Effect of N6-isopentenyladenine concentration on growth initiation in vitro and rooting of bilberry and lingonberry microshoots

Buds and shoot tips of wild bilberry (Vaccinium myrtillus L.) and lingonberry (V. vitis-idaea L.) plants were cultured on a modified MS medium containing N⁶-isopentenyladenine (2iP), 9.8–78.4 μM, in order to study the effect of the 2iP-concentration on the initiation of growth. The experiment was first performed in the autumn and repeated in the spring to determine the influence of season on growth initiation. To optimise rooting, three different rooting treatments were tested for the bilberry and lingonberry microshoots. Shoots were rooted either in vitro with 0.49 μM IBA (indole-3-butyric acid) or ex vitro, incubating microshoots in 2.07 mM KIBA-solution (potassium salt of IBA) before planting, or microshoots were planted directly on peat without exogenous auxin. The best 2iP concentration for the initiation of the growth for bilberry was 49.2 μM and for lingonberry 24.6 μM. It was observed that increasing the 2iP concentration at the growth initiation stage increased the number of brownish explants both in bilberry and in lingonberry microcultures. Spring was a considerably better time than autumn for the initiation of new growth, for both species. The results of the rooting test showed that the KIBA-treatment before planting on peat increases rooting efficiency in both bilberry and lingonberry. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effects of non-crop habitat on spotted wing drosophila (Drosophila suzukii) abundance in fruit systems: A meta-analysis

1. Drosophila suzukii (SWD) poses a threat to soft and stone fruit globally. SWD inhabits non-crop areas adjacent to farms from where it moves into crops to cause damage. Effective IPM control strategies, considering both the crop and non-crop area, are needed to control this economically important pest.
2. We conducted a meta-analysis to quantify the impacts of different non-crop habitats around fruit farms on SWD populations, comparing abundance of SWD trapped in crop and non-crop habitats.
3. Overall, SWD abundance was greater in non-crop habitats than in cropped areas and this difference was greatest in farms adjacent to woodland, or field margins containing known SWD host plants.
4. The difference in SWD abundance between crop and non-crop habitats was not affected by crop type but was greatest in the winter months and in conventional compared to organic farms, indicating conventional approaches can reduce relative SWD abundance.
5. Drosophila suzukii overwinter in non-crop habitats which provide refuge outside the cropping season. However, certain habitats support greater relative abundance of SWD than others and this is also affected by farm management. We discuss what these findings mean for effective control of SWD.

     

Diurnal rhythm in the counts and types of milk somatic cells,neutrophil phagocytosis and plasma cortisol levels in Karan Fries cows during different seasons and parity

Chances of mammary infections are comparatively higher in high producing cows during harsh environmental conditions and are usually characterised by changes occurring in various somatic cells secreted in the milk and their activities. The present study was conducted to record diurnal rhythmicity in milk somatic cell counts (SCC), neutrophil: macrophage (N: M) ratio, phagocytic activity (PA) of milk neutrophils and plasma cortisol concentrations during different seasons and parity in high producing Karan Fries cows. Values of milk SCC, N: M ratio and plasma cortisol levels were lowest during thermoneutral (TN), intermediate in winter and highest during the summer season. Diurnal rhythm in the milk SCC and N: M ratio was noticed in the summer while plasma cortisol exhibited diurnal rhythm in both winter and summer seasons. Milk SCC, N: M ratio and plasma cortisol increased in multiparous cows, but diurnal variation was noticed only in the N: M ratio and plasma cortisol in cows having more than four parity. Phagocytic activity of milk neutrophils was highest during TN, intermediate in winter and lowest during the summer season. Phagocytic activity was higher and similar in cows up to fourth parity but decreased in subsequent lactation cycles. Diurnal rhythm in the PA was noticed in winter and summer seasons and in cows having more than four parity where morning samples showed higher phagocytosis as compared to the evening samples. These results can be used for immunomodulatory interventions and therapeutic approaches in treating mastitis of crossbred cows reared under tropical conditions.     

Focusing modelling on the tracheid development period – An alternative method for treatment of xylogenesis intra-annual data

Intra-annual repeated micro-sampling of the developing tree ring is getting more and more applied in xylogenesis studies. Variability in growth magnitude, notably due to different sampling positions on the stem, encouraged application of standardization and modelling techniques. Among these, methods using Gompertz equation had become widely spread, but tests made with black spruce revealed a frequent occurrence of crossovers between the cumulative number of cells in enlargement and the cumulative number of cells in wall thickening. This was due to a localized problem in the fitting for values close to the asymptote and was a major problem for estimating the timing of each individual cell development phases, which is an interesting application of these data. In this paper, a new method, based on a different approach, has been developed in order to avoid that problem and applied to intra-annual growth curves from four sites in Quebec (Canada). Since tracheid development analysis allows discriminating between active and inactive period of a phase, modelling can be restricted on the active period alone. The new method did not cause crossovers between the fitted curves. Therefore, it has been considered appropriate for estimating the timing for each individual cell in the whole range of data. Since resulting functions are polynomials from degree 1 to 3, possible studies concerning general tendency should be easy to lead. Also, the method has been tested with different sampling frequencies. To do this, number of observations from weekly samplings has been halved to simulate a semi-monthly sampling frequency and a comparison of the results from the new method applied on each version of the datasets has been tested. Generally, the simulated semi-monthly sampled dataset did not give significantly different results from the original weekly sampled dataset, in terms of general tendency and predicted intercept time in the extremities of the data range. This is very encouraging for situations when only semi-monthly sampling is available.     

In vitro morphogenesis of pearl millet [Pennisetum glaucum (L.) R.Br.]: efficient production of multiple shoots and inflorescences from shoot apices

 This report presents a procedure for high-frequency multiple shoot production from cultured shoot apical meristems of pearl millet [Pennisetum glaucum (L.) R. Br.]. Shoot apices from 1-week-old aseptically germinated seedlings were cultured in vitro on MS medium containing various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and benzyladenine (BA) with biweekly subculture. A low concentration of 2,4-D coupled with four different concentrations of BA induced the production of adventitious shoots from the enlarged shoot apical meristems. Somatic embryogenesis was also observed at higher concentrations of BA. The use of higher levels of 2,4-D resulted in callusing of shoot apical meristems, while the shoot tips produced many leaves and in vitro flowering in 2,4-D-free media containing BA. All four pearl millet genotypes produced similar results. Fertile pearl millet plants were produced from in vitro-produced multiple shoots. Received: 1 April 1999 / Revision received: 8 July 1999 / Accepted: 17 August 1999     

Seasonal variations in nematode assemblages on an Australian temperate ocean beach; the effect of heavy seas and unusually high tides

Free-living nematodes inhabiting a sandy beach exposed to strong ocean waves were sampled at bimonthly intervals for two years. Six 1.3-litre core samples were taken on each occasion down to a depth of 60 cm. The numbers of each species and their status as juveniles, males and females (with or without eggs) was recorded. In the common species all these stages occur throughout the year, but the population increases in the warmer months of the year and falls to a much lower level in winter. Most species are dispersed throughout the sand to a depth of at least 60 cm, but several species where almost always found below the water table at about 60 cm. The faunal composition of the nematode assemblages changed significantly from month to month. Additional samples were taken to monitor the effects of very strong waves coupled with a very high tide which remodelled the beach. The nematode fauna was partially reconstituted by this event. It is concluded that the intertidal beach fauna is a dynamic extension of the near shore sub-littoral nematode fauna.     

Columbian sharp-tailed grouse female and nest survival in northwestern Colorado

Wildlife management and conservation can be challenging when the demography of a focal species is unknown or limited given that fecundity and adult survival influence population growth. The Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) have been reduced to ≤10% of their former range since the early 1900s. We conducted a 3-year study (2015–2017) across 4 study sites in northwestern Colorado, USA, to evaluate female hazard and nest survival. We trapped and marked 270 female sharp-tailed grouse and identified 275 nests for our hazard and survival analyses. Females during the breeding stage of the reproductive season experienced more hazard compared to the nesting and the early and late post-nesting stages for females without broods. Females experienced a higher degree of hazard during the breeding stage and mortality risk was >3 times higher than the nesting stage, >7 times higher than early post-nesting (EPN)-no brood stage, and >5 times higher than the late post-nesting (LPN)-unsuccessful stage. Two reproductive season stages (LPN-successful and EPN-brood) provided marginal inference. Nest incubation initiation date and nest age best described nest daily survival. Females that initiated incubation of initial nests earlier in the season experienced lower nest daily survival than later in the incubation season. Because female Columbian sharp-tailed grouse hazard varied among different reproductive season stages, we recommend that wildlife managers develop management actions that reduce hazard during the specific reproductive season stages (i.e., the breeding season). For Columbian sharp-tailed grouse in Colorado, we recommend that Colorado Parks and Wildlife collaborate with federal farm program agencies to implement a no-tillage restriction from 1 May through 30 June for active agricultural fields within 2 km of active Columbian sharp-tailed grouse leks to enhance nest survival.     

Diel patterns in singing activity of humpback whales in a winter breeding area in Okinawan (Ryukyuan) waters

Male humpback whales produce complex sounds known as songs during their breeding season. Previous studies have shown diel patterns of song in their breeding areas, but there had been no similar studies in the breeding area around Okinawa, Japan. To study diel patterns of song and the behavior of humpback whales in Okinawa, we conducted 24 hr recording with a fixed hydrophone in 2007, and vessel-based sighting surveys during 2014–2017. Song was monitored for 15 days, with peaks at sunrise and around 2200. Singing activity declined significantly between sunrise and sunset, then increased until 2200. Activity levels at night were higher and more stable than during the day. During 278 days of sighting surveys, 2,551 whales in 1,382 groups were observed. 79 individuals were confirmed as singers, all of which were lone whales. In six cases, singing individuals stopped singing before joining a group or began singing after leaving a group. Previous studies have shown that group size of humpback whales increases through the day. Considering the results from our study and the former studies, the decrease in singing activity as the day progresses may be a result of aggregation increasing, thus reducing the number of lone singers during the day.     

Luminescence characteristics and X-ray-induced defects in BaFBr:Eu2+ storage phosphor

Three different approaches used to synthesize a sensitive BaFBr:Eu²⁺ X-ray storage photostimulated luminescence (PSL) phosphor at 850°C for 1 h in a reducing atmosphere are reported. The effects of F/Br and Eu concentration on photoluminescence (PL) and PSL sensitivities synthesized by the three approaches were compared. In the first recipe, BaFBr:Eu²⁺ prepared using a BaF₂, BaBr₂ and EuF₃ mixture using solid-state diffusion (Recipe I), even in a reducing atmosphere, yielded a low PL and PSL intensity due to oxygen contamination that acted as competing hole traps. When BaFBr:Eu²⁺ was prepared using ammonium bromide and ammonium fluoride by two different recipes (Recipes II and III), oxygen contamination was eliminated, resulting in enhanced PSL efficiency. The proposed PSL process in BaFBr:Eu²⁺ was consistent with the experimental results. Increased F/Br molar ratios would incorporate fluorine ion interstitials that act as hole traps accompanied by bromine ion vacancies that act as electron traps. Although two types of F centres, F(Br⁻) and F(F⁻) are possible, F(Br⁻) centres formed during X-irradiation are only vital for the PSL process. Structural, morphology, and thermoluminescence (TL) properties of the samples were also examined using XRD, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDAX), and TL studies.