Patterns of richness of freshwater mollusks from Chile: predictions of its distribution based on null models

The freshwater mussels from Chile are characterized by a high percentage of endemism and a fragmented latitudinal diversity, which has been attributed to the features and geomorphological history sculpted by the hydrographic basins. In this work, a set of hypothesis under a macroecological approach is addressed, with the aim to explore environmental, topographic and hydrological factors that define the latitudinal distribution of this mussel group. In order to achieve this goal, Rapoport’s rule, geometrics limits and co-ocurrence were evaluated. In addition, we analyze the source and sink hypotheses through the nested analysis. We observed a noticeable mid-domain effect (MDE), where a major richness than expected was randomly observed between 40 and 41°S. The results revealed that the distribution pattern was not concordant with Rapoport’s rule (r = 0.123; p = 0.128). Regarding to historical dynamic of the distribution, the results show a significant nestedness pattern, suggesting a source-sink dynamic, that is, poorer communities are a subset of richer communities in species. According to the co-occurrence analysis, an aggregate pattern existed, suggesting potential regulatory mechanisms. The specific richness pattern is explained by the variable seasonality of the temperature with a variance percentage explained of 35%. The full model indicated that variables which characterize the heterogeneity of habitat (i.e. range, Shannon), water availability (i.e., precipitation, density of water bodies) and topography (i.e., altitude area available) jointly explain 40% of the variability of the observed richness. This study shows that the geographical distribution of mollusc richness is mainly explained by mainly climatic and topographical environmental components, as well as by the source-sink dynamics.

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Molecular mechanisms mediating root hydrotropism: what we have observed since the rediscovery of hydrotropism

Journal of Plant Research ◽

10.1007/s10265-019-01153-3 ◽

2019 ◽

Vol 133 (1) ◽

pp. 3-14

Author(s):

Yutaka Miyazawa ◽

Hideyuki Takahashi

Keyword(s):

Arabidopsis Thaliana ◽

Water Potential ◽

Water Availability ◽

Molecular Mechanisms ◽

Current Knowledge ◽

Potential Gradient ◽

Regulatory Mechanisms ◽

Directional Growth ◽

Plant Adaptation ◽

Water Potential Gradient

AbstractRoots display directional growth toward moisture in response to a water potential gradient. Root hydrotropism is thought to facilitate plant adaptation to continuously changing water availability. Hydrotropism has not been as extensively studied as gravitropism. However, comparisons of hydrotropic and gravitropic responses identified mechanisms that are unique to hydrotropism. Regulatory mechanisms underlying the hydrotropic response appear to differ among different species. We recently performed molecular and genetic analyses of root hydrotropism in Arabidopsis thaliana. In this review, we summarize the current knowledge of specific mechanisms mediating root hydrotropism in several plant species.

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Estimating Organ Contribution to Grain Filling and Potential for Source Upregulation in Wheat Cultivars with a Contrasting Source–Sink Balance

Agronomy ◽

10.3390/agronomy10101527 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1527

Author(s):

Carolina Rivera-Amado ◽

Gemma Molero ◽

Eliseo Trujillo-Negrellos ◽

Matthew Reynolds ◽

John Foulkes

Keyword(s):

Grain Growth ◽

Photosynthetic Rate ◽

Grain Filling ◽

Leaf Sheath ◽

Grain Weight ◽

Yield Potential ◽

Wheat Cultivars ◽

Sink Limitation ◽

Source Sink ◽

Source And Sink

Grain filling may be limited by the joint source and sink capacity in modern wheat cultivars, indicating a need to research the co-limitation of yield by both photosynthesis and the number and potential size of grains. The extent to which the post-anthesis source may be limiting final grain size can be estimated by partial degraining of spikes, while defoliation and shading treatments can be useful to estimate if any excess photosynthetic capacity exists. In the current study, degraining was applied to a set of 26 elite spring wheat cultivars from the International Maize and Wheat Improvement Center (CIMMYT)’s core germplasm (CIMCOG) panel, while lamina defoliation and shading through stem-and-leaf-sheath covering treatments were applied to a subset of the same cultivars. Responses to source treatments in grain weight, pre-anthesis reserve contribution to grain weight, dry-matter translocation efficiency, and flag-leaf and spike photosynthetic rate were measured and compared to an unmanipulated control treatment. Grain weight responses to degraining among cultivars ranged from no response to increases of 28%, suggesting a range of responses from sink limitation, to probable source and sink co-limitation of grain growth. Grain weight’s response to degraining increased linearly with the years of cultivar release from 1966 to 2009, indicating that the current highest yield potential CIMMYT spring wheats have a co-limitation of grain growth by source and sink. This may have been due to an increase in grain sink strength with years of cultivar release with no commensurate increase in post-anthesis source capacity. The relatively low decreases in grain weight with defoliation compared to decreases in light interception by defoliation indicated that sink limitation was still likely predominating in the cultivars with co-limitation. The stem-and-leaf-sheath covering treatment decreased grain weight by nearly 10%, indicating that stem-and-leafsheath photosynthesis plays a key role in grain growth during grain filling. In addition, pre-anthesis reserve contribution to grain weight was increased by ca. 50% in response to lamina defoliation. Our results showed that increasing the post-anthesis source capacity, through increases in stem-and-leaf-sheath photosynthetic rate during grain filling and pre-anthesis reserve contribution to grain weight, is an important objective in enhancing yield potential in wheat through maintaining a source–sink balance.

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Influence of Heat Source/Sink on Free Convection in Annular Porous Region

International Journal of Heat and Technology ◽

10.18280/ijht.390318 ◽

2021 ◽

Vol 39 (3) ◽

pp. 841-850

Author(s):

Anurag ◽

Shyam Lal Yadav ◽

Ashok Kumar Singh

Keyword(s):

Heat Source ◽

Darcy Number ◽

Constant Heat Flux ◽

Petroleum Engineering ◽

Temperature Dependent ◽

Porous Region ◽

Annular Gap ◽

Source Sink ◽

Thermal Technique ◽

Source And Sink

The significant interpretation of this model is to explore the influence of temperature-dependent heat source/sink on laminar free-convective flow in an annular porous region such as petroleum engineering, thermal technique and groundwater hydrology. For a unified solution of the Brinkman-Darcy model, the regulatory equations solved analytically by applying the variation of parameter technique in terms of Bessel's functions for the heat source and sink. Moreover, we have investigated the Variations of Darcy number, Heat source/sink and viscosity ratio in the presence of isothermal and constant heat flux sequentially. As a result, we received the critical value of the velocity for the radii ratio (R = 2.05 and 2.92) in both the cases of source and sink (S = 1.0 and Si = 0.1) respectively which is exhibited through the graphs. Further, the numerical outcomes present of the skin friction including volume flow with annular gap by the graphs as well as tables.

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Genotypic variation in morphological source and sink traits affects the response of rice photosynthesis and growth to elevated atmospheric CO2

10.1101/694307 ◽

2019 ◽

Author(s):

Denis Fabre ◽

Michael Dingkuhn ◽

Xinyou Yin ◽

Anne Clément-Vidal ◽

Sandrine Roques ◽

...

Keyword(s):

Photosynthetic Capacity ◽

Flag Leaf ◽

Genotypic Variation ◽

Growth Cycle ◽

Plant Production ◽

Leaf Photosynthesis ◽

Elevated Atmospheric Co2 ◽

Rice Genotypes ◽

Source Sink ◽

Source And Sink

AbstractThis study aimed to understand the response of photosynthesis and growth to e-CO2conditions (800 vs. 400 μmol mol-1) of rice genotypes differing in source-sink relationships. A proxy trait called local C source-sink ratio was defined as the ratio of flag leaf area over the number of spikelets on the corresponding panicle, and five genotypes differing in this ratio were grown in a controlled greenhouse. Differential CO2resources were applied either during the two weeks following heading (EXP1) or during the whole growth cycle (EXP2). Under e-CO2, low source-sink ratio cultivars (LSS) had greater gains in photosynthesis, and they accumulated less nonstructural carbohydrate in the flag leaf than high source-sink ratio cultivars (HSS). In EXP2, grain yield and biomass gain was also greater in LSS probably caused by their strong sink. Photosynthetic capacity response to e-CO2was negatively correlated across genotypes with local C source-sink ratio, a trait highly conserved across environments. HSS were sink-limited under e-CO2, probably associated with low triose phosphate utilization (TPU) capacity. We suggest that the local C source-sink ratio is a potential target for selecting more CO2-responsive cultivars, pending validation for a broader genotypic spectrum and for field conditions.HighlightRice local carbon source-sink ratio and sink plasticity can drive genotypic responses of leaf photosynthesis and plant production in a CO2elevation context.

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Characteristics and coordination of source-sink relationships in super hybrid rice

Open Life Sciences ◽

10.1515/biol-2016-0061 ◽

2016 ◽

Vol 11 (1) ◽

pp. 470-475 ◽

Cited By ~ 4

Author(s):

Pu Bai ◽

Ruoqi Bai ◽

Yuxue Jin

Keyword(s):

Photosynthetic Efficiency ◽

Hybrid Rice ◽

Area Ratio ◽

Vascular Structure ◽

Super Hybrid Rice ◽

Midday Depression ◽

Local Environments ◽

Field Management ◽

Source Sink ◽

Source And Sink

AbstractThis paper discusses the characteristics of source and sink for super hybrid rice and how to coordinate its source-sink relationships for high-yielding cultivation. It is known that super hybrid rice possesses a higher net photosynthetic rate than non-hybrid rice because of its higher grain-leaf area ratio, better stornata traits and less midday depression. However, the sink of super hybrid rice remains large due to its large and numerous spikelets. Furthermore, the relocation of assimilates is smooth in super hybrid rice because of its well-developed vascular structure. However, due to the very large sink of super hybrid rice, it is relatively inefficient in supplying of assimilate products to spikelets, in particular to inferior spikelets. Therefore, reducing the discrepancy between source and sink in super hybrid rice is essential for developing high-yielding cultivation. This can only be achieved by planting cultivars adapted for local environments, raising strong seedling, setting up populations with a high photosynthetic efficiency for increasing the supply of source, and improving the field management in filling stages to the duration of supply of photosynthate to grains.

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Geographic evidence for source-sink dynamics in deep-sea neogastropods of the eastern North Atlantic: an approach using nested analysis

Global Ecology and Biogeography ◽

10.1111/geb.12005 ◽

2012 ◽

Vol 22 (4) ◽

pp. 433-439 ◽

Cited By ~ 17

Author(s):

Solange Brault ◽

Carol T. Stuart ◽

Martine C. Wagstaff ◽

Michael A. Rex

Keyword(s):

North Atlantic ◽

Deep Sea ◽

Eastern North Atlantic ◽

Source Sink ◽

Nested Analysis

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Electrocaloric devices part II: All-solid heat pump without moving parts

Journal of Advanced Dielectrics ◽

10.1142/s2010135x20500290 ◽

2020 ◽

Vol 10 (06) ◽

pp. 2050029

Author(s):

Farrukh Najmi ◽

Jianping He ◽

Lorenzo Cremaschi ◽

Z.-Y. Cheng

Keyword(s):

Thermal Conductivity ◽

Heat Capacity ◽

Heat Conduction ◽

Electric Fields ◽

Heat Pumps ◽

Source To Sink ◽

Heat Transformation ◽

Source Sink ◽

Continuous Heat ◽

Source And Sink

Various designs have been introduced to build heat pumps using the electrocaloric effect (ECE). Each of all the current designs uses at least one moving part, which significantly reduces the reliability of the pump and adds complexities. In this work, a new all-solid design is introduced, in which two layers of an electrocaloric material (ECM) are permanently sandwiched in the source and sink, which would significantly increase the device’s reliability since nothing moves and all are permanently bound together. More importantly, the electric fields applied on two ECM layers are independently controlled. A special sequence for the electric fields on two ECM layers is introduced. Numerical calculation was used to simulate the device’s performance by using the newly introduced analytical solutions for the heat conduction in the system. It is concluded that a continuous heat transformation from the source to sink at the same temperature can be achieved when the contacting coefficient, [Formula: see text], is very small, where [Formula: see text], [Formula: see text], and [Formula: see text] are thermal conductivity, density, and heat capacity, respectively, while the superscript [Formula: see text] and [Formula: see text] represent the ECM and source/sink, respectively.

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