Dependence of needle architecture and chemical composition on canopy light availability in three North American Pinus species with contrasting needle length

Morphology and chemical composition of needles of shade-intolerant southern conifers (Pinus palustris Mill. (mean needle length +/- SD = 29.1 +/- 4.1 cm), P. taeda L. (12.3 +/- 2.9 cm) and P. virginiana Mill. (5.1 +/- 0.8 cm)) were studied to test the hypothesis that foliage acclimation potential to canopy light gradients is generally low for shade-intolerant species, and in particular, because of mechanical limitations, in species with longer needles. Plasticity for each needle variable was defined as the slope of the foliar characteristic versus irradiance relationship. A novel geometrical model for needle area and volume calculation was employed for the three-needled species P. palustris and P. taeda. Needle thickness (T) strongly increased, but width (W) was less variable with increasing daily integrated quantum flux density averaged over the season (Q(int)), resulting in changes in cross-sectional needle shape that were manifested in a positive relationship between the total to projected needle area ratio (A(T)/A(P)) and Q(int) in the three-needled species. In contrast, cross-sectional needle geometry was only slightly modified by irradiance in the two-needled conifer P. virginiana. Needle dry mass per unit total needle area (M(T)) was positively related to Q(int) in all species, leading to greater foliar nitrogen contents per unit area at higher irradiances. Separate examination of the components of M(T) (density (D) and the volume (V) to A(T) ratio; M(T) = DV/A(T)) indicated that the positive effect of light on M(T) resulted solely from increases in V/A(T), i.e., from increases in the thickness of foliage elements. Foliar chlorophyll content per unit mass increased with increasing Q(int), allowing an improvement in light-harvesting efficiency in low light. The variables characterizing needle material properties (D, the dry to fresh mass ratio, and needle carbon content per unit mass) were generally independent of Q(int), suggesting that needles were less stiff and had greater tip deflections under their own weight at lower irradiances because of smaller W and T. Comparisons with the literature revealed that plasticity in foliar characteristics tended to be lower in the studied shade- intolerant species than in shade-tolerant conifers, but plasticity among the investigated species was unaffected by needle length. However, we argue that, because of mechanical limitations, plastic changes in needle cross section in response to low irradiance may decrease rather than increase light-interception efficiency in long-needled species.     

Evaluation of genomic approaches for marker‐based improvement of lodging tolerance in triticale

Lodging tolerance is an important agronomic trait as it can have a severe negative impact on grain yield and quality. Here, we used a large mapping population of 647 doubled haploid triticale lines derived from four families to dissect the genetic architecture underlying lodging tolerance and to assess different approaches for a genomics‐based improvement of the trait. The plants were evaluated for lodging in two environments and genotyped with 1710 genomewide DArT markers. We observed a large genotypic variation for lodging and transgressive segregation in all families. Employing two complementary QTL mapping approaches, we identified both main effect and epistatic QTL. Using cross‐validation, we showed that the proportion of genotypic variance explained by the detected QTL is low, thus limiting the efficiency of marker‐assisted selection to improve this trait. By contrast, the cross‐validated predictive ability of genomic prediction was approximately twice as high as that of the QTL‐based selection approaches. In conclusion, our results show that lodging tolerance is a complex trait that can be improved by classical breeding but also assisted by marker‐based approaches.     

Consequences of ex situ cultivation of plants: Genetic diversity, fitness and adaptation of the monocarpic Cynoglossum officinale L. in botanic gardens

Ex situ collections in botanic gardens have great potential in contributing to the conservation of rare plants. However, little is known about the effects of cultivation on the genetic diversity and fitness of garden populations, about genetic changes due to unconscious selection and potential adaptation to the artificial conditions. We compared the genetic variability and fitness of the rare, short-lived perennial Cynoglossum officinale from 12 botanic gardens and five natural populations in Germany. Genetic variability was assessed with eight nuclear microsatellites. Plants were grown in a common garden and performance was measured over 2 years. Mean genetic diversity was very similar in botanic garden and natural populations. However, four of the garden populations exhibited no genetic variability at all. Moreover, the genetic diversity of garden populations decreased with increasing duration of cultivation, indicating genetic drift. Plant performance from natural and garden populations in terms of growth, flowering and seed production was similar and in garden populations only seed mass was strongly related to genetic diversity. Several lines of evidence indicated genetic changes in garden populations in response to cultivation. Seed dormancy was strongly reduced in garden populations, and in response to nutrient addition garden plants increased the size of their main inflorescence, while wild plants increased the number of inflorescences. These changes could be maladaptive in nature and reduce the suitability of garden populations as a source for reintroductions. We suggest that botanic gardens should pay more attention to the problem of potential genetic changes in their plant collections.     

Developing an online professional network for veterinary education: the NOVICE project

An online professional network for veterinarians, veterinary students, veterinary educationalists, and ICT (Information and Communication Technology) educationalists is being developed under the EU (European Union) Lifelong Learning Programme. The network uses Web 2.0, a term used to describe the new, more interactive version of the Internet, and includes tools such as wikis, blogs, and discussion boards. Focus groups conducted with qualified and student veterinarians within the project's five founding countries (The Netherlands, Germany, United Kingdom, Hungary, Romania) demonstrated that online professional communities can be valuable for accessing information and establishing contacts. Online networks have the potential to overcome common challenges to face-to-face communities-such as distance, cost, and timing-but they have their own drawbacks, such as security and professionalism issues. The Network Of Veterinary ICt in Education (NOVICE) was developed using Elgg, an open-source, free social networking platform, after several software options had been considered. NOVICE aims to promote the understanding of Web 2.0, confidence to use social software tools, and participation in an online community. Therefore, the Web site contains help sections, Frequently Asked Questions, and access to support from ICT experts. Five months after the network's launch (and just over one year into the project) 515 members from 28 countries had registered. Further research will include analysis of a core group's activities, which will inform ongoing support for and development of informal, lifelong learning in a veterinary context.