Discrimination ability of leaf and stem water potential at different times of the day through a meta-analysis in grapevine (Vitis vinifera L.)

Water potential is considered to be the “gold-standard” measure for plant water status determination. However, there are some discrepancies on how and at what time of the day water potential measurements should be performed in order to obtain meaningful information. The aim of this work is to evaluate the discrimination ability of water potential measurements in grapevines depending on the time of the day and of the measurement procedure (leaf vs. stem). To do so, a meta-analysis was performed using>78,000 measurements of water potential data obtained in field irrigation experiments, provided by 13 research teams working in this subject in Spain. For each measurement day and experiment, Discrimination Ratio (DR) was calculated and used to determine the discrimination ability of each method, and then pooled for comparison. The measurement procedure with the greatest DR can be hypothesised to be the most suitable under the average working conditions. Leaf water potential showed lower DR mean values than predawn or stem water potential. The climatic conditions and the cultivar may affect to the discrimination ability, although the abovementioned trend was always maintained. Leaf water potential in vineyards should therefore be replaced, as a general rule, by either stem or predawn water potential readings, without a clear pre-eminence of the performance of predawn and stem water potential measurements. Building a common dataset and its subsequent meta-analysis has been proved to be an efficient and robust tool to compare plant measurements, and should be implemented for other species and/or measurement procedures

The signatures of Anthropocene defaunation: cascading effects of the seed dispersal collapse

Anthropogenic activity is driving population declines and extinctions of large-bodied, fruit-eating animals worldwide. Loss of these frugivores is expected to trigger negative cascading effects on plant populations if remnant species fail to replace the seed dispersal services provided by the extinct frugivores. A collapse of seed dispersal may not only affect plant demography (i.e., lack of recruitment), but should also supress gene flow via seed dispersal. Yet little empirical data still exist demonstrating the genetic consequences of defaunation for animal-dispersed plant species. Here, we first document a significant reduction of seed dispersal distances along a gradient of human-driven defaunation, with increasing loss of large- and medium-bodied frugivores. We then show that local plant neighbourhoods have higher genetic similarity and smaller effective population sizes when large seed dispersers become extinct (i.e., only small frugivores remain) or are even partially downgraded (i.e., medium-sized frugivores providing less efficient seed dispersal). Our results demonstrate that preservation of large frugivores is crucial to maintain functional seed dispersal services and their associated genetic imprints, a central conservation target. Early signals of reduced dispersal distances that accompany the Anthropogenic defaunation forecast multiple, cascading effects on plant populations

Plant ecology meets animal cognition: impacts of animal memory on seed dispersal

We propose that an understanding of animal learning and memory is critical to predicting the impacts of animals on plant populations through processes such as seed dispersal, pollination and herbivory. Focussing on endozoochory, we review the evidence that animal memory plays a role in seed dispersal, and present a model which allows us to explore the fundamental consequences of memory for this process. We demonstrate that decision-making by animals based on their previous experiences has the potential to determine which plants are visited, which fruits are selected to be eaten from the plant and where seeds are subsequently deposited, as well as being an important determinant of animal survival. Collectively, these results suggest that the impact of animal learning and memory on seed dispersal is likely to be extremely important, although to date our understanding of these processes suffers from a conspicuous lack of empirical support. This is partly because of the difficulty of conducting appropriate experiments but is also the result of limited interaction between plant ecologists and those who work on animal cognition

Comparative genomics of the major parasitic worms

Parasitic nematodes (roundworms) and platyhelminths (flatworms) cause debilitating chronic infections of humans and animals, decimate crop production and are a major impediment to socioeconomic development. Here we report a broad comparative study of 81 genomes of parasitic and non-parasitic worms. We have identified gene family births and hundreds of expanded gene families at key nodes in the phylogeny that are relevant to parasitism. Examples include gene families that modulate host immune responses, enable parasite migration though host tissues or allow the parasite to feed. We reveal extensive lineage-specific differences in core metabolism and protein families historically targeted for drug development. From an in silico screen, we have identified and prioritized new potential drug targets and compounds for testing. This comparative genomics resource provides a much-needed boost for the research community to understand and combat parasitic worms

The acid test: the discovery of two-pore channels (TPCs) as NAADP-gated endolysosomal Ca2+ release channels

In this review, we describe the background and implications of our recent discovery that two-pore channels (TPCs) comprise a novel class of calcium release channels gated by the intracellular messenger nicotinic acid adenine dinucleotide phosphate (NAADP). Their localisation to the endolysosomal system highlights a new function for these organelles as targets for NAADP-mediated Ca(2+) mobilisation. In addition, we describe how TPCs may also trigger further Ca(2+) release by coupling to the endoplasmic reticular stores through activation of IP(3) receptors and ryanodine receptors

Relationship of collapse potential and swell pressure with suction of unsaturated expansive soil

by Saloni P. Pandya, Narendra Sarswat and Ajanta Sacha

Impact of freshwater inputs on the spatial structure of benthic macroinvertebrate communities in two landlocked coastal lagoons

Landlocked lagoons are naturally stressed environments. They are strongly influenced by freshwater input which not only varies naturally, but which is also impacted by anthropogenic activities. This study investigated the direct influence of freshwater discharges on the distribution patterns and abundance of benthic communities in two neighbouring landlocked coastal lagoons, assessing the whole system and the confluence area of each tributary. Sampling occurred in the wet and dry seasons of 2011 at two distances from freshwater discharge locations. Both lagoons were colonized by species from tw o different pools, freshwater and marine. Freshwater flow rates had a direct influence on the spatial structure of the benthic communities of brackish-water/freshwater interface areas, where also specific taxa can act as early indicators of freshwater input variations. The intensity of this influence is highly dependent on lagoon size, creating spatial heterogeneity or affecting the entire system. The benthic fauna at the confluence of the tributary that depends almost exclusively on groundwater showed the lowest variability, suggesting that the biogeochemical nature of the groundwater may be a central cause for setting specific ecotones. The results suggest that benthic communities of landlocked coastal lagoons can be highly impacted by flow reduction from freshwater aquifers under drought conditions or water abstraction activities

Anelídeos poliquetas como isco vivo: caracterização da actividade de apanha em ambientes salobros costeiros portugueses

A captura de isco vivo para a pesca, efetuada em sedimentos intertidais, tem aumentado em todo o Mundo, pois face ao incremento da procura, constitui uma importante fonte de rendimento para as populações que vivem junto à costa. Macroinvertebrados, tais como, moluscos, crustáceos e anelídeos poliquetas, entre outros, são capturados em muitos sistemas estuarinos portugueses, sendo a dimensão real das capturas subestimada. Este é o caso das capturas de anelídeos poliquetas para utilização, quer como isco vivo, quer como suplemento alimentar em atividades de aquacultura. Com o intuito de estimar o esforço da apanha de isco, espécies-alvo, técnicas e ferramentas utilizadas nesta atividade e as características dos apanhadores (número, idade e género), foram escolhidos como locais de estudo os estuários do Tejo e do Sado e as Rias de Aveiro e Formosa, no âmbito do projeto “Anelídeos Poliquetas como Isco Vivo em Portugal: Gestão da Apanha, Importação e Cultivo”, financiado pelo Programa PROMAR. Os resultados obtidos nestes sistemas mostraram que: i) os apanhadores de moluscos bivalves foram claramente maioritários no Estuário do Tejo e nas Rias de Aveiro e Formosa. No Estuário do Sado, o número de apanhadores que procuravam anelídeos poliquetas para isco foi muito semelhante ao número de apanhadores que se dedicavam a outras capturas; ii) os anelídeos poliquetas foram o grupo alvo de 28,8% e 14,9% dos apanhadores no Estuário do Sado (dias úteis e não úteis, respetivamente), 10,4% na Ria de Aveiro, 2,4% na Ria Formosa e 0,5% no Estuário do Tejo (apenas em dias úteis); iii) na Ria de Aveiro, no Estuário do Tejo e na Ria Formosa, a espécie Diopatra neapolitana (“casulo”), foi o isco mais procurado, enquanto no Estuário do Sado a espécie Marphysa sanguinea (“ganso”), foi claramente dominante; iv) a captura da espécie Hediste diversicolor, vulgarmente designada por minhocada- lama, outrora preponderante, parece ser agora marginal nas capturas; v) apenas no Estuário do Sado se verificou ser relevante a captura por apanhadores do sexo feminino, principalmente durante os dias úteis. Globalmente, a baixa incidência da procura de anelídeos poliquetas como isco vivo poderá dever-se ao facto de ser mais rentável a apanha de moluscos bivalves (amêijoajaponesa, Ruditapes philippinarum) e, no caso da minhoca-dalama, à concorrência do isco importado. Além dos efeitos diretos nas populações das espécies exploradas, a apanha intertidal de anelídeos poliquetas tem fortes impactos indiretos provocados pelo pisoteio e revolvimento de grandes extensões de sedimento, influenciando de forma significativa, tanto os ciclos biogeoquímicos, como as comunidades biológicas estuarinas. Deste modo, é fundamental a implementação de uma gestão racional a uma escala nacional desta atividade, designadamente através de restrições espaciais e temporais que contribuam para a sua sustentabilidade