Root development in winter wheat grown at different N/P supply: Root length patterns and N-P interactions in phosphate uptake

Effects of different N/P ratios on several root parameters and on net P uptake were studied in winter wheat, Triticum aestivum cv. Starke II, grown in water culture. In the First experiment N/P ratios of (0/4, 2/3, 4/2, 6/1 and 8/0) were used, and plants were harvested at age 3, 5, 8, 11 and 14 days. In the second experiment N/P ratios of 6/1, 10/1, 15/1, 17/1, 20/1 and 25/1 were applied at two different N,P levels. Root length and number were determined using a digitizer connected to a computer. In the first experiment. the 6/1 N/P ratio gave the largest plants at day 14, and growth decreased with decreasing N/P ratio, The same pattern was found fur lateral root length and root number (seminal and lateral). In the second experiment the root weights decreased with increasing N/P ratio within each level. Lateral root number and overall length decreased with increasing N/P ratio at both levels as did the average lateral root length at the high N,P level. At the low N.P level, average lateral root length was about the same at all N/P ratios. Increasing the N/P ratio increased net uptake of P at the low N,P level, but decreased net P uptake at the high N,P level. Net P uptake increased with increasing P concentration in the roots and then decreased with further increase in P concentration. Net P uptake based on calculated root length [m (g root)⁻¹] showed no significant deviation from weight-based uptake plots. The effect of N and P on root structure is discussed as well as the interaction of N and P in P uptake. The relevance of a proper basis for expressing root activity is stressed.     

A Theft-Resistant Adjustable Security Box for Digital Cameras

Abstract: Remote camera traps are becoming an increasingly popular, affordable, and valuable tool for wildlife research. However, theft and vandalism of these camera systems can result in substantial financial loss and loss of valuable data. We developed an adjustable steel camera security box to protect our Cuddeback® (Non Typical, Inc., Park Falls, WI) digital scouting cameras. Our cameras were deployed for 160 days and experienced no theft or vandalism during that time. Our armored camera box successfully protected our equipment and data, can be sized to accommodate any brand of camera, and can be used in a variety of field situations.     

Quadrat covariance analysis and the scales of interspecific association during primary succession

Abstract. Three term covariance analysis is used to investigate interspecific association at a range of spatial scales, using both density and presence/absence data to evaluate the strength of species interactions. This procedure also investigates the relationship between the spatial patterns of species. These methods are applied to the vegetation on a series of glacial moraines near Mt. Robson, British Columbia, Canada, in order to test whether the plants of different species and their patterns become more independent and more random during succession. Another hypothesis tested is that if a species exerts a positive influence on others by increasing soil nutrients, this effect decreases with surface age. The vegetation analysed supports both these hypotheses to the extent that most species pairs have maximum covariance intensity on medium aged surfaces. The covariance-blocksize graphs derived from density data and from presence/absence data were qualitatively similar in their trends; however, the results are sufficiently different to suggest that the relationships among species can be subtle, affecting density rather than presence. The results also show that the affect of scale on species associations is more complex than simple models predict.     

Development of cranial muscles in the actinopterygian fish Senegal bichir,Polypterus senegalus Cuvier, 1829

Polypterus senegalus Cuvier, 1829 is one of the most basal living actinopterygian fish and a member of the Actinopterygii. We analyzed the spatial and temporal pattern of cranial muscle development of P. senegalus using whole‐mount immunostaining and serial sectioning. We described the detailed structure of the external gill muscles which divided into dorsal and ventral parts after yolk exhaustion. The pattern of the division is similar to that of urodeles. We suggest that, the external gill muscles of P. senegalus are involved in spreading and folding of the external gill stem and the branches. The fibers of the external gill muscles appear postero‐lateral to the auditory capsule. In addition, the facial nerve passes through the external gills. Therefore, the external gill muscles are probably derived from the m. constrictor hyoideus dorsalis. In contrast to previous studies, we described the mm. interhyoideus and hyohyoideus fibers as independent components in the yolk‐sac larvae. The m. hyohyoideus fibers appear lateral to the edge of the ventral portion of the external gill muscles, which are probably derived from the m. constrictor hyoideus dorsalis. These findings suggest that the m. hyohyoidues is derived from the m. constrictor hyoideus dorsalis in P. senegalus . In other actinopterygians, the m. hyohyoideus is derived from the m. constrictor hyoideus ventralis; therefore, the homology of the m. hyohyoidues of P. senegalus and other actinopterygians remains unclear. J. Morphol. 278:450–463, 2017. © 2017 Wiley Periodicals, Inc.     

Homarus Americanus Stomatogastric Nervous System Dissection

With the goal of understanding how nervous systems produce activity and respond to the environment, neuroscientists turn to model systems that exhibit the activity of interest and are accessible and amenable to experimental methods. The stomatogastric nervous system (STNS) of the American lobster (Homarus americanus; also know was the Atlantic or Maine lobster) has been established as a model system for studying rhythm generating networks and neuromodulation of networks. The STNS consists of 3 anterior ganglia (2 commissural ganglia and an oesophageal ganglion), containing modulatory neurons that project centrally to the stomatogastric ganglion (STG). The STG contains approximately 30 neurons that comprise two central pattern generating networks, the pyloric and gastric networks that underlie feeding behaviors in crustaceans^1,2. While it is possible to study this system in vivo³, the STNS continues to produce its rhythmic activity when isolated in vitro. Physical isolation of the STNS in a dish allows for easy access to the somata in the ganglia for intracellular electrophysiological recordings and to the nerves of the STNS for extracellular recordings. Isolating the STNS is a two-part process. The first part, dissecting the stomach from the animal, is described in an accompanying video article⁴. In this video article, fine dissection techniques are used to isolate the STNS from the stomach. This procedure results in a nervous system preparation that is available for electrophysiological recordings.     

Uncertainty in the detection of disturbance spatial patterns in temperate forests

The use of individual-based models in the study of the spatial patterns of disturbances has opened new horizons in forest ecosystem research. However, no studies so far have addressed (i) the uncertainty in geostatistical modelling of the spatial relationships in dendrochronological data, (ii) the number of increment cores necessary to study disturbance spatial patterns, and (iii) the choice of an appropriate geostatistical model in relation to disturbance regime. In addressing these issues, we hope to contribute to advances in research methodology as well as to improve interpretations and generalizations from case studies.We used data from the beech-dominated Žofínský Prales forest reserve (Czech Republic), where we cored 3020 trees on 74 ha. Block bootstrap and geostatistics were applied to the data, which covered five decades with highly different disturbance histories. This allowed us to assess the general behavior of various mathematical models. Uncertainty in the spatial patterns and stability of the models was measured as the length of the 95% confidence interval (CI) of model parameters.According to Akaike Information Criterion (AIC), the spherical model fitted best at the range of ca. 20 m, while the exponential model was best at the range of ca. 60 m. However, the best fitting models were not always the most stable. The stability of models grew significantly with sample size. At <500 cores the spherical model was the most stable, while the Gaussian model was very unstable at <300 cores. The pure nugget model produced the most precise nugget estimate. The choice of model should thus be based on the expected spatial relations of the forest ecosystem under study. Sill was the most stable parameter, with an error of ±6–20% for ≥1110 core series. By contrast, practical range was the most sensitive, with an error of at least ±59%. The estimation of the spatial pattern of severe disturbances was more precise than that of fine-scale disturbances.The results suggest that with a sample size of 1000–1400 cores and a properly chosen model, one reaches a certain precision in estimation that does not increase significantly with growing sample size. It appears that in temperate old-growth forests controlled by fine-scale disturbances, it is necessary to have at least 500 cores to estimate sill, nugget and relative nugget, while to estimate practical range at least 1000 cores are needed. When choosing the best model, the stability of the model should be considered together with the value of AIC. Our results indicate the general limits of disturbance spatial pattern studies using dendrochronological and geostatistical methods, which can be only partially overcome by sample size or sampling design.     

Identification and comprehensive analysis of the CLV3/ESR‐related (CLE) gene family in Brassica napus L.

• The CLE (CLAVATA3/ESR) gene family, encoding a group of small secretory peptides, plays important roles in cell‐to‐cell communication, thereby controlling a broad spectrum of development processes. The CLE family has been systematically characterized in some plants, but not in Brassica napus.
• In the present study, 116 BnCLE genes were identified in the B. napus genome, including seven unannotated, six incorrectly predicted and five multi‐CLE domain‐encoding genes. These BnCLE members were separated into seven distinct groups based on phylogenetic analysis, which might facilitate the functional characterization of the peptides.
• Further characterization of CLE pre‐propeptides revealed 31 unique CLE peptides from 45 BnCLE genes, which may give rise to distinct roles of BnCLE and expansion of the gene family. The biological activity of these unique CLE dodecamer peptides was tested further through in vitro peptide assays. Variations in several important residues were identified as key contributors to the functional differentiation of BnCLE and expansion of the gene family in B. napus. Expression profile analysis helped to characterize possible functional redundancy and sub‐functionalization among the BnCLE members.
• This study presents a comprehensive overview of the CLE gene family in B. napus and provides a foundation for future evolutionary and functional studies.