreidemotteSitotroga cerealella (Oliv.) oder auf Eiern der MehlmotteEphestia kuehniella Zell. gezüchtet. Die Freilassung erfolgte in den Versuchsparzellen durch Anbringen von Eikarten mit jeweils etwa 1000 parasitierten Wirtseiern an Bl?ttern von Maispflanzen in Abst?nden von 14 Metern. VierTrichogramma-Freilassungen in w?chentlichen Abst?nden mit jeweils 45000 Parasiten pro Hektar ergaben hohe Parasitierungsraten bei denO. nubilalis-Eiern und starke Verminderungen des Larvenbefalls. In den Parzellen, in denen aufS. cerealella-Eiern gezüchtete Parasiten freigelassen wurden, lagen die Parasitierungsraten zwischen 81,7 und 82,3% im Vergleich zu 63,0 und 84,3% bei den aufE. kuehniella gezüchteten Trichogrammen. Die Verminderung des bei der Ernte festgestelltenO. nubilalis-Larvenbefalls im Vergleich zur unbehandelten Kontrolle lag bei den aufS. cerealella gezüchteten Parasiten zwischen 75,5 und 94,8% verglichen mit 77,6 und 89,9% bei den aufE. kuehniella gezüchteten Tieren. Es gab somit keine signifikanten Unterschiede zwischen den beiden getestetenTrichogramma-St?mmen.

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Summary The effectiveness of a strain ofTrichogramma evanescens Westw. especially adapted to the European corn borerOstrinia nubilalis Hübner was examined in 4 field experiments. The parasites were reared on either the Angoumois grain mothSitotroga cerealella (Oliv.) or the Mediterranean flour mothEphestia kuehniella Zell. and were released in separate experimental plots by attaching egg cards, each containing about 1000 parasitized host eggs, to corn leaves at distances of 14 meters in the field. FourTrichogramma treatments at 1 week intervals using 45000 parasites per hectar per treatment resulted in high parasitization rates ofO. nubilalis-eggs and large reductions in larval damage. In experimental plots whereT. evanescens, reared onS. cerealella-eggs, were released, the parasitization rates ofO. nubilalis-eggs varied between 81,7 and 82,3%, compared with 63,0 and 84,3% forT. evanescens reared onE. kuehniella. The reduction inO. nubilalis larval infestation at the harvest in the treated plots, compared to untreated controls varied between 75,5 and 94,8% forT. evanescens that was reared onS. cerealella, compared with 77,6 and 89,8% forT. evanescens that was reared onE. kuehniella. There were no significant differences in efficiency between the two tested methods of rearingTrichogramma.

     

Inhibitors of superoxide dismutases: A cautionary tale

An extensive search resulted in the identification of pamoic acid as an inhibitor of superoxide dismutases. Pamoic acid appeared to rapidly and reversibly inhibit all types of superoxide dismutases and did so in both the cytochrome c reduction and in the dianisidine photooxidation assays, used to measure this activity. It could nevertheless be shown that pamoic acid did not at all inhibit superoxide dismutase but rather diminished the sensitivity of the assays. The mechanism proposed to account for this effect involved oxidation of pamoate, by O₂^?, to yield a pamoate radical which can then reduce cytochrome c or oxidize pyrogallol. Pamoate thus competes with superoxide dismutase for the available O₂^?, without affecting the observable effects of that O₂^? upon cytochrome c or upon pyrogallol. It consequently makes these assays less responsive to superoxide dismutase, while appearing to be without effect in the absence of superoxide dismutase. Several of the predicted consequences of this proposal were affirmed. Other workers, interested in finding inhibitors for superoxide dismutases, are hereby forwarned of this subtle snare.     

Die Wirkung von Kernpolyedern (Baculovirus spec.) ausMamestra brassicae aufTrichogramma cacoeciae [Hym.: Trichogrammatidae] undChrysopa carnea [Neur.: Chrysopidae]

Zusammenfassung Kernpolyeder vonMamestra brassicae (L.) wurden auf Nebenwirkungen an zwei Entomophagen-Arten in der Basis- Konzentration (LC₁₀₀ für den natürlichen Wirt) sowie der 5- und 10 fachen Konzentration geprüft. Schadwirkung durch Kontakt mit frisch angetrocknetem Belag bzw. durch Verfüttern eines kontaminierten N?hrsubstrates auf den EiparasitenTrichogramma cacoeciae Marchal konnte nicht nachgewiesen werden. Ebenso wurde die Entwicklung vonT. cacoeciae in parasitierten Wirtseiern durch eine Tauchbehandlung mit der Kernpolyeder-Suspension in verschiedenen Intervallen nach der Parasitierung nicht gest?rt. Im Wahl- und Nichtwahlversuch konnte keine Repellentwirkung von Wirtseiern festgstellt werden, die in eine Kernpolyeder-Suspension getaucht worden waren. Die r?uberischen Larven vonChrysopa carnea Steph. waren gegenüber der 10fachen Basiskonzentration bei direktem Bespritzen der Larven, Kontakt mit einem frisch angetrockneten sprit zbelag sowie bei peroraler Aufnahme unempfindlich, wie die Frassleistung der Larven, die Fekundit?t der Imagines sowie die Schlüpfrate der Eier zeigte. Bei praktischen Eins?tzen von Kernpolyeder-Pr?paraten zur Bek?mpfung der Kohleule sind im Gegensatz zu den üblichen Anwendungen von Phosphors?ureestern keine direkten Nebenwirkungen auf die untersuchten Nutzinsekten zu erwarten.

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Summary The side effect of a water suspension of polyhedral inclusion bodies of nuclnear polyhedrosis virus (NPV) fromMamestra brassicae (L.) in a concentration of 1-, 5-, and 10-fold of the LC₁₀₀ for the natural host was tested on two beneficial insects. No reduction in the parasitization capacity ofTrichogramma cacoeciae Marchal (Hym.: Trichogrammatidae) was recorded when adults were exposed to a fresh dry film, or fed on contaminated honey-agar. The development of the parasite inSitotroga cerealella Oliv. host eggs was not affected when these were dipped in a suspension of the NPV at different time intervals after parasitization. In additional tests, it was shown that deposit of the NPV suspension had no repellent effect onTrichogramma. The feeding capacity of the predatory larve ofChrysopa carnea Steph., fecundity of the adults as well as viability of the eggs were not affected when the larvae were directly sprayed with the highest tested concentration of the suspension, exposed to fresh dry film or fed on contaminated diet. These experiments indicate that, in contrast to the use of the conventional organophosphorus insecticides, no hazard to the tested beneficial insects should be expected when the preparation of the polyhedral inclusion bodies will be used in the field.

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Nr. 2 der Serie: Wirkung von Insektenpathogenen auf Entomophagen. Als Nr. 1 gilt:S. Hassan & A. Krieg: über die schonende Wirkung vonBacillus thuringiensis-Pr?paraten auf den ParasitenTrichogramma cacoeciae (Hym.: Trichogrammatidae). — Z. Pfl. Krankh. Pfl. Schutz, 82, 515–521, 1975.