Deepest known plant life discovered on an uncharted seamount

The discovery of abundant autotrophic macrophytes living below 200 meters indicates their importance to primary productivity, food webs, sedimentary processes, and as reef builders in clear oceanic waters. Estimates concerning minimum light levels for macroalgal photosynthesis and macrophytic contributions to the biology and geology of tropical insular and continental borderlands must now be revised.     

Effects of dietary vitamin E and fat supplementation on pork quality

The effects of dietary vitamin E (VE, alpha-tocopherol acetate) and fat supplementation on growth and carcass quality characteristics, oxidative stability of fresh and cooked pork patty in storage, fatty acid profiles of muscle and adipose tissue, and VE concentrations of plasma, muscle, and adipose tissue were studied. Six hundred pigs were allocated to 1 of 6 diets and fed for 63 d in a 3 x 2 factorial design. The dietary treatments included 3 fat levels (normal corn, high oil corn, high oil corn plus added beef tallow) and 2 levels of VE supplementation (40 IU/kg, normal VE supplementation; and 200 IU/kg, high VE supplementation). At 113 kg of BW, 54 pigs were slaughtered as a subsample to evaluate dietary effects on pork quality. Growth performance and meat quality characteristics did not differ (P > 0.05) among treatment groups. The high level of VE supplementation had a beneficial effect on the oxidative stability of pork as indicated by thiobarbituric acid reactive substance (TBARS) values. Lean tissue had lower (P < 0.05) TBARS in the group fed the high VE than in those fed the normal VE level. The TBARS values differed among storage periods (0 to 6 d) and also between fresh and cooked ground ham. Fat type did not significantly affect total saturated and unsaturated fatty acids proportions in the neutral and polar fraction of muscle. Adding VE acetate led to greater (P < 0.05) monounsaturated and total unsaturated fatty acid proportions in neutral lipids of muscle and adipose tissues. Increasing dietary levels of VE acetate increased the concentration of VE in plasma and muscle. These results indicate that dietary VE acetate supplementation increased (P < 0.05) lipid stability and the VE concentration of muscle.     

A dominant gene for garnet brown seed coats at the <Emphasis Type="Italic">Rk</Emphasis> locus in ‘Dorado’ common bean and mapping <Emphasis Type="Italic">Rk</Emphasis> to linkage group 1

The color of the seed coats of ‘Dorado’ (Phaseolus vulgaris L.) is garnet brown (dark red kidney bean color) and differs from most other dry bean varieties in the Honduran red bean market class. A genetic investigation of the color of ‘Dorado’ (same as DOR364) and G19833 (Liborino market class) seed coats was conducted. Crosses with genetic tester stocks demonstrated that the gene for garnet brown (GB) in ‘Dorado’ was not allelic with the R gene for dominant red (oxblood) seed coat. An allelism test between the ‘Dorado’ gene for GB seed coat and the rk ^drv gene for recessive expression of GB demonstrated allelism. We propose the gene symbol for Rk ^r for the ‘Dorado’ GB seed coat color gene. Rk ^r expresses partial dominance over Rk, where Rk ^r/Rk expresses a paler and highly variable intermediate red color. The interactions of Rk ^r, rk ^drv, and c ^u are discussed. Segregation analysis in the mapping population made up of DOR364 (same as ‘Dorado’) × G19833 recombinant inbred lines showed that the Rk ^r gene mapped to linkage group 1. The new allele at Rk was located at a distance of 17 cM from the RFLP marker Bng130 with a LOD > 3.0.     

Conversion of grassland to coniferous woodland has limited effects on soil nitrogen cycle processes

In the last century, conversion of native North American grasslands to Juniperus virginiana forests or woodlands has dramatically altered ecosystem structure and significantly increased ecosystem carbon (C) stocks. We compared soils under recently established J. virginiana forests and adjacent native C₄-dominated grassland to assess changes in potential soil nitrogen (N) transformations and plant available N. Over a 2-year period, concentrations of extractable inorganic N were measured in soils from forest and grassland sites. Potential gross N ammonification, nitrification, and consumption rates were determined using ¹⁵N isotope-dilution under laboratory conditions, controlling for soil temperature and moisture content. Potential nitrification rates (V_max) and microbial biomass, as well as soil physical and chemical properties were also assessed. Extractable NH₄⁺ concentrations were significantly greater in grassland soils across the study period (P ≤ 0.01), but analysis by date indicated that differences in extractable inorganic N occurred more frequently in fall and winter, when grasses were senescent but J. virginiana was still active. Laboratory-based rates of gross N mineralization (ammonification) and nitrification were greater in grassland soils (P ≤ 0.05), but only on one of four dates. Potential nitrification rates (V_max) were an order of magnitude greater than gross nitrification rates in both ecosystems, suggesting that nitrification is highly constrained by NH₄⁺ availability. Differences in plant uptake of N, C inputs, and soil microclimate as forests replace grasslands may influence plant available N in the field, as evidenced by seasonal differences in soil extractable NH₄⁺, and total soil C and N accumulation. However, we found few differences in potential soil N transformations under laboratory conditions, suggesting that this grassland-to-forest conversion caused little change in mineralizable organic N pools or potential microbial activity.     

The alley farming index: Preliminary steps towards a more realistic model

This paper presents the Alley Farming Index (AFI), a modification of the replacement value of the intercrop (RVI) index. The RVI index is used to assist in determining the ecological and economic benefits of a polyculture system and is potentially useful in intercropping situations where only annual crops are utilized. Alley farming is a modification of the alley cropping system where food crops are planted in between, regularly pruned, widely spaced trees. Unlike the RVI index the modified equation, presented here, accommodates alley farming where perennials and the amount of tree prunings used as green manure are important parameters. The AFI is presented in two forms, one that assumes a linear relationship between the quantity of tree prunings applied as green manure and annual crop yield, and a second more generalized form which accommodates other relationships between green manure application and crop yield (e.g., logarithmic or parabolic). Although designed specifically for alley farming the modified index can also accommodate alley cropping systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

Stocking density and shelter type for the optimal growth and survival of western rock lobster Panulirus cygnus (George)

The growth and survival of three size classes of wild caught western rock lobster, Panulirus cygnus (post-pueruli: mean 2.14 ± 0.07 g, 13.2 ± 0.1 mm CL; year 1: post-settlement juveniles, 57.1 ± 1.1 g, 38.7 ± 0.28 mm CL; and year 2 post-settlement juveniles, mean 138.2 ± 2.26 g, 51.9 ± 0.25 mm CL) were examined at combinations of two stocking densities (post-pueruli: 50 and 100 m^− 2; year 1: 11 and 23 m^− 2; year 2: 10 and 19 m^− 2) and two shelter types (a novel rigid plastic mesh shelter or bricks) over a period of 6 months. Survival of lobsters held at the lower densities (90–95%) was significantly greater than for lobsters held at higher densities (post-pueruli = 78%, year 1 = 86%, year 2 = 88%). Post-pueruli survival was significantly higher in tanks with mesh shelters (91.7%) than brick shelters (75.8%) with a similar trend exhibited by year 1 and year 2 lobsters. Densities tested did not significantly affect lobster growth for any size class. Growth of post-pueruli was considerably higher in tanks with mesh shelters (641.7% weight gain; specific growth rate 1.07 BW day^− 1) (p < 0.05) but there was no difference in the growth of year 1 and year 2 lobsters between mesh and brick shelters. Feed intake (g pellet dry matter lobster^− 1 day^− 1) was not significantly different between densities. This study has shown that P. cygnus is well suited for aquaculture based on the collection and ongrowing of wild caught pueruli, as this species exhibits good survival at high densities (up to 100 m^− 2) without adverse effects on growth, and shows no captivity-related health problems. We recommend mesh shelters, with stocking densities of 50 m^− 2 for post-pueruli and between 20 and 25 m^− 2 for year 1 and year 2 juveniles, to maximise survival and production.     

Long-term management impacts on soil C, N and physical fertility: Part II: Bad Lauchstadt static and extreme FYM experiments

Manure is a source of plant nutrients and can make a valuable contribution to soil organic matter (SOM). Two experimental sites were studied on a Halpic Phaeozem soil near Bad Lauchstadt in Germany. The first experiment, called the static experiment, commenced in 1902. The impact of fresh farmyard manure (FYM) (0, 20 and 30 t ha⁻¹ 2 year⁻¹) combined with P, K and N fertiliser application on total organic C (C_T), labile C (C_L), non-labile C (C_NL), total N (N_T), mean weight diameter (MWD) and unsaturated hydraulic conductivity (K_unsat) was investigated. The second experiment commenced in 1984 and investigated the effect of extreme rates of fresh FYM applications (0, 50, 100 and 200 t ha⁻¹ year⁻¹) and cropping, or a continuous tilled fallow on the same soil properties. At both sites a nearby grassland site served as a reference. On the static experiment, FYM application increased all C fractions, particularly C_L, where application of 30 t ha⁻¹ 2 year⁻¹ increased C_L by 70% compared with no FYM application. Fertiliser additions to the static experiment had a positive influence on C fractions while N_T increased from both FYM and fertiliser application. MWD increased as a result of FYM application, but did not reach that of the grassland site. Both fertiliser and FYM application increased K_unsat (10 mm tension) on the static experiment. In the second experiment application of 200 t ha⁻¹ year⁻¹ of FYM increased concentrations of C_L by 173% and of C_NL by 80%, compared with no FYM application to make them equivalent to, or greater than the grassland site. A continuously tilled fallow resulted in significant decreases in all C fractions, N_T and MWD compared with the cropped site, while K_unsat (10 mm tension) was increased on the 0 and 50 t ha⁻¹ year⁻¹ treatments as a result of a recent tillage. There was no difference in K_unsat between the cropped and the continuous tilled fallow at FYM applications of 100 and 200 t ha⁻¹ year⁻¹. There were similar significant positive correlations of all C fractions and N_T with MWD on both experimental sites but the relationships were much stronger on the extreme FYM experiment. Weaker relationships of C fractions and N_T with K_unsat (10 mm tension) occurred for the static experimental site but these were not significant for the extreme FYM experimental site. The strongest relationship between C fractions and K_unsat was with C_L. This research has shown that applications of FYM can increase SOM and improve soil physical fertility. However, the potential risk of very high rates of FYM on the environment need to be taken into consideration, especially since the application of organic materials to soils is likely to increase in the future.